Commit-ID: a9b3c6998d4a7d53a787cf4d0fd4a4c11239e517 Gitweb: https://git.kernel.org/tip/a9b3c6998d4a7d53a787cf4d0fd4a4c11239e517 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Wed, 8 May 2019 14:30:48 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 25 Jun 2019 10:23:45 +0200 x86/stackframe: Move ENCODE_FRAME_POINTER to asm/frame.h In preparation for wider use, move the ENCODE_FRAME_POINTER macros to a common header and provide inline asm versions. These macros are used to encode a pt_regs frame for the unwinder; see unwind_frame.c:decode_frame_pointer(). Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/entry/calling.h | 15 -------------- arch/x86/entry/entry_32.S | 16 --------------- arch/x86/include/asm/frame.h | 49 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 31 deletions(-) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index efb0d1b1f15f..9f1f9e3b8230 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -172,21 +172,6 @@ For 32-bit we have the following conventions - kernel is built with .endif .endm -/* - * This is a sneaky trick to help the unwinder find pt_regs on the stack. The - * frame pointer is replaced with an encoded pointer to pt_regs. The encoding - * is just setting the LSB, which makes it an invalid stack address and is also - * a signal to the unwinder that it's a pt_regs pointer in disguise. - * - * NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts - * the original rbp. - */ -.macro ENCODE_FRAME_POINTER ptregs_offset=0 -#ifdef CONFIG_FRAME_POINTER - leaq 1+\ptregs_offset(%rsp), %rbp -#endif -.endm - #ifdef CONFIG_PAGE_TABLE_ISOLATION /* diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 7040d7e96250..ac2b3b4e09f7 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -246,22 +246,6 @@ .Lend_\@: .endm -/* - * This is a sneaky trick to help the unwinder find pt_regs on the stack. The - * frame pointer is replaced with an encoded pointer to pt_regs. The encoding - * is just clearing the MSB, which makes it an invalid stack address and is also - * a signal to the unwinder that it's a pt_regs pointer in disguise. - * - * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the - * original rbp. - */ -.macro ENCODE_FRAME_POINTER -#ifdef CONFIG_FRAME_POINTER - mov %esp, %ebp - andl $0x7fffffff, %ebp -#endif -.endm - .macro RESTORE_INT_REGS popl %ebx popl %ecx diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h index 5cbce6fbb534..296b346184b2 100644 --- a/arch/x86/include/asm/frame.h +++ b/arch/x86/include/asm/frame.h @@ -22,6 +22,35 @@ pop %_ASM_BP .endm +#ifdef CONFIG_X86_64 +/* + * This is a sneaky trick to help the unwinder find pt_regs on the stack. The + * frame pointer is replaced with an encoded pointer to pt_regs. The encoding + * is just setting the LSB, which makes it an invalid stack address and is also + * a signal to the unwinder that it's a pt_regs pointer in disguise. + * + * NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts + * the original rbp. + */ +.macro ENCODE_FRAME_POINTER ptregs_offset=0 + leaq 1+\ptregs_offset(%rsp), %rbp +.endm +#else /* !CONFIG_X86_64 */ +/* + * This is a sneaky trick to help the unwinder find pt_regs on the stack. The + * frame pointer is replaced with an encoded pointer to pt_regs. The encoding + * is just clearing the MSB, which makes it an invalid stack address and is also + * a signal to the unwinder that it's a pt_regs pointer in disguise. + * + * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the + * original ebp. + */ +.macro ENCODE_FRAME_POINTER + mov %esp, %ebp + andl $0x7fffffff, %ebp +.endm +#endif /* CONFIG_X86_64 */ + #else /* !__ASSEMBLY__ */ #define FRAME_BEGIN \ @@ -30,12 +59,32 @@ #define FRAME_END "pop %" _ASM_BP "\n" +#ifdef CONFIG_X86_64 +#define ENCODE_FRAME_POINTER \ + "lea 1(%rsp), %rbp\n\t" +#else /* !CONFIG_X86_64 */ +#define ENCODE_FRAME_POINTER \ + "movl %esp, %ebp\n\t" \ + "andl $0x7fffffff, %ebp\n\t" +#endif /* CONFIG_X86_64 */ + #endif /* __ASSEMBLY__ */ #define FRAME_OFFSET __ASM_SEL(4, 8) #else /* !CONFIG_FRAME_POINTER */ +#ifdef __ASSEMBLY__ + +.macro ENCODE_FRAME_POINTER ptregs_offset=0 +.endm + +#else /* !__ASSEMBLY */ + +#define ENCODE_FRAME_POINTER + +#endif + #define FRAME_BEGIN #define FRAME_END #define FRAME_OFFSET 0
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