kernel/arch/mips/include/asm/uaccess.h, branch linux-rolling-stable

uaccess: generalize access_ok()

2022-02-25T08:36:05Z

There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig Acked-by: Mark Rutland [arm64, asm-generic] Acked-by: Geert Uytterhoeven Acked-by: Stafford Horne Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann

MIPS: use simpler access_ok()

2022-02-25T08:36:05Z

Before unifying the mips version of __access_ok() with the generic code, this converts it to the same algorithm. This is a change in behavior on mips64, as now address in the user segment, the lower 2^62 bytes, is taken to be valid, relying on a page fault for addresses that are within that segment but not valid on that CPU. The new version should be the most effecient way to do this, but it gets rid of the special handling for size=0 that most other architectures ignore as well. Signed-off-by: Arnd Bergmann

uaccess: add generic __{get,put}_kernel_nofault

2022-02-25T08:36:05Z

Nine architectures are still missing __{get,put}_kernel_nofault: alpha, ia64, microblaze, nds32, nios2, openrisc, sh, sparc32, xtensa. Add a generic version that lets everything use the normal copy_{from,to}_kernel_nofault() code based on these, removing the last use of get_fs()/set_fs() from architecture-independent code. Reviewed-by: Christoph Hellwig Acked-by: Geert Uytterhoeven Signed-off-by: Arnd Bergmann

arch: remove compat_alloc_user_space

2021-09-08T22:32:35Z

All users of compat_alloc_user_space() and copy_in_user() have been removed from the kernel, only a few functions in sparc remain that can be changed to calling arch_copy_in_user() instead. Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: Christoph Hellwig Cc: Al Viro Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Eric Biederman Cc: Feng Tang Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Michael Ellerman Cc: Paul Mackerras Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

MIPS: Fix strnlen_user access check

2021-04-15T21:42:21Z

Commit 04324f44cb69 ("MIPS: Remove get_fs/set_fs") changed the access_ok for strnlen_user to check the whole range, which broke some callers of strndup_user(). Restore the old behaviour and just check the first byte. Fixes: 04324f44cb69 ("MIPS: Remove get_fs/set_fs") Signed-off-by: Thomas Bogendoerfer

MIPS: Fix access_ok() for the last byte of user space

2021-04-13T12:28:19Z

The MIPS implementation of access_ok() incorrectly reports that access to the final byte of user memory is not OK, much as the alpha & SH versions did prior to commit 94bd8a05cd4d ("Fix 'acccess_ok()' on alpha and SH"). For example on a MIPS64 system with __UA_LIMIT == 0xffff000000000000 we incorrectly fail in the following cases: access_ok(0xffffffffffff, 0x1) = 0 access_ok(0xfffffffffffe, 0x2) = 0 Fix MIPS in the same way as alpha & SH, by subtracting one from the addr + size condition when size is non-zero. With this the access_ok() calls above return 1 indicating that the access may be valid. The cost of the improved check is pretty minimal - we gain 2410 bytes, or 0.03%, in kernel code size for a 64r6el_defconfig kernel built using GCC 8.1.0. Signed-off-by: Paul Burton Reported-by: Linus Torvalds Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Thomas Bogendoerfer

MIPS: uaccess: Reduce number of nested macros

2021-04-12T14:42:20Z

Clean up macros even further after removal get_fs/set_fs. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: Remove get_fs/set_fs

2021-04-06T13:12:58Z

All get_fs/set_fs calls in MIPS code are gone, so remove implementation of it. With the clear separation of user/kernel space access we no longer need the EVA special handling, so get rid of that, too. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: uaccess: Added get/put_kernel_nofault

2021-04-06T12:36:56Z

Added __get/__put_kernel_nofault as preparation for removing get/set_fs. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Christoph Hellwig

MIPS: Remove KVM_GUEST support

2021-03-10T14:18:40Z

KVM_GUEST is broken and unmaintained, so let's remove it. Reviewed-by: Huacai Chen Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer

kernel/arch/mips/include/asm/uaccess.h, branch linux-rolling-stable

uaccess: generalize access_ok()

MIPS: use simpler access_ok()

uaccess: add generic __{get,put}_kernel_nofault

arch: remove compat_alloc_user_space

MIPS: Fix strnlen_user access check

MIPS: Fix access_ok() for the last byte of user space

MIPS: uaccess: Reduce number of nested macros

MIPS: Remove get_fs/set_fs

MIPS: uaccess: Added __get/__put_kernel_nofault

MIPS: Remove KVM_GUEST support

MIPS: uaccess: Added get/put_kernel_nofault