diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-02 07:58:56 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-02 07:58:56 -0800 |
commit | e23b62256a361611cbd45cd1456638f1a5106b5c (patch) | |
tree | 472968c961432a1d9d0c3634ca20433f1d9cd29b /arch/arc/kernel/stacktrace.c | |
parent | aebb2afd5420c860b7fbc3882a323ef1247fbf16 (diff) | |
parent | 8ccfe6675fa974bd06d64f74d0fdee6a5267d2aa (diff) |
Merge tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull new ARC architecture from Vineet Gupta:
"Initial ARC Linux port with some fixes on top for 3.9-rc1:
I would like to introduce the Linux port to ARC Processors (from
Synopsys) for 3.9-rc1. The patch-set has been discussed on the public
lists since Nov and has received a fair bit of review, specially from
Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb...
The arch bits are in arch/arc, some asm-generic changes (acked by
Arnd), a minor change to PARISC (acked by Helge).
The series is a touch bigger for a new port for 2 main reasons:
1. It enables a basic kernel in first sub-series and adds
ptrace/kgdb/.. later
2. Some of the fallout of review (DeviceTree support, multi-platform-
image support) were added on top of orig series, primarily to
record the revision history.
This updated pull request additionally contains
- fixes due to our GNU tools catching up with the new syscall/ptrace
ABI
- some (minor) cross-arch Kconfig updates."
* tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits)
ARC: split elf.h into uapi and export it for userspace
ARC: Fixup the current ABI version
ARC: gdbserver using regset interface possibly broken
ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window
ARC: make a copy of flat DT
ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed"
ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled
ARC: Fix pt_orig_r8 access
ARC: [3.9] Fallout of hlist iterator update
ARC: 64bit RTSC timestamp hardware issue
ARC: Don't fiddle with non-existent caches
ARC: Add self to MAINTAINERS
ARC: Provide a default serial.h for uart drivers needing BASE_BAUD
ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux
ARC: [Review] Multi-platform image #8: platform registers SMP callbacks
ARC: [Review] Multi-platform image #7: SMP common code to use callbacks
ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional
ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core
ARC: [Review] Multi-platform image #4: Isolate platform headers
ARC: [Review] Multi-platform image #3: switch to board callback
...
Diffstat (limited to 'arch/arc/kernel/stacktrace.c')
-rw-r--r-- | arch/arc/kernel/stacktrace.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c new file mode 100644 index 000000000000..a63ff842564b --- /dev/null +++ b/arch/arc/kernel/stacktrace.c @@ -0,0 +1,254 @@ +/* + * 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 + * -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 <linux/ptrace.h> +#include <linux/export.h> +#include <linux/stacktrace.h> +#include <linux/kallsyms.h> +#include <asm/arcregs.h> +#include <asm/unwind.h> +#include <asm/switch_to.h> + +/*------------------------------------------------------------------------- + * Unwinder Iterator + *------------------------------------------------------------------------- + */ + +#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) +{ + if (tsk == NULL && regs == NULL) { + 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) { + + 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.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 += 64; + 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; + } +} + +#endif + +static 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; + unsigned int address; + struct unwind_frame_info frame_info; + + seed_unwind_frame_info(tsk, regs, &frame_info); + + while (1) { + address = UNW_PC(&frame_info); + + if (address && __kernel_text_address(address)) { + if (consumer_fn(address, arg) == -1) + break; + } + + ret = arc_unwind(&frame_info); + + if (ret == 0) { + frame_info.regs.r63 = frame_info.regs.r31; + continue; + } else { + break; + } + } + + 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("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) +{ + __print_symbol(" %s\n", address); + return 0; +} + +#ifdef CONFIG_STACKTRACE + +/* Call-back which plugs into unwinding core to capture the + * traces needed by kernel on /proc/<pid>/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); +} + +/* Expected by Rest of kernel code */ +void dump_stack(void) +{ + show_stacktrace(NULL, NULL); +} +EXPORT_SYMBOL(dump_stack); + +/* Another API expected by schedular, shows up in "ps" as Wait Channel + * Ofcourse 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/<pid>/stack is queried by userland + */ +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + 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); +} +#endif |