diff options
| -rw-r--r-- | arch/sh/Kconfig.debug | 8 | ||||
| -rw-r--r-- | arch/sh/Makefile | 4 | ||||
| -rw-r--r-- | arch/sh/include/asm/dwarf.h | 402 | ||||
| -rw-r--r-- | arch/sh/include/asm/entry-macros.S | 12 | ||||
| -rw-r--r-- | arch/sh/include/asm/sections.h | 1 | ||||
| -rw-r--r-- | arch/sh/include/asm/vmlinux.lds.h | 17 | ||||
| -rw-r--r-- | arch/sh/kernel/Makefile_32 | 1 | ||||
| -rw-r--r-- | arch/sh/kernel/Makefile_64 | 1 | ||||
| -rw-r--r-- | arch/sh/kernel/cpu/sh3/entry.S | 1 | ||||
| -rw-r--r-- | arch/sh/kernel/dwarf.c | 901 | ||||
| -rw-r--r-- | arch/sh/kernel/entry-common.S | 8 | ||||
| -rw-r--r-- | arch/sh/kernel/irq.c | 4 | ||||
| -rw-r--r-- | arch/sh/kernel/vmlinux.lds.S | 4 |
13 files changed, 1363 insertions, 1 deletions
diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug index 763b792b161..741d20fab2e 100644 --- a/arch/sh/Kconfig.debug +++ b/arch/sh/Kconfig.debug @@ -110,6 +110,14 @@ config DUMP_CODE Those looking for more verbose debugging output should say Y. +config DWARF_UNWINDER + bool "Enable the DWARF unwinder for stacktraces" + select FRAME_POINTER + default n + help + Enabling this option will make stacktraces more accurate, at + the cost of an increase in overall kernel size. + config SH_NO_BSS_INIT bool "Avoid zeroing BSS (to speed-up startup on suitable platforms)" depends on DEBUG_KERNEL diff --git a/arch/sh/Makefile b/arch/sh/Makefile index b6ff337fd85..e26421bf997 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -191,6 +191,10 @@ ifeq ($(CONFIG_MCOUNT),y) KBUILD_CFLAGS += -pg endif +ifeq ($(CONFIG_DWARF_UNWINDER),y) + KBUILD_CFLAGS += -fasynchronous-unwind-tables +endif + libs-$(CONFIG_SUPERH32) := arch/sh/lib/ $(libs-y) libs-$(CONFIG_SUPERH64) := arch/sh/lib64/ $(libs-y) diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h new file mode 100644 index 00000000000..60b180728d8 --- /dev/null +++ b/arch/sh/include/asm/dwarf.h @@ -0,0 +1,402 @@ +/* + * Copyright (C) 2009 Matt Fleming <matt@console-pimps.org> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + */ +#ifndef __ASM_SH_DWARF_H +#define __ASM_SH_DWARF_H + +#ifdef CONFIG_DWARF_UNWINDER + +/* + * DWARF expression operations + */ +#define DW_OP_addr 0x03 +#define DW_OP_deref 0x06 +#define DW_OP_const1u 0x08 +#define DW_OP_const1s 0x09 +#define DW_OP_const2u 0x0a +#define DW_OP_const2s 0x0b +#define DW_OP_const4u 0x0c +#define DW_OP_const4s 0x0d +#define DW_OP_const8u 0x0e +#define DW_OP_const8s 0x0f +#define DW_OP_constu 0x10 +#define DW_OP_consts 0x11 +#define DW_OP_dup 0x12 +#define DW_OP_drop 0x13 +#define DW_OP_over 0x14 +#define DW_OP_pick 0x15 +#define DW_OP_swap 0x16 +#define DW_OP_rot 0x17 +#define DW_OP_xderef 0x18 +#define DW_OP_abs 0x19 +#define DW_OP_and 0x1a +#define DW_OP_div 0x1b +#define DW_OP_minus 0x1c +#define DW_OP_mod 0x1d +#define DW_OP_mul 0x1e +#define DW_OP_neg 0x1f +#define DW_OP_not 0x20 +#define DW_OP_or 0x21 +#define DW_OP_plus 0x22 +#define DW_OP_plus_uconst 0x23 +#define DW_OP_shl 0x24 +#define DW_OP_shr 0x25 +#define DW_OP_shra 0x26 +#define DW_OP_xor 0x27 +#define DW_OP_skip 0x2f +#define DW_OP_bra 0x28 +#define DW_OP_eq 0x29 +#define DW_OP_ge 0x2a +#define DW_OP_gt 0x2b +#define DW_OP_le 0x2c +#define DW_OP_lt 0x2d +#define DW_OP_ne 0x2e +#define DW_OP_lit0 0x30 +#define DW_OP_lit1 0x31 +#define DW_OP_lit2 0x32 +#define DW_OP_lit3 0x33 +#define DW_OP_lit4 0x34 +#define DW_OP_lit5 0x35 +#define DW_OP_lit6 0x36 +#define DW_OP_lit7 0x37 +#define DW_OP_lit8 0x38 +#define DW_OP_lit9 0x39 +#define DW_OP_lit10 0x3a +#define DW_OP_lit11 0x3b +#define DW_OP_lit12 0x3c +#define DW_OP_lit13 0x3d +#define DW_OP_lit14 0x3e +#define DW_OP_lit15 0x3f +#define DW_OP_lit16 0x40 +#define DW_OP_lit17 0x41 +#define DW_OP_lit18 0x42 +#define DW_OP_lit19 0x43 +#define DW_OP_lit20 0x44 +#define DW_OP_lit21 0x45 +#define DW_OP_lit22 0x46 +#define DW_OP_lit23 0x47 +#define DW_OP_lit24 0x48 +#define DW_OP_lit25 0x49 +#define DW_OP_lit26 0x4a +#define DW_OP_lit27 0x4b +#define DW_OP_lit28 0x4c +#define DW_OP_lit29 0x4d +#define DW_OP_lit30 0x4e +#define DW_OP_lit31 0x4f +#define DW_OP_reg0 0x50 +#define DW_OP_reg1 0x51 +#define DW_OP_reg2 0x52 +#define DW_OP_reg3 0x53 +#define DW_OP_reg4 0x54 +#define DW_OP_reg5 0x55 +#define DW_OP_reg6 0x56 +#define DW_OP_reg7 0x57 +#define