+++ /dev/null
-/**
- * @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>
-
-/*
- * 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;
- unsigned long *prev_pfs_loc; /* state for WAR for old spinlock ool code */
-} ia64_backtrace_t;
-
-/* 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 = 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);
-}
projects / users / jedix / linux-maple.git / commitdiff