10 files changed, 132 insertions, 62 deletions

diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 881c467c6982..cd9cec9e39e9 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -11,6 +11,7 @@ obj-y		+= cpu-probe.o branch.o entry.o genex.o irq.o process.o \
 binfmt_irix-objs        := irixelf.o irixinv.o irixioctl.o irixsig.o    \
                            irix5sys.o sysirix.o
 
+obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 obj-$(CONFIG_MODULES)           += mips_ksyms.o module.o
 
 obj-$(CONFIG_APM)               += apm.o
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 37fda3dcdfc5..af6ef2fd8300 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -220,8 +220,8 @@ NESTED(except_vec_vi_handler, 0, sp)
         CLI
         TRACE_IRQS_OFF
         move    a0, sp
-        jalr    v0
-        j       ret_from_irq
+        PTR_LA  ra, ret_from_irq
+        jr      v0
         END(except_vec_vi_handler)
 
 /*
@@ -349,8 +349,8 @@ NESTED(nmi_handler, PT_SIZE, sp)
         .set    at
         __BUILD_\verbose \exception
         move    a0, sp
-        jal     do_\handler
-        j       ret_from_exception
+        PTR_LA  ra, ret_from_exception
+        j       do_\handler
         END(handle_\exception)
         .endm
 
diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c
index ea36c8e8852c..48e3418c217b 100644
--- a/arch/mips/kernel/i8259.c
+++ b/arch/mips/kernel/i8259.c
@@ -302,11 +302,11 @@ static struct irqaction irq2 = {
 };
 
 static struct resource pic1_io_resource = {
-        .name = "pic1", .start = 0x20, .end = 0x3f, .flags = IORESOURCE_BUSY
+        .name = "pic1", .start = 0x20, .end = 0x21, .flags = IORESOURCE_BUSY
 };
 
 static struct resource pic2_io_resource = {
-        .name = "pic2", .start = 0xa0, .end = 0xbf, .flags = IORESOURCE_BUSY
+        .name = "pic2", .start = 0xa0, .end = 0xa1, .flags = IORESOURCE_BUSY
 };
 
 /*
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 2613a0dd4b82..045d987bc683 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -40,6 +40,7 @@
 #include <asm/elf.h>
 #include <asm/isadep.h>
 #include <asm/inst.h>
+#include <asm/stacktrace.h>
 #ifdef CONFIG_MIPS_MT_SMTC
 #include <asm/mipsmtregs.h>
 extern void smtc_idle_loop_hook(void);
@@ -398,7 +399,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 #ifdef CONFIG_KALLSYMS
 /* used by show_backtrace() */
 unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
-                           unsigned long pc, unsigned long ra)
+                           unsigned long pc, unsigned long *ra)
 {
         unsigned long stack_page;
         struct mips_frame_info info;
@@ -406,18 +407,42 @@ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
         char namebuf[KSYM_NAME_LEN + 1];
         unsigned long size, ofs;
         int leaf;
+        extern void ret_from_irq(void);
+        extern void ret_from_exception(void);
 
         stack_page = (unsigned long)task_stack_page(task);
         if (!stack_page)
                 return 0;
 
+        /*
+         * If we reached the bottom of interrupt context,
+         * return saved pc in pt_regs.
+         */
+        if (pc == (unsigned long)ret_from_irq ||
+            pc == (unsigned long)ret_from_exception) {
+                struct pt_regs *regs;
+                if (*sp >= stack_page &&
+                    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
+                        regs = (struct pt_regs *)*sp;
+                        pc = regs->cp0_epc;
+                        if (__kernel_text_address(pc)) {
+                                *sp = regs->regs[29];
+                                *ra = regs->regs[31];
+                                return pc;
+                        }
+                }
+                return 0;
+        }
         if (!kallsyms_lookup(pc, &size, &ofs, &modname, namebuf))
                 return 0;
         /*
          * Return ra if an exception occured at the first instruction
          */
-        if (unlikely(ofs == 0))
-                return ra;
+        if (unlikely(ofs == 0)) {
+                pc = *ra;
+                *ra = 0;
+                return pc;
+        }
 
         info.func = (void *)(pc - ofs);
         info.func_size = ofs;   /* analyze from start to ofs */
@@ -436,11 +461,12 @@ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
                  * one. In that cases avoid to return always the
                  * same value.
                  */
-                pc = pc != ra ? ra : 0;
+                pc = pc != *ra ? *ra : 0;
         else
                 pc = ((unsigned long *)(*sp))[info.pc_offset];
 
