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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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46651c650f
Implement arch_stack_walk() for Alpha using a simple kernel stack scanning walker. Start from regs+1 for current tasks to skip pt_regs and use pcb.ksp for blocked tasks. Filter candidates with __kernel_text_address() and stop at stack bounds via kstack_end(). Enable CONFIG_STACKTRACE_SUPPORT and CONFIG_ARCH_STACKWALK so generic stacktrace users (dump_stack(), /proc/*/stack, SysRq backtraces, etc.) work on Alpha. This provides functional in-kernel stack traces without requiring frame pointer unwinding. Reviewed-by: Matt Turner <mattst88@gmail.com> Tested-by: Matt Turner <mattst88@gmail.com> Signed-off-by: Magnus Lindholm <linmag7@gmail.com> Link: https://lore.kernel.org/r/20260706170019.2941459-3-linmag7@gmail.com Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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#include <linux/stacktrace.h>
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#include <linux/kallsyms.h>
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#include <asm/thread_info.h>
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#include <asm/ptrace.h>
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static __always_inline unsigned long alpha_get_current_ksp(void)
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{
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unsigned long sp;
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asm volatile("mov $30, %0" : "=r"(sp));
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return sp;
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}
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static void alpha_scan_kernel_stack(unsigned long ksp,
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stack_trace_consume_fn consume_entry,
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void *cookie)
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{
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unsigned long *p = (unsigned long *)ksp;
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if (unlikely(ksp & (sizeof(unsigned long) - 1)))
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return;
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while (!kstack_end(p)) {
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unsigned long addr = READ_ONCE_NOCHECK(*p++);
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if (!__kernel_text_address(addr))
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continue;
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if (!consume_entry(cookie, addr))
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break;
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}
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}
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noinline void arch_stack_walk(stack_trace_consume_fn consume_entry,
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void *cookie,
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struct task_struct *task,
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struct pt_regs *regs)
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{
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unsigned long ksp;
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if (!task)
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task = current;
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if (regs && task == current) {
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/*
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* pt_regs is stored on the kernel stack; regs+1 matches
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* what arch/alpha/kernel/traps.c uses as the trace start.
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*/
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ksp = (unsigned long)(regs + 1);
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} else if (task == current) {
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ksp = alpha_get_current_ksp();
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} else {
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ksp = task_thread_info(task)->pcb.ksp;
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}
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alpha_scan_kernel_stack(ksp, consume_entry, cookie);
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}
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