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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Paul Walmsley:
- Add support for control flow integrity for userspace processes.
This is based on the standard RISC-V ISA extensions Zicfiss and
Zicfilp
- Improve ptrace behavior regarding vector registers, and add some
selftests
- Optimize our strlen() assembly
- Enable the ISO-8859-1 code page as built-in, similar to ARM64, for
EFI volume mounting
- Clean up some code slightly, including defining copy_user_page() as
copy_page() rather than memcpy(), aligning us with other
architectures; and using max3() to slightly simplify an expression
in riscv_iommu_init_check()
* tag 'riscv-for-linus-7.0-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits)
riscv: lib: optimize strlen loop efficiency
selftests: riscv: vstate_exec_nolibc: Use the regular prctl() function
selftests: riscv: verify ptrace accepts valid vector csr values
selftests: riscv: verify ptrace rejects invalid vector csr inputs
selftests: riscv: verify syscalls discard vector context
selftests: riscv: verify initial vector state with ptrace
selftests: riscv: test ptrace vector interface
riscv: ptrace: validate input vector csr registers
riscv: csr: define vtype register elements
riscv: vector: init vector context with proper vlenb
riscv: ptrace: return ENODATA for inactive vector extension
kselftest/riscv: add kselftest for user mode CFI
riscv: add documentation for shadow stack
riscv: add documentation for landing pad / indirect branch tracking
riscv: create a Kconfig fragment for shadow stack and landing pad support
arch/riscv: add dual vdso creation logic and select vdso based on hw
arch/riscv: compile vdso with landing pad and shadow stack note
riscv: enable kernel access to shadow stack memory via the FWFT SBI call
riscv: add kernel command line option to opt out of user CFI
riscv/hwprobe: add zicfilp / zicfiss enumeration in hwprobe
...
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On several powerpc platforms, a page table entry may not imply whether the
relevant mapping is for userspace or kernelspace. Instead, such platforms
infer this by the address which is being accessed.
Add an additional address argument to each of these routines in order to
provide support for page table check on powerpc.
[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-9-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[__]page_table_check_pte_clear()
This reverts commit aa232204c468 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pte_clear").
Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.
[ajd@linux.ibm.com: rebase, fix additional occurrence and loop handling]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-8-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[__]page_table_check_pmd_clear()
This reverts commit 1831414cd729 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pmd_clear").
Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.
[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-7-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[__]page_table_check_pud_clear()
This reverts commit 931c38e16499 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pud_clear").
Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.
[ajd@linux.ibm.com: rebase on arm64 changes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-6-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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To provide support for powerpc platforms, provide an addr parameter to the
__page_table_check_ptes_set() and page_table_check_ptes_set() routines.
This parameter is needed on some powerpc platforms which do not encode
whether a mapping is for user or kernel in the pte. On such platforms,
this can be inferred from the addr parameter.
[ajd@linux.ibm.com: rebase on arm64 + riscv changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-5-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[__]page_table_check_pmd[s]_set()
This reverts commit a3b837130b58 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pmd_set").
Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the
page in the pte, but instead in the address of the access.
Apply this to __page_table_check_pmds_set(), page_table_check_pmd_set(), and
the page_table_check_pmd_set() wrapper macro.
[ajd@linux.ibm.com: rebase on arm64 + riscv changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-4-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[__]page_table_check_pud[s]_set()
This reverts commit 6d144436d954 ("mm/page_table_check: remove unused
parameter in [__]page_table_check_pud_set").
Reinstate previously unused parameters for the purpose of supporting
powerpc platforms, as many do not encode user/kernel ownership of the page
in the pte, but instead in the address of the access.
Apply this to __page_table_check_puds_set(), page_table_check_puds_set()
and the page_table_check_pud_set() wrapper macro.
[ajd@linux.ibm.com: rebase on riscv + arm64 changes, update commit message]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-3-755bc151a50b@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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'fork' implements copy-on-write (COW) by making pages readonly in both
child and parent.
ptep_set_wrprotect() and pte_wrprotect() clear _PAGE_WRITE in PTE.
The assumption is that the page is readable and, on a fault,
copy-on-write happens.
To implement COW on shadow stack pages, clearing the W bit makes them
XWR = 000. This will result in the wrong PTE setting, which allows no
permissions, but with V=1 and the PFN field pointing to the final
page. Instead, the desired behavior is to turn it into a readable
page, take an access (load/store) fault on sspush/sspop (shadow stack)
and then perform COW on such pages. This way regular reads would still
be allowed and not lead to COW maintaining current behavior of COW on
non-shadow stack but writeable memory.
On the other hand, this doesn't interfere with existing COW for
read-write memory. The assumption is always that _PAGE_READ must have
been set, and thus, setting _PAGE_READ is harmless.
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-9-b55691eacf4f@rivosinc.com
[pjw@kernel.org: clarify patch description]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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pte_mkwrite() creates PTEs with WRITE encodings for the underlying
architecture. The underlying architecture can have two types of
writeable mappings: one that can be written using regular store
instructions, and another one that can only be written using
specialized store instructions (like shadow stack stores).
pte_mkwrite can select write PTE encoding based on VMA range (i.e.
VM_SHADOW_STACK)
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-8-b55691eacf4f@rivosinc.com
[pjw@kernel.org: cleaned up patch description]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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This patch implements the creation of a shadow stack pte on
riscv. Creating shadow stack PTE on riscv means clearing RWX and then
setting W=1.
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-7-b55691eacf4f@rivosinc.com
[pjw@kernel.org: cleaned up patch description]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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'arch_calc_vm_prot_bits' is implemented on risc-v to return VM_READ |
VM_WRITE if PROT_WRITE is specified. Similarly 'riscv_sys_mmap' is
updated to convert all incoming PROT_WRITE to (PROT_WRITE | PROT_READ).
This is to make sure that any existing apps using PROT_WRITE still work.
Earlier 'protection_map[VM_WRITE]' used to pick read-write PTE encodings.
Now 'protection_map[VM_WRITE]' will always pick PAGE_SHADOWSTACK PTE
encodings for shadow stack. The above changes ensure that existing apps
continue to work because underneath, the kernel will be picking
'protection_map[VM_WRITE|VM_READ]' PTE encodings.
