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authorIngo Molnar <mingo@elte.hu>2008-07-08 09:53:57 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-08 09:53:57 +0200
commit1b8ba39a3fad9c58532f6dad12c94d6e675be656 (patch)
tree9ae9b4c4545b4c91f5dbb3a1085c4c721961c4f2 /arch/x86/kernel/irq_32.c
parent58cf35228fec541418cc3bd781d6c069d904815e (diff)
parentcbd6712406a3ea861b49fbfd46e23cbf5f8e073f (diff)
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Merge branch 'x86/irq' into x86/devel
Conflicts: arch/x86/kernel/i8259.c arch/x86/kernel/irqinit_64.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/irq_32.c')
-rw-r--r--arch/x86/kernel/irq_32.c216
1 files changed, 119 insertions, 97 deletions
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 468acd0..47a6f6f 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -48,6 +48,29 @@ void ack_bad_irq(unsigned int irq)
#endif
}
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+/* Debugging check for stack overflow: is there less than 1KB free? */
+static int check_stack_overflow(void)
+{
+ long sp;
+
+ __asm__ __volatile__("andl %%esp,%0" :
+ "=r" (sp) : "0" (THREAD_SIZE - 1));
+
+ return sp < (sizeof(struct thread_info) + STACK_WARN);
+}
+
+static void print_stack_overflow(void)
+{
+ printk(KERN_WARNING "low stack detected by irq handler\n");
+ dump_stack();
+}
+
+#else
+static inline int check_stack_overflow(void) { return 0; }
+static inline void print_stack_overflow(void) { }
+#endif
+
#ifdef CONFIG_4KSTACKS
/*
* per-CPU IRQ handling contexts (thread information and stack)
@@ -59,48 +82,29 @@ union irq_ctx {
static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
-#endif
-/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
- */
-unsigned int do_IRQ(struct pt_regs *regs)
-{
- struct pt_regs *old_regs;
- /* high bit used in ret_from_ code */
- int irq = ~regs->orig_ax;
- struct irq_desc *desc = irq_desc + irq;
-#ifdef CONFIG_4KSTACKS
- union irq_ctx *curctx, *irqctx;
- u32 *isp;
-#endif
+static char softirq_stack[NR_CPUS * THREAD_SIZE]
+ __attribute__((__section__(".bss.page_aligned")));
- if (unlikely((unsigned)irq >= NR_IRQS)) {
- printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
- __func__, irq);
- BUG();
- }
+static char hardirq_stack[NR_CPUS * THREAD_SIZE]
+ __attribute__((__section__(".bss.page_aligned")));
- old_regs = set_irq_regs(regs);
- irq_enter();
-#ifdef CONFIG_DEBUG_STACKOVERFLOW
- /* Debugging check for stack overflow: is there less than 1KB free? */
- {
- long sp;
-
- __asm__ __volatile__("andl %%esp,%0" :
- "=r" (sp) : "0" (THREAD_SIZE - 1));
- if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
- printk("do_IRQ: stack overflow: %ld\n",
- sp - sizeof(struct thread_info));
- dump_stack();
- }
- }
-#endif
+static void call_on_stack(void *func, void *stack)
+{
+ asm volatile("xchgl %%ebx,%%esp \n"
+ "call *%%edi \n"
+ "movl %%ebx,%%esp \n"
+ : "=b" (stack)
+ : "0" (stack),
+ "D"(func)
+ : "memory", "cc", "edx", "ecx", "eax");
+}
-#ifdef CONFIG_4KSTACKS
+static inline int
+execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
+{
+ union irq_ctx *curctx, *irqctx;
+ u32 *isp, arg1, arg2;
curctx = (union irq_ctx *) current_thread_info();
irqctx = hardirq_ctx[smp_processor_id()];
@@ -111,52 +115,39 @@ unsigned int do_IRQ(struct pt_regs *regs)
* handler) we can't do that and just have to keep using the
* current stack (which is the irq stack already after all)
*/
- if (curctx != irqctx) {
- int arg1, arg2, bx;
+ if (unlikely(curctx == irqctx))
+ return 0;
- /* build the stack frame on the IRQ stack */
- isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
- irqctx->tinfo.task = curctx->tinfo.task;
- irqctx->tinfo.previous_esp = current_stack_pointer;
+ /* build the stack frame on the IRQ stack */
+ isp = (u32 *) ((char*)irqctx + sizeof(*irqctx));
+ irqctx->tinfo.task = curctx->tinfo.task;
+ irqctx->tinfo.previous_esp = current_stack_pointer;
- /*
- * Copy the softirq bits in preempt_count so that the
- * softirq checks work in the hardirq context.
