On 6/12/24 13:41, Max Filippov wrote:
On Thu, Dec 5, 2024 at 3:24 PM Philippe Mathieu-Daudé <phi...@linaro.org> wrote:In preparation of heterogeneous emulation where cores with different endianness can run concurrently, we need to remove the tswap() calls -- which use a fixed per-binary endianness. Get the endianness of the CPU accessed using the libisa xtensa_isa_is_big_endian() call and replace the tswap() calls by bswap() ones when necessary. Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org> --- target/xtensa/xtensa-semi.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/target/xtensa/xtensa-semi.c b/target/xtensa/xtensa-semi.c index fa21b7e11fc..21d23e39de5 100644 --- a/target/xtensa/xtensa-semi.c +++ b/target/xtensa/xtensa-semi.c @@ -328,10 +328,17 @@ void HELPER(simcall)(CPUXtensaState *env) struct timeval tv = {0}; if (target_tv) { + bool cpu_big_endian = xtensa_isa_is_big_endian(env->config->isa); + bool swap_needed = HOST_BIG_ENDIAN != cpu_big_endian; + cpu_memory_rw_debug(cs, target_tv, (uint8_t *)target_tvv, sizeof(target_tvv), 0); - tv.tv_sec = (int32_t)tswap32(target_tvv[0]); - tv.tv_usec = (int32_t)tswap32(target_tvv[1]); + if (swap_needed) { + bswap32s(&target_tvv[0]); + bswap32s(&target_tvv[1]); + } + tv.tv_sec = (int32_t)target_tvv[0]; + tv.tv_usec = (int32_t)target_tvv[1];This conversion looks a bit heavy. Maybe it would be better to give tswap*() an additional env argument and give the target a way to deal with it?
Yeah, something like that. TBH I'm not really happy with these changes, and am having hard time figuring out a simple and meaningful API.
} if (fd < 3 && sim_console) { if ((fd == 1 || fd == 2) && rq == SELECT_ONE_WRITE) { @@ -381,6 +388,8 @@ void HELPER(simcall)(CPUXtensaState *env) int argc = semihosting_get_argc(); int str_offset = (argc + 1) * sizeof(uint32_t); int i; + bool cpu_big_endian = xtensa_isa_is_big_endian(env->config->isa); + bool swap_needed = HOST_BIG_ENDIAN != cpu_big_endian; uint32_t argptr; for (i = 0; i < argc; ++i) { @@ -388,6 +397,9 @@ void HELPER(simcall)(CPUXtensaState *env) int str_size = strlen(str) + 1; argptr = tswap32(regs[3] + str_offset);The tswap() is still here.
Oops!
+ if (swap_needed) { + bswap32s(&argptr); + } cpu_memory_rw_debug(cs, regs[3] + i * sizeof(uint32_t),