Reviewed-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-6-b55691eacf4f@rivosinc.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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These marcos are not used after commit b5b4287accd7 ("riscv: mm: Use
hint address in mmap if available"). Cleanup VA_USER_XXX definitions
in asm/pgtable.h.
Fixes: b5b4287accd7 ("riscv: mm: Use hint address in mmap if available")
Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20251201005850.702569-1-guoren@kernel.org
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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Let's not call atomic_long_xchg() on something that's not an
atomic_long_t, and just use xchg() instead. Continues the cleanup
from commit 546e42c8c6d94 ("riscv: Use an atomic xchg in
pudp_huge_get_and_clear()"),
Cc: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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When !CONFIG_SMP, there's no need for atomic operations in
ptep_get_and_clear(), so, similar to x86, let's not use atomics in
this case.
Cc: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Paul Walmsley <pjw@kernel.org>
|
|
When !CONFIG_SMP, there's no need for atomic operations in
pmdp_huge_get_and_clear(), so, similar to what x86 does, let's not use
atomics in this case. See also commit 546e42c8c6d94 ("riscv: Use an
atomic xchg in pudp_huge_get_and_clear()").
Cc: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Paul Walmsley:
- Enable parallel hotplug for RISC-V
- Optimize vector regset allocation for ptrace()
- Add a kernel selftest for the vector ptrace interface
- Enable the userspace RAID6 test to build and run using RISC-V vectors
- Add initial support for the Zalasr RISC-V ratified ISA extension
- For the Zicbop RISC-V ratified ISA extension to userspace, expose
hardware and kernel support to userspace and add a kselftest for
Zicbop
- Convert open-coded instances of 'asm goto's that are controlled by
runtime ALTERNATIVEs to use riscv_has_extension_{un,}likely(),
following arm64's alternative_has_cap_{un,}likely()
- Remove an unnecessary mask in the GFP flags used in some calls to
pagetable_alloc()
* tag 'riscv-for-linus-6.19-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
selftests/riscv: Add Zicbop prefetch test
riscv: hwprobe: Expose Zicbop extension and its block size
riscv: Introduce Zalasr instructions
riscv: hwprobe: Export Zalasr extension
dt-bindings: riscv: Add Zalasr ISA extension description
riscv: Add ISA extension parsing for Zalasr
selftests: riscv: Add test for the Vector ptrace interface
riscv: ptrace: Optimize the allocation of vector regset
raid6: test: Add support for RISC-V
raid6: riscv: Allow code to be compiled in userspace
raid6: riscv: Prevent compiler from breaking inline vector assembly code
riscv: cmpxchg: Use riscv_has_extension_likely
riscv: bitops: Use riscv_has_extension_likely
riscv: hweight: Use riscv_has_extension_likely
riscv: checksum: Use riscv_has_extension_likely
riscv: pgtable: Use riscv_has_extension_unlikely
riscv: Remove __GFP_HIGHMEM masking
RISC-V: Enable HOTPLUG_PARALLEL for secondary CPUs
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The Svrsw60t59b extension allows to free the PTE reserved bits 60 and 59
for software, this patch uses bit 60 for uffd-wp tracking
Additionally for tracking the uffd-wp state as a PTE swap bit, we borrow
bit 4 which is not involved into swap entry computation.
Link: https://lkml.kernel.org/r/20251113072806.795029-6-zhangchunyan@iscas.ac.cn
Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Conor Dooley <conor@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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The Svrsw60t59b extension allows to free the PTE reserved bits 60 and 59
for software, this patch uses bit 59 for soft-dirty.
To add swap PTE soft-dirty tracking, we borrow bit 3 which is available
for swap PTEs on RISC-V systems.
Link: https://lkml.kernel.org/r/20251113072806.795029-5-zhangchunyan@iscas.ac.cn
Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Conor Dooley <conor@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
Use riscv_has_extension_unlikely() to check for RISCV_ISA_EXT_SVVPTC,
replacing the use of asm goto with ALTERNATIVE.
The "unlikely" variant is used to match the behavior of the original
implementation using ALTERNATIVE("nop", "j %l[svvptc]", ...).
Note that this makes the check for RISCV_ISA_EXT_SVVPTC a runtime one if
RISCV_ALTERNATIVE=n, but it should still be worthwhile to do so given
that TLB flushes are relatively slow.
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Link: https://patch.msgid.link/20251020-riscv-altn-helper-wip-v4-1-ef941c87669a@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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The pgprot_dmacoherent() is used when allocating memory for
non-coherent devices and by default pgprot_dmacoherent() is
same as pgprot_noncached() unless architecture overrides it.
Currently, there is no pgprot_dmacoherent() definition for
RISC-V hence non-coherent device memory is being mapped as
IO thereby making CPU access to such memory slow.
Define pgprot_dmacoherent() to be same as pgprot_writecombine()
for RISC-V so that CPU access non-coherent device memory as
NOCACHE which is better than accessing it as IO.
Fixes: ff689fd21cb1 ("riscv: add RISC-V Svpbmt extension support")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Tested-by: Han Gao <rabenda.cn@gmail.com>
Tested-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
Link: https://lore.kernel.org/r/20250820152316.1012757-1-apatel@ventanamicro.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Paul Walmsley
- Replacement of __ASSEMBLY__ with __ASSEMBLER__ in header files (other
architectures have already merged this type of cleanup)
- The introduction of ioremap_wc() for RISC-V
- Cleanup of the RISC-V kprobes code to use mostly-extant macros rather
than open code
- A RISC-V kprobes unit test
- An architecture-specific endianness swap macro set implementation,
leveraging some dedicated RISC-V instructions for this purpose if
they are available
- The ability to identity and communicate to userspace the presence
of a MIPS P8700-specific ISA extension, and to leverage its
MIPS-specific PAUSE implementation in cpu_relax()
- Several other miscellaneous cleanups
* tag 'riscv-for-linus-6.18-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (39 commits)
riscv: errata: Fix the PAUSE Opcode for MIPS P8700
riscv: hwprobe: Document MIPS xmipsexectl vendor extension
riscv: hwprobe: Add MIPS vendor extension probing
riscv: Add xmipsexectl instructions
riscv: Add xmipsexectl as a vendor extension
dt-bindings: riscv: Add xmipsexectl ISA extension description
riscv: cpufeature: add validation for zfa, zfh and zfhmin
perf: riscv: skip empty batches in counter start
selftests: riscv: Add README for RISC-V KSelfTest
riscv: sbi: Switch to new sys-off handler API
riscv: Move vendor errata definitions to new header
RISC-V: ACPI: enable parsing the BGRT table
riscv: Enable ARCH_HAVE_NMI_SAFE_CMPXCHG
riscv: pi: use 'targets' instead of extra-y in Makefile
riscv: introduce asm/swab.h
riscv: mmap(): use unsigned offset type in riscv_sys_mmap
drivers/perf: riscv: Remove redundant ternary operators
riscv: mm: Use mmu-type from FDT to limit SATP mode
riscv: mm: Return intended SATP mode for noXlvl options
riscv: kprobes: Remove duplication of RV_EXTRACT_ITYPE_IMM
...
