Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261472AbUKIKt4 (ORCPT ); Tue, 9 Nov 2004 05:49:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261484AbUKIKru (ORCPT ); Tue, 9 Nov 2004 05:47:50 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:52374 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S261472AbUKIKjB (ORCPT ); Tue, 9 Nov 2004 05:39:01 -0500 Subject: [PATCH 4/11] oprofile: ia64 support for oprofile stack trace sampling From: Greg Banks To: Andrew Morton Cc: OProfile List , Linux Kernel Mailing List Content-Type: multipart/mixed; boundary="=-4I3gGUzWv865ZpKzB6SL" Organization: Silicon Graphics Inc, Australian Software Group. Message-Id: <1099996728.1985.787.camel@hole.melbourne.sgi.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6-1mdk Date: Tue, 09 Nov 2004 21:38:48 +1100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10089 Lines: 303 --=-4I3gGUzWv865ZpKzB6SL Content-Type: text/plain Content-Transfer-Encoding: 7bit -- Greg Banks, R&D Software Engineer, SGI Australian Software Group. I don't speak for SGI. --=-4I3gGUzWv865ZpKzB6SL Content-Disposition: attachment; filename=oprofile-callgraph-ia64 Content-Type: text/plain; name=oprofile-callgraph-ia64; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit oprofile ia64 arch updates, including some internal API changes and support for stack trace sampling. Signed-off-by: John Levon Signed-off-by: Keith Owens Signed-off-by: Greg Banks --- arch/ia64/kernel/ia64_ksyms.c | 3 arch/ia64/kernel/unwind.c | 2 arch/ia64/oprofile/Makefile | 2 arch/ia64/oprofile/backtrace.c | 150 +++++++++++++++++++++++++++++++++++++++++ arch/ia64/oprofile/init.c | 10 +- arch/ia64/oprofile/perfmon.c | 15 +--- 6 files changed, 167 insertions(+), 15 deletions(-) Index: linux/arch/ia64/oprofile/perfmon.c =================================================================== --- linux.orig/arch/ia64/oprofile/perfmon.c 2004-10-19 07:53:51.%N +1000 +++ linux/arch/ia64/oprofile/perfmon.c 2004-11-06 01:20:07.%N +1100 @@ -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; Index: linux/arch/ia64/oprofile/backtrace.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux/arch/ia64/oprofile/backtrace.c 2004-11-06 01:20:07.%N +1100 @@ -0,0 +1,150 @@ +/** + * @file backtrace.c + * + * @remark Copyright 2004 Silicon Graphics Inc. All Rights Reserved. + * @remark Read the file COPYING + * + * @author Greg Banks + * @author Keith Owens + * 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 +#include +#include +#include +#include + +/* + * 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); +} Index: linux/arch/ia64/kernel/unwind.c =================================================================== --- linux.orig/arch/ia64/kernel/unwind.c 2004-11-06 01:12:10.%N +1100 +++ linux/arch/ia64/kernel/unwind.c 2004-11-06 01:20:07.%N +1100 @@ -2110,6 +2110,8 @@ 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) { Index: linux/arch/ia64/oprofile/Makefile =================================================================== --- linux.orig/arch/ia64/oprofile/Makefile 2004-10-19 07:53:43.%N +1000 +++ linux/arch/ia64/oprofile/Makefile 2004-11-06 01:20:07.%N +1100 @@ -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 Index: linux/arch/ia64/kernel/ia64_ksyms.c =================================================================== --- linux.orig/arch/ia64/kernel/ia64_ksyms.c 2004-10-19 07:54:07.%N +1000 +++ linux/arch/ia64/kernel/ia64_ksyms.c 2004-11-06 01:20:07.%N +1100 @@ -122,3 +122,6 @@ EXPORT_SYMBOL(ia64_spinlock_contention); # endif # endif #endif + +extern char ia64_ivt[]; +EXPORT_SYMBOL(ia64_ivt); Index: linux/arch/ia64/oprofile/init.c =================================================================== --- linux.orig/arch/ia64/oprofile/init.c 2004-10-19 07:53:21.%N +1000 +++ linux/arch/ia64/oprofile/init.c 2004-11-06 01:20:07.%N +1100 @@ -12,15 +12,17 @@ #include #include -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; } --=-4I3gGUzWv865ZpKzB6SL-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/