diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-31 11:48:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-31 11:48:12 -0800 |
| commit | f5a376eddec424f00e38aa19bd26c2febbfc934d (patch) | |
| tree | 8bead178bea50804794386fa777f8ed3d78d758f | |
| parent | 17b756d0376fd45f98abb6d758c3d5befb01e3fa (diff) | |
| parent | 0bab9cb2d980d7c075cffb9216155f7835237f98 (diff) | |
Merge tag 'x86_entry_for_v5.11_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
"A single fix for objtool to generate proper unwind info for newer
toolchains which do not generate section symbols anymore. And a
cleanup ontop.
This was originally going to go during the next merge window but
people can already trigger a build error with binutils-2.36 which
doesn't emit section symbols - something which objtool relies on - so
let's expedite it"
* tag 'x86_entry_for_v5.11_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Remove put_ret_addr_in_rdi THUNK macro argument
x86/entry: Emit a symbol for register restoring thunk
| -rw-r--r-- | Documentation/asm-annotations.rst | 5 | ||||
| -rw-r--r-- | arch/x86/entry/thunk_64.S | 15 | ||||
| -rw-r--r-- | include/linux/linkage.h | 5 |
3 files changed, 15 insertions, 10 deletions
diff --git a/Documentation/asm-annotations.rst b/Documentation/asm-annotations.rst index 32ea57483378..76424e0431f4 100644 --- a/Documentation/asm-annotations.rst +++ b/Documentation/asm-annotations.rst @@ -100,6 +100,11 @@ Instruction Macros ~~~~~~~~~~~~~~~~~~ This section covers ``SYM_FUNC_*`` and ``SYM_CODE_*`` enumerated above. +``objtool`` requires that all code must be contained in an ELF symbol. Symbol +names that have a ``.L`` prefix do not emit symbol table entries. ``.L`` +prefixed symbols can be used within a code region, but should be avoided for +denoting a range of code via ``SYM_*_START/END`` annotations. + * ``SYM_FUNC_START`` and ``SYM_FUNC_START_LOCAL`` are supposed to be **the most frequent markings**. They are used for functions with standard calling conventions -- global and local. Like in C, they both align the functions to diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S index ccd32877a3c4..496b11ec469d 100644 --- a/arch/x86/entry/thunk_64.S +++ b/arch/x86/entry/thunk_64.S @@ -10,7 +10,7 @@ #include <asm/export.h> /* rdi: arg1 ... normal C conventions. rax is saved/restored. */ - .macro THUNK name, func, put_ret_addr_in_rdi=0 + .macro THUNK name, func SYM_FUNC_START_NOALIGN(\name) pushq %rbp movq %rsp, %rbp @@ -25,13 +25,8 @@ SYM_FUNC_START_NOALIGN(\name) pushq %r10 pushq %r11 - .if \put_ret_addr_in_rdi - /* 8(%rbp) is return addr on stack */ - movq 8(%rbp), %rdi - .endif - call \func - jmp .L_restore + jmp __thunk_restore SYM_FUNC_END(\name) _ASM_NOKPROBE(\name) .endm @@ -44,7 +39,7 @@ SYM_FUNC_END(\name) #endif #ifdef CONFIG_PREEMPTION -SYM_CODE_START_LOCAL_NOALIGN(.L_restore) +SYM_CODE_START_LOCAL_NOALIGN(__thunk_restore) popq %r11 popq %r10 popq %r9 @@ -56,6 +51,6 @@ SYM_CODE_START_LOCAL_NOALIGN(.L_restore) popq %rdi popq %rbp ret - _ASM_NOKPROBE(.L_restore) -SYM_CODE_END(.L_restore) + _ASM_NOKPROBE(__thunk_restore) +SYM_CODE_END(__thunk_restore) #endif diff --git a/include/linux/linkage.h b/include/linux/linkage.h index 5bcfbd972e97..dbf8506decca 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -178,6 +178,11 @@ * Objtool generates debug info for both FUNC & CODE, but needs special * annotations for each CODE's start (to describe the actual stack frame). * + * Objtool requires that all code must be contained in an ELF symbol. Symbol + * names that have a .L prefix do not emit symbol table entries. .L + * prefixed symbols can be used within a code region, but should be avoided for + * denoting a range of code via ``SYM_*_START/END`` annotations. + * * ALIAS -- does not generate debug info -- the aliased function will */ |