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Make sure we return the right pud value and not a value that could
have been overwritten in between by a different core.
Fixes: c3cc2a4a3a23 ("riscv: Add support for PUD THP")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250814-dev-alex-thp_pud_xchg-v1-1-b4704dfae206@rivosinc.com
[pjw@kernel.org: use xchg rather than atomic_long_xchg; avoid atomic op for !CONFIG_SMP like x86]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize on
the __ASSEMBLER__ macro that is provided by the compilers now.
This originally was a completely mechanical patch (done with a
simple "sed -i" statement), with some manual fixups during
rebasing of the patch later.
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20250606070952.498274-3-thuth@redhat.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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Compared with IO attributes, NC attributes can improve performance,
specifically in these aspects: Relaxed Order, Gathering, Supports Read
Speculation, Supports Unaligned Access.
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Signed-off-by: Qingfang Deng <qingfang.deng@siflower.com.cn>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250722091504.45974-2-cuiyunhui@bytedance.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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Now that DAX and all other reference counts to ZONE_DEVICE pages are
managed normally there is no need for the special devmap PTE/PMD/PUD page
table bits. So drop all references to these, freeing up a software
defined page table bit on architectures supporting it.
Link: https://lkml.kernel.org/r/6389398c32cc9daa3dfcaa9f79c7972525d310ce.1750323463.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Will Deacon <will@kernel.org> # arm64
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: Chunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Björn Töpel <bjorn@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Inki Dae <m.szyprowski@samsung.com>
Cc: John Groves <john@groves.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V Fixes for 5.16-rc4
- .rodata is no longer linkd into PT_DYNAMIC.
It was not supposed to be there in the first place and resulted in
invalid (but unused) entries. This manifests as at least warnings in
llvm-readelf
- A fix for runtime constants with all-0 upper 32-bits. This should
only manifest on MMU=n kernels
- A fix for context save/restore on systems using the T-Head vector
extensions
- A fix for a conflicting "+r"/"r" register constraint in the VDSO
getrandom syscall wrapper, which is undefined behavior in clang
- A fix for a missing register clobber in the RVV raid6 implementation.
This manifests as a NULL pointer reference on some compilers, but
could trigger in other ways
- Misaligned accesses from userspace at faulting addresses are now
handled correctly
- A fix for an incorrect optimization that allowed access_ok() to mark
invalid addresses as accessible, which can result in userspace
triggering BUG()s
- A few fixes for build warnings, and an update to Drew's email address
* tag 'riscv-for-linus-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: export boot_cpu_hartid
Revert "riscv: Define TASK_SIZE_MAX for __access_ok()"
riscv: Fix sparse warning in vendor_extensions/sifive.c
Revert "riscv: misaligned: fix sleeping function called during misaligned access handling"
MAINTAINERS: Update Drew Fustini's email address
RISC-V: uaccess: Wrap the get_user_8 uaccess macro
raid6: riscv: Fix NULL pointer dereference caused by a missing clobber
RISC-V: vDSO: Correct inline assembly constraints in the getrandom syscall wrapper
riscv: vector: Fix context save/restore with xtheadvector
riscv: fix runtime constant support for nommu kernels
riscv: vdso: Exclude .rodata from the PT_DYNAMIC segment
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This reverts commit ad5643cf2f69 ("riscv: Define TASK_SIZE_MAX for
__access_ok()").
This commit changes TASK_SIZE_MAX to be LONG_MAX to optimize access_ok(),
because the previous TASK_SIZE_MAX (default to TASK_SIZE) requires some
computation.
The reasoning was that all user addresses are less than LONG_MAX, and all
kernel addresses are greater than LONG_MAX. Therefore access_ok() can
filter kernel addresses.
Addresses between TASK_SIZE and LONG_MAX are not valid user addresses, but
access_ok() let them pass. That was thought to be okay, because they are
not valid addresses at hardware level.
Unfortunately, one case is missed: get_user_pages_fast() happily accepts
addresses between TASK_SIZE and LONG_MAX. futex(), for instance, uses
get_user_pages_fast(). This causes the problem reported by Robert [1].
Therefore, revert this commit. TASK_SIZE_MAX is changed to the default:
TASK_SIZE.
This unfortunately reduces performance, because TASK_SIZE is more expensive
to compute compared to LONG_MAX. But correctness first, we can think about
optimization later, if required.
Reported-by: <rtm@csail.mit.edu>
Closes: https://lore.kernel.org/linux-riscv/77605.1750245028@localhost/
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Fixes: ad5643cf2f69 ("riscv: Define TASK_SIZE_MAX for __access_ok()")
Link: https://lore.kernel.org/r/20250619155858.1249789-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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Make pte_swp_exclusive return bool instead of int. This will better
reflect how pte_swp_exclusive is actually used in the code.
This fixes swap/swapoff problems on Alpha due pte_swp_exclusive not
returning correct values when _PAGE_SWP_EXCLUSIVE bit resides in upper
32-bits of PTE (like on alpha).
