4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mark Rutland <[email protected]> From: Will Deacon <[email protected]> commit 669474e772b952b14f4de4845a1558fd4c0414a4 upstream. For CPUs capable of data value prediction, CSDB waits for any outstanding predictions to architecturally resolve before allowing speculative execution to continue. Provide macros to expose it to the arch code. Reviewed-by: Mark Rutland <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Catalin Marinas <[email protected]> Signed-off-by: Mark Rutland <[email protected] [v4.9 backport] Tested-by: Greg Hackmann <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm64/include/asm/assembler.h | 7 +++++++ arch/arm64/include/asm/barrier.h | 2 ++ 2 files changed, 9 insertions(+) --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -87,6 +87,13 @@ .endm /* + * Value prediction barrier + */ + .macro csdb + hint #20 + .endm + +/* * NOP sequence */ .macro nops, num --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -31,6 +31,8 @@ #define dmb(opt) asm volatile("dmb " #opt : : : "memory") #define dsb(opt) asm volatile("dsb " #opt : : : "memory") +#define csdb() asm volatile("hint #20" : : : "memory") + #define mb() dsb(sy) #define rmb() dsb(ld) #define wmb() dsb(st)
