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[MIPS] Improve unwind_stack()

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This patch allows unwind_stack() to return ra for leaf function.
But it tries to detects cases where get_frame_info() wrongly
consider nested function as a leaf one.

It also pass 'unsinged long *sp' instead of 'unsigned long **sp'
as second parameter. The code looks cleaner.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Franck Bui-Huu 2006-08-03 09:29:21 +02:00 committed by Ralf Baechle
parent 0cceb4aa9a
commit 4d157d5eac
2 changed files with 35 additions and 26 deletions
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37
arch/mips/kernel/process.c
View File

@ -448,15 +448,16 @@ unsigned long get_wchan(struct task_struct *p)
}
#ifdef CONFIG_KALLSYMS
/* used by show_frametrace() */
unsigned long unwind_stack(struct task_struct *task,
unsigned long **sp, unsigned long pc)
/* used by show_backtrace() */
unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
unsigned long pc, unsigned long ra)
{
unsigned long stack_page;
struct mips_frame_info info;
char *modname;
char namebuf[KSYM_NAME_LEN + 1];
unsigned long size, ofs;
int leaf;
stack_page = (unsigned long)task_stack_page(task);
if (!stack_page)
@ -469,18 +470,26 @@ unsigned long unwind_stack(struct task_struct *task,
info.func = (void *)(pc - ofs);
info.func_size = ofs; /* analyze from start to ofs */
if (get_frame_info(&info)) {
/* leaf or unknown */
*sp += info.frame_size / sizeof(long);
return 0;
}
if ((unsigned long)*sp < stack_page ||
(unsigned long)*sp + info.frame_size / sizeof(long) >
stack_page + THREAD_SIZE - 32)
leaf = get_frame_info(&info);
if (leaf < 0)
return 0;
pc = (*sp)[info.pc_offset];
*sp += info.frame_size / sizeof(long);
return pc;
if (*sp < stack_page ||
*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
return 0;
if (leaf)
/*
* For some extreme cases, get_frame_info() can
* consider wrongly a nested function as a leaf
* one. In that cases avoid to return always the
* same value.
*/
pc = pc != ra ? ra : 0;
else
pc = ((unsigned long *)(*sp))[info.pc_offset];
*sp += info.frame_size;
return __kernel_text_address(pc) ? pc : 0;
}
#endif

24
arch/mips/kernel/traps.c
View File

@ -74,8 +74,9 @@ void (*board_ejtag_handler_setup)(void);
void (*board_bind_eic_interrupt)(int irq, int regset);
static void show_raw_backtrace(unsigned long *sp)
static void show_raw_backtrace(unsigned long reg29)
{
unsigned long *sp = (unsigned long *)reg29;
unsigned long addr;
printk("Call Trace:");
@ -99,30 +100,29 @@ static int __init set_raw_show_trace(char *str)
}
__setup("raw_show_trace", set_raw_show_trace);
extern unsigned long unwind_stack(struct task_struct *task,
unsigned long **sp, unsigned long pc);
extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
unsigned long pc, unsigned long ra);
static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
{
unsigned long *sp = (long *)regs->regs[29];
unsigned long sp = regs->regs[29];
unsigned long ra = regs->regs[31];
unsigned long pc = regs->cp0_epc;
int top = 1;
if (raw_show_trace || !__kernel_text_address(pc)) {
show_raw_backtrace(sp);
return;
}
printk("Call Trace:\n");
while (__kernel_text_address(pc)) {
do {
print_ip_sym(pc);
pc = unwind_stack(task, &sp, pc);
if (top && pc == 0)
pc = regs->regs[31]; /* leaf? */
top = 0;
}
pc = unwind_stack(task, &sp, pc, ra);
ra = 0;
} while (pc);
printk("\n");
}
#else
#define show_backtrace(task, r) show_raw_backtrace((long *)(r)->regs[29]);
#define show_backtrace(task, r) show_raw_backtrace((r)->regs[29]);
#endif
/*