Messages in this thread | | | Subject | Re: [PATCH 04/24] x86/entry: Expose the address of .Lgs_change to traps.c | From | Lai Jiangshan <> | Date | Thu, 2 Sep 2021 17:20:26 +0800 |
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On 2021/9/2 17:14, Peter Zijlstra wrote: > On Wed, Sep 01, 2021 at 01:50:05AM +0800, Lai Jiangshan wrote: > >> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S >> index e38a4cf795d9..9164e85b36b8 100644 >> --- a/arch/x86/entry/entry_64.S >> +++ b/arch/x86/entry/entry_64.S >> @@ -729,6 +729,7 @@ _ASM_NOKPROBE(common_interrupt_return) >> SYM_FUNC_START(asm_load_gs_index) >> FRAME_BEGIN >> swapgs >> +SYM_INNER_LABEL(asm_load_gs_index_gs_change, SYM_L_GLOBAL) >> .Lgs_change: > > After all the patches, there's only a single .Lgs_change reference left. > Can't we convert the _ASM_EXTABLE() entry to use the new label and > totally remove it?
The label .Lgs_change is still needed in ASM code for extable.
I tried the way as you suggested, and the result is:
warning: objtool: __ex_table+0x0: don't know how to handle non-section reloc symbol asm_load_gs_index_gs_change
But never mind, I have already converted load_gs_index into C code. I will send it later.
> >> movl %edi, %gs >> 2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE >> @@ -1011,7 +1012,7 @@ SYM_CODE_START_LOCAL(error_entry) >> movl %ecx, %eax /* zero extend */ >> cmpq %rax, RIP+8(%rsp) >> je .Lbstep_iret >> - cmpq $.Lgs_change, RIP+8(%rsp) >> + cmpq $asm_load_gs_index_gs_change, RIP+8(%rsp) >> jne .Lerror_entry_done_lfence
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