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-rw-r--r--arch/arc/kernel/stacktrace.c118
1 files changed, 73 insertions, 45 deletions
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index f8b7d880304d..ea99c066ef25 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* stacktrace.c : stacktracing APIs needed by rest of kernel
* (wrappers over ARC dwarf based unwinder)
*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
* vineetg: aug 2009
* -Implemented CONFIG_STACKTRACE APIs, primarily save_stack_trace_tsk( )
* for displaying task's kernel mode call stack in /proc/<pid>/stack
@@ -18,7 +15,7 @@
* = specifics of data structs where trace is saved(CONFIG_STACKTRACE etc)
*
* vineetg: March 2009
- * -Implemented correct versions of thread_saved_pc() and get_wchan()
+ * -Implemented correct versions of thread_saved_pc() and __get_wchan()
*
* rajeshwarr: 2008
* -Initial implementation
@@ -28,8 +25,11 @@
#include <linux/export.h>
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
+#include <linux/sched/debug.h>
+
#include <asm/arcregs.h>
#include <asm/unwind.h>
+#include <asm/stacktrace.h>
#include <asm/switch_to.h>
/*-------------------------------------------------------------------------
@@ -39,11 +39,27 @@
#ifdef CONFIG_ARC_DW2_UNWIND
-static void seed_unwind_frame_info(struct task_struct *tsk,
- struct pt_regs *regs,
- struct unwind_frame_info *frame_info)
+static int
+seed_unwind_frame_info(struct task_struct *tsk, struct pt_regs *regs,
+ struct unwind_frame_info *frame_info)
{
- if (tsk == NULL && regs == NULL) {
+ if (regs) {
+ /*
+ * Asynchronous unwinding of intr/exception
+ * - Just uses the pt_regs passed
+ */
+ frame_info->task = tsk;
+
+ frame_info->regs.r27 = regs->fp;
+ frame_info->regs.r28 = regs->sp;
+ frame_info->regs.r31 = regs->blink;
+ frame_info->regs.r63 = regs->ret;
+ frame_info->call_frame = 0;
+ } else if (tsk == NULL || tsk == current) {
+ /*
+ * synchronous unwinding (e.g. dump_stack)
+ * - uses current values of SP and friends
+ */
unsigned long fp, sp, blink, ret;
frame_info->task = current;
@@ -60,13 +76,22 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
frame_info->regs.r31 = blink;
frame_info->regs.r63 = ret;
frame_info->call_frame = 0;
- } else if (regs == NULL) {
+ } else {
+ /*
+ * Asynchronous unwinding of a likely sleeping task
+ * - first ensure it is actually sleeping
+ * - if so, it will be in __switch_to, kernel mode SP of task
+ * is safe-kept and BLINK at a well known location in there
+ */
+
+ if (task_is_running(tsk))
+ return -1;
frame_info->task = tsk;
- frame_info->regs.r27 = KSTK_FP(tsk);
- frame_info->regs.r28 = KSTK_ESP(tsk);
- frame_info->regs.r31 = KSTK_BLINK(tsk);
+ frame_info->regs.r27 = TSK_K_FP(tsk);
+ frame_info->regs.r28 = TSK_K_ESP(tsk);
+ frame_info->regs.r31 = TSK_K_BLINK(tsk);
frame_info->regs.r63 = (unsigned int)__switch_to;
/* In the prologue of __switch_to, first FP is saved on stack
@@ -82,45 +107,42 @@ static void seed_unwind_frame_info(struct task_struct *tsk,
frame_info->regs.r28 += 60;
frame_info->call_frame = 0;
- } else {
- frame_info->task = tsk;
-
- frame_info->regs.r27 = regs->fp;
- frame_info->regs.r28 = regs->sp;
- frame_info->regs.r31 = regs->blink;
- frame_info->regs.r63 = regs->ret;
- frame_info->call_frame = 0;
}
+ return 0;
}
#endif
-static noinline unsigned int
+notrace noinline unsigned int
arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
int (*consumer_fn) (unsigned int, void *), void *arg)
