[PATCH 1/2] arm64: reduce el2_setup branching
Mark Rutland
mark.rutland at arm.com
Wed Feb 15 06:54:16 PST 2017
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.
Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Marc Zyngier <marc.zyngier at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
---
arch/arm64/kernel/head.S | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 4fb6ccd..2c37334 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -534,13 +534,8 @@ ENTRY(kimage_vaddr)
ENTRY(el2_setup)
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
@@ -548,7 +543,11 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
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,
--
1.9.1
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