在 2023/10/29 上午5:35, Richard Henderson 写道:
On 10/9/23 20:37, Song Gao wrote:
Signed-off-by: Song Gao <gaos...@loongson.cn>
---
linux-user/loongarch64/signal.c | 107 ++++++++++++++++++++++++++------
1 file changed, 87 insertions(+), 20 deletions(-)
diff --git a/linux-user/loongarch64/signal.c
b/linux-user/loongarch64/signal.c
index 277e9f5757..4b09e50a5f 100644
--- a/linux-user/loongarch64/signal.c
+++ b/linux-user/loongarch64/signal.c
@@ -33,6 +33,14 @@ struct target_fpu_context {
uint32_t fcsr;
} QEMU_ALIGNED(FPU_CTX_ALIGN);
+#define LSX_CTX_MAGIC 0x53580001
+#define LSX_CTX_ALIGN 16
+struct target_lsx_context {
+ uint64_t regs[2 * 32];
+ uint64_t fcc;
+ uint32_t fcsr;
+} QEMU_ALIGNED(LSX_CTX_ALIGN);
It probably doesn't matter here because fo the alignment, but all
types within target structures should be using abi_{ullong,uint} etc.
Ok,
@@ -99,8 +109,15 @@ static abi_ptr setup_extcontext(struct
extctx_layout *extctx, abi_ptr sp)
/* For qemu, there is no lazy fp context switch, so fp always
present. */
extctx->flags = SC_USED_FP;
- sp = extframe_alloc(extctx, &extctx->fpu,
+
+ if (env->extctx_flags & EXTCTX_FLAGS_LSX) {
+ sp = extframe_alloc(extctx, &extctx->lsx,
+ sizeof(struct target_lsx_context),
LSX_CTX_ALIGN, sp);
+
+ } else if (env->extctx_flags & EXTCTX_FLAGS_FPU) {
+ sp = extframe_alloc(extctx, &extctx->fpu,
sizeof(struct target_fpu_context),
FPU_CTX_ALIGN, sp);
+ }
I think this is overly complicated. (1) The fpu is always present,
and (2) you don't need a special flag on env, you can check the same
CSR bits as for system mode.
I think extctx_flags is incorrectly named, fp_alive_flags or
vec_alive_flags would be more appropriate.
The flags function like the kernel's 'thread_lsx_context_live',
'thread_lasx_context_live' functions, checking if the LSX/LASX
instructions are used.
If we don't use the LSX/LASX instructions, we don't need to use
lsx_context/lasx_context even though the LSX/LASX enable bit is set.
and EXTCTX_FLAGS_FPU is not required.
Thanks.
Song Gao
I'll note that while this layout matches the kernel, it is an
unfortunate set of data structures. Any program has to look for all
of {FPU,LSX,LASX}_CTX_MAGIC in order to find the basic fp registers.
r~