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/lkml/20250218175735.19882-2-linmag7@gmail.com/
Link: https://lore.kernel.org/lkml/20250602041118.GA2675383@ZenIV/
[ Applied as the 'sed' script Al suggested - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Palmer Dabbelt:
- Support for the FWFT SBI extension, which is part of SBI 3.0 and a
dependency for many new SBI and ISA extensions
- Support for getrandom() in the VDSO
- Support for mseal
- Optimized routines for raid6 syndrome and recovery calculations
- kexec_file() supports loading Image-formatted kernel binaries
- Improvements to the instruction patching framework to allow for
atomic instruction patching, along with rules as to how systems need
to behave in order to function correctly
- Support for a handful of new ISA extensions: Svinval, Zicbop, Zabha,
some SiFive vendor extensions
- Various fixes and cleanups, including: misaligned access handling,
perf symbol mangling, module loading, PUD THPs, and improved uaccess
routines
* tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (69 commits)
riscv: uaccess: Only restore the CSR_STATUS SUM bit
RISC-V: vDSO: Wire up getrandom() vDSO implementation
riscv: enable mseal sysmap for RV64
raid6: Add RISC-V SIMD syndrome and recovery calculations
riscv: mm: Add support for Svinval extension
RISC-V: Documentation: Add enough title underlines to CMODX
riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE
MAINTAINERS: Update Atish's email address
riscv: uaccess: do not do misaligned accesses in get/put_user()
riscv: process: use unsigned int instead of unsigned long for put_user()
riscv: make unsafe user copy routines use existing assembly routines
riscv: hwprobe: export Zabha extension
riscv: Make regs_irqs_disabled() more clear
perf symbols: Ignore mapping symbols on riscv
RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND
riscv: module: Optimize PLT/GOT entry counting
riscv: Add support for PUD THP
riscv: xchg: Prefetch the destination word for sc.w
riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
riscv: Add support for Zicbop
...
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Add the necessary page table functions to deal with PUD THP, this
enables the use of PUD pfnmap.
Link: https://lore.kernel.org/r/20250321123954.225097-1-alexghiti@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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Most architectures simply call pfn_pte(). Centralise that as the normal
definition and remove the definition of mk_pte() from the architectures
which have either that exact definition or something similar.
Link: https://lkml.kernel.org/r/20250402181709.2386022-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> # s390
Cc: Zi Yan <ziy@nvidia.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Richard Weinberger <richard@nod.at>
Cc: <x86@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Samuel Holland <samuel.holland@sifive.com> says:
Currently, RISC-V NOMMU kernels are linked at CONFIG_PAGE_OFFSET, and
since they are not relocatable, must be loaded at this address as well.
CONFIG_PAGE_OFFSET is not a user-visible Kconfig option, so its value is
not obvious, and users must patch the kernel source if they want to load
it at a different address.
Make NOMMU kernels more portable by making them relocatable by default.
This allows a single kernel binary to work when loaded at any address.
* b4-shazam-merge:
riscv: Remove CONFIG_PAGE_OFFSET
riscv: Support CONFIG_RELOCATABLE on riscv32
asm-generic: Always define Elf_Rel and Elf_Rela
riscv: Support CONFIG_RELOCATABLE on NOMMU
riscv: Allow NOMMU kernels to access all of RAM
riscv: Remove duplicate CONFIG_PAGE_OFFSET definition
Link: https://lore.kernel.org/r/20241026171441.3047904-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The current definition of CONFIG_PAGE_OFFSET is problematic for a couple
of reasons:
1) The value is misleading for normal 64-bit kernels, where it is
overridden at runtime if Sv48 or Sv39 is chosen. This is especially
the case for XIP kernels, which always use Sv39.
2) The option is not user-visible, but for NOMMU kernels it must be a
valid RAM address, and for !RELOCATABLE it must additionally be the
exact address where the kernel is loaded.
Fix both of these by removing the option.
1) For MMU kernels, drop the indirection through Kconfig. Additionally,
for XIP, drop the indirection through kernel_map.
2) For NOMMU kernels, use the user-visible physical RAM base if
provided. Otherwise, force the kernel to be relocatable.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Jesse Taube <mr.bossman075@gmail.com>
Link: https://lore.kernel.org/r/20241026171441.3047904-7-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Move relocate_kernel() out of the CONFIG_MMU block so it can be called
from the NOMMU version of setup_vm(). Set some offsets in kernel_map so
relocate_kernel() does not need to be modified. Relocatable NOMMU
kernels can be loaded to any physical memory address; they no longer
depend on CONFIG_PAGE_OFFSET.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20241026171441.3047904-4-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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NOMMU kernels currently cannot access memory below the kernel link
address. Remove this restriction by setting PAGE_OFFSET to the actual
start of RAM, as determined from the devicetree. The kernel link address
must be a constant, so keep using CONFIG_PAGE_OFFSET for that purpose.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Jesse Taube <mr.bossman075@gmail.com>
Link: https://lore.kernel.org/r/20241026171441.3047904-3-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Use RSW0 as the special bit for pmds and puds, just like for ptes.
Also define the {pte,pmd,pud}_pgprot helpers which were previously
missing and are needed for the follow_pfnmap APIs.
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250108135700.2614848-1-abrestic@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
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In sparse vmemmap model, the virtual address of vmemmap is calculated as:
((struct page *)VMEMMAP_START - (phys_ram_base >> PAGE_SHIFT)).
And the struct page's va can be calculated with an offset:
(vmemmap + (pfn)).
However, when initializing struct pages, kernel actually starts from the
first page from the same section that phys_ram_base belongs to. If the
first page's physical address is not (phys_ram_base >> PAGE_SHIFT), then
we get an va below VMEMMAP_START when calculating va for it's struct page.
For example, if phys_ram_base starts from 0x82000000 with pfn 0x82000, the
first page in the same section is actually pfn 0x80000. During
init_unavailable_range(), we will initialize struct page for pfn 0x80000
with virtual address ((struct page *)VMEMMAP_START - 0x2000), which is
below VMEMMAP_START as well as PCI_IO_END.
This commit fixes this bug by introducing a new variable
'vmemmap_start_pfn' which is aligned with memory section size and using
it to calculate vmemmap address instead of phys_ram_base.
Fixes: a11dd49dcb93 ("riscv: Sparse-Memory/vmemmap out-of-bounds fix")
Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20241209122617.53341-1-luxu.kernel@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Pull more kvm updates from Paolo Bonzini:
- ARM fixes
- RISC-V Svade and Svadu (accessed and dirty bit) extension support for
host and guest
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: riscv: selftests: Add Svade and Svadu Extension to get-reg-list test
RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VM
dt-bindings: riscv: Add Svade and Svadu Entries
RISC-V: Add Svade and Svadu Extensions Support
KVM: arm64: Use MDCR_EL2.HPME to evaluate overflow of hyp counters
KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status
KVM: arm64: Mark set_sysreg_masks() as inline to avoid build failure
KVM: arm64: vgic-its: Add stronger type-checking to the ITS entry sizes
KVM: arm64: vgic: Kill VGIC_MAX_PRIVATE definition
KVM: arm64: vgic: Make vgic_get_irq() more robust
KVM: arm64: vgic-v3: Sanitise guest writes to GICR_INVLPIR
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Svade and Svadu extensions represent two schemes for managing the PTE A/D
bits. When the PTE A/D bits need to be set, Svade extension intdicates
that a related page fault will be raised. In contrast, the Svadu extension
supports hardware updating of PTE A/D bits. Since the Svade extension is
mandatory and the Svadu extension is optional in RVA23 profile, by default
the M-mode firmware will enable the Svadu extension in the menvcfg CSR
when only Svadu is present in DT.
