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[PATCH 2/3] [MIPS] lockdep: add STACKTRACE_SUPPORT and enable LOCKDEP_SU

To: linux-mips@linux-mips.org
Subject: [PATCH 2/3] [MIPS] lockdep: add STACKTRACE_SUPPORT and enable LOCKDEP_SUPPORT
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Tue, 26 Sep 2006 23:44:01 +0900 (JST)
Cc: ralf@linux-mips.org, mingo@redhat.com
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
Implement stacktrace interface by using unwind_stack().
And enable lockdep support.

This is a patch againt linux-mips.org git tree.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>

 arch/mips/Kconfig             |    8 ++
 arch/mips/kernel/Makefile     |    1 
 arch/mips/kernel/process.c    |    1 
 arch/mips/kernel/stacktrace.c |  113 ++++++++++++++++++++++++++++++++++++++++++
 arch/mips/kernel/traps.c      |   37 +------------
 include/asm-mips/stacktrace.h |   44 ++++++++++++++++
 6 files changed, 170 insertions(+), 34 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 929b9b4..c8bcf0e 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1836,6 +1836,14 @@ config RWSEM_GENERIC_SPINLOCK
        bool
        default y
 
+config LOCKDEP_SUPPORT
+       bool
+       default y
+
+config STACKTRACE_SUPPORT
+       bool
+       default y
+
 source "init/Kconfig"
 
 menu "Bus options (PCI, PCMCIA, EISA, ISA, TC)"
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 881c467..cd9cec9 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -11,6 +11,7 @@ obj-y         += cpu-probe.o branch.o entry.o g
 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/process.c b/arch/mips/kernel/process.c
index 951bf9c..277fdce 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -40,6 +40,7 @@ #include <asm/io.h>
 #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);
diff --git a/arch/mips/kernel/stacktrace.c b/arch/mips/kernel/stacktrace.c
new file mode 100644
index 0000000..c258088
--- /dev/null
+++ b/arch/mips/kernel/stacktrace.c
@@ -0,0 +1,113 @@
+/*
+ * 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 inline void
+save_raw_context_stack(struct stack_trace *trace, unsigned int skip,
+                      unsigned long reg29)
+{
+       unsigned long *sp = (unsigned long *)reg29;
+       unsigned long addr;
+
+       while (!kstack_end(sp)) {
+               addr = *sp++;
+               if (__kernel_text_address(addr)) {
+                       if (!skip)
+                               trace->entries[trace->nr_entries++] = addr;
+                       else
+                               skip--;
+                       if (trace->nr_entries >= trace->max_entries)
+                               break;
+               }
+       }
+}
+
+static inline struct pt_regs *
+save_context_stack(struct stack_trace *trace, unsigned int skip,
+                  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;
+       extern void ret_from_irq(void);
+
+       if (raw_show_trace || !__kernel_text_address(pc)) {
+               save_raw_context_stack(trace, skip, sp);
+               return NULL;
+       }
+       do {
+               if (!skip)
+                       trace->entries[trace->nr_entries++] = pc;
+               else
+                       skip--;
+               if (trace->nr_entries >= trace->max_entries)
+                       break;
+               /*
+                * If we reached the bottom of interrupt context,
+                * return saved pt_regs.
+                */
+               if (pc == (unsigned long)ret_from_irq) {
+                       unsigned long stack_page =
+                               (unsigned long)task_stack_page(task);
+                       if (!stack_page ||
+                           sp < stack_page ||
+                           sp > stack_page + THREAD_SIZE - 32)
+                               break;
+                       return (struct pt_regs *)sp;
+               }
+               pc = unwind_stack(task, &sp, pc, ra);
+               ra = 0;
+       } while (pc);
+#else
+       save_raw_context_stack(sp);
+#endif
+
+       return NULL;
+}
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ * If all_contexts is set, all contexts (hardirq, softirq and process)
+ * are saved. If not set then only the current context is saved.
+ */
+void save_stack_trace(struct stack_trace *trace,
+                     struct task_struct *task, int all_contexts,
+                     unsigned int skip)
+{
+       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);
+       }
+
+       while (1) {
+               regs = save_context_stack(trace, skip, task, regs);
+               if (!all_contexts || !regs ||
+                   trace->nr_entries >= trace->max_entries)
+                       break;
+               trace->entries[trace->nr_entries++] = ULONG_MAX;
+               if (trace->nr_entries >= trace->max_entries)
+                       break;
+               skip = 0;
+       }
+}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index e51d8fd..440b865 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -41,6 +41,7 @@ #include <asm/uaccess.h>
 #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 @@ #endif
 }
 
 #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)
 {
@@ -121,9 +120,6 @@ static void show_backtrace(struct task_s
        } 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 +154,6 @@ static void show_stacktrace(struct task_
        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 +180,6 @@ 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);
 }
diff --git a/include/asm-mips/stacktrace.h b/include/asm-mips/stacktrace.h
new file mode 100644
index 0000000..231f6f8
--- /dev/null
+++ b/include/asm-mips/stacktrace.h
@@ -0,0 +1,44 @@
+#ifndef _ASM_STACKTRACE_H
+#define _ASM_STACKTRACE_H
+
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_KALLSYMS
+extern int raw_show_trace;
+extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+                                 unsigned long pc, unsigned long ra);
+#else
+#define raw_show_trace 1
+#define unwind_stack(task, sp, pc, ra) 0
+#endif
+
+static __always_inline void prepare_frametrace(struct pt_regs *regs)
+{
+#ifndef CONFIG_KALLSYMS
+       /*
+        * Remove any garbage that may be in regs (specially func
+        * addresses) to avoid show_raw_backtrace() to report them
+        */
+       memset(regs, 0, sizeof(*regs));
+#endif
+       __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");
+}
+
+#endif /* _ASM_STACKTRACE_H */

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