Messages in this thread Patch in this message | | | Date | Wed, 29 Apr 2020 00:33:27 +0200 | From | Peter Zijlstra <> | Subject | Re: Remaining randconfig objtool warnings, linux-next-20200428 |
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On Tue, Apr 28, 2020 at 05:03:53PM -0500, Josh Poimboeuf wrote: > On Tue, Apr 28, 2020 at 11:55:54PM +0200, Peter Zijlstra wrote:
> > binutils.git/gas/configure/tc-i386.c:i386_generate_nops > > > > When there's too many NOPs (as here) it generates a JMP across the NOPS. > > It makes some sort of sense, at some point executing NOPs is going to be > > more expensive than a branch.. But shees.. > > Urgh. Even if I tell it specifically to pad with NOPs, it still does > this "trick". I have no idea how to deal with this in objtool.
This is horrible... but it _might_ just work.
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 0e9504fabe52..545f50f5de56 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -599,7 +599,18 @@ SYM_CODE_END(common_spurious) _ASM_NOKPROBE(common_spurious) /* common_interrupt is a hotpath. Align it */ +SYM_FUNC_START_LOCAL_NOALIGN(__ignore_me) .p2align CONFIG_X86_L1_CACHE_SHIFT +SYM_FUNC_END(__ignore_me) + +.pushsection .discard.func_stack_frame_non_standard + .align 8 + .type __func_stack_frame_non_standard___ignore_me, @object + .size __func_stack_frame_non_standard___ignore_me, 8 +__func_stack_frame_non_standard___ignore_me: + .quad __ignore_me +.popsection + SYM_CODE_START_LOCAL(common_interrupt) addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */ call interrupt_entry
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