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Subject[PATCHv5 11/21] arm64: don't restore GPRs when context tracking
Date
Now that syscalls are invoked with pt_regs, we no longer need to ensure
that the argument regsiters are live in the entry assembly, and it's
fine to not restore them after context_tracking_user_exit() has
corrupted them.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/kernel/entry.S | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 156c4e3fd1a4..c41b84d06644 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -41,19 +41,9 @@
* Context tracking subsystem. Used to instrument transitions
* between user and kernel mode.
*/
- .macro ct_user_exit, syscall = 0
+ .macro ct_user_exit
#ifdef CONFIG_CONTEXT_TRACKING
bl context_tracking_user_exit
- .if \syscall == 1
- /*
- * Save/restore needed during syscalls. Restore syscall arguments from
- * the values already saved on stack during kernel_entry.
- */
- ldp x0, x1, [sp]
- ldp x2, x3, [sp, #S_X2]
- ldp x4, x5, [sp, #S_X4]
- ldp x6, x7, [sp, #S_X6]
- .endif
#endif
.endm

--
2.11.0
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