ARM: Add stack unwinding support
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer
parent
cad14480bf
commit
084df155d3
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@ -115,6 +115,16 @@ config ARM_OPTIMZED_STRING_FUNCTIONS
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These functions work much faster than the normal versions but
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increase your binary size.
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config ARM_UNWIND
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bool "enable stack unwinding support"
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depends on AEABI
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help
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This option enables stack unwinding support in barebox
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using the information automatically generated by the
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compiler. The resulting kernel image is slightly bigger but
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the performance is not affected. Currently, this feature
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only works with EABI compilers. If unsure say Y.
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endmenu
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source common/Kconfig
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@ -34,6 +34,10 @@ else
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CFLAGS_ABI :=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) $(call cc-option,-mno-thumb-interwork,)
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endif
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ifeq ($(CONFIG_ARM_UNWIND),y)
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CFLAGS_ABI +=-funwind-tables
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endif
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CPPFLAGS += $(CFLAGS_ABI) $(arch-y) $(tune-y)
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AFLAGS += -include asm/unified.h
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@ -27,6 +27,7 @@
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#include <common.h>
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#include <asm/ptrace.h>
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#include <asm/unwind.h>
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void do_undefined_instruction (struct pt_regs *pt_regs);
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void do_software_interrupt (struct pt_regs *pt_regs);
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@ -115,6 +116,9 @@ void show_regs (struct pt_regs *regs)
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fast_interrupts_enabled (regs) ? "on" : "off",
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processor_modes[processor_mode (regs)],
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thumb_mode (regs) ? " (T)" : "");
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#ifdef CONFIG_ARM_UNWIND
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unwind_backtrace(regs);
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#endif
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}
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/**
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@ -0,0 +1,16 @@
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#ifndef __ASM_STACKTRACE_H
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#define __ASM_STACKTRACE_H
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struct stackframe {
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unsigned long fp;
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unsigned long sp;
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unsigned long lr;
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unsigned long pc;
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};
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extern int unwind_frame(struct stackframe *frame);
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extern void walk_stackframe(struct stackframe *frame,
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int (*fn)(struct stackframe *, void *), void *data);
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#endif /* __ASM_STACKTRACE_H */
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@ -0,0 +1,54 @@
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/*
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* arch/arm/include/asm/unwind.h
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*
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* Copyright (C) 2008 ARM Limited
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __ASM_UNWIND_H
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#define __ASM_UNWIND_H
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#ifndef __ASSEMBLY__
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/* Unwind reason code according the the ARM EABI documents */
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enum unwind_reason_code {
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URC_OK = 0, /* operation completed successfully */
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URC_CONTINUE_UNWIND = 8,
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URC_FAILURE = 9 /* unspecified failure of some kind */
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};
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struct unwind_idx {
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unsigned long addr;
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unsigned long insn;
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};
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struct unwind_table {
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struct list_head list;
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struct unwind_idx *start;
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struct unwind_idx *stop;
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unsigned long begin_addr;
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unsigned long end_addr;
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};
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extern struct unwind_table *unwind_table_add(unsigned long start,
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unsigned long size,
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unsigned long text_addr,
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unsigned long text_size);
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extern void unwind_table_del(struct unwind_table *tab);
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extern void unwind_backtrace(struct pt_regs *regs);
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_UNWIND_H */
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@ -14,7 +14,7 @@ obj-y += ashldi3.o
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obj-y += lshrdi3.o
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obj-$(CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS) += memcpy.o
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obj-$(CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS) += memset.o
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obj-$(CONFIG_ARM_UNWIND) += unwind.o
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obj-$(CONFIG_MODULES) += module.o
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extra-$(CONFIG_GENERIC_LINKER_SCRIPT) += barebox.lds
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@ -51,6 +51,22 @@ SECTIONS
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. = ALIGN(4);
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.rodata : { *(.rodata*) }
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#ifdef CONFIG_ARM_UNWIND
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/*
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* Stack unwinding tables
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*/
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. = ALIGN(8);
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.ARM.unwind_idx : {
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__start_unwind_idx = .;
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*(.ARM.exidx*)
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__stop_unwind_idx = .;
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}
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.ARM.unwind_tab : {
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__start_unwind_tab = .;
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*(.ARM.extab*)
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__stop_unwind_tab = .;
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}
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#endif
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_etext = .; /* End of text and rodata section */
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. = ALIGN(4);
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@ -0,0 +1,344 @@
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#include <common.h>
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#include <init.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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#include <asm-generic/sections.h>
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/* Dummy functions to avoid linker complaints */
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void __aeabi_unwind_cpp_pr0(void)
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{
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};
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EXPORT_SYMBOL(__aeabi_unwind_cpp_pr0);
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void __aeabi_unwind_cpp_pr1(void)
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{
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};
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EXPORT_SYMBOL(__aeabi_unwind_cpp_pr1);
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void __aeabi_unwind_cpp_pr2(void)
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{
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};
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EXPORT_SYMBOL(__aeabi_unwind_cpp_pr2);
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struct unwind_ctrl_block {
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unsigned long vrs[16]; /* virtual register set */
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unsigned long *insn; /* pointer to the current instructions word */
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int entries; /* number of entries left to interpret */
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int byte; /* current byte number in the instructions word */
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};
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enum regs {
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FP = 11,
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SP = 13,
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LR = 14,
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PC = 15
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};
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#define THREAD_SIZE 8192
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extern struct unwind_idx __start_unwind_idx[];
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extern struct unwind_idx __stop_unwind_idx[];
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/* Convert a prel31 symbol to an absolute address */
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#define prel31_to_addr(ptr) \
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({ \
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/* sign-extend to 32 bits */ \
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long offset = (((long)*(ptr)) << 1) >> 1; \
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(unsigned long)(ptr) + offset; \
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})
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static inline int is_kernel_text(unsigned long addr)
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{
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if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext))
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return 1;
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return 0;
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}
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void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
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{
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#ifdef CONFIG_KALLSYMS
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printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
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#else
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printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
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#endif
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}
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/*
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* Binary search in the unwind index. The entries entries are
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* guaranteed to be sorted in ascending order by the linker.