         *sp += info.frame_size;
+        *ra = 0;
         return __kernel_text_address(pc) ? pc : 0;
 }
 #endif
@@ -453,6 +479,7 @@ unsigned long get_wchan(struct task_struct *task)
         unsigned long pc = 0;
 #ifdef CONFIG_KALLSYMS
         unsigned long sp;
+        unsigned long ra = 0;
 #endif
 
         if (!task || task == current || task->state == TASK_RUNNING)
@@ -466,7 +493,7 @@ unsigned long get_wchan(struct task_struct *task)
         sp = task->thread.reg29 + schedule_mfi.frame_size;
 
         while (in_sched_functions(pc))
-                pc = unwind_stack(task, &sp, pc, 0);
+                pc = unwind_stack(task, &sp, pc, &ra);
 #endif
 
 out:
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index e71785102206..61362e6fa9ec 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -28,18 +28,7 @@
 NESTED(handle_sys, PT_SIZE, sp)
         .set    noat
         SAVE_SOME
-#ifdef CONFIG_TRACE_IRQFLAGS
-        TRACE_IRQS_ON
-#ifdef CONFIG_64BIT
-        LONG_L  $8, PT_R8(sp)
-        LONG_L  $9, PT_R9(sp)
-#endif
-        LONG_L  $7, PT_R7(sp)
-        LONG_L  $6, PT_R6(sp)
-        LONG_L  $5, PT_R5(sp)
-        LONG_L  $4, PT_R4(sp)
-        LONG_L  $2, PT_R2(sp)
-#endif
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 4c22d0b4825d..6c7b5ed0ea6e 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -34,7 +34,7 @@ NESTED(handle_sys64, PT_SIZE, sp)
          */
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 #endif
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index f25c2a2f1038..6d9f18727ac5 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -33,7 +33,7 @@ NESTED(handle_sysn32, PT_SIZE, sp)
 #ifndef CONFIG_MIPS32_O32
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
 #endif
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 288ee4ac4dbb..2e6d0673163e 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -28,7 +28,7 @@
 NESTED(handle_sys, PT_SIZE, sp)
         .set    noat
         SAVE_SOME
-        TRACE_IRQS_ON
+        TRACE_IRQS_ON_RELOAD
         STI
         .set    at
         ld      t1, PT_EPC(sp)          # skip syscall on return
diff --git a/arch/mips/kernel/stacktrace.c b/arch/mips/kernel/stacktrace.c
new file mode 100644
index 000000000000..4aabe526a68e
--- /dev/null
+++ b/arch/mips/kernel/stacktrace.c
@@ -0,0 +1,85 @@
+/*
+ * arch/mips/kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ *  Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <asm/stacktrace.h>
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer:
+ */
+static void save_raw_context_stack(struct stack_trace *trace,
+        unsigned long reg29)
+{
+        unsigned long *sp = (unsigned long *)reg29;
+        unsigned long addr;
+
+        while (!kstack_end(sp)) {
+                addr = *sp++;
+                if (__kernel_text_address(addr)) {
+                        if (trace->skip > 0)
+                                trace->skip--;
+                        else
+                                trace->entries[trace->nr_entries++] = addr;
+                        if (trace->nr_entries >= trace->max_entries)
+                                break;
+                }
+        }
+}
+
+static void save_context_stack(struct stack_trace *trace,
+        struct task_struct *task, struct pt_regs *regs)
+{
+        unsigned long sp = regs->regs[29];
+#ifdef CONFIG_KALLSYMS
+        unsigned long ra = regs->regs[31];
+        unsigned long pc = regs->cp0_epc;
+
+        if (raw_show_trace || !__kernel_text_address(pc)) {
+                unsigned long stack_page =
+                        (unsigned long)task_stack_page(task);
+                if (stack_page && sp >= stack_page &&
+                    sp <= stack_page + THREAD_SIZE - 32)
+                        save_raw_context_stack(trace, sp);
+                return;
+        }
+        do {
+                if (trace->skip > 0)
+                        trace->skip--;
+                else
+                        trace->entries[trace->nr_entries++] = pc;
+                if (trace->nr_entries >= trace->max_entries)
+                        break;
+                pc = unwind_stack(task, &sp, pc, &ra);
+        } while (pc);
+#else
+        save_raw_context_stack(sp);
+#endif
+}
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
+{
+        struct pt_regs dummyregs;
+        struct pt_regs *regs = &dummyregs;
+
+        WARN_ON(trace->nr_entries || !trace->max_entries);
+
+        if (task && task != current) {
+                regs->regs[29] = task->thread.reg29;
+                regs->regs[31] = 0;
+                regs->cp0_epc = task->thread.reg31;
+        } else {
+                if (!task)
+                        task = current;
+                prepare_frametrace(regs);
+        }
+
+        save_context_stack(trace, task, regs);
+}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index e51d8fd9a152..b7292a56d4cd 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -41,6 +41,7 @@
 #include <asm/mmu_context.h>
 #include <asm/watch.h>
 #include <asm/types.h>
+#include <asm/stacktrace.h>
 
