ARM: hyp-stub: improve ABI

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.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15d073a..f3e9ba5 100644 (file)
--- 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)