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Subject[RFC PATCH v4 35/37] arm64: entry: Annotate code switching to tasks
Date
From: Julien Thierry <jthierry@redhat.com>

Add UNWIND_HINT_REGS in kernel_entry after saving pt_regs.

Whether returning to userland or creating a new task, sp is
pointing to a pt_regs frame.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
arch/arm64/kernel/entry.S | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index eeb576ec97ba..c7ab5143949f 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -220,6 +220,7 @@ alternative_cb_end
stp x24, x25, [sp, #16 * 12]
stp x26, x27, [sp, #16 * 13]
stp x28, x29, [sp, #16 * 14]
+ UNWIND_HINT_REGS

.if \el == 0
clear_gp_regs
@@ -602,6 +603,7 @@ SYM_CODE_START_LOCAL(ret_to_kernel)
SYM_CODE_END(ret_to_kernel)

SYM_CODE_START_LOCAL(ret_to_user)
+ UNWIND_HINT_REGS
ldr x19, [tsk, #TSK_TI_FLAGS] // re-check for single-step
enable_step_tsk x19, x2
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
@@ -874,6 +876,7 @@ NOKPROBE(cpu_switch_to)
* This is how we return from a fork.
*/
SYM_CODE_START(ret_from_fork)
+ UNWIND_HINT_REGS
bl schedule_tail
cbz x19, 1f // not a kernel thread
mov x0, x20
--
2.17.1
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