Re: [lkp-robot] [x86/asm] f5caf621ee: PANIC:double_fault

[Josh Poimboeuf]

On Thu, Sep 28, 2017 at 11:44:22AM -0500, Josh Poimboeuf wrote:
> Agreed, changing it to "unsigned long" and "rsp" will probably fix it.
> 
> I had made it "unsigned int" because of a clang issue with "unsigned
> long":
> 
>     CC      arch/x86/entry/vdso/vdso32/vclock_gettime.o
>   In file included from arch/x86/entry/vdso/vdso32/vclock_gettime.c:32:
>   In file included from arch/x86/entry/vdso/vdso32/../vclock_gettime.c:15:
>   In file included from ./arch/x86/include/asm/vgtod.h:5:
>   In file included from ./include/linux/clocksource.h:12:
>   In file included from ./include/linux/timex.h:56:
>   In file included from ./include/uapi/linux/timex.h:56:
>   In file included from ./include/linux/time.h:5:
>   In file included from ./include/linux/seqlock.h:35:
>   In file included from ./include/linux/spinlock.h:50:
>   In file included from ./include/linux/preempt.h:10:
>   In file included from ./include/linux/list.h:8:
>   In file included from ./include/linux/kernel.h:10:
>   In file included from ./include/linux/bitops.h:37:
>   In file included from ./arch/x86/include/asm/bitops.h:16:
>   In file included from ./arch/x86/include/asm/alternative.h:9:
>   ./arch/x86/include/asm/asm.h:142:42: error: register 'rsp' unsuitable for global register variables on this target
>   register unsigned long __asm_call_sp asm("rsp");
> 
> And I think we saw the same error in the realmode code.
> 
> So we may need to tweak the macro a bit.

Going to try the following patch.

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index c1eadbaf1115..30c3c9ac784a 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -11,10 +11,12 @@
 # define __ASM_FORM_COMMA(x) " " #x ","
 #endif
 
-#ifdef CONFIG_X86_32
+#ifndef __x86_64__
+/* 32 bit */
 # define __ASM_SEL(a,b) __ASM_FORM(a)
 # define __ASM_SEL_RAW(a,b) __ASM_FORM_RAW(a)
 #else
+/* 64 bit */
 # define __ASM_SEL(a,b) __ASM_FORM(b)
 # define __ASM_SEL_RAW(a,b) __ASM_FORM_RAW(b)
 #endif
@@ -139,7 +141,7 @@
  * gets set up by the containing function.  If you forget to do this, objtool
  * may print a "call without frame pointer save/setup" warning.
  */
-register unsigned int __asm_call_sp asm("esp");
+register unsigned long __asm_call_sp asm(_ASM_SP);
 #define ASM_CALL_CONSTRAINT "+r" (__asm_call_sp)
 #endif