diff mbox series

[17/17] arm64: entry: cleanup sp_el0 manipulation

Message ID 20200108185634.1163-18-mark.rutland@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: entry deasmification and cleanup | expand

Commit Message

Mark Rutland Jan. 8, 2020, 6:56 p.m. UTC 
The kernel stashes the current task struct in sp_el0 so that this can be
acquired consistently/cheaply when required. When we take an exception
from EL0 we have to:

1) stash the original sp_el0 value
2) find the current task
3) update sp_el0 with the current task pointer

Currently steps #1 and #2 occur in one place, and step #3 a while later.
As the value of sp_el0 is immaterial between these points, let's move
them together to make the code clearer and minimize ifdeffery.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/entry.S | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 537b44c413df..40d1cd8fb4c6 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -152,6 +152,7 @@  alternative_cb_end
 	clear_gp_regs
 	mrs	x21, sp_el0
 	ldr_this_cpu	tsk, __entry_task, x20
+	msr	sp_el0, tsk
 
 	apply_ssbd 1, x22, x23
 
@@ -208,13 +209,6 @@  alternative_else_nop_endif
 
 	stp	x22, x23, [sp, #S_PC]
 
-	/*
-	 * Set sp_el0 to current thread_info.
-	 */
-	.if	\el == 0
-	msr	sp_el0, tsk
-	.endif
-
 	/* Save pmr */
 alternative_if ARM64_HAS_IRQ_PRIO_MASKING
 	mrs_s	x20, SYS_ICC_PMR_EL1