arm64: Add do_softirq_own_stack() and enable irq_stacks
entry.S is modified to switch to the per_cpu irq_stack during el{0,1}_irq.
irq_count is used to detect recursive interrupts on the irq_stack, it is
updated late by do_softirq_own_stack(), when called on the irq_stack, before
__do_softirq() re-enables interrupts to process softirqs.
do_softirq_own_stack() is added by this patch, but does not yet switch
stack.
This patch adds the dummy stack frame and data needed by the previous
stack tracing patches.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 245fa68..8f7e737 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -27,6 +27,7 @@
#include <asm/cpufeature.h>
#include <asm/errno.h>
#include <asm/esr.h>
+#include <asm/irq.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
@@ -175,6 +176,42 @@
mrs \rd, sp_el0
.endm
+ .macro irq_stack_entry, dummy_lr
+ mov x19, sp // preserve the original sp
+
+ adr_l x25, irq_stack
+ mrs x26, tpidr_el1
+ add x25, x25, x26
+
+ /*
+ * Check the lowest address on irq_stack for the irq_count value,
+ * incremented by do_softirq_own_stack if we have re-enabled irqs
+ * while on the irq_stack.
+ */
+ ldr x26, [x25]
+ cbnz x26, 9998f // recursive use?
+
+ /* switch to the irq stack */
+ mov x26, #IRQ_STACK_START_SP
+ add x26, x25, x26
+ mov sp, x26
+
+ /* Add a dummy stack frame */
+ stp x29, \dummy_lr, [sp, #-16]! // dummy stack frame
+ mov x29, sp
+ stp xzr, x19, [sp, #-16]!
+
+9998:
+ .endm
+
+ /*
+ * x19 should be preserved between irq_stack_entry and
+ * irq_stack_exit.
+ */
+ .macro irq_stack_exit
+ mov sp, x19
+ .endm
+
/*
* These are the registers used in the syscall handler, and allow us to
* have in theory up to 7 arguments to a function - x0 to x6.
@@ -190,10 +227,11 @@
* Interrupt handling.
*/
.macro irq_handler
- adrp x1, handle_arch_irq
- ldr x1, [x1, #:lo12:handle_arch_irq]
+ ldr_l x1, handle_arch_irq
mov x0, sp
+ irq_stack_entry x22
blr x1
+ irq_stack_exit
.endm
.text
