From 6d3ef04893bdea3e7aa08be3cce5141902836a31 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 15 Dec 2020 11:47:59 -0600 Subject: tcg: Use memset for large vector byte replication In f47db80cc07, we handled odd-sized tail clearing for the case of hosts that have vector operations, but did not handle the case of hosts that do not have vector ops. This was ok until e2e7168a214b, which changed the encoding of simd_desc such that the odd sizes are impossible. Add memset as a tcg helper, and use that for all out-of-line byte stores to vectors. This includes, but is not limited to, the tail clearing operation in question. Cc: qemu-stable@nongnu.org Buglink: https://bugs.launchpad.net/bugs/1907817 Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- accel/tcg/tcg-runtime.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'accel') diff --git a/accel/tcg/tcg-runtime.h b/accel/tcg/tcg-runtime.h index 4eda24e63a..2e36d6eb0c 100644 --- a/accel/tcg/tcg-runtime.h +++ b/accel/tcg/tcg-runtime.h @@ -28,6 +28,17 @@ DEF_HELPER_FLAGS_1(lookup_tb_ptr, TCG_CALL_NO_WG_SE, ptr, env) DEF_HELPER_FLAGS_1(exit_atomic, TCG_CALL_NO_WG, noreturn, env) +#ifndef IN_HELPER_PROTO +/* + * Pass calls to memset directly to libc, without a thunk in qemu. + * Do not re-declare memset, especially since we fudge the type here; + * we assume sizeof(void *) == sizeof(size_t), which is true for + * all supported hosts. + */ +#define helper_memset memset +DEF_HELPER_FLAGS_3(memset, TCG_CALL_NO_RWG, ptr, ptr, int, ptr) +#endif /* IN_HELPER_PROTO */ + #ifdef CONFIG_SOFTMMU DEF_HELPER_FLAGS_5(atomic_cmpxchgb, TCG_CALL_NO_WG, -- cgit v1.2.3-55-g7522