From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
will@kernel.org, james.morse@arm.com
Cc: mark.rutland@arm.com, keescook@chromium.org, maz@kernel.org,
broonie@kernel.org, labbott@redhat.com, robin.murphy@arm.com,
julien.thierry.kdev@gmail.com, alex.popov@linux.com
Subject: [PATCH 17/17] arm64: entry: cleanup sp_el0 manipulation
Date: Wed, 8 Jan 2020 18:56:34 +0000 [thread overview]
Message-ID: <20200108185634.1163-18-mark.rutland@arm.com> (raw)
In-Reply-To: <20200108185634.1163-1-mark.rutland@arm.com>
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 --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
--
2.11.0
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prev parent reply other threads:[~2020-01-08 19:01 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 18:56 [PATCH 00/17] arm64: entry deasmification and cleanup Mark Rutland
2020-01-08 18:56 ` [PATCH 01/17] arm64: entry: mark all entry code as notrace Mark Rutland
2020-01-09 5:21 ` Anshuman Khandual
2020-01-13 15:44 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 02/17] arm64: entry: cleanup el0 svc handler naming Mark Rutland
2020-01-09 5:33 ` Anshuman Khandual
2020-01-08 18:56 ` [PATCH 03/17] arm64: entry: move arm64_preempt_schedule_irq to entry-common.c Mark Rutland
2020-01-09 5:36 ` Anshuman Khandual
2020-01-08 18:56 ` [PATCH 04/17] arm64: entry: move preempt logic to C Mark Rutland
2020-01-09 6:43 ` Anshuman Khandual
2020-01-09 12:22 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 05/17] arm64: entry: add a call_on_stack helper Mark Rutland
2020-01-09 8:00 ` Anshuman Khandual
2020-01-14 18:24 ` Mark Rutland
2020-01-09 14:30 ` Laura Abbott
2020-01-09 14:46 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 06/17] arm64: entry: convert irq entry to C Mark Rutland
2020-01-08 18:56 ` [PATCH 07/17] arm64: entry: convert error " Mark Rutland
2020-01-09 9:12 ` Anshuman Khandual
2020-01-09 12:49 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 08/17] arm64: entry: Split el0_sync_compat from el0_sync Mark Rutland
2020-01-09 9:50 ` Anshuman Khandual
2020-01-08 18:56 ` [PATCH 09/17] arm64: entry: organise handler stubs consistently Mark Rutland
2020-01-09 10:01 ` Anshuman Khandual
2020-01-08 18:56 ` [PATCH 10/17] arm64: entry: consolidate EL1 return paths Mark Rutland
2020-01-10 3:39 ` Anshuman Khandual
2020-01-10 16:02 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 11/17] stackleak: allow C to call stackleak_erase() Mark Rutland
2020-01-10 3:45 ` Anshuman Khandual
2020-01-10 16:07 ` Mark Rutland
2020-01-27 23:00 ` Kees Cook
2020-01-08 18:56 ` [PATCH 12/17] arm64: debug-monitors: refactor MDSCR manipulation Mark Rutland
2020-01-10 4:35 ` Anshuman Khandual
2020-01-10 16:09 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 13/17] arm64: entry: move common el0 entry/return work to C Mark Rutland
2020-01-09 15:19 ` Mark Rutland
2020-01-08 18:56 ` [PATCH 14/17] arm64: entry: move NO_SYSCALL setup " Mark Rutland
2020-01-10 5:37 ` Anshuman Khandual
2020-01-08 18:56 ` [PATCH 15/17] arm64: entry: move ARM64_ERRATUM_845719 workaround " Mark Rutland
2020-01-08 18:56 ` [PATCH 16/17] arm64: entry: move ARM64_ERRATUM_1418040 " Mark Rutland
2020-01-08 18:56 ` Mark Rutland [this message]
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