openwrt-owl/target/linux/generic/patches-4.9/040-02-MIPS-Stack-unwinding...

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From: Matt Redfearn <matt.redfearn@imgtec.com>
Date: Mon, 19 Dec 2016 14:20:57 +0000
Subject: [PATCH] MIPS: Stack unwinding while on IRQ stack
Within unwind stack, check if the stack pointer being unwound is within
the CPU's irq_stack and if so use that page rather than the task's stack
page.
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
---
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -33,6 +33,7 @@
#include <asm/dsemul.h>
#include <asm/dsp.h>
#include <asm/fpu.h>
+#include <asm/irq.h>
#include <asm/msa.h>
#include <asm/pgtable.h>
#include <asm/mipsregs.h>
@@ -511,7 +512,19 @@ EXPORT_SYMBOL(unwind_stack_by_address);
unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
unsigned long pc, unsigned long *ra)
{
- unsigned long stack_page = (unsigned long)task_stack_page(task);
+ unsigned long stack_page = 0;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (on_irq_stack(cpu, *sp)) {
+ stack_page = (unsigned long)irq_stack[cpu];
+ break;
+ }
+ }
+
+ if (!stack_page)
+ stack_page = (unsigned long)task_stack_page(task);
+
return unwind_stack_by_address(stack_page, sp, pc, ra);
}
#endif