- */
- irqctx->tinfo.preempt_count =
- (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
- (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
-
- asm volatile(
- " xchgl %%ebx,%%esp \n"
- " call *%%edi \n"
- " movl %%ebx,%%esp \n"
- : "=a" (arg1), "=d" (arg2), "=b" (bx)
- : "0" (irq), "1" (desc), "2" (isp),
- "D" (desc->handle_irq)
- : "memory", "cc", "ecx"
- );
- } else
-#endif
- desc->handle_irq(irq, desc);
-
- irq_exit();
- set_irq_regs(old_regs);
+ /*
+ * Copy the softirq bits in preempt_count so that the
+ * softirq checks work in the hardirq context.
+ */
+ irqctx->tinfo.preempt_count =
+ (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
+ (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
+
+ if (unlikely(overflow))
+ call_on_stack(print_stack_overflow, isp);
+
+ asm volatile("xchgl %%ebx,%%esp \n"
+ "call *%%edi \n"
+ "movl %%ebx,%%esp \n"
+ : "=a" (arg1), "=d" (arg2), "=b" (isp)
+ : "0" (irq), "1" (desc), "2" (isp),
+ "D" (desc->handle_irq)
+ : "memory", "cc", "ecx");
return 1;
}
-#ifdef CONFIG_4KSTACKS
-
-static char softirq_stack[NR_CPUS * THREAD_SIZE]
- __attribute__((__section__(".bss.page_aligned")));
-
-static char hardirq_stack[NR_CPUS * THREAD_SIZE]
- __attribute__((__section__(".bss.page_aligned")));
-
/*
* allocate per-cpu stacks for hardirq and for softirq processing
*/
-void irq_ctx_init(int cpu)
+void __cpuinit irq_ctx_init(int cpu)
{
union irq_ctx *irqctx;
@@ -164,25 +155,25 @@ void irq_ctx_init(int cpu)
return;
irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
- irqctx->tinfo.task = NULL;
- irqctx->tinfo.exec_domain = NULL;
- irqctx->tinfo.cpu = cpu;
- irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
- irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
+ irqctx->tinfo.task = NULL;
+ irqctx->tinfo.exec_domain = NULL;
+ irqctx->tinfo.cpu = cpu;
+ irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
+ irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
hardirq_ctx[cpu] = irqctx;
irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
- irqctx->tinfo.task = NULL;
- irqctx->tinfo.exec_domain = NULL;
- irqctx->tinfo.cpu = cpu;
- irqctx->tinfo.preempt_count = 0;
- irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
+ irqctx->tinfo.task = NULL;
+ irqctx->tinfo.exec_domain = NULL;
+ irqctx->tinfo.cpu = cpu;
+ irqctx->tinfo.preempt_count = 0;
+ irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
softirq_ctx[cpu] = irqctx;
- printk("CPU %u irqstacks, hard=%p soft=%p\n",
- cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
+ printk(KERN_DEBUG "CPU %u irqstacks, hard=%p soft=%p\n",
+ cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
}
void irq_ctx_exit(int cpu)
@@ -211,25 +202,56 @@ asmlinkage void do_softirq(void)
/* build the stack frame on the softirq stack */
isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
- asm volatile(
- " xchgl %%ebx,%%esp \n"
- " call __do_softirq \n"
- " movl %%ebx,%%esp \n"
- : "=b"(isp)
- : "0"(isp)
- : "memory", "cc", "edx", "ecx", "eax"
- );
+ call_on_stack(__do_softirq, isp);
/*
* Shouldnt happen, we returned above if in_interrupt():
- */
+ */
WARN_ON_ONCE(softirq_count());
}
local_irq_restore(flags);
}
+
+#else
+static inline int
+execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; }
#endif
/*
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+unsigned int do_IRQ(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs;
+ /* high bit used in ret_from_ code */
+ int overflow, irq = ~regs->orig_ax;
+ struct irq_desc *desc = irq_desc + irq;
+
+ if (unlikely((unsigned)irq >= NR_IRQS)) {
+ printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
+ __func__, irq);
+ BUG();
+ }
+
+ old_regs = set_irq_regs(regs);
+ irq_enter();
+
+ overflow = check_stack_overflow();
+
+ if (!execute_on_irq_stack(overflow, desc, irq)) {
+ if (unlikely(overflow))
+ print_stack_overflow();
+ desc->handle_irq(irq, desc);
+ }
+
+ irq_exit();
+ set_irq_regs(old_regs);
+ return 1;
+}
+
+/*
* Interrupt statistics:
*/