diff options
| author | Will Deacon <will.deacon@arm.com> | 2016-09-06 16:40:23 +0100 |
|---|---|---|
| committer | Amit Pundir <amit.pundir@linaro.org> | 2017-01-16 15:40:33 +0530 |
| commit | 7129edb752e8a01b3a56858b9153efedda038310 (patch) | |
| tree | 2ad8dc0ece91849280efad759c2fa8543faee174 /arch | |
| parent | 1b1d2ba5e9d46803a2ca503be276f826b2f7f4c3 (diff) | |
BACKPORT: arm64: barriers: introduce nops and __nops macros for NOP sequences
NOP sequences tend to get used for padding out alternative sections
and uarch-specific pipeline flushes in errata workarounds.
This patch adds macros for generating these sequences as both inline
asm blocks, but also as strings suitable for embedding in other asm
blocks directly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Bug: 31432001
Change-Id: I7f82b677a065ede302a763d39ffcc3fef83f8fbe
(cherry picked from commit f99a250cb6a3b301b101b4c0f5fcb80593bba6dc)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 9 | ||||
| -rw-r--r-- | arch/arm64/include/asm/barrier.h | 3 |
2 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index d8732b773bd1..211003d861a1 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -109,6 +109,15 @@ dmb \opt .endm +/* + * NOP sequence + */ + .macro nops, num + .rept \num + nop + .endr + .endm + #define USER(l, x...) \ 9999: x; \ .section __ex_table,"a"; \ diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 2666c9b84ca0..3577413c35f7 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -20,6 +20,9 @@ #ifndef __ASSEMBLY__ +#define __nops(n) ".rept " #n "\nnop\n.endr\n" +#define nops(n) asm volatile(__nops(n)) + #define sev() asm volatile("sev" : : : "memory") #define wfe() asm volatile("wfe" : : : "memory") #define wfi() asm volatile("wfi" : : : "memory") |