This patch detects Svade and Svadu extensions from DT and adds
arch_has_hw_pte_young() to enable optimization in MGLRU and
__wp_page_copy_user() when we have the PTE A/D bits hardware updating
support.
Co-developed-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Jinyu Tang <tjytimi@163.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20240726084931.28924-2-yongxuan.wang@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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set_pxd_safe() helpers that serve a specific purpose for both x86 and
riscv platforms, do not need to be in the common memory code. Otherwise
they just unnecessarily make the common API more complicated. This moves
the helpers from common code to platform instead.
Link: https://lkml.kernel.org/r/20241003044842.246016-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Alexandre Ghiti <alexghiti@rivosinc.com> says:
In RISC-V, after a new mapping is established, a sfence.vma needs to be
emitted for different reasons:
- if the uarch caches invalid entries, we need to invalidate it otherwise
we would trap on this invalid entry,
- if the uarch does not cache invalid entries, a reordered access could fail
to see the new mapping and then trap (sfence.vma acts as a fence).
We can actually avoid emitting those (mostly) useless and costly sfence.vma
by handling the traps instead:
- for new kernel mappings: only vmalloc mappings need to be taken care of,
other new mapping are rare and already emit the required sfence.vma if
needed.
That must be achieved very early in the exception path as explained in
patch 3, and this also fixes our fragile way of dealing with vmalloc faults.
- for new user mappings: Svvptc makes update_mmu_cache() a no-op but we can
take some gratuitous page faults (which are very unlikely though).
Patch 1 and 2 introduce Svvptc extension probing.
On our uarch that does not cache invalid entries and a 6.5 kernel, the
gains are measurable:
* Kernel boot: 6%
* ltp - mmapstress01: 8%
* lmbench - lat_pagefault: 20%
* lmbench - lat_mmap: 5%
Here are the corresponding numbers of sfence.vma emitted:
* Ubuntu boot to login:
Before: ~630k sfence.vma
After: ~200k sfence.vma
* ltp - mmapstress01
Before: ~45k
After: ~6.3k
* lmbench - lat_pagefault
Before: ~665k
After: 832 (!)
* lmbench - lat_mmap
Before: ~546k
After: 718 (!)
Thanks to Ved and Matt Evans for triggering the discussion that led to
this patchset!
* b4-shazam-merge:
riscv: Stop emitting preventive sfence.vma for new userspace mappings with Svvptc
riscv: Stop emitting preventive sfence.vma for new vmalloc mappings
dt-bindings: riscv: Add Svvptc ISA extension description
riscv: Add ISA extension parsing for Svvptc
Link: https://lore.kernel.org/r/20240717060125.139416-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Svvptc
The preventive sfence.vma were emitted because new mappings must be made
visible to the page table walker but Svvptc guarantees that it will
happen within a bounded timeframe, so no need to sfence.vma for the uarchs
that implement this extension, we will then take gratuitous (but very
unlikely) page faults, similarly to x86 and arm64.
This allows to drastically reduce the number of sfence.vma emitted:
* Ubuntu boot to login:
Before: ~630k sfence.vma
After: ~200k sfence.vma
* ltp - mmapstress01
Before: ~45k
After: ~6.3k
* lmbench - lat_pagefault
Before: ~665k
After: 832 (!)
* lmbench - lat_mmap
Before: ~546k
After: 718 (!)
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240717060125.139416-5-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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XIP_OFFSET is the hard-coded offset of writable data section within the
kernel.
By hard-coding this value, the read-only section of the kernel (which is
placed before the writable data section) is restricted in size. This causes
build failures if the kernel gets too big [1].
Remove this limit.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404211031.J6l2AfJk-lkp@intel.com [1]
Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/3bf3a77be10ebb0d8086c028500baa16e7a8e648.1717789719.git.namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The XIP_FIXUP macro is used to fix addresses early during boot before MMU:
generated code "thinks" the data section is in ROM while it is actually in
RAM. So this macro corrects the addresses in the data section.
This macro determines if the address needs to be fixed by checking if it is
within the range starting from ROM address up to the size of (2 *
XIP_OFFSET).
This means if the kernel size is bigger than (2 * XIP_OFFSET), some
addresses would not be fixed up.
XIP kernel can still work if the above scenario does not happen. But this
macro is obviously incorrect.
Rewrite this macro to only fix up addresses within the data section.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/95f50a4ec8204ec4fcbf2a80c9addea0e0609e3b.1717789719.git.namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- In the series "mm: Avoid possible overflows in dirty throttling" Jan
Kara addresses a couple of issues in the writeback throttling code.
These fixes are also targetted at -stable kernels.
- Ryusuke Konishi's series "nilfs2: fix potential issues related to
reserved inodes" does that. This should actually be in the
mm-nonmm-stable tree, along with the many other nilfs2 patches. My
bad.
- More folio conversions from Kefeng Wang in the series "mm: convert to
folio_alloc_mpol()"
- Kemeng Shi has sent some cleanups to the writeback code in the series
"Add helper functions to remove repeated code and improve readability
of cgroup writeback"
- Kairui Song has made the swap code a little smaller and a little
faster in the series "mm/swap: clean up and optimize swap cache
index".
- In the series "mm/memory: cleanly support zeropage in
vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
Hildenbrand has reworked the rather sketchy handling of the use of
the zeropage in MAP_SHARED mappings. I don't see any runtime effects
here - more a cleanup/understandability/maintainablity thing.
- Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
of higher addresses, for aarch64. The (poorly named) series is
"Restructure va_high_addr_switch".
- The core TLB handling code gets some cleanups and possible slight
optimizations in Bang Li's series "Add update_mmu_tlb_range() to
simplify code".
