[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
Marc Zyngier
marc.zyngier at arm.com
Mon Mar 6 06:24:34 PST 2017
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.
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm64/include/asm/virt.h | 9 +++++++++
arch/arm64/kernel/hyp-stub.S | 13 ++++++++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 439f6b5d31f6..f24f1eb72dc0 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -39,6 +39,14 @@
*/
#define HVC_SOFT_RESTART 2
+/*
+ * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
+ */
+#define HVC_RESET_VECTORS 3
+
+/* Max number of HYP stub hypercalls */
+#define HVC_STUB_HCALL_NR 4
+
#define BOOT_CPU_MODE_EL1 (0xe11)
#define BOOT_CPU_MODE_EL2 (0xe12)
@@ -62,6 +70,7 @@ extern u32 __boot_cpu_mode[2];
void __hyp_set_vectors(phys_addr_t phys_vector_base);
phys_addr_t __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
/* Reports the availability of HYP mode */
static inline bool is_hyp_mode_available(void)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d3b5f75e652e..a162182d5662 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -79,8 +79,11 @@ el1_sync:
mov x1, x3
br x4 // no return
+3: cmp x0, #HVC_RESET_VECTORS
+ beq 9f // Nothing to reset!
+
/* Someone called kvm_call_hyp() against the hyp-stub... */
-3: mov x0, #ARM_EXCEPTION_HYP_GONE
+ mov x0, #ARM_EXCEPTION_HYP_GONE
9: eret
ENDPROC(el1_sync)
@@ -137,3 +140,11 @@ ENTRY(__hyp_set_vectors)
ldr lr, [sp], #16
ret
ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_reset_vectors)
+ str lr, [sp, #-16]!
+ mov x0, #HVC_RESET_VECTORS
+ hvc #0
+ ldr lr, [sp], #16
+ ret
+ENDPROC(__hyp_reset_vectors)
--
2.11.0
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