From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- arch/ia64/oprofile/backtrace.c | 131 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 arch/ia64/oprofile/backtrace.c (limited to 'arch/ia64/oprofile/backtrace.c') diff --git a/arch/ia64/oprofile/backtrace.c b/arch/ia64/oprofile/backtrace.c new file mode 100644 index 000000000..6a219a946 --- /dev/null +++ b/arch/ia64/oprofile/backtrace.c @@ -0,0 +1,131 @@ +/** + * @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 + +/* + * 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); +} -- cgit v1.2.3