- Jane Chu has improved the handling of our
fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
the series "Enhance soft hwpoison handling and injection".
- Jeff Johnson has sent a billion patches everywhere to add
MODULE_DESCRIPTION() to everything. Some landed in this pull.
- In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
has simplified migration's use of hardware-offload memory copying.
- Yosry Ahmed performs more folio API conversions in his series "mm:
zswap: trivial folio conversions".
- In the series "large folios swap-in: handle refault cases first",
Chuanhua Han inches us forward in the handling of large pages in the
swap code. This is a cleanup and optimization, working toward the end
objective of full support of large folio swapin/out.
- In the series "mm,swap: cleanup VMA based swap readahead window
calculation", Huang Ying has contributed some cleanups and a possible
fixlet to his VMA based swap readahead code.
- In the series "add mTHP support for anonymous shmem" Baolin Wang has
taught anonymous shmem mappings to use multisize THP. By default this
is a no-op - users must opt in vis sysfs controls. Dramatic
improvements in pagefault latency are realized.
- David Hildenbrand has some cleanups to our remaining use of
page_mapcount() in the series "fs/proc: move page_mapcount() to
fs/proc/internal.h".
- David also has some highmem accounting cleanups in the series
"mm/highmem: don't track highmem pages manually".
- Build-time fixes and cleanups from John Hubbard in the series
"cleanups, fixes, and progress towards avoiding "make headers"".
- Cleanups and consolidation of the core pagemap handling from Barry
Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
and utilize them".
- Lance Yang's series "Reclaim lazyfree THP without splitting" has
reduced the latency of the reclaim of pmd-mapped THPs under fairly
common circumstances. A 10x speedup is seen in a microbenchmark.
It does this by punting to aother CPU but I guess that's a win unless
all CPUs are pegged.
- hugetlb_cgroup cleanups from Xiu Jianfeng in the series
"mm/hugetlb_cgroup: rework on cftypes".
- Miaohe Lin's series "Some cleanups for memory-failure" does just that
thing.
- Someone other than SeongJae has developed a DAMON feature in Honggyu
Kim's series "DAMON based tiered memory management for CXL memory".
This adds DAMON features which may be used to help determine the
efficiency of our placement of CXL/PCIe attached DRAM.
- DAMON user API centralization and simplificatio work in SeongJae
Park's series "mm/damon: introduce DAMON parameters online commit
function".
- In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
David Hildenbrand does some maintenance work on zsmalloc - partially
modernizing its use of pageframe fields.
- Kefeng Wang provides more folio conversions in the series "mm: remove
page_maybe_dma_pinned() and page_mkclean()".
- More cleanup from David Hildenbrand, this time in the series
"mm/memory_hotplug: use PageOffline() instead of PageReserved() for
!ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
pages" and permits the removal of some virtio-mem hacks.
- Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()" is a cleanup to the anon folio handling in
preparation for mTHP (multisize THP) swapin.
- Kefeng Wang's series "mm: improve clear and copy user folio"
implements more folio conversions, this time in the area of large
folio userspace copying.
- The series "Docs/mm/damon/maintaier-profile: document a mailing tool
and community meetup series" tells people how to get better involved
with other DAMON developers. From SeongJae Park.
- A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
that.
- David Hildenbrand sends along more cleanups, this time against the
migration code. The series is "mm/migrate: move NUMA hinting fault
folio isolation + checks under PTL".
- Jan Kara has found quite a lot of strangenesses and minor errors in
the readahead code. He addresses this in the series "mm: Fix various
readahead quirks".
- SeongJae Park's series "selftests/damon: test DAMOS tried regions and
{min,max}_nr_regions" adds features and addresses errors in DAMON's
self testing code.
- Gavin Shan has found a userspace-triggerable WARN in the pagecache
code. The series "mm/filemap: Limit page cache size to that supported
by xarray" addresses this. The series is marked cc:stable.
- Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
and cleanup" cleans up and slightly optimizes KSM.
- Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
code motion. The series (which also makes the memcg-v1 code
Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
under config option" and "mm: memcg: put cgroup v1-specific memcg
data under CONFIG_MEMCG_V1"
- Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
adds an additional feature to this cgroup-v2 control file.
- The series "Userspace controls soft-offline pages" from Jiaqi Yan
permits userspace to stop the kernel's automatic treatment of
excessive correctable memory errors. In order to permit userspace to
monitor and handle this situation.
- Kefeng Wang's series "mm: migrate: support poison recover from
migrate folio" teaches the kernel to appropriately handle migration
from poisoned source folios rather than simply panicing.
- SeongJae Park's series "Docs/damon: minor fixups and improvements"
does those things.
- In the series "mm/zsmalloc: change back to per-size_class lock"
Chengming Zhou improves zsmalloc's scalability and memory
utilization.
- Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
pinning memfd folios" makes the GUP code use FOLL_PIN rather than
bare refcount increments. So these paes can first be moved aside if
they reside in the movable zone or a CMA block.
- Andrii Nakryiko has added a binary ioctl()-based API to
/proc/pid/maps for much faster reading of vma information. The series
is "query VMAs from /proc/<pid>/maps".
- In the series "mm: introduce per-order mTHP split counters" Lance
Yang improves the kernel's presentation of developer information
related to multisize THP splitting.
- Michael Ellerman has developed the series "Reimplement huge pages
without hugepd on powerpc (8xx, e500, book3s/64)". This permits
userspace to use all available huge page sizes.
- In the series "revert unconditional slab and page allocator fault
injection calls" Vlastimil Babka removes a performance-affecting and
not very useful feature from slab fault injection.
* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
mm/mglru: fix ineffective protection calculation
mm/zswap: fix a white space issue
mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
mm/hugetlb: fix possible recursive locking detected warning
mm/gup: clear the LRU flag of a page before adding to LRU batch
mm/numa_balancing: teach mpol_to_str about the balancing mode
mm: memcg1: convert charge move flags to unsigned long long
alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
lib: reuse page_ext_data() to obtain codetag_ref
lib: add missing newline character in the warning message
mm/mglru: fix overshooting shrinker memory
mm/mglru: fix div-by-zero in vmpressure_calc_level()
mm/kmemleak: replace strncpy() with strscpy()
mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
mm: ignore data-race in __swap_writepage
hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
mm: shmem: rename mTHP shmem counters
mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
mm/migrate: putback split folios when numa hint migration fails
...
