kernel/include/asm-generic/vmlinux.lds.h, branch linux-5.11.y

static_call: Allow module use without exposing static_call_key

2021-03-30T12:30:12Z

[ Upstream commit 73f44fe19d359635a607e8e8daa0da4001c1cfc2 ] When exporting static_call_key; with EXPORT_STATIC_CALL*(), the module can use static_call_update() to change the function called. This is not desirable in general. Not exporting static_call_key however also disallows usage of static_call(), since objtool needs the key to construct the static_call_site. Solve this by allowing objtool to create the static_call_site using the trampoline address when it builds a module and cannot find the static_call_key symbol. The module loader will then try and map the trampole back to a key before it constructs the normal sites list. Doing this requires a trampoline -> key associsation, so add another magic section that keeps those. Originally-by: Peter Zijlstra (Intel) Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20210127231837.ifddpn7rhwdaepiu@treble Signed-off-by: Sasha Levin

vmlinux.lds.h: Define SANTIZER_DISCARDS with CONFIG_GCOV_KERNEL=y

2021-03-04T11:13:34Z

commit f5b6a74d9c08b19740ca056876bf6584acdba582 upstream. clang produces .eh_frame sections when CONFIG_GCOV_KERNEL is enabled, even when -fno-asynchronous-unwind-tables is in KBUILD_CFLAGS: $ make CC=clang vmlinux ... ld: warning: orphan section `.eh_frame' from `init/main.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/version.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/do_mounts.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/do_mounts_initrd.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/initramfs.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/calibrate.o' being placed in section `.eh_frame' ld: warning: orphan section `.eh_frame' from `init/init_task.o' being placed in section `.eh_frame' ... $ rg "GCOV_KERNEL|GCOV_PROFILE_ALL" .config CONFIG_GCOV_KERNEL=y CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y CONFIG_GCOV_PROFILE_ALL=y This was already handled for a couple of other options in commit d812db78288d ("vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections") and there is an open LLVM bug for this issue. Take advantage of that section for this config as well so that there are no more orphan warnings. Link: https://bugs.llvm.org/show_bug.cgi?id=46478 Link: https://github.com/ClangBuiltLinux/linux/issues/1069 Reported-by: kernel test robot Reviewed-by: Fangrui Song Reviewed-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Fixes: d812db78288d ("vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210130004650.2682422-1-nathan@kernel.org Signed-off-by: Greg Kroah-Hartman

vmlinux.lds.h: add DWARF v5 sections

2021-03-04T11:13:31Z

commit 3c4fa46b30c551b1df2fb1574a684f68bc22067c upstream. We expect toolchains to produce these new debug info sections as part of DWARF v5. Add explicit placements to prevent the linker warnings from --orphan-section=warn. Compilers may produce such sections with explicit -gdwarf-5, or based on the implicit default version of DWARF when -g is used via DEBUG_INFO. This implicit default changes over time, and has changed to DWARF v5 with GCC 11. .debug_sup was mentioned in review, but without compilers producing it today, let's wait to add it until it becomes necessary. Cc: stable@vger.kernel.org Link: https://bugzilla.redhat.com/show_bug.cgi?id=1922707 Reported-by: Chris Murphy Suggested-by: Fangrui Song Reviewed-by: Nathan Chancellor Reviewed-by: Mark Wielaard Tested-by: Sedat Dilek Signed-off-by: Nick Desaulniers Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

firmware_loader: align .builtin_fw to 8

2021-02-10T01:26:44Z

arm64 references the start address of .builtin_fw (__start_builtin_fw) with a pair of R_AARCH64_ADR_PREL_PG_HI21/R_AARCH64_LDST64_ABS_LO12_NC relocations. The compiler is allowed to emit the R_AARCH64_LDST64_ABS_LO12_NC relocation because struct builtin_fw in include/linux/firmware.h is 8-byte aligned. The R_AARCH64_LDST64_ABS_LO12_NC relocation requires the address to be a multiple of 8, which may not be the case if .builtin_fw is empty. Unconditionally align .builtin_fw to fix the linker error. 32-bit architectures could use ALIGN(4) but that would add unnecessary complexity, so just use ALIGN(8). Link: https://lkml.kernel.org/r/20201208054646.2913063-1-maskray@google.com Link: https://github.com/ClangBuiltLinux/linux/issues/1204 Fixes: 5658c76 ("firmware: allow firmware files to be built into kernel image") Signed-off-by: Fangrui Song Reported-by: kernel test robot Acked-by: Arnd Bergmann Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Tested-by: Douglas Anderson Acked-by: Nathan Chancellor Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmlinux.lds.h: Keep .ctors.* with .ctors

2020-10-27T18:13:41Z

Under some circumstances, the compiler generates .ctors.* sections. This is seen doing a cross compile of x86_64 from a powerpc64el host: x86_64-linux-gnu-ld: warning: orphan section `.ctors.65435' from `kernel/trace/trace_clock.o' being placed in section `.ctors.65435' x86_64-linux-gnu-ld: warning: orphan section `.ctors.65435' from `kernel/trace/ftrace.o' being placed in section `.ctors.65435' x86_64-linux-gnu-ld: warning: orphan section `.ctors.65435' from `kernel/trace/ring_buffer.o' being placed in section `.ctors.65435' Include these orphans along with the regular .ctors section. Reported-by: Stephen Rothwell Tested-by: Stephen Rothwell Fixes: 83109d5d5fba ("x86/build: Warn on orphan section placement") Signed-off-by: Kees Cook Acked-by: Nick Desaulniers Link: https://lore.kernel.org/r/20201005025720.2599682-1-keescook@chromium.org

