[Minios-devel] [UNIKRAFT PATCHv2 12/25] arch/include: Add a _regs member to save origial stack pointer

[Wei Chen <wei.chen@xxxxxxx>]

There is a issue about stack alignment check in url[1]. There
might be case where the stack pointer is not aligned at EL1
exception. We will force align the stack for EL1 exceptions,
so we add a sp to save original stack pointer in this patch.

[1] https://www.spinics.net/lists/arm-kernel/msg678761.html

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 arch/arm/arm64/include/uk/asm/lcpu.h | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/arm/arm64/include/uk/asm/lcpu.h 
b/arch/arm/arm64/include/uk/asm/lcpu.h
index 2719313..9eea746 100644
--- a/arch/arm/arm64/include/uk/asm/lcpu.h
+++ b/arch/arm/arm64/include/uk/asm/lcpu.h
@@ -35,13 +35,20 @@
  * Stack size to save general purpose registers and essential system
  * registers. 8 * (30 + lr + elr_el1 + spsr_el1 + esr_el1) = 272.
  * From exceptions come from EL0, we have to save sp_el0. So the
- * TRAP_STACK_SIZE should be 272 + 8 = 280
+ * TRAP_STACK_SIZE should be 272 + 8 = 280. But we enable the stack
+ * alignment check, we will force align the stack for EL1 exceptions,
+ * so we add a sp to save original stack pointer: 280 + 8 = 288
  *
  * TODO: We'd better to calculate this size automatically later.
  */
-#define __TRAP_STACK_SIZE 280
+#define __TRAP_STACK_SIZE      288
+#define __SP_OFFSET            272
+#define __SP_EL0_OFFSET                280
 #else
-/* Change this structure must update TRAP_STACK_SIZE at the same time */
+/*
+ * Change this structure must update TRAP_STACK_SIZE at the same time.
+ * This data structure must be 16-byte alignment.
+ */
 struct __regs {
        /* Generic Purpose registers, from x0 ~ x29 */
        unsigned long x[30];
@@ -60,6 +67,9 @@ struct __regs {
 
        /* Stack Pointer */
        unsigned long sp;
+
+       /* Stack Pointer from el0 */
+       unsigned long sp_el0;
 };
 
 /*
-- 
2.17.1


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