lkml.org 
[lkml]   [2019]   [Aug]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectAsm & local labels for functions [was: [PATCH v8 05/28] x86/asm: annotate local pseudo-functions]
From
Date
On 15. 08. 19, 18:07, Borislav Petkov wrote:
> --- a/arch/x86/kernel/head_64.S
> +++ b/arch/x86/kernel/head_64.S
> @@ -283,7 +283,7 @@ ENTRY(early_idt_handler_array)
> UNWIND_HINT_IRET_REGS offset=8
> .endif
> pushq $i # 72(%rsp) Vector number
> - jmp early_idt_handler_common
> + jmp .Learly_idt_handler_common
> UNWIND_HINT_IRET_REGS
> i = i + 1
> .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
> @@ -291,7 +291,7 @@ ENTRY(early_idt_handler_array)
> UNWIND_HINT_IRET_REGS offset=16
> END(early_idt_handler_array)
>
> -SYM_CODE_START_LOCAL(early_idt_handler_common)
> +SYM_CODE_START_LOCAL(.Learly_idt_handler_common)
> /*
> * The stack is the hardware frame, an error code or zero, and the
> * vector number.
> @@ -333,7 +333,7 @@ SYM_CODE_START_LOCAL(early_idt_handler_common)
> 20:
> decl early_recursion_flag(%rip)
> jmp restore_regs_and_return_to_kernel
> -SYM_CODE_END(early_idt_handler_common)
> +SYM_CODE_END(.Learly_idt_handler_common)

...

> All except this one can be local labels and be removed from vmlinux'
> symtable:
>
> $ readelf -a vmlinux | grep -E "(bad_(gs|(get|put)_user)|bogus_64_magic|early_idt_handler_common|verify_cpu)"
> 45: ffffffff810000e0 241 FUNC LOCAL DEFAULT 1 verify_cpu
> $

Thanks for all the review hints.

Let's start with this one: do you really want me to get rid of (local)
symbols like this? It would make backtraces completely misleading as the
unwinder would put a name of the previous function (or some garbage,
depending on unwinder) into the backtrace...

thanks,
--
js
suse labs

\
 
 \ /
  Last update: 2019-08-28 13:49    [W:0.075 / U:1.536 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site