On April 26, 2017 1:55:04 PM PDT, Matthias Kaehlcke <[email protected]> wrote: >In difference to gas clang doesn't seem to infer the size from the >operands. Add and use the _ASM_MUL macro which determines the operand >size and resolves to the 'mul' instruction with the corresponding >suffix. > >This 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 <[email protected]> >--- >Changes in v2: >- use _ASM_MUL instead of #ifdef >- updated commit message > > arch/x86/include/asm/asm.h | 1 + > arch/x86/lib/kaslr.c | 3 ++- > 2 files changed, 3 insertions(+), 1 deletion(-) > >diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h >index 7acb51c49fec..7a9df3beb89b 100644 >--- a/arch/x86/include/asm/asm.h >+++ b/arch/x86/include/asm/asm.h >@@ -32,6 +32,7 @@ > #define _ASM_ADD __ASM_SIZE(add) > #define _ASM_SUB __ASM_SIZE(sub) > #define _ASM_XADD __ASM_SIZE(xadd) >+#define _ASM_MUL __ASM_SIZE(mul) > > #define _ASM_AX __ASM_REG(ax) > #define _ASM_BX __ASM_REG(bx) >diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c >index 121f59c6ee54..0c7fe444dcdd 100644 >--- a/arch/x86/lib/kaslr.c >+++ b/arch/x86/lib/kaslr.c >@@ -5,6 +5,7 @@ > * kernel starts. This file is included in the compressed kernel and > * normally linked in the regular. > */ >+#include <asm/asm.h> > #include <asm/kaslr.h> > #include <asm/msr.h> > #include <asm/archrandom.h> >@@ -79,7 +80,7 @@ unsigned long kaslr_get_random_long(const char >*purpose) > } > > /* Circular multiply for better bit diffusion */ >- asm("mul %3" >+ asm(_ASM_MUL "%3" > : "=a" (random), "=d" (raw) > : "a" (random), "rm" (mix_const)); > random += raw;
This really feels like a "fix your compiler" issue. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
