6.12-stable review patch. If anyone has any objections, please let me know.
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From: Kirill A. Shutemov kirill.shutemov@linux.intel.com
[ Upstream commit bd72baff229920da1d57c14364c11ecdbaf5b458 ]
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@linux.intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Brian Gerst brgerst@gmail.com Cc: H. Peter Anvin hpa@zytor.com Cc: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/r/20250304153342.2016569-1-kirill.shutemov@linux.int... Stable-dep-of: 284922f4c563 ("x86: uaccess: don't use runtime-const rewriting in modules") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6652ebddfd02f..8d983cfd06ea6 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 89ecd57c9d423..853a2e6287698 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