DW_OP_reg8 0x58 +#define DW_OP_reg9 0x59 +#define DW_OP_reg10 0x5a +#define DW_OP_reg11 0x5b +#define DW_OP_reg12 0x5c +#define DW_OP_reg13 0x5d +#define DW_OP_reg14 0x5e +#define DW_OP_reg15 0x5f +#define DW_OP_reg16 0x60 +#define DW_OP_reg17 0x61 +#define DW_OP_reg18 0x62 +#define DW_OP_reg19 0x63 +#define DW_OP_reg20 0x64 +#define DW_OP_reg21 0x65 +#define DW_OP_reg22 0x66 +#define DW_OP_reg23 0x67 +#define DW_OP_reg24 0x68 +#define DW_OP_reg25 0x69 +#define DW_OP_reg26 0x6a +#define DW_OP_reg27 0x6b +#define DW_OP_reg28 0x6c +#define DW_OP_reg29 0x6d +#define DW_OP_reg30 0x6e +#define DW_OP_reg31 0x6f +#define DW_OP_breg0 0x70 +#define DW_OP_breg1 0x71 +#define DW_OP_breg2 0x72 +#define DW_OP_breg3 0x73 +#define DW_OP_breg4 0x74 +#define DW_OP_breg5 0x75 +#define DW_OP_breg6 0x76 +#define DW_OP_breg7 0x77 +#define DW_OP_breg8 0x78 +#define DW_OP_breg9 0x79 +#define DW_OP_breg10 0x7a +#define DW_OP_breg11 0x7b +#define DW_OP_breg12 0x7c +#define DW_OP_breg13 0x7d +#define DW_OP_breg14 0x7e +#define DW_OP_breg15 0x7f +#define DW_OP_breg16 0x80 +#define DW_OP_breg17 0x81 +#define DW_OP_breg18 0x82 +#define DW_OP_breg19 0x83 +#define DW_OP_breg20 0x84 +#define DW_OP_breg21 0x85 +#define DW_OP_breg22 0x86 +#define DW_OP_breg23 0x87 +#define DW_OP_breg24 0x88 +#define DW_OP_breg25 0x89 +#define DW_OP_breg26 0x8a +#define DW_OP_breg27 0x8b +#define DW_OP_breg28 0x8c +#define DW_OP_breg29 0x8d +#define DW_OP_breg30 0x8e +#define DW_OP_breg31 0x8f +#define DW_OP_regx 0x90 +#define DW_OP_fbreg 0x91 +#define DW_OP_bregx 0x92 +#define DW_OP_piece 0x93 +#define DW_OP_deref_size 0x94 +#define DW_OP_xderef_size 0x95 +#define DW_OP_nop 0x96 +#define DW_OP_push_object_address 0x97 +#define DW_OP_call2 0x98 +#define DW_OP_call4 0x99 +#define DW_OP_call_ref 0x9a +#define DW_OP_form_tls_address 0x9b +#define DW_OP_call_frame_cfa 0x9c +#define DW_OP_bit_piece 0x9d +#define DW_OP_lo_user 0xe0 +#define DW_OP_hi_user 0xff + +/* + * Addresses used in FDE entries in the .eh_frame section may be encoded + * using one of the following encodings. + */ +#define DW_EH_PE_absptr 0x00 +#define DW_EH_PE_omit 0xff +#define DW_EH_PE_uleb128 0x01 +#define DW_EH_PE_udata2 0x02 +#define DW_EH_PE_udata4 0x03 +#define DW_EH_PE_udata8 0x04 +#define DW_EH_PE_sleb128 0x09 +#define DW_EH_PE_sdata2 0x0a +#define DW_EH_PE_sdata4 0x0b +#define DW_EH_PE_sdata8 0x0c +#define DW_EH_PE_signed 0x09 + +#define DW_EH_PE_pcrel 0x10 + +/* + * The architecture-specific register number that contains the return + * address in the .debug_frame table. + */ +#define DWARF_ARCH_RA_REG 17 + +#ifndef __ASSEMBLY__ +/* + * Read either the frame pointer (r14) or the stack pointer (r15). + * NOTE: this MUST be inlined. + */ +static __always_inline unsigned long dwarf_read_arch_reg(unsigned int reg) +{ + unsigned long value; + + switch (reg) { + case 14: + __asm__ __volatile__("mov r14, %0\n" : "=r" (value)); + break; + case 15: + __asm__ __volatile__("mov r15, %0\n" : "=r" (value)); + break; + default: + BUG(); + } + + return value; +} + +/** + * dwarf_cie - Common Information Entry + */ +struct dwarf_cie { + unsigned long length; + unsigned long cie_id; + unsigned char version; + const char *augmentation; + unsigned int code_alignment_factor; + int data_alignment_factor; + + /* Which column in the rule table represents return addr of func. */ + unsigned int return_address_reg; + + unsigned char *initial_instructions; + unsigned char *instructions_end; + + unsigned char encoding; + + unsigned long cie_pointer; + + struct list_head link; + + unsigned long flags; +#define DWARF_CIE_Z_AUGMENTATION (1 << 0) +}; + +/** + * dwarf_fde - Frame Description Entry + */ +struct dwarf_fde { + unsigned long length; + unsigned long cie_pointer; + struct dwarf_cie *cie; + unsigned long initial_location; + unsigned long address_range; + unsigned char *instructions; + unsigned char *end; + struct list_head link; +}; + +/** + * dwarf_frame - DWARF information for a frame in the call stack + */ +struct dwarf_frame { + struct dwarf_frame *prev, *next; + + unsigned long pc; + + struct dwarf_reg *regs; + unsigned int num_regs; /* how many regs are allocated? */ + + unsigned int depth; /* what level are we in the callstack? */ + + unsigned long cfa; + + /* Valid when