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Let's make update_mmu_tlb() simply a generic wrapper around
update_mmu_tlb_range(). Only the latter can now be overridden by the
architecture. We can now remove __HAVE_ARCH_UPDATE_MMU_TLB as well.
Link: https://lkml.kernel.org/r/20240522061204.117421-3-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Add update_mmu_tlb_range() to simplify code", v4.
This series of commits mainly adds the update_mmu_tlb_range() to batch
update tlb in an address range and implement update_mmu_tlb() using
update_mmu_tlb_range().
After commit 19eaf44954df ("mm: thp: support allocation of anonymous
multi-size THP"), We may need to batch update tlb of a certain address
range by calling update_mmu_tlb() in a loop. Using the
update_mmu_tlb_range(), we can simplify the code and possibly reduce the
execution of some unnecessary code in some architectures.
This patch (of 3):
Add update_mmu_tlb_range(), we can batch update tlb of an address range.
Link: https://lkml.kernel.org/r/20240522061204.117421-1-libang.li@antgroup.com
Link: https://lkml.kernel.org/r/20240522061204.117421-2-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Björn Töpel <bjorn@kernel.org> says:
From: Björn Töpel <bjorn@rivosinc.com>
================================================================
Memory Hot(Un)Plug support (and ZONE_DEVICE) for the RISC-V port
================================================================
Introduction
============
To quote "Documentation/admin-guide/mm/memory-hotplug.rst": "Memory
hot(un)plug allows for increasing and decreasing the size of physical
memory available to a machine at runtime."
This series adds memory hot(un)plugging, and ZONE_DEVICE support for
the RISC-V Linux port.
MM configuration
================
RISC-V MM has the following configuration:
* Memory blocks are 128M, analogous to x86-64. It uses PMD
("hugepage") vmemmaps. From that follows that 2M (PMD) worth of
vmemmap spans 32768 pages á 4K which gets us 128M.
* The pageblock size is the minimum minimum virtio_mem size, and on
RISC-V it's 2M (2^9 * 4K).
Implementation
==============
The PGD table on RISC-V is shared/copied between for all processes. To
avoid doing page table synchronization, the first patch (patch 1)
pre-allocated the PGD entries for vmemmap/direct map. By doing that
the init_mm PGD will be fixed at kernel init, and synchronization can
be avoided all together.
The following two patches (patch 2-3) does some preparations, followed
by the actual MHP implementation (patch 4-5). Then, MHP and virtio-mem
are enabled (patch 6-7), and finally ZONE_DEVICE support is added
(patch 8).
MHP and locking
===============
TL;DR: The MHP does not step on any toes, except for ptdump.
Additional locking is required for ptdump.
Long version: For v2 I spent some time digging into init_mm
synchronization/update. Here are my findings, and I'd love them to be
corrected if incorrect.
It's been a gnarly path...
The `init_mm` structure is a special mm (perhaps not a "real" one).
It's a "lazy context" that tracks kernel page table resources, e.g.,
the kernel page table (swapper_pg_dir), a kernel page_table_lock (more
about the usage below), mmap_lock, and such.
`init_mm` does not track/contain any VMAs. Having the `init_mm` is
convenient, so that the regular kernel page table walk/modify
functions can be used.
Now, `init_mm` being special means that the locking for kernel page
tables are special as well.
On RISC-V the PGD (top-level page table structure), similar to x86, is
shared (copied) with user processes. If the kernel PGD is modified, it
has to be synched to user-mode processes PGDs. This is avoided by
pre-populating the PGD, so it'll be fixed from boot.
The in-kernel pgd regions are documented in
`Documentation/arch/riscv/vm-layout.rst`.
The distinct regions are:
* vmemmap
* vmalloc/ioremap space
* direct mapping of all physical memory
* kasan
* modules, BPF
* kernel
Memory hotplug is the process of adding/removing memory to/from the
kernel.
Adding is done in two phases:
1. Add the memory to the kernel
2. Online memory, making it available to the page allocator.
Step 1 is partially architecture dependent, and updates the init_mm
page table:
* Update the direct map page tables. The direct map is a linear map,
representing all physical memory: `virt = phys + PAGE_OFFSET`
* Add a `struct page` for each added page of memory. Update the
vmemmap (virtual mapping to the `struct page`, so we can easily
transform a kernel virtual address to a `struct page *` address.
From an MHP perspective, there are two regions of the PGD that are
updated:
* vmemmap
* direct mapping of all physical memory
The `struct mm_struct` has a couple of locks in play:
* `spinlock_t page_table_lock` protects the page table, and some
counters
* `struct rw_semaphore mmap_lock` protect an mm's VMAs
Note again that `init_mm` does not contain any VMAs, but still uses
the mmap_lock in some places.
The `page_table_lock` was originally used to to protect all pages
tables, but more recently a split page table lock has been introduced.
The split lock has a per-table lock for the PTE and PMD tables. If
split lock is disabled, all tables are guarded by
`mm->page_table_lock` (for user processes). Split page table locks are
not used for init_mm.
MHP operations is typically synchronized using
`DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock)`.
Actors
------
The following non-MHP actors in the kernel traverses (read), and/or
modifies the kernel PGD.
* `ptdump`
Walks the entire `init_mm`, via `ptdump_walk_pgd()` with the
`mmap_write_lock(init_mm)` taken.
Observation: ptdump can race with MHP, and needs additional locking
to avoid crashes/races.
* `set_direct_*` / `arch/riscv/mm/pageattr.c`
The `set_direct_*` functionality is used to "synchronize" the
direct map to other kernel mappings, e.g. modules/kernel text. The
direct map is using "as large huge table mappings as possible",
which means that the `set_direct_*` might need to split the direct
map.
The `set_direct_*` functions operates with the
`mmap_write_lock(init_mm)` taken.
Observation: `set_direct_*` uses the direct map, but will never
modify the same entry as MHP. If there is a mapping, that entry will
never race with MHP. Further, MHP acts when memory is offline.
* HVO / `mm/hugetlb_vmemmap`
HVO optimizes the backing `struct page` for hugetlb pages, which
means changing the "vmemmap" region. HVO can split (merge?) a
vmemmap pmd. However, it will never race with MHP, since HVO only
operates at online memory. HVO cannot touch memory being MHP added
or removed.
