In handle_syscall, it is unnecessary to call SAVE_STATIC for all syscalls,
only clone and clone3 need to do this operation, so it is better to check
the syscall number before call SAVE_STATIC.
With this patch, it can reduce many store instructions.
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/loongarch/kernel/entry.S | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index d5b3dbc..a0f7fcc 100644
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -14,6 +14,7 @@
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/thread_info.h>
+#include <asm/unistd.h>
.text
.cfi_sections .debug_frame
@@ -56,8 +57,17 @@ SYM_FUNC_START(handle_syscall)
cfi_st u0, PT_R21
cfi_st fp, PT_R22
+ /* Syscall number held in a7, only clone and clone3 need to call SAVE_STATIC. */
+ li.w t3, __NR_clone
+ beq a7, t3, 1f
+ li.w t3, __NR_clone3
+ beq a7, t3, 1f
+ b 2f
+
+1:
SAVE_STATIC
+2:
move u0, t0
li.d tp, ~_THREAD_MASK
and tp, tp, sp
--
2.1.0