{
#ifdef CONFIG_ARC_DW2_UNWIND
- int ret = 0;
+ int ret = 0, cnt = 0;
unsigned int address;
struct unwind_frame_info frame_info;
- seed_unwind_frame_info(tsk, regs, &frame_info);
+ if (seed_unwind_frame_info(tsk, regs, &frame_info))
+ return 0;
while (1) {
address = UNW_PC(&frame_info);
- if (address && __kernel_text_address(address)) {
- if (consumer_fn(address, arg) == -1)
- break;
- }
+ if (!address || !__kernel_text_address(address))
+ break;
- ret = arc_unwind(&frame_info);
+ if (consumer_fn(address, arg) == -1)
+ break;
- if (ret == 0) {
- frame_info.regs.r63 = frame_info.regs.r31;
- continue;
- } else {
+ ret = arc_unwind(&frame_info);
+ if (ret)
break;
+
+ frame_info.regs.r63 = frame_info.regs.r31;
+
+ if (cnt++ > 128) {
+ printk("unwinder looping too long, aborting !\n");
+ return 0;
}
}
@@ -128,10 +150,10 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
#else
/* On ARC, only Dward based unwinder works. fp based backtracing is
* not possible (-fno-omit-frame-pointer) because of the way function
- * prelogue is setup (callee regs saved and then fp set and not other
+ * prologue is setup (callee regs saved and then fp set and not other
* way around
*/
- pr_warn("CONFIG_ARC_DW2_UNWIND needs to be enabled\n");
+ pr_warn_once("CONFIG_ARC_DW2_UNWIND needs to be enabled\n");
return 0;
#endif
@@ -148,9 +170,11 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
/* Call-back which plugs into unwinding core to dump the stack in
* case of panic/OOPs/BUG etc
*/
-static int __print_sym(unsigned int address, void *unused)
+static int __print_sym(unsigned int address, void *arg)
{
- __print_symbol(" %s\n", address);
+ const char *loglvl = arg;
+
+ printk("%s %pS\n", loglvl, (void *)address);
return 0;
}
@@ -207,24 +231,25 @@ static int __get_first_nonsched(unsigned int address, void *unused)
*-------------------------------------------------------------------------
*/
-noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs)
+noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+ const char *loglvl)
{
- pr_info("\nStack Trace:\n");
- arc_unwind_core(tsk, regs, __print_sym, NULL);
+ printk("%s\nStack Trace:\n", loglvl);
+ arc_unwind_core(tsk, regs, __print_sym, (void *)loglvl);
}
EXPORT_SYMBOL(show_stacktrace);
/* Expected by sched Code */
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
{
- show_stacktrace(tsk, NULL);
+ show_stacktrace(tsk, NULL, loglvl);
}
/* Another API expected by schedular, shows up in "ps" as Wait Channel
- * Ofcourse just returning schedule( ) would be pointless so unwind until
+ * Of course just returning schedule( ) would be pointless so unwind until
* the function is not in schedular code
*/
-unsigned int get_wchan(struct task_struct *tsk)
+unsigned int __get_wchan(struct task_struct *tsk)
{
return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL);
}
@@ -237,11 +262,14 @@ unsigned int get_wchan(struct task_struct *tsk)
*/
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
+ /* Assumes @tsk is sleeping so unwinds from __switch_to */
arc_unwind_core(tsk, NULL, __collect_all_but_sched, trace);
}
void save_stack_trace(struct stack_trace *trace)
{
- arc_unwind_core(current, NULL, __collect_all, trace);
+ /* Pass NULL for task so it unwinds the current call frame */
+ arc_unwind_core(NULL, NULL, __collect_all, trace);
}
+EXPORT_SYMBOL_GPL(save_stack_trace);
#endif
generated by cgit (git 2.34.1) at 2025-12-21 21:16:08 +0000