target/linux/generic/patches-4.9/040-01-MIPS-Introduce-irq_stack.patch

   1 From: Matt Redfearn <matt.redfearn@imgtec.com>
   2 Date: Mon, 19 Dec 2016 14:20:56 +0000
   3 Subject: [PATCH] MIPS: Introduce irq_stack
   4
   5 Allocate a per-cpu irq stack for use within interrupt handlers.
   6
   7 Also add a utility function on_irq_stack to determine if a given stack
   8 pointer is within the irq stack for that cpu.
   9
  10 Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
  11 ---
  12
  13 --- a/arch/mips/include/asm/irq.h
  14 +++ b/arch/mips/include/asm/irq.h
  15 @@ -17,6 +17,18 @@
  16
  17  #include <irq.h>
  18
  19 +#define IRQ_STACK_SIZE                 THREAD_SIZE
  20 +
  21 +extern void *irq_stack[NR_CPUS];
  22 +
  23 +static inline bool on_irq_stack(int cpu, unsigned long sp)
  24 +{
  25 +       unsigned long low = (unsigned long)irq_stack[cpu];
  26 +       unsigned long high = low + IRQ_STACK_SIZE;
  27 +
  28 +       return (low <= sp && sp <= high);
  29 +}
  30 +
  31  #ifdef CONFIG_I8259
  32  static inline int irq_canonicalize(int irq)
  33  {
  34 --- a/arch/mips/kernel/asm-offsets.c
  35 +++ b/arch/mips/kernel/asm-offsets.c
  36 @@ -102,6 +102,7 @@ void output_thread_info_defines(void)
  37         OFFSET(TI_REGS, thread_info, regs);
  38         DEFINE(_THREAD_SIZE, THREAD_SIZE);
  39         DEFINE(_THREAD_MASK, THREAD_MASK);
  40 +       DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
  41         BLANK();
  42  }
  43
  44 --- a/arch/mips/kernel/irq.c
  45 +++ b/arch/mips/kernel/irq.c
  46 @@ -25,6 +25,8 @@
  47  #include <linux/atomic.h>
  48  #include <asm/uaccess.h>
  49
  50 +void *irq_stack[NR_CPUS];
  51 +
  52  /*
  53   * 'what should we do if we get a hw irq event on an illegal vector'.
  54   * each architecture has to answer this themselves.
  55 @@ -58,6 +60,15 @@ void __init init_IRQ(void)
  56                 clear_c0_status(ST0_IM);
  57
  58         arch_init_irq();
  59 +
  60 +       for_each_possible_cpu(i) {
  61 +               int irq_pages = IRQ_STACK_SIZE / PAGE_SIZE;
  62 +               void *s = (void *)__get_free_pages(GFP_KERNEL, irq_pages);
  63 +
  64 +               irq_stack[i] = s;
  65 +               pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
  66 +                       irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
  67 +       }
  68  }
  69
  70  #ifdef CONFIG_DEBUG_STACKOVERFLOW