2017-04-06 12:49:29

by Amit Pundir

[permalink] [raw]
Subject: [PATCH for-4.4 2/7] MIPS: Stack unwinding while on IRQ stack

From: Matt Redfearn <[email protected]>

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 <[email protected]>
Acked-by: Jason A. Donenfeld <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Maciej W. Rozycki <[email protected]>
Cc: Marcin Nowakowski <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/14741/
Signed-off-by: Ralf Baechle <[email protected]>
(cherry picked from commit d42d8d106b0275b027c1e8992c42aecf933436ea)
Signed-off-by: Amit Pundir <[email protected]>
---
arch/mips/kernel/process.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index fc537d1..8c26eca 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -32,6 +32,7 @@
#include <asm/cpu.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>
@@ -552,7 +553,19 @@ 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
--
2.7.4