From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- arch/arc/kernel/stacktrace.c | 275 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 275 insertions(+) create mode 100644 arch/arc/kernel/stacktrace.c (limited to 'arch/arc/kernel/stacktrace.c') diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c new file mode 100644 index 000000000..a211e87aa --- /dev/null +++ b/arch/arc/kernel/stacktrace.c @@ -0,0 +1,275 @@ +/* + * 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//stack + * -Iterator based approach to have single copy of unwinding core and APIs + * needing unwinding, implement the logic in iterator regarding: + * = which frame onwards to start capture + * = which frame to stop capturing (wchan) + * = specifics of data structs where trace is saved(CONFIG_STACKTRACE etc) + * + * vineetg: March 2009 + * -Implemented correct versions of thread_saved_pc() and get_wchan() + * + * rajeshwarr: 2008 + * -Initial implementation + */ + +#include +#include +#include +#include +#include + +#include +#include +#include + +/*------------------------------------------------------------------------- + * Unwinder Iterator + *------------------------------------------------------------------------- + */ + +#ifdef CONFIG_ARC_DW2_UNWIND + +static int +seed_unwind_frame_info(struct task_struct *tsk, struct pt_regs *regs, + struct unwind_frame_info *frame_info) +{ + /* + * synchronous unwinding (e.g. dump_stack) + * - uses current values of SP and friends + */ + if (regs == NULL && (tsk == NULL || tsk == current)) { + unsigned long fp, sp, blink, ret; + frame_info->task = current; + + __asm__ __volatile__( + "mov %0,r27\n\t" + "mov %1,r28\n\t" + "mov %2,r31\n\t" + "mov %3,r63\n\t" + : "=r"(fp), "=r"(sp), "=r"(blink), "=r"(ret) + ); + + frame_info->regs.r27 = fp; + frame_info->regs.r28 = sp; + frame_info->regs.r31 = blink; + frame_info->regs.r63 = ret; + frame_info->call_frame = 0; + } else if (regs == NULL) { + /* + * 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 (tsk->state == TASK_RUNNING) + return -1; + + frame_info->task = 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 + * and then SP is copied to FP. Dwarf assumes cfa as FP based + * but we didn't save FP. The value retrieved above is FP's + * state in previous frame. + * As a work around for this, we unwind from __switch_to start + * and adjust SP accordingly. The other limitation is that + * __switch_to macro is dwarf rules are not generated for inline + * assembly code + */ + frame_info->regs.r27 = 0; + frame_info->regs.r28 += 60; + frame_info->call_frame = 0; + + } else { + /* + * 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; + } + + return 0; +} + +#endif + +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, cnt = 0; + unsigned int address; + struct unwind_frame_info 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)) + break; + + if (consumer_fn(address, arg) == -1) + break; + + 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; + } + } + + return address; /* return the last address it saw */ +#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 + * way around + */ + pr_warn_once("CONFIG_ARC_DW2_UNWIND needs to be enabled\n"); + return 0; + +#endif +} + +/*------------------------------------------------------------------------- + * callbacks called by unwinder iterator to implement kernel APIs + * + * The callback can return -1 to force the iterator to stop, which by default + * keeps going till the bottom-most frame. + *------------------------------------------------------------------------- + */ + +/* 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) +{ + printk(" %pS\n", (void *)address); + return 0; +} + +#ifdef CONFIG_STACKTRACE + +/* Call-back which plugs into unwinding core to capture the + * traces needed by kernel on /proc//stack + */ +static int __collect_all(unsigned int address, void *arg) +{ + struct stack_trace *trace = arg; + + if (trace->skip > 0) + trace->skip--; + else + trace->entries[trace->nr_entries++] = address; + + if (trace->nr_entries >= trace->max_entries) + return -1; + + return 0; +} + +static int __collect_all_but_sched(unsigned int address, void *arg) +{ + struct stack_trace *trace = arg; + + if (in_sched_functions(address)) + return 0; + + if (trace->skip > 0) + trace->skip--; + else + trace->entries[trace->nr_entries++] = address; + + if (trace->nr_entries >= trace->max_entries) + return -1; + + return 0; +} + +#endif + +static int __get_first_nonsched(unsigned int address, void *unused) +{ + if (in_sched_functions(address)) + return 0; + + return -1; +} + +/*------------------------------------------------------------------------- + * APIs expected by various kernel sub-systems + *------------------------------------------------------------------------- + */ + +noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs) +{ + pr_info("\nStack Trace:\n"); + arc_unwind_core(tsk, regs, __print_sym, NULL); +} +EXPORT_SYMBOL(show_stacktrace); + +/* Expected by sched Code */ +void show_stack(struct task_struct *tsk, unsigned long *sp) +{ + show_stacktrace(tsk, NULL); +} + +/* Another API expected by schedular, shows up in "ps" as Wait Channel + * 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) +{ + return arc_unwind_core(tsk, NULL, __get_first_nonsched, NULL); +} + +#ifdef CONFIG_STACKTRACE + +/* + * API required by CONFIG_STACKTRACE, CONFIG_LATENCYTOP. + * A typical use is when /proc//stack is queried by userland + */ +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) +{ + /* 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 -- cgit v1.2.3