From: Greg Banks <gnb@melbourne.sgi.com>
oprofile ia64 arch updates, including some internal API changes and support
for stack trace sampling.
Signed-off-by: John Levon <levon@movementarian.org>
Signed-off-by: Keith Owens <kaos@melbourne.sgi.com>
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/ia64/kernel/ia64_ksyms.c | 3
25-akpm/arch/ia64/kernel/unwind.c | 2
25-akpm/arch/ia64/oprofile/Makefile | 2
25-akpm/arch/ia64/oprofile/backtrace.c | 150 +++++++++++++++++++++++++++++++++
25-akpm/arch/ia64/oprofile/init.c | 10 +-
25-akpm/arch/ia64/oprofile/perfmon.c | 15 +--
6 files changed, 167 insertions(+), 15 deletions(-)
diff -puN arch/ia64/kernel/ia64_ksyms.c~oprofile-ia64-support-for-oprofile-stack-trace arch/ia64/kernel/ia64_ksyms.c
--- 25/arch/ia64/kernel/ia64_ksyms.c~oprofile-ia64-support-for-oprofile-stack-trace Tue Nov 9 13:55:25 2004
+++ 25-akpm/arch/ia64/kernel/ia64_ksyms.c Tue Nov 9 13:55:25 2004
@@ -122,3 +122,6 @@ EXPORT_SYMBOL(ia64_spinlock_contention);
# endif
# endif
#endif
+
+extern char ia64_ivt[];
+EXPORT_SYMBOL(ia64_ivt);
diff -puN arch/ia64/kernel/unwind.c~oprofile-ia64-support-for-oprofile-stack-trace arch/ia64/kernel/unwind.c
--- 25/arch/ia64/kernel/unwind.c~oprofile-ia64-support-for-oprofile-stack-trace Tue Nov 9 13:55:25 2004
+++ 25-akpm/arch/ia64/kernel/unwind.c Tue Nov 9 13:55:25 2004
@@ -2051,6 +2051,8 @@ unw_init_frame_info (struct unw_frame_in
find_save_locs(info);
}
+EXPORT_SYMBOL(unw_init_frame_info);
+
void
unw_init_from_blocked_task (struct unw_frame_info *info, struct task_struct *t)
{
diff -puN /dev/null arch/ia64/oprofile/backtrace.c
--- /dev/null Thu Apr 11 07:25:15 2002
+++ 25-akpm/arch/ia64/oprofile/backtrace.c Tue Nov 9 13:55:25 2004
@@ -0,0 +1,150 @@
+/**
+ * @file backtrace.c
+ *
+ * @remark Copyright 2004 Silicon Graphics Inc. All Rights Reserved.
+ * @remark Read the file COPYING
+ *
+ * @author Greg Banks <gnb@melbourne.sgi.com>
+ * @author Keith Owens <kaos@melbourne.sgi.com>
+ * Based on work done for the ia64 port of the SGI kernprof patch, which is
+ * Copyright (c) 2003-2004 Silicon Graphics Inc. All Rights Reserved.
+ */
+
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <asm/ptrace.h>
+#include <asm/system.h>
+
+/*
+ * For IA64 we need to perform a complex little dance to get both
+ * the struct pt_regs and a synthetic struct switch_stack in place
+ * to allow the unwind code to work. This dance requires our unwind
+ * using code to be called from a function called from unw_init_running().
+ * There we only get a single void* data pointer, so use this struct
+ * to hold all the data we need during the unwind.
+ */
+typedef struct
+{
+ unsigned int depth;
+ struct pt_regs *regs;
+ struct unw_frame_info frame;
+ u64 *prev_pfs_loc; /* state for WAR for old spinlock ool code */
+} ia64_backtrace_t;
+
+#if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
+/*
+ * Returns non-zero if the PC is in the spinlock contention out-of-line code
+ * with non-standard calling sequence (on older compilers).
