user/sven/linux.git/include/linux/compiler.h, branch v6.1.152

compiler: remove __ADDRESSABLE_ASM{_STR,}() again

2025-08-28T14:26:17Z

[ Upstream commit 8ea815399c3fcce1889bd951fec25b5b9a3979c1 ] __ADDRESSABLE_ASM_STR() is where the necessary stringification happens. As long as "sym" doesn't contain any odd characters, no quoting is required for its use with .quad / .long. In fact the quotation gets in the way with gas 2.25; it's only from 2.26 onwards that quoted symbols are half-way properly supported. However, assembly being different from C anyway, drop __ADDRESSABLE_ASM_STR() and its helper macro altogether. A simple .global directive will suffice to get the symbol "declared", i.e. into the symbol table. While there also stop open-coding STATIC_CALL_TRAMP() and STATIC_CALL_KEY(). Fixes: 0ef8047b737d ("x86/static-call: provide a way to do very early static-call updates") Signed-off-by: Jan Beulich Acked-by: Josh Poimboeuf Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross Message-ID: <609d2c74-de13-4fae-ab1a-1ec44afb948d@suse.com> [ Adjust context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

x86/static-call: provide a way to do very early static-call updates

2024-12-19T17:08:58Z

commit 0ef8047b737d7480a5d4c46d956e97c190f13050 upstream. Add static_call_update_early() for updating static-call targets in very early boot. This will be needed for support of Xen guest type specific hypercall functions. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Co-developed-by: Peter Zijlstra Co-developed-by: Josh Poimboeuf Signed-off-by: Greg Kroah-Hartman

treewide: Drop function_nocfi

2022-09-26T17:13:14Z

With -fsanitize=kcfi, we no longer need function_nocfi() as the compiler won't change function references to point to a jump table. Remove all implementations and uses of the macro. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-14-samitolvanen@google.com

cfi: Drop __CFI_ADDRESSABLE

2022-09-26T17:13:13Z

The __CFI_ADDRESSABLE macro is used for init_module and cleanup_module to ensure we have the address of the CFI jump table, and with CONFIG_X86_KERNEL_IBT to ensure LTO won't optimize away the symbols. As __CFI_ADDRESSABLE is no longer necessary with -fsanitize=kcfi, add a more flexible version of the __ADDRESSABLE macro and always ensure these symbols won't be dropped. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-5-samitolvanen@google.com

tracing: Define the is_signed_type() macro once

2022-08-29T20:29:40Z

There are two definitions of the is_signed_type() macro: one in and a second definition in . As suggested by Linus, move the definition of the is_signed_type() macro into the header file. Change the definition of the is_signed_type() macro to make sure that it does not trigger any sparse warnings with future versions of sparse for bitwise types. Link: https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/ Link: https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/ Cc: Rasmus Villemoes Cc: Steven Rostedt Acked-by: Kees Cook Signed-off-by: Bart Van Assche Signed-off-by: Linus Torvalds

objtool: Add CONFIG_OBJTOOL

2022-04-22T10:32:03Z

Now that stack validation is an optional feature of objtool, add CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with it. CONFIG_STACK_VALIDATION can now be considered to be frame-pointer specific. CONFIG_UNWINDER_ORC is already inherently valid for live patching, so no need to "validate" it. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com

x86,objtool: Move the ASM_REACHABLE annotation to objtool.h

2022-03-15T09:32:45Z

Because we need a variant for .S files too. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/Yi9gOW9f1GGwwUD6@hirez.programming.kicks-ass.net

x86/bug: Merge annotate_reachable() into _BUG_FLAGS() asm

2022-02-02T22:41:04Z

In __WARN_FLAGS(), we had two asm statements (abbreviated): asm volatile("ud2"); asm volatile(".pushsection .discard.reachable"); These pair of statements are used to trigger an exception, but then help objtool understand that for warnings, control flow will be restored immediately afterwards. The problem is that volatile is not a compiler barrier. GCC explicitly documents this: > Note that the compiler can move even volatile asm instructions > relative to other code, including across jump instructions. Also, no clobbers are specified to prevent instructions from subsequent statements from being scheduled by compiler before the second asm statement. This can lead to instructions from subsequent statements being emitted by the compiler before the second asm statement. Providing a scheduling model such as via -march= options enables the compiler to better schedule instructions with known latencies to hide latencies from data hazards compared to inline asm statements in which latencies are not estimated. If an instruction gets scheduled by the compiler between the two asm statements, then objtool will think that it is not reachable, producing a warning. To prevent instructions from being scheduled in between the two asm statements, merge them. Also remove an unnecessary unreachable() asm annotation from BUG() in favor of __builtin_unreachable(). objtool is able to track that the ud2 from BUG() terminates control flow within the function. Link: https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Volatile Link: https://github.com/ClangBuiltLinux/linux/issues/1483 Signed-off-by: Nick Desaulniers Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220202205557.2260694-1-ndesaulniers@google.com

compiler.h: Fix annotation macro misplacement with Clang

2021-12-21T23:09:46Z

When building with Clang and CONFIG_TRACE_BRANCH_PROFILING, there are a lot of unreachable warnings, like: arch/x86/kernel/traps.o: warning: objtool: handle_xfd_event()+0x134: unreachable instruction Without an input to the inline asm, 'volatile' is ignored for some reason and Clang feels free to move the reachable() annotation away from its intended location. Fix that by re-adding the counter value to the inputs. Fixes: f1069a8756b9 ("compiler.h: Avoid using inline asm operand modifiers") Fixes: c199f64ff93c ("instrumentation.h: Avoid using inline asm operand modifiers") Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/0417e96909b97a406323409210de7bf13df0b170.1636410380.git.jpoimboe@redhat.com Cc: Peter Zijlstra Cc: x86@kernel.org Cc: Vasily Gorbik Cc: Miroslav Benes

compiler.h: Introduce absolute_pointer macro

2021-09-15T19:04:28Z

absolute_pointer() disassociates a pointer from its originating symbol type and context. Use it to prevent compiler warnings/errors such as drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe': arch/m68k/include/asm/string.h:72:25: error: '__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread] Such warnings may be reported by gcc 11.x for string and memory operations on fixed addresses. Suggested-by: Linus Torvalds Signed-off-by: Guenter Roeck Reviewed-by: Geert Uytterhoeven Signed-off-by: Linus Torvalds