[PATCH 4.9 14/21] arm64: move !VHE work to end of el2_setup

From: Greg Kroah-Hartman
Date: Mon Jan 10 2022 - 02:26:37 EST


From: Mark Rutland <mark.rutland@xxxxxxx>

commit d61c97a7773d0848b4bf5c4697855c7ce117362c upstream.

We only need to initialise sctlr_el1 if we're installing an EL2 stub, so
we may as well defer this until we're doing so. Similarly, we can defer
intialising CPTR_EL2 until then, as we do not access any trapped
functionality as part of el2_setup.

This patch modified el2_setup accordingly, allowing us to remove a
branch and simplify the code flow.

Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/head.S | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -553,26 +553,6 @@ set_hcr:
msr vpidr_el2, x0
msr vmpidr_el2, x1

- /*
- * When VHE is not in use, early init of EL2 and EL1 needs to be
- * done here.
- * When VHE _is_ in use, EL1 will not be used in the host and
- * requires no configuration, and all non-hyp-specific EL2 setup
- * will be done via the _EL1 system register aliases in __cpu_setup.
- */
- cbnz x2, 1f
-
- /* sctlr_el1 */
- mov x0, #0x0800 // Set/clear RES{1,0} bits
-CPU_BE( movk x0, #0x33d0, lsl #16 ) // Set EE and E0E on BE systems
-CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
- msr sctlr_el1, x0
-
- /* Coprocessor traps. */
- mov x0, #0x33ff
- msr cptr_el2, x0 // Disable copro. traps to EL2
-1:
-
#ifdef CONFIG_COMPAT
msr hstr_el2, xzr // Disable CP15 traps to EL2
#endif
@@ -598,6 +578,23 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // C
ret

install_el2_stub:
+ /*
+ * When VHE is not in use, early init of EL2 and EL1 needs to be
+ * done here.
+ * When VHE _is_ in use, EL1 will not be used in the host and
+ * requires no configuration, and all non-hyp-specific EL2 setup
+ * will be done via the _EL1 system register aliases in __cpu_setup.
+ */
+ /* sctlr_el1 */
+ mov x0, #0x0800 // Set/clear RES{1,0} bits
+CPU_BE( movk x0, #0x33d0, lsl #16 ) // Set EE and E0E on BE systems
+CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
+ msr sctlr_el1, x0
+
+ /* Coprocessor traps. */
+ mov x0, #0x33ff
+ msr cptr_el2, x0 // Disable copro. traps to EL2
+
/* Hypervisor stub */
adrp x0, __hyp_stub_vectors
add x0, x0, #:lo12:__hyp_stub_vectors