Messages in this thread Patch in this message | | | From | Matthias Kaehlcke <> | Subject | [PATCH] x86/mm/kaslr: Add operand size suffix to 'mul' instruction | Date | Wed, 26 Apr 2017 12:01:12 -0700 |
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In difference to gas clang doesn't seem to infer the size from the operands. Adding the suffix fixes the following error when building with clang:
CC arch/x86/lib/kaslr.o /tmp/kaslr-dfe1ad.s: Assembler messages: /tmp/kaslr-dfe1ad.s:182: Error: no instruction mnemonic suffix given and no register operands; can't size instruction
Signed-off-by: Matthias Kaehlcke <mka@chromium.org> --- arch/x86/lib/kaslr.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c index 121f59c6ee54..947d4aa92ff7 100644 --- a/arch/x86/lib/kaslr.c +++ b/arch/x86/lib/kaslr.c @@ -79,7 +79,11 @@ unsigned long kaslr_get_random_long(const char *purpose) } /* Circular multiply for better bit diffusion */ - asm("mul %3" +#ifdef CONFIG_X86_64 + asm("mulq %3" +#else + asm("mull %3" +#endif : "=a" (random), "=d" (raw) : "a" (random), "rm" (mix_const)); random += raw; -- 2.13.0.rc0.306.g87b477812d-goog
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