SP needs to be 16-bytes aligned before accessing memory through it. When
handling exceptions from EL2, there is no guarantee that SP is already
aligned.
Ensure SP is aligned upon entries from EL2.
Signed-off-by: Julien Thierry <julien.thie...@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
---
arch/arm64/kvm/hyp/hyp-entry.S | 63 ++++++++++++++++++++++++++++++++++--------
1 file changed, 52 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index da31386..f611072 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -184,6 +184,10 @@ el2_error:
ccmp x0, x1, #4, ne
b.ne __hyp_panic
mov x0, #(1 << ARM_EXIT_WITH_SERROR_BIT)
+
+ /* Restore the stack */
+ ldr x1, [sp]
+ mov sp, x1
eret
ENTRY(__hyp_do_panic)
@@ -221,29 +225,66 @@ ENDPROC(\label)
.align 11
-.macro valid_vect target
+/*
+ * Aligns the stack and stores the old sp value. This is what the stack
+ * looks like after this code:
+ *
+ * +--------+
+ * | |
+ * |--------|--> old_sp (upon entry)
+ * | x1 |--> (only used for local save/restore)
+ * |--------|--> old_sp - 8
+ * | |--> padding
+ * |--------|--> aligned_sp + 8
+ * | old_sp |
+ * |--------|--> sp = aligned_sp
+ * | |
+ * +--------+
+ */
+.macro align_sp_el2
+ xchg_sp x0
+ str x1, [x0, #-8] // save x1
+ mov x1, x0 // x1 = old_sp
+ sub x0, x0, #0x10 // save space for x1 + old_sp
+ bic x0, x0, #0xf // align down to 16-bytes
+ xchg_sp x0
+ str x1, [sp] // save old_sp
+ ldr x1, [x1, #-8]
+.endm
+
+.macro valid_vect target, el=1
.align 7
+ .if \el == 2
+ align_sp_el2
+ .endif
+
stp x0, x1, [sp, #-16]!
b \target
.endm
-.macro invalid_vect target
+.macro invalid_vect target, el=1
.align 7
+ .if \el == 2
+ align_sp_el2
+ .endif
+
b \target
+ .if \el == 1
ldp x0, x1, [sp], #16
b \target
+ .endif
.endm
ENTRY(__kvm_hyp_vector)
- invalid_vect el2t_sync_invalid // Synchronous EL2t
- invalid_vect el2t_irq_invalid // IRQ EL2t
- invalid_vect el2t_fiq_invalid // FIQ EL2t
- invalid_vect el2t_error_invalid // Error EL2t
-
- invalid_vect el2h_sync_invalid // Synchronous EL2h
- invalid_vect el2h_irq_invalid // IRQ EL2h
- invalid_vect el2h_fiq_invalid // FIQ EL2h
- valid_vect el2_error // Error EL2h
+ invalid_vect el2t_sync_invalid, 2 // Synchronous EL2t
+ invalid_vect el2t_irq_invalid, 2 // IRQ EL2t
+ invalid_vect el2t_fiq_invalid, 2 // FIQ EL2t
+ invalid_vect el2t_error_invalid, 2 // Error EL2t
+
+ invalid_vect el2h_sync_invalid, 2 // Synchronous EL2h
+ invalid_vect el2h_irq_invalid, 2 // IRQ EL2h
+ invalid_vect el2h_fiq_invalid, 2 // FIQ EL2h
+ valid_vect el2_error, 2 // Error EL2h
valid_vect el1_sync // Synchronous 64-bit EL1
valid_vect el1_irq // IRQ 64-bit EL1
--
1.9.1
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
