[PATCH 1/2] ARM: hyp-stub: improve ABI

Russell King
2016-12-14T10:46:30Z

Improve the hyp-stub ABI to allow it to do more than just get/set the
vectors. We follow the example in ARM64, where r0 is used as an opcode
with the other registers as an argument.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
arch/arm/kernel/hyp-stub.S | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15d073ae5da2..f3e9ba5fb642 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,6 +22,9 @@
#include <asm/assembler.h>
#include <asm/virt.h>

+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+
#ifndef ZIMAGE
/*
* For the kernel proper, we need to find out the CPU boot mode long after
@@ -202,9 +205,19 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
ENDPROC(__hyp_stub_install_secondary)

__hyp_stub_do_trap:
- cmp r0, #-1
- mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
- mcrne p15, 4, r0, c12, c0, 0 @ set HVBAR
+ teq r0, #HVC_GET_VECTORS
+ bne 1f
+ mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
+ b __hyp_stub_exit
+
+1: teq r0, #HVC_SET_VECTORS
+ bne 1f
+ mcr p15, 4, r1, c12, c0, 0 @ set HVBAR
+ b __hyp_stub_exit
+
+1: mov r0, #-1
+
+__hyp_stub_exit:
__ERET
ENDPROC(__hyp_stub_do_trap)

@@ -231,10 +244,14 @@ ENDPROC(__hyp_stub_do_trap)
* initialisation entry point.
*/
ENTRY(__hyp_get_vectors)
- mov r0, #-1
+ mov r0, #HVC_GET_VECTORS
+ __HVC(0)
+ ret lr
ENDPROC(__hyp_get_vectors)
- @ fall through
+
ENTRY(__hyp_set_vectors)
+ mov r1, r0
+ mov r0, #HVC_SET_VECTORS
__HVC(0)
ret lr
ENDPROC(__hyp_set_vectors)
--
2.7.4