x86: irq_32 move 4kstacks code to one place

Move the 4KSTACKS related code to one place. This allows to un#ifdef
do_IRQ() and share the executed on stack for the stack overflow printk
and the softirq call.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 77 insertions, 86 deletions

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 1c470d2e5af7..4e3e8ec60276 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -83,26 +83,28 @@ union irq_ctx {
 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 
-static inline void call_on_stack(void *func, void *stack,
-                                 unsigned long arg1, void *arg2)
+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")));
+
+static void call_on_stack(void *func, void *stack)
 {
-        unsigned long bx;
-
-        asm volatile(
-                        "       xchgl  %%ebx,%%esp    \n"
-                        "       call   *%%edi         \n"
-                        "       movl   %%ebx,%%esp    \n"
-                        : "=a" (arg1), "=d" (arg2), "=b" (bx)
-                        :  "0" (arg1),   "1" (arg2),  "2" (stack),
-                           "D" (func)
-                        : "memory", "cc", "ecx");
+        asm volatile("xchgl     %%ebx,%%esp     \n"
+                     "call      *%%edi          \n"
+                     "movl      %%ebx,%%esp     \n"
+                     : "=b" (stack)
+                     : "0" (stack),
+                       "D"(func)
+                     : "memory", "cc", "edx", "ecx", "eax");
 }
 
 static inline int
 execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
 {
         union irq_ctx *curctx, *irqctx;
-        u32 *isp;
+        u32 *isp, arg1, arg2;
 
         curctx = (union irq_ctx *) current_thread_info();
         irqctx = hardirq_ctx[smp_processor_id()];
@@ -130,64 +132,22 @@ execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
                 (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 
         if (unlikely(overflow))
-                call_on_stack(print_stack_overflow, isp, 0, NULL);
-
-        call_on_stack(desc->handle_irq, isp, irq, desc);
-
-        return 1;
-}
-
-#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);
+                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;
 
@@ -195,25 +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)
@@ -242,25 +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:
  */