arm64: Rename the VHE switch to "finalise_el2"

as we are about to perform a lot more in 'mutate_to_vhe' than
we currently do, this function really becomes the point where
we finalise the basic EL2 configuration.

Reflect this into the code by renaming a bunch of things:
- HVC_VHE_RESTART -> HVC_FINALISE_EL2
- switch_to_vhe --> finalise_el2
- mutate_to_vhe -> __finalise_el2

No functional changes.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220630160500.1536744-2-maz@kernel.orgSigned-off-by: Will Deacon <will@kernel.org>

Documentation/virt/kvm/arm/hyp-abi.rst

@@ -60,12 +60,13 @@ these functions (see arch/arm{,64}/include/asm/virt.h):
 
 * ::
 
-    x0 = HVC_VHE_RESTART (arm64 only)
+    x0 = HVC_FINALISE_EL2 (arm64 only)
 
-  Attempt to upgrade the kernel's exception level from EL1 to EL2 by enabling
-  the VHE mode. This is conditioned by the CPU supporting VHE, the EL2 MMU
-  being off, and VHE not being disabled by any other means (command line
-  option, for example).
+  Finish configuring EL2 depending on the command-line options,
+  including an attempt to upgrade the kernel's exception level from
+  EL1 to EL2 by enabling the VHE mode. This is conditioned by the CPU
+  supporting VHE, the EL2 MMU being off, and VHE not being disabled by
+  any other means (command line option, for example).
 
 Any other value of r0/x0 triggers a hypervisor-specific handling,
 which is not documented here.

arch/arm64/include/asm/virt.h

@@ -36,9 +36,9 @@
 #define HVC_RESET_VECTORS 2
 
 /*
- * HVC_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible
+ * HVC_FINALISE_EL2 - Upgrade the CPU from EL1 to EL2, if possible
  */
-#define HVC_VHE_RESTART	3
+#define HVC_FINALISE_EL2	3
 
 /* Max number of HYP stub hypercalls */
 #define HVC_STUB_HCALL_NR 4

arch/arm64/kernel/head.S

@@ -459,7 +459,7 @@ SYM_FUNC_START_LOCAL(__primary_switched)
 	mov	x0, x22				// pass FDT address in x0
 	bl	init_feature_override		// Parse cpu feature overrides
 	mov	x0, x20
-	bl	switch_to_vhe			// Prefer VHE if possible
+	bl	finalise_el2			// Prefer VHE if possible
 	ldp	x29, x30, [sp], #16
 	bl	start_kernel
 	ASM_BUG()
@@ -542,7 +542,7 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
 	eret
 
 __cpu_stick_to_vhe:
-	mov	x0, #HVC_VHE_RESTART
+	mov	x0, #HVC_FINALISE_EL2
 	hvc	#0
 	mov	x0, #BOOT_CPU_MODE_EL2
 	ret
@@ -592,7 +592,7 @@ SYM_FUNC_START_LOCAL(secondary_startup)
 	 * Common entry point for secondary CPUs.
 	 */
 	mov	x20, x0				// preserve boot mode
-	bl	switch_to_vhe
+	bl	finalise_el2
 	bl	__cpu_secondary_check52bitva
 #if VA_BITS > 48
 	ldr_l	x0, vabits_actual

arch/arm64/kernel/hyp-stub.S

@@ -51,8 +51,8 @@ SYM_CODE_START_LOCAL(elx_sync)
 	msr	vbar_el2, x1
 	b	9f
 
-1:	cmp	x0, #HVC_VHE_RESTART
-	b.eq	mutate_to_vhe
+1:	cmp	x0, #HVC_FINALISE_EL2
+	b.eq	__finalise_el2
 
 2:	cmp	x0, #HVC_SOFT_RESTART
 	b.ne	3f
@@ -73,8 +73,8 @@ SYM_CODE_START_LOCAL(elx_sync)
 	eret
 SYM_CODE_END(elx_sync)
 
-// nVHE? No way! Give me the real thing!
-SYM_CODE_START_LOCAL(mutate_to_vhe)
+SYM_CODE_START_LOCAL(__finalise_el2)
+	// nVHE? No way! Give me the real thing!
 	// Sanity check: MMU *must* be off
 	mrs	x1, sctlr_el2
 	tbnz	x1, #0, 1f
@@ -140,10 +140,10 @@ SYM_CODE_START_LOCAL(mutate_to_vhe)
 	msr	spsr_el1, x0
 
 	b	enter_vhe
-SYM_CODE_END(mutate_to_vhe)
+SYM_CODE_END(__finalise_el2)
 
 	// At the point where we reach enter_vhe(), we run with
-	// the MMU off (which is enforced by mutate_to_vhe()).
+	// the MMU off (which is enforced by __finalise_el2()).
 	// We thus need to be in the idmap, or everything will
 	// explode when enabling the MMU.
 
@@ -222,11 +222,11 @@ SYM_FUNC_START(__hyp_reset_vectors)
 SYM_FUNC_END(__hyp_reset_vectors)
 
 /*
- * Entry point to switch to VHE if deemed capable
+ * Entry point to finalise EL2 and switch to VHE if deemed capable
  *
  * w0: boot mode, as returned by init_kernel_el()
  */
-SYM_FUNC_START(switch_to_vhe)
+SYM_FUNC_START(finalise_el2)
 	// Need to have booted at EL2
 	cmp	w0, #BOOT_CPU_MODE_EL2
 	b.ne	1f
@@ -236,9 +236,8 @@ SYM_FUNC_START(switch_to_vhe)
 	cmp	x0, #CurrentEL_EL1
 	b.ne	1f
 
-	// Turn the world upside down
-	mov	x0, #HVC_VHE_RESTART
+	mov	x0, #HVC_FINALISE_EL2
 	hvc	#0
 1:
 	ret
-SYM_FUNC_END(switch_to_vhe)
+SYM_FUNC_END(finalise_el2)

arch/arm64/kernel/sleep.S

@@ -100,7 +100,7 @@ SYM_FUNC_END(__cpu_suspend_enter)
 	.pushsection ".idmap.text", "awx"
 SYM_CODE_START(cpu_resume)
 	bl	init_kernel_el
-	bl	switch_to_vhe
+	bl	finalise_el2
 	bl	__cpu_setup
 	/* enable the MMU early - so we can access sleep_save_stash by va */
 	adrp	x1, swapper_pg_dir