lkml.org 
[lkml]   [2016]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5/9] arm64: entry: only restore the syscall registers once
Date
There are two pachs which will restore the syscall registers (x0 - x7)
separately: the hardirq trace code and the context tracking code.

This patch makes the code to restore the syscall registers only once.

Signed-off-by: Huang Shijie <shijie.huang@arm.com>
---
arch/arm64/kernel/entry.S | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 102fd8b..98d8dd1 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -46,12 +46,9 @@
* 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
- restore_syscall_regs
- .endif
#endif
.endm

@@ -729,12 +726,12 @@ el0_svc:
uxtw scno, w26 // syscall number in w8
mov sc_nr, #__NR_syscalls
el0_svc_naked: // compat entry point
-#ifdef CONFIG_TRACE_IRQFLAGS
- restore_syscall_regs
-#endif
stp x19, scno, [sp, #S_ORIG_X0] // save the original x0 and syscall number
enable_dbg_and_irq
- ct_user_exit 1
+ ct_user_exit
+#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING)
+ restore_syscall_regs
+#endif

ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks
tst x16, #_TIF_SYSCALL_WORK
--
2.5.5
\
 
 \ /
  Last update: 2016-05-30 05:21    [W:0.064 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site