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[MIPS] Improve unwind_stack()
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>
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@ -448,15 +448,16 @@ unsigned long get_wchan(struct task_struct *p)
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}
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#ifdef CONFIG_KALLSYMS
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/* used by show_frametrace() */
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unsigned long unwind_stack(struct task_struct *task,
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unsigned long **sp, unsigned long pc)
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/* used by show_backtrace() */
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unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
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unsigned long pc, unsigned long ra)
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{
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unsigned long stack_page;
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struct mips_frame_info info;
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char *modname;
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char namebuf[KSYM_NAME_LEN + 1];
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unsigned long size, ofs;
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int leaf;
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stack_page = (unsigned long)task_stack_page(task);
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if (!stack_page)
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@ -469,18 +470,26 @@ unsigned long unwind_stack(struct task_struct *task,
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info.func = (void *)(pc - ofs);
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info.func_size = ofs; /* analyze from start to ofs */
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if (get_frame_info(&info)) {
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/* leaf or unknown */
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*sp += info.frame_size / sizeof(long);
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return 0;
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}
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if ((unsigned long)*sp < stack_page ||
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(unsigned long)*sp + info.frame_size / sizeof(long) >
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stack_page + THREAD_SIZE - 32)
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leaf = get_frame_info(&info);
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if (leaf < 0)
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return 0;
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pc = (*sp)[info.pc_offset];
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*sp += info.frame_size / sizeof(long);
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return pc;
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if (*sp < stack_page ||
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*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
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return 0;
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if (leaf)
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/*
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* For some extreme cases, get_frame_info() can
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* consider wrongly a nested function as a leaf
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* one. In that cases avoid to return always the
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* same value.
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*/
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pc = pc != ra ? ra : 0;
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else
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pc = ((unsigned long *)(*sp))[info.pc_offset];
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*sp += info.frame_size;
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return __kernel_text_address(pc) ? pc : 0;
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}
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#endif
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@ -74,8 +74,9 @@ void (*board_ejtag_handler_setup)(void);
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void (*board_bind_eic_interrupt)(int irq, int regset);
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static void show_raw_backtrace(unsigned long *sp)
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static void show_raw_backtrace(unsigned long reg29)
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{
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unsigned long *sp = (unsigned long *)reg29;
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unsigned long addr;
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printk("Call Trace:");
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@ -99,30 +100,29 @@ static int __init set_raw_show_trace(char *str)
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}
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__setup("raw_show_trace", set_raw_show_trace);
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extern unsigned long unwind_stack(struct task_struct *task,
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unsigned long **sp, unsigned long pc);
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extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
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unsigned long pc, unsigned long ra);
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static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
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{
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unsigned long *sp = (long *)regs->regs[29];
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unsigned long sp = regs->regs[29];
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unsigned long ra = regs->regs[31];
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unsigned long pc = regs->cp0_epc;
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int top = 1;
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if (raw_show_trace || !__kernel_text_address(pc)) {
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show_raw_backtrace(sp);
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return;
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}
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printk("Call Trace:\n");
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while (__kernel_text_address(pc)) {
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do {
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print_ip_sym(pc);
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pc = unwind_stack(task, &sp, pc);
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if (top && pc == 0)
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pc = regs->regs[31]; /* leaf? */
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top = 0;
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}
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pc = unwind_stack(task, &sp, pc, ra);
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ra = 0;
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} while (pc);
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printk("\n");
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}
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#else
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#define show_backtrace(task, r) show_raw_backtrace((long *)(r)->regs[29]);
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#define show_backtrace(task, r) show_raw_backtrace((r)->regs[29]);
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#endif
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/*
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