arm64: reduce el2_setup branching

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>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 4fb6ccd886d11ef219efe411b1f712e31167d943..2c3733408c0d3c33aeea59beea862c816b98193f 100644 (file)
--- 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,