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| author | Vineet Gupta | 2014-11-13 11:17:46 +0100 |
|---|---|---|
| committer | Vineet Gupta | 2014-12-12 11:32:46 +0100 |
| commit | 88ec11b0f82b517b4f1c13f57096db5c8872fccb (patch) | |
| tree | f119899229726c594668a6ac4c50df6a79cbcaca /arch/arc/include/asm/irqflags.h | |
| parent | ARC: R-M-W assist locks only needed for !LLSC (diff) | |
| download | kernel-qcow2-linux-88ec11b0f82b517b4f1c13f57096db5c8872fccb.tar.gz kernel-qcow2-linux-88ec11b0f82b517b4f1c13f57096db5c8872fccb.tar.xz kernel-qcow2-linux-88ec11b0f82b517b4f1c13f57096db5c8872fccb.zip | |
ARC: document memory clobber in irq control macros
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include/asm/irqflags.h')
| -rw-r--r-- | arch/arc/include/asm/irqflags.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arc/include/asm/irqflags.h b/arch/arc/include/asm/irqflags.h index 742816f1b210..27ecc6975a58 100644 --- a/arch/arc/include/asm/irqflags.h +++ b/arch/arc/include/asm/irqflags.h @@ -41,6 +41,15 @@ /****************************************************************** * IRQ Control Macros + * + * All of them have "memory" clobber (compiler barrier) which is needed to + * ensure that LD/ST requiring irq safetly (R-M-W when LLSC is not available) + * are redone after IRQs are re-enabled (and gcc doesn't reuse stale register) + * + * Noted at the time of Abilis Timer List corruption + * Orig Bug + Rejected solution : https://lkml.org/lkml/2013/3/29/67 + * Reasoning : https://lkml.org/lkml/2013/4/8/15 + * ******************************************************************/ /* |