+ */
+static __inline__ int in_old_ool_spinlock_code(unsigned long pc)
+{
+ extern const char ia64_spinlock_contention_pre3_4[] __attribute__ ((weak));
+ extern const char ia64_spinlock_contention_pre3_4_end[] __attribute__ ((weak));
+ unsigned long sc_start = (unsigned long)ia64_spinlock_contention_pre3_4;
+ unsigned long sc_end = (unsigned long)ia64_spinlock_contention_pre3_4_end;
+ return (sc_start && sc_end && pc >= sc_start && pc < sc_end);
+}
+#else
+/* Newer spinlock code does a proper br.call and works fine with the unwinder */
+#define in_old_ool_spinlock_code(pc) 0
+#endif
+
+/* Returns non-zero if the PC is in the Interrupt Vector Table */
+static __inline__ int in_ivt_code(unsigned long pc)
+{
+ extern char ia64_ivt[];
+ return (pc >= (u_long)ia64_ivt && pc < (u_long)ia64_ivt+32768);
+}
+
+/*
+ * Unwind to next stack frame.
+ */
+static __inline__ int next_frame(ia64_backtrace_t *bt)
+{
+ /*
+ * Avoid unsightly console message from unw_unwind() when attempting
+ * to unwind through the Interrupt Vector Table which has no unwind
+ * information.
+ */
+ if (in_ivt_code(bt->frame.ip))
+ return 0;
+
+ /*
+ * WAR for spinlock contention from leaf functions. ia64_spinlock_contention_pre3_4
+ * has ar.pfs == r0. Leaf functions do not modify ar.pfs so ar.pfs remains
+ * as 0, stopping the backtrace. Record the previous ar.pfs when the current
+ * IP is in ia64_spinlock_contention_pre3_4 then unwind, if pfs_loc has not changed
+ * after unwind then use pt_regs.ar_pfs which is where the real ar.pfs is for
+ * leaf functions.
+ */
+ if (bt->prev_pfs_loc && bt->regs && bt->frame.pfs_loc == bt->prev_pfs_loc)
+ bt->frame.pfs_loc = &bt->regs->ar_pfs;
+ bt->prev_pfs_loc = (in_old_ool_spinlock_code(bt->frame.ip) ? bt->frame.pfs_loc : NULL);
+
+ return unw_unwind(&bt->frame) == 0;
+}
+
+
+static void do_ia64_backtrace(struct unw_frame_info *info, void *vdata)
+{
+ ia64_backtrace_t *bt = vdata;
+ struct switch_stack *sw;
+ int count = 0;
+ u_long pc, sp;
+
+ sw = (struct switch_stack *)(info+1);
+ /* padding from unw_init_running */
+ sw = (struct switch_stack *)(((unsigned long)sw + 15) & ~15);
+
+ unw_init_frame_info(&bt->frame, current, sw);
+
+ /* skip over interrupt frame and oprofile calls */
+ do {
+ unw_get_sp(&bt->frame, &sp);
+ if (sp >= (u_long)bt->regs)
+ break;
+ if (!next_frame(bt))
+ return;
+ } while (count++ < 200);
+
+ /* finally, grab the actual sample */
+ while (bt->depth-- && next_frame(bt)) {
+ unw_get_ip(&bt->frame, &pc);
+ oprofile_add_trace(pc);
+ if (unw_is_intr_frame(&bt->frame)) {
+ /*
+ * Interrupt received on kernel stack; this can
+ * happen when timer interrupt fires while processing
+ * a softirq from the tail end of a hardware interrupt
+ * which interrupted a system call. Don't laugh, it
+ * happens! Splice the backtrace into two parts to
+ * avoid spurious cycles in the gprof output.
+ */
+ /* TODO: split rather than drop the 2nd half */
+ break;
+ }
+ }
+}
+
+void
+ia64_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+ ia64_backtrace_t bt;
+ unsigned long flags;
+
+ /*
+ * On IA64 there is little hope of getting backtraces from
+ * user space programs -- the problems of getting the unwind
+ * information from arbitrary user programs are extreme.
