The following commit has been merged into the x86/asm branch of tip: Commit-ID: c84f87de474c9aec84f706ceb732b70751122746 Gitweb: https://git.kernel.org/tip/c84f87de474c9aec84f706ceb732b70751122746 Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> AuthorDate: Tue, 04 Mar 2025 17:33:42 +02:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Thu, 06 Mar 2025 11:27:31 +01:00 x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro Add an assembly macro to refer runtime cost. It hides linker magic and makes assembly more readable. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20250304153342.2016569-1-kirill.shutemov@xxxxxxxxxxxxxxx --- arch/x86/include/asm/runtime-const.h | 13 +++++++++++++ arch/x86/lib/getuser.S | 7 ++----- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/runtime-const.h b/arch/x86/include/asm/runtime-const.h index 6652ebd..8d983cf 100644 --- a/arch/x86/include/asm/runtime-const.h +++ b/arch/x86/include/asm/runtime-const.h @@ -2,6 +2,18 @@ #ifndef _ASM_RUNTIME_CONST_H #define _ASM_RUNTIME_CONST_H +#ifdef __ASSEMBLY__ + +.macro RUNTIME_CONST_PTR sym reg + movq $0x0123456789abcdef, %\reg + 1: + .pushsection runtime_ptr_\sym, "a" + .long 1b - 8 - . + .popsection +.endm + +#else /* __ASSEMBLY__ */ + #define runtime_const_ptr(sym) ({ \ typeof(sym) __ret; \ asm_inline("mov %1,%0\n1:\n" \ @@ -58,4 +70,5 @@ static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), } } +#endif /* __ASSEMBLY__ */ #endif diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S index 89ecd57..853a2e6 100644 --- a/arch/x86/lib/getuser.S +++ b/arch/x86/lib/getuser.S @@ -34,16 +34,13 @@ #include <asm/thread_info.h> #include <asm/asm.h> #include <asm/smap.h> +#include <asm/runtime-const.h> #define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC .macro check_range size:req .if IS_ENABLED(CONFIG_X86_64) - movq $0x0123456789abcdef,%rdx - 1: - .pushsection runtime_ptr_USER_PTR_MAX,"a" - .long 1b - 8 - . - .popsection + RUNTIME_CONST_PTR USER_PTR_MAX, rdx cmp %rdx, %rax cmova %rdx, %rax .else
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