* `apply_to_page_range`
Walks a range, creates pages and applies a callback (setting
permissions) for the page.
When creating a table, it might use `int __pte_alloc_kernel(pmd_t
*pmd)` which takes the `init_mm.page_table_lock` to synchronize pmd
populate.
Used by: `mm/vmalloc.c` and `mm/kasan/shadow.c`. The KASAN callback
takes the `init_mm.page_table_lock` to synchronize pte creation.
Observations: `apply_to_page_range` applies to the "vmalloc/ioremap
space" region, and "kasan" region. *Not* affected by MHP.
* `apply_to_existing_page_range`
Walks a range, applies a callback (setting permissions) for the
page (no page creation).
Used by: `kernel/bpf/arena.c` and `mm/kasan/shadow.c`. The KASAN
callback takes the `init_mm.page_table_lock` to synchronize pte
creation. *Not* affected by MHP regions.
* `apply_to_existing_page_range` applies to the "vmalloc/ioremap
space" region, and "kasan" region. *Not* affected by MHP regions.
* `ioremap_page_range` and `vmap_page_range`
Uses the same internal function, and might create table entries at
the "vmalloc/ioremap space" region. Can call
`__pte_alloc_kernel()` which takes the `init_mm.page_table_lock`
synchronizing pmd populate in the region. *Not* affected by MHP
regions.
Summary:
* MHP add will never modify the same page table entries, as any of
the other actors.
* MHP remove is done when memory is offlined, and will not clash
with any of the actors.
* Functions that walk the entire kernel page table need
synchronization
* It's sufficient to add the MHP lock ptdump.
Testing
=======
This series adds basic DT supported hotplugging. There is a QEMU
series enabling MHP for the RISC-V "virt" machine here: [1]
ACPI/MSI support is still in the making for RISC-V, and prior proper
(ACPI) PCI MSI support lands [2] and NUMA SRAT support [3], it hard to
try it out.
I've prepared a QEMU branch with proper ACPI GED/PC-DIMM support [4],
and a this series with the required prerequisites [5] (AIA, ACPI AIA
MADT, ACPI NUMA SRAT).
To test with virtio-mem, e.g.:
| qemu-system-riscv64 \
| -machine virt,aia=aplic-imsic \
| -cpu rv64,v=true,vlen=256,elen=64,h=true,zbkb=on,zbkc=on,zbkx=on,zkr=on,zkt=on,svinval=on,svnapot=on,svpbmt=on \
| -nodefaults \
| -nographic -smp 8 -kernel rv64-u-boot.bin \
| -drive file=rootfs.img,format=raw,if=virtio \
| -device virtio-rng-pci \
| -m 16G,slots=3,maxmem=32G \
| -object memory-backend-ram,id=mem0,size=16G \
| -numa node,nodeid=0,memdev=mem0 \
| -serial chardev:char0 \
| -mon chardev=char0,mode=readline \
| -chardev stdio,mux=on,id=char0 \
| -device pci-serial,id=serial0,chardev=char0 \
| -object memory-backend-ram,id=vmem0,size=2G \
| -device virtio-mem-pci,id=vm0,memdev=vmem0,node=0
where "rv64-u-boot.bin" is U-boot with EFI/ACPI-support (use [6] if
you're lazy).
In the QEMU monitor:
| (qemu) info memory-devices
| (qemu) qom-set vm0 requested-size 1G
...to test DAX/KMEM, use the follow QEMU parameters:
| -object memory-backend-file,id=mem1,share=on,mem-path=virtio_pmem.img,size=4G \
| -device virtio-pmem-pci,memdev=mem1,id=nv1
and the regular ndctl/daxctl dance.
If you're brave to try the ACPI branch, add "acpi=on" to "-machine
virt", and test PC-DIMM MHP (in addition to virtio-{p},mem):
In the QEMU monitor:
| (qemu) object_add memory-backend-ram,id=mem1,size=1G
| (qemu) device_add pc-dimm,id=dimm1,memdev=mem1
You can also try hot-remove with some QEMU options, say:
| -object memory-backend-file,id=mem-1,size=256M,mem-path=/pagesize-2MB
| -device pc-dimm,id=mem1,memdev=mem-1
| -object memory-backend-file,id=mem-2,size=1G,mem-path=/pagesize-1GB
| -device pc-dimm,id=mem2,memdev=mem-2
| -object memory-backend-file,id=mem-3,size=256M,mem-path=/pagesize-2MB
| -device pc-dimm,id=mem3,memdev=mem-3
Remove "acpi=on" to run with DT.
Thanks to Alex, Andrew, David, and Oscar for all
comments/tests/fixups.
References
==========
[1] https://lore.kernel.org/qemu-devel/20240521105635.795211-1-bjorn@kernel.org/
[2] https://lore.kernel.org/linux-riscv/20240501121742.1215792-1-sunilvl@ventanamicro.com/
[3] https://lore.kernel.org/linux-riscv/cover.1713778236.git.haibo1.xu@intel.com/
[4] https://github.com/bjoto/qemu/commits/virtio-mem-pc-dimm-mhp-acpi-v2/
[5] https://github.com/bjoto/linux/commits/mhp-v4-acpi
[6] https://github.com/bjoto/riscv-rootfs-utils/tree/acpi
* b4-shazam-merge:
riscv: Enable DAX VMEMMAP optimization
riscv: mm: Add support for ZONE_DEVICE
virtio-mem: Enable virtio-mem for RISC-V
riscv: Enable memory hotplugging for RISC-V
riscv: mm: Take memory hotplug read-lock during kernel page table dump
riscv: mm: Add memory hotplugging support
riscv: mm: Add pfn_to_kaddr() implementation
riscv: mm: Refactor create_linear_mapping_range() for memory hot add
riscv: mm: Change attribute from __init to __meminit for page functions
riscv: mm: Pre-allocate vmemmap/direct map/kasan PGD entries
riscv: mm: Properly forward vmemmap_populate() altmap parameter
Link: https://lore.kernel.org/r/20240605114100.315918-1-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
|
ZONE_DEVICE pages need DEVMAP PTEs support to function
(ARCH_HAS_PTE_DEVMAP). Claim another RSW (reserved for software) bit
in the PTE for DEVMAP mark, add the corresponding helpers, and enable
ARCH_HAS_PTE_DEVMAP for riscv64.
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20240605114100.315918-11-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
|