+ */
+ if (user_mode(regs))
+ return;
+
+ bt.depth = depth;
+ bt.regs = regs;
+ bt.prev_pfs_loc = NULL;
+ local_irq_save(flags);
+ unw_init_running(do_ia64_backtrace, &bt);
+ local_irq_restore(flags);
+}
diff -puN arch/ia64/oprofile/init.c~oprofile-ia64-support-for-oprofile-stack-trace arch/ia64/oprofile/init.c
--- 25/arch/ia64/oprofile/init.c~oprofile-ia64-support-for-oprofile-stack-trace Tue Nov 9 13:55:25 2004
+++ 25-akpm/arch/ia64/oprofile/init.c Tue Nov 9 13:55:25 2004
@@ -12,15 +12,17 @@
#include <linux/init.h>
#include <linux/errno.h>
-extern int perfmon_init(struct oprofile_operations ** ops);
+extern int perfmon_init(struct oprofile_operations * ops);
extern void perfmon_exit(void);
+extern void ia64_backtrace(struct pt_regs * const regs, unsigned int depth);
-int __init oprofile_arch_init(struct oprofile_operations ** ops)
+void __init oprofile_arch_init(struct oprofile_operations * ops)
{
#ifdef CONFIG_PERFMON
- return perfmon_init(ops);
+ /* perfmon_init() can fail, but we have no way to report it */
+ perfmon_init(ops);
#endif
- return -ENODEV;
+ ops->backtrace = ia64_backtrace;
}
diff -puN arch/ia64/oprofile/Makefile~oprofile-ia64-support-for-oprofile-stack-trace arch/ia64/oprofile/Makefile
--- 25/arch/ia64/oprofile/Makefile~oprofile-ia64-support-for-oprofile-stack-trace Tue Nov 9 13:55:25 2004
+++ 25-akpm/arch/ia64/oprofile/Makefile Tue Nov 9 13:55:25 2004
@@ -6,5 +6,5 @@ DRIVER_OBJS := $(addprefix ../../../driv
oprofilefs.o oprofile_stats.o \
timer_int.o )
-oprofile-y := $(DRIVER_OBJS) init.o
+oprofile-y := $(DRIVER_OBJS) init.o backtrace.o
oprofile-$(CONFIG_PERFMON) += perfmon.o
diff -puN arch/ia64/oprofile/perfmon.c~oprofile-ia64-support-for-oprofile-stack-trace arch/ia64/oprofile/perfmon.c
--- 25/arch/ia64/oprofile/perfmon.c~oprofile-ia64-support-for-oprofile-stack-trace Tue Nov 9 13:55:25 2004
+++ 25-akpm/arch/ia64/oprofile/perfmon.c Tue Nov 9 13:55:25 2004
@@ -21,8 +21,6 @@ static int
perfmon_handler(struct task_struct *task, void *buf, pfm_ovfl_arg_t *arg,
struct pt_regs *regs, unsigned long stamp)
{
- int cpu = smp_processor_id();
- unsigned long eip = instruction_pointer(regs);
int event = arg->pmd_eventid;
arg->ovfl_ctrl.bits.reset_ovfl_pmds = 1;
@@ -31,7 +29,7 @@ perfmon_handler(struct task_struct *task
* without perfmon being shutdown (e.g. SIGSEGV)
*/
if (allow_ints)
- oprofile_add_sample(eip, !user_mode(regs), event, cpu);
+ oprofile_add_sample(regs, event);
return 0;
}
@@ -75,21 +73,18 @@ static char * get_cpu_type(void)
/* all the ops are handled via userspace for IA64 perfmon */
-static struct oprofile_operations perfmon_ops = {
- .start = perfmon_start,
- .stop = perfmon_stop,
-};
static int using_perfmon;
-int perfmon_init(struct oprofile_operations ** ops)
+int perfmon_init(struct oprofile_operations * ops)
{
int ret = pfm_register_buffer_fmt(&oprofile_fmt);
if (ret)
return -ENODEV;
- perfmon_ops.cpu_type = get_cpu_type();
- *ops = &perfmon_ops;
+ ops->cpu_type = get_cpu_type();
+ ops->start = perfmon_start;
+ ops->stop = perfmon_stop;
using_perfmon = 1;
printk(KERN_INFO "oprofile: using perfmon.\n");
return 0;
_