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authorGeoff Levand <geoff@infradead.org>2016-04-27 17:47:03 +0100
committerAlex Shi <alex.shi@linaro.org>2016-05-24 17:15:29 +0800
commit7379956d36d1886ffd4d8c96984a4d8ec3b50c1f (patch)
treef58b426d3f0450a97e278f02cc6d536c86232aa5
parent8411a7b227dac86913d60ee360a5283402b5c50f (diff)
downloadlinux-linaro-stable-7379956d36d1886ffd4d8c96984a4d8ec3b50c1f.tar.gz
arm64: hyp/kvm: Make hyp-stub extensible
The existing arm64 hcall implementations are limited in that they only allow for two distinct hcalls; with the x0 register either zero or not zero. Also, the API of the hyp-stub exception vector routines and the KVM exception vector routines differ; hyp-stub uses a non-zero value in x0 to implement __hyp_set_vectors, whereas KVM uses it to implement kvm_call_hyp. To allow for additional hcalls to be defined and to make the arm64 hcall API more consistent across exception vector routines, change the hcall implementations to reserve all x0 values below 0xfff for hcalls such as {s,g}et_vectors(). Define two new preprocessor macros HVC_GET_VECTORS, and HVC_SET_VECTORS to be used as hcall type specifiers and convert the existing __hyp_get_vectors() and __hyp_set_vectors() routines to use these new macros when executing an HVC call. Also, change the corresponding hyp-stub and KVM el1_sync exception vector routines to use these new macros. Signed-off-by: Geoff Levand <geoff@infradead.org> [Merged two hcall patches, moved immediate value from esr to x0, use lr as a scratch register, changed limit to 0xfff] Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> (cherry picked from commit ad72e59ff2bad55f6b9e7ac1fe5d824831ea2550) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--arch/arm64/include/asm/virt.h16
-rw-r--r--arch/arm64/kernel/hyp-stub.S34
-rw-r--r--arch/arm64/kvm/hyp.S4
-rw-r--r--arch/arm64/kvm/hyp/hyp-entry.S4
4 files changed, 44 insertions, 14 deletions
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 9f22dd607958..06e6a5238c4c 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -18,6 +18,22 @@
#ifndef __ASM__VIRT_H
#define __ASM__VIRT_H
+/*
+ * The arm64 hcall implementation uses x0 to specify the hcall type. A value
+ * less than 0xfff indicates a special hcall, such as get/set vector.
+ * Any other value is used as a pointer to the function to call.
+ */
+
+/* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
+#define HVC_GET_VECTORS 0
+
+/*
+ * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
+ *
+ * @x1: Physical address of the new vector table.
+ */
+#define HVC_SET_VECTORS 1
+
#define BOOT_CPU_MODE_EL1 (0xe11)
#define BOOT_CPU_MODE_EL2 (0xe12)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 7eab8acbbbd9..894fb40fb378 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -22,6 +22,7 @@
#include <linux/irqchip/arm-gic-v3.h>
#include <asm/assembler.h>
+#include <asm/kvm_arm.h>
#include <asm/ptrace.h>
#include <asm/virt.h>
@@ -53,15 +54,26 @@ ENDPROC(__hyp_stub_vectors)
.align 11
el1_sync:
- mrs x1, esr_el2
- lsr x1, x1, #26
- cmp x1, #0x16
- b.ne 2f // Not an HVC trap
- cbz x0, 1f
- msr vbar_el2, x0 // Set vbar_el2
- b 2f
-1: mrs x0, vbar_el2 // Return vbar_el2
-2: eret
+ mrs x30, esr_el2
+ lsr x30, x30, #ESR_ELx_EC_SHIFT
+
+ cmp x30, #ESR_ELx_EC_HVC64
+ b.ne 9f // Not an HVC trap
+
+ cmp x0, #HVC_GET_VECTORS
+ b.ne 1f
+ mrs x0, vbar_el2
+ b 9f
+
+1: cmp x0, #HVC_SET_VECTORS
+ b.ne 2f
+ msr vbar_el2, x1
+ b 9f
+
+ /* Unrecognised call type */
+2: mov x0, xzr
+
+9: eret
ENDPROC(el1_sync)
.macro invalid_vector label
@@ -102,7 +114,7 @@ ENDPROC(\label)
ENTRY(__hyp_get_vectors)
str lr, [sp, #-16]!
- mov x0, xzr
+ mov x0, #HVC_GET_VECTORS
hvc #0
ldr lr, [sp], #16
ret
@@ -110,6 +122,8 @@ ENDPROC(__hyp_get_vectors)
ENTRY(__hyp_set_vectors)
str lr, [sp, #-16]!
+ mov x1, x0
+ mov x0, #HVC_SET_VECTORS
hvc #0
ldr lr, [sp], #16
ret
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index b8fe4d1f1c1e..8d231f19453e 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -35,8 +35,8 @@
* in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are
* passed in x0.
*
- * A function pointer with a value of 0 has a special meaning, and is
- * used to implement __hyp_get_vectors in the same way as in
+ * A function pointer with a value less than 0xfff has a special meaning,
+ * and is used to implement __hyp_get_vectors in the same way as in
* arch/arm64/kernel/hyp_stub.S.
* HVC behaves as a 'bl' call and will clobber lr.
*/
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index f4e6e0f4b8fa..af82312bc6e1 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -79,8 +79,8 @@ el1_sync: // Guest trapped into EL2
/* Here, we're pretty sure the host called HVC. */
restore_x0_to_x3
- /* Check for __hyp_get_vectors */
- cbnz x0, 1f
+ cmp x0, #HVC_GET_VECTORS
+ b.ne 1f
mrs x0, vbar_el2
b 2f