DW_FRAME_CFA_REG_OFFSET is set in flags */ + unsigned int cfa_register; + unsigned int cfa_offset; + + /* Valid when DW_FRAME_CFA_REG_EXP is set in flags */ + unsigned char *cfa_expr; + unsigned int cfa_expr_len; + + unsigned long flags; +#define DWARF_FRAME_CFA_REG_OFFSET (1 << 0) +#define DWARF_FRAME_CFA_REG_EXP (1 << 1) + + unsigned long return_addr; +}; + +/** + * dwarf_reg - DWARF register + * @flags: Describes how to calculate the value of this register + */ +struct dwarf_reg { + unsigned long addr; + unsigned long flags; +#define DWARF_REG_OFFSET (1 << 0) +}; + +/** + * dwarf_stack - a DWARF stack contains a collection of DWARF frames + * @depth: the number of frames in the stack + * @level: an array of DWARF frames, indexed by stack level + * + */ +struct dwarf_stack { + unsigned int depth; + struct dwarf_frame **level; +}; + +/* + * Call Frame instruction opcodes. + */ +#define DW_CFA_advance_loc 0x40 +#define DW_CFA_offset 0x80 +#define DW_CFA_restore 0xc0 +#define DW_CFA_nop 0x00 +#define DW_CFA_set_loc 0x01 +#define DW_CFA_advance_loc1 0x02 +#define DW_CFA_advance_loc2 0x03 +#define DW_CFA_advance_loc4 0x04 +#define DW_CFA_offset_extended 0x05 +#define DW_CFA_restore_extended 0x06 +#define DW_CFA_undefined 0x07 +#define DW_CFA_same_value 0x08 +#define DW_CFA_register 0x09 +#define DW_CFA_remember_state 0x0a +#define DW_CFA_restore_state 0x0b +#define DW_CFA_def_cfa 0x0c +#define DW_CFA_def_cfa_register 0x0d +#define DW_CFA_def_cfa_offset 0x0e +#define DW_CFA_def_cfa_expression 0x0f +#define DW_CFA_expression 0x10 +#define DW_CFA_offset_extended_sf 0x11 +#define DW_CFA_def_cfa_sf 0x12 +#define DW_CFA_def_cfa_offset_sf 0x13 +#define DW_CFA_val_offset 0x14 +#define DW_CFA_val_offset_sf 0x15 +#define DW_CFA_val_expression 0x16 +#define DW_CFA_lo_user 0x1c +#define DW_CFA_hi_user 0x3f + +/* + * Some call frame instructions encode their operands in the opcode. We + * need some helper functions to extract both the opcode and operands + * from an instruction. + */ +static inline unsigned int DW_CFA_opcode(unsigned long insn) +{ + return (insn & 0xc0); +} + +static inline unsigned int DW_CFA_operand(unsigned long insn) +{ + return (insn & 0x3f); +} + +#define DW_EH_FRAME_CIE 0 /* .eh_frame CIE IDs are 0 */ +#define DW_CIE_ID 0xffffffff +#define DW64_CIE_ID 0xffffffffffffffffULL + +/* + * DWARF FDE/CIE length field values. + */ +#define DW_EXT_LO 0xfffffff0 +#define DW_EXT_HI 0xffffffff +#define DW_EXT_DWARF64 DW_EXT_HI + +extern void dwarf_unwinder_init(void); + +extern struct dwarf_frame *dwarf_unwind_stack(unsigned long, + struct dwarf_frame *); +#endif /* __ASSEMBLY__ */ + +#define CFI_STARTPROC .cfi_startproc +#define CFI_ENDPROC .cfi_endproc +#define CFI_DEF_CFA .cfi_def_cfa +#define CFI_REGISTER .cfi_register +#define CFI_REL_OFFSET .cfi_rel_offset + +#else + +/* + * Use the asm comment character to ignore the rest of the line. + */ +#define CFI_IGNORE ! + +#define CFI_STARTPROC CFI_IGNORE +#define CFI_ENDPROC CFI_IGNORE +#define CFI_DEF_CFA CFI_IGNORE +#define CFI_REGISTER CFI_IGNORE +#define CFI_REL_OFFSET CFI_IGNORE + +#ifndef __ASSEMBLY__ +static inline void dwarf_unwinder_init(void) +{ +} +#endif + +#endif /* CONFIG_DWARF_UNWINDER */ + +#endif /* __ASM_SH_DWARF_H */ diff --git a/arch/sh/include/asm/entry-macros.S b/arch/sh/include/asm/entry-macros.S index 1bdd93891cd..64fd0de24da 100644 --- a/arch/sh/include/asm/entry-macros.S +++ b/arch/sh/include/asm/entry-macros.S @@ -108,3 +108,15 @@ #else # define PREF(x) nop #endif + + /* + * Macro for use within assembly. Because the DWARF unwinder + * needs to use the frame register to unwind the stack, we + * need to setup r14 with the value of the stack pointer as + * the return address is usually on the stack somewhere. + */ + .macro setup_frame_reg +#ifdef CONFIG_DWARF_UNWINDER + mov r15, r14 +#endif + .endm diff --git a/arch/sh/include/asm/sections.h b/arch/sh/include/asm/sections.h index 01a4076a371..a78701da775 100644 --- a/arch/sh/include/asm/sections.h +++ b/arch/sh/include/asm/sections.h @@ -7,6 +7,7 @@ extern void __nosave_begin, __nosave_end; extern long __machvec_start, __machvec_end; extern char __uncached_start, __uncached_end; extern char _ebss[]; +extern char __start_eh_frame[], __stop_eh_frame[]; #endif /* __ASM_SH_SECTIONS_H */ diff --git a/arch/sh/include/asm/vmlinux.lds.h b/arch/sh/include/asm/vmlinux.lds.h new file mode 100644 index 00000000000..244ec4ad9a7 --- /dev/null +++ b/arch/sh/include/asm/vmlinux.lds.h @@ -0,0 +1,17 @@ +#ifndef __ASM_SH_VMLINUX_LDS_H +#define __ASM_SH_VMLINUX_LDS_H + +#include <asm-generic/vmlinux.lds.h> + +#ifdef CONFIG_DWARF_UNWINDER +#define DWARF_EH_FRAME \ + .eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start_eh_frame) = .; \ + *(.eh_frame) \ + VMLINUX_SYMBOL(__stop_eh_frame) = .; \ + } +#else +#define DWARF_EH_FRAME +#endif + +#endif /* __ASM_SH_VMLINUX_LDS_H */ diff --git a/arch/sh/kernel/Makefile_32 b/arch/sh/kernel/Makefile_32 index 37a3b7704fc..f2245ebf0b3 100644 --- a/arch/sh/kernel/Makefile_32 +++ b/arch/sh/kernel/Makefile_32 @@ -33,6 +33,7 @@ obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_DUMP_CODE) += disassemble.o obj-$(CONFIG_HIBERNATION) += swsusp.o +obj-$(CONFIG_DWARF_UNWINDER) += dwarf.o obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += localtimer.o diff --git a/arch/sh/kernel/Makefile_64 b/arch/sh/kernel/Makefile_64 index 00b73e7598c..639ee514266 100644 --- a/arch/sh/kernel/Makefile_64 +++ b/arch/sh/kernel/Makefile_64 @@ -13,6 +13,7 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_IO_TRAPPED) += io_trapped.o obj-$(CONFIG_GENERIC_GPIO) += gpio.o +obj-$(CONFIG_DWARF_UNWINDER) += dwarf.o obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += localtimer.o diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S index 3cb531f233f..67ad6467c69 100644 --- a/arch/sh/kernel/cpu/sh3/entry.S +++ b/arch/sh/kernel/cpu/sh3/entry.S @@ -137,6 +137,7 @@ ENTRY(tlb_protection_violation_store) mov #1, r5 call_dpf: + setup_frame_reg mov.l 1f, r0 mov r5, r8 mov.l @r0, r6 diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c new file mode 100644 index 00000000000..83f3cc92549 --- /dev/null +++ b/arch/sh/kernel/dwarf.c @@ -0,0 +1,901 @@ +/* + * Copyright (C) 2009 Matt Fleming <matt@console-pimps.org> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * This is an implementation of a DWARF unwinder. Its main purpose is + * for generating stacktrace information. Based on the DWARF 3 + * specification from http://www.dwarfstd.org. + * + * TODO: + * - DWARF64 doesn't work. + */ + +/* #define DEBUG */ +#include <linux/kernel.h> +#include <linux/io.h> +#include <linux/list.h> +#include <linux/mm.h> +#include <asm/dwarf.h> +#include <asm/unwinder.h> +#include <asm/sections.h> +#include <asm/unaligned.h> +#include <asm/dwarf.h> +#include <asm/stacktrace.h> + +static LIST_HEAD(dwarf_cie_list); +DEFINE_SPINLOCK(dwarf_cie_lock); + +static LIST_HEAD(dwarf_fde_list); +DEFINE_SPINLOCK(dwarf_fde_lock); + +static struct dwarf_cie *cached_cie; + +/* + * Figure out whether we need to allocate some dwarf registers. If dwarf + * registers have already been allocated then we may need to realloc + * them. "reg" is a register number that we need to be able to access + * after this call. + * + * Register numbers start at zero, therefore we need to allocate space + * for "reg" + 1 registers. + */ +static void dwarf_frame_alloc_regs(struct dwarf_frame *frame, + unsigned int reg) +{ + struct dwarf_reg *regs; + unsigned int num_regs = reg + 1; + size_t new_size; + size_t old_size; + + new_size = num_regs * sizeof(*regs); + old_size = frame->num_regs * sizeof(*regs); + + /* Fast path: don't allocate any regs if we've already got enough. */ + if (frame->num_regs >= num_regs) + return; + + regs = kzalloc(new_size, GFP_KERNEL); + if (!regs) { + printk(KERN_WARNING "Unable to allocate DWARF registers\n"); + /* + * Let's just bomb hard here, we have no way to + * gracefully recover. + */ + BUG(); + } + + if (frame->regs) { + memcpy(regs, frame->regs, old_size); + kfree(frame->regs); + } + + frame->regs = regs; + frame->num_regs = num_regs; +} + +/** + * dwarf_read_addr - read dwarf data + * @src: source address of data + * @dst: destination address to store the data to + * + * Read 'n' bytes from @src, where 'n' is the size of an address on + * the native machine. We return the number of bytes read, which + * should always be 'n'. We also have to be careful when reading + * from @src and writing to @dst, because they can be arbitrarily + * aligned. Return 'n' - the