On Sun, Jul 12, 2020 at 10:54:29PM -0400, Arvind Sankar wrote:
> On Sun, Jul 12, 2020 at 06:24:22PM -0700, Jian Cai wrote:
> > Clang's integrated assembler does not allow symbols with non-absolute
> > values to be reassigned. This patch allows the affected code to be
> > compatible with IAS.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1043
> > Reported-by: Nick Desaulniers <ndesaulni...@google.com>
> > Reported-by: Sedat Dilek <sedat.di...@gmail.com>
> > Suggested-by: Nick Desaulniers <ndesaulni...@google.com>
> > Tested-by: Sedat Dilek <sedat.di...@gmail.com>
> > Signed-off-by: Jian Cai <caij2...@gmail.com>
> > ---
> > arch/x86/include/asm/idtentry.h | 22 ++++++++++------------
> > 1 file changed, 10 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/idtentry.h
> > b/arch/x86/include/asm/idtentry.h
> > index f3d70830bf2a..77beed2cd6d9 100644
> > --- a/arch/x86/include/asm/idtentry.h
> > +++ b/arch/x86/include/asm/idtentry.h
> > @@ -468,34 +468,32 @@ __visible noinstr void func(struct pt_regs *regs,
> > \
> > */
> > .align 8
> > SYM_CODE_START(irq_entries_start)
> > - vector=FIRST_EXTERNAL_VECTOR
> > - pos = .
> > + i = 1
> > + pos1 = .
> > .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
> > UNWIND_HINT_IRET_REGS
> > - .byte 0x6a, vector
> > + .byte 0x6a, FIRST_EXTERNAL_VECTOR + i - 1
> > jmp asm_common_interrupt
> > nop
> > /* Ensure that the above is 8 bytes max */
> > - . = pos + 8
> > - pos=pos+8
> > - vector=vector+1
> > + . = pos1 + 8 * i
> > + i = i + 1
> > .endr
> > SYM_CODE_END(irq_entries_start)
>
> I think it would be a little cleaner to initialize i to 0, and drop pos.
> i.e. couldn't we do
> i = 0
> ...
> .byte 0x6a, FIRST_EXTERNAL_VECTOR + i
> ...
> i = i + 1
> . = irq_entries_start + 8 * i
>
Or maybe just:
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index eeac6dc2adaa..c774039d130b 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,15 +469,14 @@ __visible noinstr void func(struct pt_regs *regs,
\
.align 8
SYM_CODE_START(irq_entries_start)
vector=FIRST_EXTERNAL_VECTOR
- pos = .
.rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
+ 0:
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
jmp asm_common_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
+ . = 0b + 8
vector=vector+1
.endr
SYM_CODE_END(irq_entries_start)
@@ -486,15 +485,14 @@ SYM_CODE_END(irq_entries_start)
.align 8
SYM_CODE_START(spurious_entries_start)
vector=FIRST_SYSTEM_VECTOR
- pos = .
.rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
+ 0:
UNWIND_HINT_IRET_REGS
.byte 0x6a, vector
jmp asm_spurious_interrupt
nop
/* Ensure that the above is 8 bytes max */
- . = pos + 8
- pos=pos+8
+ . = 0b + 8
vector=vector+1
.endr
SYM_CODE_END(spurious_entries_start)