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*/
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static struct unwind_idx *search_index(unsigned long addr,
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struct unwind_idx *first,
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struct unwind_idx *last)
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{
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pr_debug("%s(%08lx, %p, %p)\n", __func__, addr, first, last);
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if (addr < first->addr) {
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pr_warning("unwind: Unknown symbol address %08lx\n", addr);
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return NULL;
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} else if (addr >= last->addr)
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return last;
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while (first < last - 1) {
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struct unwind_idx *mid = first + ((last - first + 1) >> 1);
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if (addr < mid->addr)
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last = mid;
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else
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first = mid;
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}
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return first;
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}
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static struct unwind_idx *unwind_find_idx(unsigned long addr)
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{
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struct unwind_idx *idx = NULL;
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pr_debug("%s(%08lx)\n", __func__, addr);
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if (is_kernel_text(addr))
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/* main unwind table */
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idx = search_index(addr, __start_unwind_idx,
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__stop_unwind_idx - 1);
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else {
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/* module unwinding not supported */
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}
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pr_debug("%s: idx = %p\n", __func__, idx);
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return idx;
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}
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static unsigned long unwind_get_byte(struct unwind_ctrl_block *ctrl)
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{
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unsigned long ret;
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if (ctrl->entries <= 0) {
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pr_warning("unwind: Corrupt unwind table\n");
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return 0;
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}
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ret = (*ctrl->insn >> (ctrl->byte * 8)) & 0xff;
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if (ctrl->byte == 0) {
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ctrl->insn++;
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ctrl->entries--;
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ctrl->byte = 3;
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} else
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ctrl->byte--;
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return ret;
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}
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/*
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* Execute the current unwind instruction.
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*/
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static int unwind_exec_insn(struct unwind_ctrl_block *ctrl)
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{
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unsigned long insn = unwind_get_byte(ctrl);
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pr_debug("%s: insn = %08lx\n", __func__, insn);
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if ((insn & 0xc0) == 0x00)
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ctrl->vrs[SP] += ((insn & 0x3f) << 2) + 4;
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else if ((insn & 0xc0) == 0x40)
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ctrl->vrs[SP] -= ((insn & 0x3f) << 2) + 4;
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else if ((insn & 0xf0) == 0x80) {
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unsigned long mask;
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unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
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int load_sp, reg = 4;
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insn = (insn << 8) | unwind_get_byte(ctrl);
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mask = insn & 0x0fff;
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if (mask == 0) {
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pr_warning("unwind: 'Refuse to unwind' instruction %04lx\n",
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insn);
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return -URC_FAILURE;
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}
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/* pop R4-R15 according to mask */
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load_sp = mask & (1 << (13 - 4));
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while (mask) {
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if (mask & 1)
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ctrl->vrs[reg] = *vsp++;
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mask >>= 1;
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reg++;
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}
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if (!load_sp)
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ctrl->vrs[SP] = (unsigned long)vsp;
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} else if ((insn & 0xf0) == 0x90 &&
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(insn & 0x0d) != 0x0d)
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ctrl->vrs[SP] = ctrl->vrs[insn & 0x0f];
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else if ((insn & 0xf0) == 0xa0) {
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unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
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int reg;
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/* pop R4-R[4+bbb] */
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for (reg = 4; reg <= 4 + (insn & 7); reg++)
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ctrl->vrs[reg] = *vsp++;
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if (insn & 0x80)
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ctrl->vrs[14] = *vsp++;
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ctrl->vrs[SP] = (unsigned long)vsp;
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} else if (insn == 0xb0) {
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if (ctrl->vrs[PC] == 0)
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ctrl->vrs[PC] = ctrl->vrs[LR];
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/* no further processing */
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ctrl->entries = 0;
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} else if (insn == 0xb1) {
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unsigned long mask = unwind_get_byte(ctrl);
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unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
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int reg = 0;
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if (mask == 0 || mask & 0xf0) {
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pr_warning("unwind: Spare encoding %04lx\n",
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(insn << 8) | mask);
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return -URC_FAILURE;
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}
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/* pop R0-R3 according to mask */
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while (mask) {
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if (mask & 1)
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ctrl->vrs[reg] = *vsp++;
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mask >>= 1;
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reg++;
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}
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ctrl->vrs[SP] = (unsigned long)vsp;
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} else if (insn == 0xb2) {
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unsigned long uleb128 = unwind_get_byte(ctrl);
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ctrl->vrs[SP] += 0x204 + (uleb128 << 2);
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} else {
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pr_warning("unwind: Unhandled instruction %02lx\n", insn);
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return -URC_FAILURE;
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}
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pr_debug("%s: fp = %08lx sp = %08lx lr = %08lx pc = %08lx\n", __func__,
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ctrl->vrs[FP], ctrl->vrs[SP], ctrl->vrs[LR], ctrl->vrs[PC]);
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return URC_OK;
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}
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/*
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* Unwind a single frame starting with *sp for the symbol at *pc. It
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* updates the *pc and *sp with the new values.
