diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2021-06-07 10:46:10 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-06-07 11:35:55 +0100 |
| commit | f8049488e7d37b0a0e438ee449e83b3e46958743 (patch) | |
| tree | 915089b64f3ea1a50c6492b9c9da3f7783a49d8a /arch/arm64/kernel/entry.S | |
| parent | 101a5b665dcdff169ae7ad90556604c483d9027e (diff) | |
| download | linux-f8049488e7d37b0a0e438ee449e83b3e46958743.tar.bz2 | |
arm64: entry: add a call_on_irq_stack helper
When handling IRQ/FIQ exceptions the entry assembly may transition from
a task's stack to a CPU's IRQ stack (and IRQ shadow call stack).
In subsequent patches we want to migrate the IRQ/FIQ triage logic to C,
and as we want to perform some actions on the task stack (e.g. EL1
preemption), we need to switch stacks within the C handler. So that we
can do so, this patch adds a helper to call a function on a CPU's IRQ
stack (and shadow stack as appropriate).
Subsequent patches will make use of the new helper function.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210607094624.34689-7-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 449628290ce8..8ca74ce115ee 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -982,6 +982,42 @@ SYM_CODE_START(ret_from_fork) SYM_CODE_END(ret_from_fork) NOKPROBE(ret_from_fork) +/* + * void call_on_irq_stack(struct pt_regs *regs, + * void (*func)(struct pt_regs *)); + * + * Calls func(regs) using this CPU's irq stack and shadow irq stack. + */ +SYM_FUNC_START(call_on_irq_stack) +#ifdef CONFIG_SHADOW_CALL_STACK + stp scs_sp, xzr, [sp, #-16]! + ldr_this_cpu scs_sp, irq_shadow_call_stack_ptr, x17 +#endif + /* Create a frame record to save our LR and SP (implicit in FP) */ + stp x29, x30, [sp, #-16]! + mov x29, sp + + ldr_this_cpu x16, irq_stack_ptr, x17 + mov x15, #IRQ_STACK_SIZE + add x16, x16, x15 + + /* Move to the new stack and call the function there */ + mov sp, x16 + blr x1 + + /* + * Restore the SP from the FP, and restore the FP and LR from the frame + * record. + */ + mov sp, x29 + ldp x29, x30, [sp], #16 +#ifdef CONFIG_SHADOW_CALL_STACK + ldp scs_sp, xzr, [sp], #16 +#endif + ret +SYM_FUNC_END(call_on_irq_stack) +NOKPROBE(call_on_irq_stack) + #ifdef CONFIG_ARM_SDE_INTERFACE #include <asm/sdei.h> |