[PATCH 18/21] arm64: entry: Split up kernel_ventry macro into separate helper macros

[Will Deacon]

Handling entry from EL0, EL1h and EL1t in the 'kernel_ventry' assembly
macro is getting a bit unwieldy as the control flow becomes increasingly
dependent on the macro arguments.

Split 'kernel_ventry' into three leaf helper macros for EL0, EL1h and
EL1t, which are then dispatched by simple wrappers.

Signed-off-by: Will Deacon <will at kernel.org>
---
 arch/arm64/kernel/entry.S | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index b4df2f23ebe7..38f9327e6a0a 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -36,10 +36,7 @@
 	.endr
 	.endm
 
-	.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
-	.align 7
-.Lventry_start\@:
-	.if	\el == 0
+	.macro kernel_ventry_el0, ht:req, regsize:req, label:req
 	/*
 	 * This must be the first instruction of the EL0 vector entries. It is
 	 * skipped by the trampoline vectors, to trigger the cleanup.
@@ -52,8 +49,10 @@
 	.endif
 .Lskip_tramp_vectors_cleanup\@:
 	sub	sp, sp, #PT_REGS_SIZE
-	.else	/* \el == 1 */
-	.ifc	\ht, h
+	b	el0\ht\()_\regsize\()_\label
+	.endm
+
+	.macro kernel_ventry_el1h, regsize:req, label:req
 	sub	sp, sp, #PT_REGS_SIZE
 
 	/*
@@ -66,13 +65,23 @@
 	tbnz	x0, #THREAD_SHIFT, __bad_stack
 	sub	x0, sp, x0			// x0'' = sp' - x0' = (sp + x0) - sp = x0
 	sub	sp, sp, x0			// sp'' = sp' - x0 = (sp + x0) - x0 = sp
-	.else	/* EL1t */
+	b	el1h_\regsize\()_\label
+	.endm
+
+	.macro kernel_ventry_el1t, regsize:req, label:req
 	msr	spsel, #0			// Stay on the overflow stack
 	sub	sp, sp, #PT_REGS_SIZE
-	.endif
-	.endif
+	b	el1t_\regsize\()_\label
+	.endm
 
-	b	el\el\ht\()_\regsize\()_\label
+	.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
+	.align 7
+.Lventry_start\@:
+	.if	\el == 0
+	kernel_ventry_el0	\ht, \regsize, \label
+	.else
+	kernel_ventry_el1\ht	\regsize, \label
+	.endif
 .org .Lventry_start\@ + 128	// Did we overflow the ventry slot?
 	.endm
 
-- 
2.55.0.979.g7e5102b832-goog