diff options
| author | Matthias Kaehlcke <mka@chromium.org> | 2017-05-05 09:50:49 -0700 |
|---|---|---|
| committer | Greg Hackmann <ghackmann@google.com> | 2017-10-09 14:00:13 -0700 |
| commit | cafc5bc76374ba807d570055be4e217572d33a49 (patch) | |
| tree | 17551573635533d60ede5c59f33442e5b4a15a91 | |
| parent | 2a3a3862527dbdba157c5973cbd231a20b20d253 (diff) | |
BACKPORT: x86/mm/kaslr: Use the _ASM_MUL macro for multiplication to work around Clang incompatibility
The constraint "rm" allows the compiler to put mix_const into memory.
When the input operand is a memory location then MUL needs an operand
size suffix, since Clang can't infer the multiplication width from the
operand.
Add and use the _ASM_MUL macro which determines the operand size and
resolves to the NUL 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
Upstream commit: 121843eb02a6
Change-Id: I53f51839705dabeb6c950d1def3a45881294129c
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Davidson <md@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170501224741.133938-1-mka@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
| -rw-r--r-- | arch/x86/boot/compressed/aslr.c | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/asm.h | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c index 6a9b96b4624d..4a5fbd2da658 100644 --- a/arch/x86/boot/compressed/aslr.c +++ b/arch/x86/boot/compressed/aslr.c @@ -94,7 +94,7 @@ static unsigned long get_random_long(void) } /* Circular multiply for better bit diffusion */ - asm("mul %3" + asm(_ASM_MUL "%3" : "=a" (random), "=d" (raw) : "a" (random), "rm" (mix_const)); random += raw; diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 189679aba703..1f16ec50abeb 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) |