Merge tag 'linux-kselftest-kunit-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2020-10-18T21:45:59Z

Pull more Kunit updates from Shuah Khan: - add Kunit to kernel_init() and remove KUnit from init calls entirely. This addresses the concern that Kunit would not work correctly during late init phase. - add a linker section where KUnit can put references to its test suites. This is the first step in transitioning to dispatching all KUnit tests from a centralized executor rather than having each as its own separate late_initcall. - add a centralized executor to dispatch tests rather than relying on late_initcall to schedule each test suite separately. Centralized execution is for built-in tests only; modules will execute tests when loaded. - convert bitfield test to use KUnit framework - Documentation updates for naming guidelines and how kunit_test_suite() works. - add test plan to KUnit TAP format * tag 'linux-kselftest-kunit-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: lib: kunit: Fix compilation test when using TEST_BIT_FIELD_COMPILE lib: kunit: add bitfield test conversion to KUnit Documentation: kunit: add a brief blurb about kunit_test_suite kunit: test: add test plan to KUnit TAP format init: main: add KUnit to kernel init kunit: test: create a single centralized executor for all tests vmlinux.lds.h: add linker section for KUnit test suites Documentation: kunit: Add naming guidelines

Merge tag 'core-static_call-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-12T20:58:15Z

Pull static call support from Ingo Molnar: "This introduces static_call(), which is the idea of static_branch() applied to indirect function calls. Remove a data load (indirection) by modifying the text. They give the flexibility of function pointers, but with better performance. (This is especially important for cases where retpolines would otherwise be used, as retpolines can be pretty slow.) API overview: DECLARE_STATIC_CALL(name, func); DEFINE_STATIC_CALL(name, func); DEFINE_STATIC_CALL_NULL(name, typename); static_call(name)(args...); static_call_cond(name)(args...); static_call_update(name, func); x86 is supported via text patching, otherwise basic indirect calls are used, with function pointers. There's a second variant using inline code patching, inspired by jump-labels, implemented on x86 as well. The new APIs are utilized in the x86 perf code, a heavy user of function pointers, where static calls speed up the PMU handler by 4.2% (!). The generic implementation is not really excercised on other architectures, outside of the trivial test_static_call_init() self-test" * tag 'core-static_call-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) static_call: Fix return type of static_call_init tracepoint: Fix out of sync data passing by static caller tracepoint: Fix overly long tracepoint names x86/perf, static_call: Optimize x86_pmu methods tracepoint: Optimize using static_call() static_call: Allow early init static_call: Add some validation static_call: Handle tail-calls static_call: Add static_call_cond() x86/alternatives: Teach text_poke_bp() to emulate RET static_call: Add simple self-test for static calls x86/static_call: Add inline static call implementation for x86-64 x86/static_call: Add out-of-line static call implementation static_call: Avoid kprobes on inline static_call()s static_call: Add inline static call infrastructure static_call: Add basic static call infrastructure compiler.h: Make __ADDRESSABLE() symbol truly unique jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved() module: Properly propagate MODULE_STATE_COMING failure module: Fix up module_notifier return values ...

Merge tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-10-12T20:39:19Z

Pull orphan section checking from Ingo Molnar: "Orphan link sections were a long-standing source of obscure bugs, because the heuristics that various linkers & compilers use to handle them (include these bits into the output image vs discarding them silently) are both highly idiosyncratic and also version dependent. Instead of this historically problematic mess, this tree by Kees Cook (et al) adds build time asserts and build time warnings if there's any orphan section in the kernel or if a section is not sized as expected. And because we relied on so many silent assumptions in this area, fix a metric ton of dependencies and some outright bugs related to this, before we can finally enable the checks on the x86, ARM and ARM64 platforms" * tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) x86/boot/compressed: Warn on orphan section placement x86/build: Warn on orphan section placement arm/boot: Warn on orphan section placement arm/build: Warn on orphan section placement arm64/build: Warn on orphan section placement x86/boot/compressed: Add missing debugging sections to output x86/boot/compressed: Remove, discard, or assert for unwanted sections x86/boot/compressed: Reorganize zero-size section asserts x86/build: Add asserts for unwanted sections x86/build: Enforce an empty .got.plt section x86/asm: Avoid generating unused kprobe sections arm/boot: Handle all sections explicitly arm/build: Assert for unwanted sections arm/build: Add missing sections arm/build: Explicitly keep .ARM.attributes sections arm/build: Refactor linker script headers arm64/build: Assert for unwanted sections arm64/build: Add missing DWARF sections arm64/build: Use common DISCARDS in linker script arm64/build: Remove .eh_frame* sections due to unwind tables ...

vmlinux.lds.h: add linker section for KUnit test suites

2020-10-09T20:37:15Z

Add a linker section where KUnit can put references to its test suites. This patch is the first step in transitioning to dispatching all KUnit tests from a centralized executor rather than having each as its own separate late_initcall. Co-developed-by: Iurii Zaikin Signed-off-by: Iurii Zaikin Signed-off-by: Brendan Higgins Reviewed-by: Stephen Boyd Signed-off-by: Shuah Khan

bpf: Prevent .BTF section elimination

2020-09-21T19:50:44Z

Systems with memory or disk constraints often reduce the kernel footprint by configuring LD_DEAD_CODE_DATA_ELIMINATION. However, this can result in removal of any BTF information. Use the KEEP() macro to preserve the BTF data as done with other important sections, while still allowing for smaller kernels. Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") Signed-off-by: Tony Ambardar Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/a635b5d3e2da044e7b51ec1315e8910fbce0083f.1600417359.git.Tony.Ambardar@gmail.com