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x86/boot: Avoid using Intel mnemonics in AT&T syntax asm

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With 'GNU assembler (GNU Binutils for Debian) 2.39.90.20221231' the
build now reports:

  arch/x86/realmode/rm/../../boot/bioscall.S: Assembler messages:
  arch/x86/realmode/rm/../../boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/realmode/rm/../../boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

  arch/x86/boot/bioscall.S: Assembler messages:
  arch/x86/boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

Which is due to:

  PR gas/29525

  Note that with the dropped CMPSD and MOVSD Intel Syntax string insn
  templates taking operands, mixed IsString/non-IsString template groups
  (with memory operands) cannot occur anymore. With that
  maybe_adjust_templates() becomes unnecessary (and is hence being
  removed).

More details: https://sourceware.org/bugzilla/show_bug.cgi?id=29525

Borislav Petkov further explains:

  " the particular problem here is is that the 'd' suffix is
    "conflicting" in the sense that you can have SSE mnemonics like movsD %xmm...
    and the same thing also for string ops (which is the case here) so apparently
    the agreement in binutils land is to use the always accepted suffixes 'l' or 'q'
    and phase out 'd' slowly... "

Fixes: 7a734e7dd9 ("x86, setup: "glove box" BIOS calls -- infrastructure")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/Y71I3Ex2pvIxMpsP@hirez.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra 2023-01-10 12:15:40 +01:00 committed by Ingo Molnar
parent b7bfaa761d
commit 7c6dd961d0
1 changed files with 2 additions and 2 deletions
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4
arch/x86/boot/bioscall.S
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@ -32,7 +32,7 @@ intcall:
movw %dx, %si
movw %sp, %di
movw $11, %cx
rep; movsd
rep; movsl
/* Pop full state from the stack */
popal
@ -67,7 +67,7 @@ intcall:
jz 4f
movw %sp, %si
movw $11, %cx
rep; movsd
rep; movsl
4: addw $44, %sp
/* Restore state and return */