 extern asmlinkage void handle_int(void);
 extern asmlinkage void handle_tlbm(void);
@@ -92,16 +93,14 @@ static void show_raw_backtrace(unsigned long reg29)
 }
 
 #ifdef CONFIG_KALLSYMS
-static int raw_show_trace;
+int raw_show_trace;
 static int __init set_raw_show_trace(char *str)
 {
         raw_show_trace = 1;
         return 1;
 }
 __setup("raw_show_trace", set_raw_show_trace);
-
-extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
-                                  unsigned long pc, unsigned long ra);
+#endif
 
 static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
 {
@@ -116,14 +115,10 @@ static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
         printk("Call Trace:\n");
         do {
                 print_ip_sym(pc);
-                pc = unwind_stack(task, &sp, pc, ra);
-                ra = 0;
+                pc = unwind_stack(task, &sp, pc, &ra);
         } while (pc);
         printk("\n");
 }
-#else
-#define show_backtrace(task, r) show_raw_backtrace((r)->regs[29]);
-#endif
 
 /*
  * This routine abuses get_user()/put_user() to reference pointers
@@ -158,28 +153,6 @@ static void show_stacktrace(struct task_struct *task, struct pt_regs *regs)
         show_backtrace(task, regs);
 }
 
-static __always_inline void prepare_frametrace(struct pt_regs *regs)
-{
-        __asm__ __volatile__(
-                ".set push\n\t"
-                ".set noat\n\t"
-#ifdef CONFIG_64BIT
-                "1: dla $1, 1b\n\t"
-                "sd $1, %0\n\t"
-                "sd $29, %1\n\t"
-                "sd $31, %2\n\t"
-#else
-                "1: la $1, 1b\n\t"
-                "sw $1, %0\n\t"
-                "sw $29, %1\n\t"
-                "sw $31, %2\n\t"
-#endif
-                ".set pop\n\t"
-                : "=m" (regs->cp0_epc),
-                "=m" (regs->regs[29]), "=m" (regs->regs[31])
-                : : "memory");
-}
-
 void show_stack(struct task_struct *task, unsigned long *sp)
 {
         struct pt_regs regs;
@@ -206,11 +179,6 @@ void dump_stack(void)
 {
         struct pt_regs regs;
 
-        /*
-         * Remove any garbage that may be in regs (specially func
-         * addresses) to avoid show_raw_backtrace() to report them
-         */
-        memset(&regs, 0, sizeof(regs));
         prepare_frametrace(&regs);
         show_backtrace(current, &regs);
 }