Use break as guard instruction for the restartable sequence abort handler. Previously, the chosen signature was simply data, based on the assumption that it could always sit in a literal pool. However, some compilation environments favor disabling literal pool. Therefore, ensure the signature is a valid uncommon trap instruction.
Suggested-by: Paul Burton <[email protected]> Signed-off-by: Mathieu Desnoyers <[email protected]> CC: Paul Burton <[email protected]> CC: James Hogan <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Boqun Feng <[email protected]> Cc: [email protected] Cc: [email protected] --- tools/testing/selftests/rseq/rseq-mips.h | 34 +++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/rseq/rseq-mips.h b/tools/testing/selftests/rseq/rseq-mips.h index fe3eabcdcbe5..e989e7c14b09 100644 --- a/tools/testing/selftests/rseq/rseq-mips.h +++ b/tools/testing/selftests/rseq/rseq-mips.h @@ -7,7 +7,39 @@ * (C) Copyright 2016-2018 - Mathieu Desnoyers <[email protected]> */ -#define RSEQ_SIG 0x53053053 +/* + * RSEQ_SIG uses the break instruction. The instruction pattern is: + * + * On MIPS: + * 0350000d break 0x350 + * + * On nanoMIPS: + * 00100350 break 0x350 + * + * On microMIPS: + * 0000d407 break 0x350 + * + * For nanoMIPS32 and microMIPS, the instruction stream is encoded as 16-bit + * halfwords, so the signature halfwords need to be swapped accordingly for + * little-endian. + */ +#if defined(__nanomips__) +# ifdef __MIPSEL__ +# define RSEQ_SIG 0x03500010 +# else +# define RSEQ_SIG 0x00100350 +# endif +#elif defined(__mips_micromips) +# ifdef __MIPSEL__ +# define RSEQ_SIG 0xd4070000 +# else +# define RSEQ_SIG 0x0000d407 +# endif +#elif defined(__mips__) +# define RSEQ_SIG 0x0350000d +#else +/* Unknown MIPS architecture. */ +#endif #define rseq_smp_mb() __asm__ __volatile__ ("sync" ::: "memory") #define rseq_smp_rmb() rseq_smp_mb() -- 2.11.0
