lkml.org 
[lkml]   [2022]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 13/21] arm64: reduce el2_setup branching
Date
From: Mark Rutland <mark.rutland@arm.com>

commit 3ad47d055aa88d9f4189253f5b5c485f4c4626b2 upstream.

The early el2_setup code is a little convoluted, with two branches where
one would do. This makes the code more painful to read than is
necessary.

We can remove a branch and simplify the logic by moving the early return
in the booted-at-EL1 case earlier in the function. This separates it
from all the setup logic that only makes sense for EL2.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/kernel/head.S | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -489,13 +489,8 @@ ENTRY(el2_setup)
msr SPsel, #1 // We want to use SP_EL{1,2}
mrs x0, CurrentEL
cmp x0, #CurrentEL_EL2
- b.ne 1f
- mrs x0, sctlr_el2
-CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2
-CPU_LE( bic x0, x0, #(1 << 25) ) // Clear the EE bit for EL2
- msr sctlr_el2, x0
- b 2f
-1: mrs x0, sctlr_el1
+ b.eq 1f
+ mrs x0, sctlr_el1
CPU_BE( orr x0, x0, #(3 << 24) ) // Set the EE and E0E bits for EL1
CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
msr sctlr_el1, x0
@@ -503,7 +498,11 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clea
isb
ret

-2:
+1: mrs x0, sctlr_el2
+CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2
+CPU_LE( bic x0, x0, #(1 << 25) ) // Clear the EE bit for EL2
+ msr sctlr_el2, x0
+
#ifdef CONFIG_ARM64_VHE
/*
* Check for VHE being present. For the rest of the EL2 setup,

\
 
 \ /
  Last update: 2022-01-10 08:27    [W:0.139 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site