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*/
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int unwind_frame(struct stackframe *frame)
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{
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unsigned long high, low;
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struct unwind_idx *idx;
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struct unwind_ctrl_block ctrl;
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/* only go to a higher address on the stack */
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low = frame->sp;
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high = ALIGN(low, THREAD_SIZE);
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pr_debug("%s(pc = %08lx lr = %08lx sp = %08lx)\n", __func__,
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frame->pc, frame->lr, frame->sp);
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if (!is_kernel_text(frame->pc))
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return -URC_FAILURE;
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idx = unwind_find_idx(frame->pc);
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if (!idx) {
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pr_warning("unwind: Index not found %08lx\n", frame->pc);
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return -URC_FAILURE;
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}
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ctrl.vrs[FP] = frame->fp;
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ctrl.vrs[SP] = frame->sp;
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ctrl.vrs[LR] = frame->lr;
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ctrl.vrs[PC] = 0;
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if (idx->insn == 1)
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/* can't unwind */
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return -URC_FAILURE;
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else if ((idx->insn & 0x80000000) == 0)
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/* prel31 to the unwind table */
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ctrl.insn = (unsigned long *)prel31_to_addr(&idx->insn);
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else if ((idx->insn & 0xff000000) == 0x80000000)
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/* only personality routine 0 supported in the index */
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ctrl.insn = &idx->insn;
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else {
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pr_warning("unwind: Unsupported personality routine %08lx in the index at %p\n",
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idx->insn, idx);
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return -URC_FAILURE;
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}
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/* check the personality routine */
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if ((*ctrl.insn & 0xff000000) == 0x80000000) {
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ctrl.byte = 2;
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ctrl.entries = 1;
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} else if ((*ctrl.insn & 0xff000000) == 0x81000000) {
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ctrl.byte = 1;
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ctrl.entries = 1 + ((*ctrl.insn & 0x00ff0000) >> 16);
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} else {
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pr_warning("unwind: Unsupported personality routine %08lx at %p\n",
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*ctrl.insn, ctrl.insn);
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return -URC_FAILURE;
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}
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while (ctrl.entries > 0) {
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int urc = unwind_exec_insn(&ctrl);
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if (urc < 0)
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return urc;
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if (ctrl.vrs[SP] < low || ctrl.vrs[SP] >= high)
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return -URC_FAILURE;
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}
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if (ctrl.vrs[PC] == 0)
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ctrl.vrs[PC] = ctrl.vrs[LR];
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/* check for infinite loop */
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if (frame->pc == ctrl.vrs[PC])
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return -URC_FAILURE;
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frame->fp = ctrl.vrs[FP];
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frame->sp = ctrl.vrs[SP];
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frame->lr = ctrl.vrs[LR];
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frame->pc = ctrl.vrs[PC];
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return URC_OK;
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}
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void unwind_backtrace(struct pt_regs *regs)
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{
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struct stackframe frame;
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register unsigned long current_sp asm ("sp");
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pr_debug("%s\n", __func__);
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if (regs) {
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frame.fp = regs->ARM_fp;
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frame.sp = regs->ARM_sp;
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frame.lr = regs->ARM_lr;
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/* PC might be corrupted, use LR in that case. */
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frame.pc = is_kernel_text(regs->ARM_pc)
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? regs->ARM_pc : regs->ARM_lr;
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} else {
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frame.sp = current_sp;
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frame.lr = (unsigned long)__builtin_return_address(0);
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frame.pc = (unsigned long)unwind_backtrace;
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}
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while (1) {
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int urc;
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unsigned long where = frame.pc;
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urc = unwind_frame(&frame);
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if (urc < 0)
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break;
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dump_backtrace_entry(where, frame.pc, frame.sp - 4);
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}
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}
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||||
|
||||
static int unwind_init(void)
|
||||
{
|
||||
struct unwind_idx *idx;
|
||||
|
||||
/* Convert the symbol addresses to absolute values */
|
||||
for (idx = __start_unwind_idx; idx < __stop_unwind_idx; idx++)
|
||||
idx->addr = prel31_to_addr(&idx->addr);
|
||||
|
||||
return 0;
|
||||
}
|
||||
core_initcall(unwind_init);
|
||||
Loading…
Reference in New Issue