number of bytes read. + */ +static inline int dwarf_read_addr(unsigned long *src, unsigned long *dst) +{ + u32 val = get_unaligned(src); + put_unaligned(val, dst); + return sizeof(unsigned long *); +} + +/** + * dwarf_read_uleb128 - read unsigned LEB128 data + * @addr: the address where the ULEB128 data is stored + * @ret: address to store the result + * + * Decode an unsigned LEB128 encoded datum. The algorithm is taken + * from Appendix C of the DWARF 3 spec. For information on the + * encodings refer to section "7.6 - Variable Length Data". Return + * the number of bytes read. + */ +static inline unsigned long dwarf_read_uleb128(char *addr, unsigned int *ret) +{ + unsigned int result; + unsigned char byte; + int shift, count; + + result = 0; + shift = 0; + count = 0; + + while (1) { + byte = __raw_readb(addr); + addr++; + count++; + + result |= (byte & 0x7f) << shift; + shift += 7; + + if (!(byte & 0x80)) + break; + } + + *ret = result; + + return count; +} + +/** + * dwarf_read_leb128 - read signed LEB128 data + * @addr: the address of the LEB128 encoded data + * @ret: address to store the result + * + * Decode signed LEB128 data. The algorithm is taken from Appendix + * C of the DWARF 3 spec. Return the number of bytes read. + */ +static inline unsigned long dwarf_read_leb128(char *addr, int *ret) +{ + unsigned char byte; + int result, shift; + int num_bits; + int count; + + result = 0; + shift = 0; + count = 0; + + while (1) { + byte = __raw_readb(addr); + addr++; + result |= (byte & 0x7f) << shift; + shift += 7; + count++; + + if (!(byte & 0x80)) + break; + } + + /* The number of bits in a signed integer. */ + num_bits = 8 * sizeof(result); + + if ((shift < num_bits) && (byte & 0x40)) + result |= (-1 << shift); + + *ret = result; + + return count; +} + +/** + * dwarf_read_encoded_value - return the decoded value at @addr + * @addr: the address of the encoded value + * @val: where to write the decoded value + * @encoding: the encoding with which we can decode @addr + * + * GCC emits encoded address in the .eh_frame FDE entries. Decode + * the value at @addr using @encoding. The decoded value is written + * to @val and the number of bytes read is returned. + */ +static int dwarf_read_encoded_value(char *addr, unsigned long *val, + char encoding) +{ + unsigned long decoded_addr = 0; + int count = 0; + + switch (encoding & 0x70) { + case DW_EH_PE_absptr: + break; + case DW_EH_PE_pcrel: + decoded_addr = (unsigned long)addr; + break; + default: + pr_debug("encoding=0x%x\n", (encoding & 0x70)); + BUG(); + } + + if ((encoding & 0x07) == 0x00) + encoding |= DW_EH_PE_udata4; + + switch (encoding & 0x0f) { + case DW_EH_PE_sdata4: + case DW_EH_PE_udata4: + count += 4; + decoded_addr += get_unaligned((u32 *)addr); + __raw_writel(decoded_addr, val); + break; + default: + pr_debug("encoding=0x%x\n", encoding); + BUG(); + } + + return count; +} + +/** + * dwarf_entry_len - return the length of an FDE or CIE + * @addr: the address of the entry + * @len: the length of the entry + * + * Read the initial_length field of the entry and store the size of + * the entry in @len. We return the number of bytes read. Return a + * count of 0 on error. + */ +static inline int dwarf_entry_len(char *addr, unsigned long *len) +{ + u32 initial_len; + int count; + + initial_len = get_unaligned((u32 *)addr); + count = 4; + + /* + * An initial length field value in the range DW_LEN_EXT_LO - + * DW_LEN_EXT_HI indicates an extension, and should not be + * interpreted as a length. The only extension that we currently + * understand is the use of DWARF64 addresses. + */ + if (initial_len >= DW_EXT_LO && initial_len <= DW_EXT_HI) { + /* + * The 64-bit length field immediately follows the + * compulsory 32-bit length field. + */ + if (initial_len == DW_EXT_DWARF64) { + *len = get_unaligned((u64 *)addr + 4); + count = 12; + } else { + printk(KERN_WARNING "Unknown DWARF extension\n"); + count = 0; + } + } else + *len = initial_len; + + return count; +} + +/** + * dwarf_lookup_cie - locate the cie + * @cie_ptr: pointer to help with lookup + */ +static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr) +{ + struct dwarf_cie *cie, *n; + unsigned long flags; + + spin_lock_irqsave(&dwarf_cie_lock, flags); + + /* + * We've