[PATCH v4 16/28] ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

Marc Zyngier
2017-03-21T19:20:46Z

Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.

Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm/include/asm/virt.h | 3 +++
arch/arm/kernel/hyp-stub.S | 11 ++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 4ea16fcaf2ed..5186718aab68 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -101,6 +101,9 @@ extern char __hyp_text_end[];
#define HVC_GET_VECTORS 0
#define HVC_SET_VECTORS 1
#define HVC_SOFT_RESTART 2
+#define HVC_RESET_VECTORS 3
+
+#define HVC_STUB_HCALL_NR 4

#endif /* __ASSEMBLY__ */

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15eaa14322a7..21794d4a8f36 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,10 @@ __hyp_stub_do_trap:
bne 1f
bx r1

-1: mov r0, #-1
+1: teq r0, #HVC_RESET_VECTORS
+ beq __hyp_stub_exit
+
+ mov r0, #-1

__hyp_stub_exit:
__ERET
@@ -264,6 +267,12 @@ ENTRY(__hyp_soft_restart)
ret lr
ENDPROC(__hyp_soft_restart)

+ENTRY(__hyp_reset_vectors)
+ mov r0, #HVC_RESET_VECTORS
+ __HVC(0)
+ ret lr
+ENDPROC(__hyp_reset_vectors)
+
#ifndef ZIMAGE
.align 2
.L__boot_cpu_mode_offset:
--
2.11.0