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-rw-r--r--target/linux/generic/patches-4.4/062-01-MIPS-Introduce-irq_stack.patch70
1 files changed, 70 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/062-01-MIPS-Introduce-irq_stack.patch b/target/linux/generic/patches-4.4/062-01-MIPS-Introduce-irq_stack.patch
new file mode 100644
index 0000000000..2a929aa7e1
--- /dev/null
+++ b/target/linux/generic/patches-4.4/062-01-MIPS-Introduce-irq_stack.patch
@@ -0,0 +1,70 @@
+From: Matt Redfearn <matt.redfearn@imgtec.com>
+Date: Mon, 19 Dec 2016 14:20:56 +0000
+Subject: [PATCH] MIPS: Introduce irq_stack
+
+Allocate a per-cpu irq stack for use within interrupt handlers.
+
+Also add a utility function on_irq_stack to determine if a given stack
+pointer is within the irq stack for that cpu.
+
+Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
+---
+
+--- a/arch/mips/include/asm/irq.h
++++ b/arch/mips/include/asm/irq.h
+@@ -17,6 +17,18 @@
+
+ #include <irq.h>
+
++#define IRQ_STACK_SIZE THREAD_SIZE
++
++extern void *irq_stack[NR_CPUS];
++
++static inline bool on_irq_stack(int cpu, unsigned long sp)
++{
++ unsigned long low = (unsigned long)irq_stack[cpu];
++ unsigned long high = low + IRQ_STACK_SIZE;
++
++ return (low <= sp && sp <= high);
++}
++
+ #ifdef CONFIG_I8259
+ static inline int irq_canonicalize(int irq)
+ {
+--- a/arch/mips/kernel/asm-offsets.c
++++ b/arch/mips/kernel/asm-offsets.c
+@@ -101,6 +101,7 @@ void output_thread_info_defines(void)
+ OFFSET(TI_REGS, thread_info, regs);
+ DEFINE(_THREAD_SIZE, THREAD_SIZE);
+ DEFINE(_THREAD_MASK, THREAD_MASK);
++ DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
+ BLANK();
+ }
+
+--- a/arch/mips/kernel/irq.c
++++ b/arch/mips/kernel/irq.c
+@@ -25,6 +25,8 @@
+ #include <linux/atomic.h>
+ #include <asm/uaccess.h>
+
++void *irq_stack[NR_CPUS];
++
+ /*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+@@ -55,6 +57,15 @@ void __init init_IRQ(void)
+ irq_set_noprobe(i);
+
+ arch_init_irq();
++
++ for_each_possible_cpu(i) {
++ int irq_pages = IRQ_STACK_SIZE / PAGE_SIZE;
++ void *s = (void *)__get_free_pages(GFP_KERNEL, irq_pages);
++
++ irq_stack[i] = s;
++ pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
++ irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
++ }
+ }
+
+ #ifdef CONFIG_DEBUG_STACKOVERFLOW