cached the last CIE we looked up because chances are + * that the FDE wants this CIE. + */ + if (cached_cie && cached_cie->cie_pointer == cie_ptr) { + cie = cached_cie; + goto out; + } + + list_for_each_entry_safe(cie, n, &dwarf_cie_list, link) { + if (cie->cie_pointer == cie_ptr) { + cached_cie = cie; + break; + } + } + + /* Couldn't find the entry in the list. */ + if (&cie->link == &dwarf_cie_list) + cie = NULL; +out: + spin_unlock_irqrestore(&dwarf_cie_lock, flags); + return cie; +} + +/** + * dwarf_lookup_fde - locate the FDE that covers pc + * @pc: the program counter + */ +struct dwarf_fde *dwarf_lookup_fde(unsigned long pc) +{ + unsigned long flags; + struct dwarf_fde *fde, *n; + + spin_lock_irqsave(&dwarf_fde_lock, flags); + list_for_each_entry_safe(fde, n, &dwarf_fde_list, link) { + unsigned long start, end; + + start = fde->initial_location; + end = fde->initial_location + fde->address_range; + + if (pc >= start && pc < end) + break; + } + + /* Couldn't find the entry in the list. */ + if (&fde->link == &dwarf_fde_list) + fde = NULL; + + spin_unlock_irqrestore(&dwarf_fde_lock, flags); + + return fde; +} + +/** + * dwarf_cfa_execute_insns - execute instructions to calculate a CFA + * @insn_start: address of the first instruction + * @insn_end: address of the last instruction + * @cie: the CIE for this function + * @fde: the FDE for this function + * @frame: the instructions calculate the CFA for this frame + * @pc: the program counter of the address we're interested in + * @define_ra: keep executing insns until the return addr reg is defined? + * + * Execute the Call Frame instruction sequence starting at + * @insn_start and ending at @insn_end. The instructions describe + * how to calculate the Canonical Frame Address of a stackframe. + * Store the results in @frame. + */ +static int dwarf_cfa_execute_insns(unsigned char *insn_start, + unsigned char *insn_end, + struct dwarf_cie *cie, + struct dwarf_fde *fde, + struct dwarf_frame *frame, + unsigned long pc, + bool define_ra) +{ + unsigned char insn; + unsigned char *current_insn; + unsigned int count, delta, reg, expr_len, offset; + bool seen_ra_reg; + + current_insn = insn_start; + + /* + * If we're executing instructions for the dwarf_unwind_stack() + * FDE we need to keep executing instructions until the value of + * DWARF_ARCH_RA_REG is defined. See the comment in + * dwarf_unwind_stack() for more details. + */ + if (define_ra) + seen_ra_reg = false; + else + seen_ra_reg = true; + + while (current_insn < insn_end && (frame->pc <= pc || !seen_ra_reg) ) { + insn = __raw_readb(current_insn++); + + if (!seen_ra_reg) { + if (frame->num_regs >= DWARF_ARCH_RA_REG && + frame->regs[DWARF_ARCH_RA_REG].flags) + seen_ra_reg = true; + } + + /* + * Firstly, handle the opcodes that embed their operands + * in the instructions. + */ + switch (DW_CFA_opcode(insn)) { + case DW_CFA_advance_loc: + delta = DW_CFA_operand(insn); + delta *= cie->code_alignment_factor; + frame->pc += delta; + continue; + /* NOTREACHED */ + case DW_CFA_offset: + reg = DW_CFA_operand(insn); + count = dwarf_read_uleb128(current_insn, &offset); + current_insn += count; + offset *= cie->data_alignment_factor; + dwarf_frame_alloc_regs(frame, reg); + frame->regs[reg].addr = offset; + frame->regs[reg].flags |= DWARF_REG_OFFSET; + continue; + /* NOTREACHED */ + case DW_CFA_restore: + reg = DW_CFA_operand(insn); + continue; + /* NOTREACHED */ + } + + /* + * Secondly, handle the opcodes that don't embed their + * operands in the instruction. + */ + switch (insn) { + case DW_CFA_nop: + continue; + case DW_CFA_advance_loc1: + delta = *current_insn++; + frame->pc += delta * cie->code_alignment_factor; + break; + case DW_CFA_advance_loc2: + delta = get_unaligned((u16 *)current_insn); + current_insn += 2; + frame->pc += delta * cie->code_alignment_factor; + break; + case DW_CFA_advance_loc4: + delta = get_unaligned((u32 *)current_insn); + current_insn += 4; + frame->pc += delta * cie->code_alignment_factor; + break; + case DW_CFA_offset_extended: + count = dwarf_read_uleb128(current_insn, ®); + current_insn += count; + count = dwarf_read_uleb128(current_insn, &offset); + current_insn += count; + offset *= cie->data_alignment_factor; + break; + case DW_CFA_restore_extended: + count = dwarf_read_uleb128(current_insn, ®); + current_insn += count; + break; + case DW_CFA_undefined: + count = dwarf_read_uleb128(current_insn, ®); + current_insn += count; + break; + case DW_CFA_def_cfa: + count = dwarf_read_uleb128(current_insn, + &frame->cfa_register); + current_insn += count; + count = dwarf_read_uleb128(current_insn, + &frame->cfa_offset); + current_insn += count; + + frame->flags |= DWARF_FRAME_CFA_REG_OFFSET; + break; + case DW_CFA_def_cfa_register: + count = dwarf_read_uleb128(current_insn, + &frame->cfa_register); + current_insn += count; + frame->flags |= DWARF_FRAME_CFA_REG_OFFSET; + break; + case DW_CFA_def_cfa_offset: + count = dwarf_read_uleb128(current_insn, &offset); + current_insn += count; + frame->cfa_offset = offset; + break; + case DW_CFA_def_cfa_expression: + count = dwarf_read_uleb128(current_insn, &expr_len); + current_insn += count; + + frame->cfa_expr = current_insn; + frame->cfa_expr_len = expr_len; + current_insn += expr_len; + + frame->flags |= DWARF_FRAME_CFA_REG_EXP; + break; + case DW_CFA_offset_extended_sf: + count = dwarf_read_uleb128(current_insn, ®); + current_insn += count; + count = dwarf_read_leb128(current_insn, &offset); + current_insn += count; + offset *= cie->data_alignment_factor; + dwarf_frame_alloc_regs(frame, reg); + frame->regs[reg].flags |= DWARF_REG_OFFSET; + frame->regs[reg].addr = offset; + break; + case DW_CFA_val_offset: + count = dwarf_read_uleb128(current_insn, ®); + current_insn += count; + count = dwarf_read_leb128(current_insn, &offset); + offset *= cie->data_alignment_factor; + frame->regs[reg].flags |= DWARF_REG_OFFSET; + frame->regs[reg].addr = offset; + break; + default: + pr_debug("unhandled DWARF instruction 0x%x\n", insn); + break; + } + } + + return 0; +} + +/** + * dwarf_unwind_stack - recursively unwind the stack + * @pc: address of the function to unwind + * @prev: struct dwarf_frame of the previous stackframe on the callstack + * + * Return a struct dwarf_frame representing the most recent frame + * on the callstack. Each of the lower (older) stack frames are + * linked via the "prev" member. + */ +struct dwarf_frame *dwarf_unwind_stack(unsigned long pc, + struct dwarf_frame *prev) +{ + struct dwarf_frame *frame; + struct dwarf_cie *cie; + struct dwarf_fde *fde; + unsigned long addr; + int i, offset; + bool define_ra = false; + + /* + * If this is the first invocation of this recursive function we + * need get the contents of a physical register to get the CFA + * in order to begin the virtual unwinding of the stack. + * + * Setting "define_ra" to true indictates that we want + * dwarf_cfa_execute_insns() to continue executing instructions + * until we know how to calculate the value of DWARF_ARCH_RA_REG + * (which we need in order to kick off the whole unwinding + * process). + * + * NOTE: the return address is guaranteed to be setup by the + * time this function makes its first function call. + */ + if (!pc && !prev) { + pc = (unsigned long)&dwarf_unwind_stack; + define_ra = true; + } + + frame = kzalloc(sizeof(*frame), GFP_KERNEL); + if (!frame) + return NULL; + + frame->prev = prev; + + fde = dwarf_lookup_fde(pc); + if (!fde) { + /* + * This is our normal exit path - the one that stops the + * recursion. There's two reasons why we might exit + * here, + * + * a) pc has no asscociated DWARF frame info and so + * we don't know how to unwind this frame. This is + * usually the case when we're trying to unwind a + * frame that was called from some assembly code + * that has no DWARF info, e.g. syscalls. + * + * b) the DEBUG info for pc is bogus. There's + * really no way to distinguish this case from the + * case above, which sucks because we could print a + * warning here. + */ + return NULL; + } + + cie = dwarf_lookup_cie(fde->cie_pointer); + + frame->pc = fde->initial_location; + + /* CIE initial instructions */ + dwarf_cfa_execute_insns(cie->initial_instructions, + cie->instructions_end, cie, fde, + frame, pc, false); + + /* FDE instructions */ + dwarf_cfa_execute_insns(fde->instructions, fde->end, cie, + fde, frame, pc, define_ra); + + /* Calculate the CFA */ + switch (frame->flags) { + case DWARF_FRAME_CFA_REG_OFFSET: + if (prev) { + BUG_ON(!prev->regs[frame->cfa_register].flags); + + addr = prev->cfa; + addr += prev->regs[frame->cfa_register].addr; + frame->cfa = __raw_readl(addr); + + } else { + /* + * Again, this is the first invocation of this + * recurisve function. We need to physically + * read the contents of a register in order to + * get the Canonical Frame Address for this + * function. + */ + frame->cfa = dwarf_read_arch_reg(frame->cfa_register); + } + + frame->cfa += frame->cfa_offset; + break; + default: + BUG(); + } + + /* If we haven't seen the return address reg, we're screwed. */ + BUG_ON(!frame->regs[DWARF_ARCH_RA_REG].flags); + + for (i = 0; i <= frame->num_regs; i++) { + struct dwarf_reg *reg = &frame->regs[i]; + + if (!reg->flags) + continue; + + offset = reg->addr; + offset += frame->cfa; + } + + addr = frame->cfa + frame->regs[DWARF_ARCH_RA_REG].addr; + frame->return_addr = __raw_readl(addr); + + frame->next = dwarf_unwind_stack(frame->return_addr, frame); + return frame; +} + +static int dwarf_parse_cie(void *entry, void *p, unsigned long len, + unsigned char *end) +{ + struct dwarf_cie *cie; + unsigned long flags; + int count; + + cie = kzalloc(sizeof(*cie), GFP_KERNEL); + if (!cie) + return -ENOMEM; + + cie->length = len; + + /* + * Record the offset into the .eh_frame section + * for this CIE. It allows this CIE to be + * quickly and easily looked up from the + * corresponding FDE. + */ + cie->cie_pointer = (unsigned long)entry; + + cie->version = *(char *)p++; + BUG_ON(cie->version != 1); + + cie->augmentation = p; + p += strlen(cie->augmentation) + 1; + + count = dwarf_read_uleb128(p, &cie->code_alignment_factor); + p += count; + + count = dwarf_read_leb128(p, &cie->data_alignment_factor); + p += count; + + /* + * Which column in the rule table contains the + * return address? + */ + if (cie->version == 1) { + cie->return_address_reg = __raw_readb(p); + p++; + } else { + count = dwarf_read_uleb128(p, &cie->return_address_reg); + p += count; + } + + if (cie->augmentation[0] == 'z') { + unsigned int length, count; + cie->flags |= DWARF_CIE_Z_AUGMENTATION; + + count = dwarf_read_uleb128(p, &length); + p += count; + + BUG_ON((unsigned char *)p > end); + + cie->initial_instructions = p + length; + cie->augmentation++; + } + + while (*cie->augmentation) { + /* + * "L" indicates a byte showing how the + * LSDA pointer is encoded. Skip it. + */ + if (*cie->augmentation == 'L') { + p++; + cie->augmentation++; + } else if (*cie->augmentation == 'R') { + /* + * "R" indicates a byte showing + * how FDE addresses are + * encoded. + */ + cie->encoding = *(char *)p++; + cie->augmentation++; + } else if (*cie->augmentation == 'P') { + /* + * "R" indicates a personality + * routine in the CIE + * augmentation. + */ + BUG(); + } else if (*cie->augmentation == 'S') { + BUG(); + } else { + /* + * Unknown augmentation. Assume + * 'z' augmentation. + */ + p = cie->initial_instructions; + BUG_ON(!p); + break; + } + } + + cie->initial_instructions = p; + cie->instructions_end = end; + + /* Add to list */ + spin_lock_irqsave(&dwarf_cie_lock, flags); + list_add_tail(&cie->link, &dwarf_cie_list); + spin_unlock_irqrestore(&dwarf_cie_lock, flags); + + return 0; +} + +static int dwarf_parse_fde(void *entry, u32 entry_type, + void *start, unsigned long len) +{ + struct dwarf_fde *fde; + struct dwarf_cie *cie; + unsigned long flags; + int count; + void *p = start; + + fde = kzalloc(sizeof(*fde), GFP_KERNEL); + if (!fde) + return -ENOMEM; + + fde->length = len; + + /* + * In a .eh_frame section the CIE pointer is the + * delta between the address within the FDE + */ + fde->cie_pointer = (unsigned long)(p - entry_type - 4); + + cie = dwarf_lookup_cie(fde->cie_pointer); + fde->cie = cie; + + if (cie->encoding) + count = dwarf_read_encoded_value(p, &fde->initial_location, + cie->encoding); + else + count = dwarf_read_addr(p, &fde->initial_location); + + p += count; + + if (cie->encoding) + count = dwarf_read_encoded_value(p, &fde->address_range, + cie->encoding & 0x0f); + else + count = dwarf_read_addr(p, &fde->address_range); + + p += count; + + if (fde->cie->flags & DWARF_CIE_Z_AUGMENTATION) { + unsigned int length; + count = dwarf_read_uleb128(p, &length); + p += count + length; + } + + /* Call frame instructions. */ + fde->instructions = p; + fde->end = start + len; + + /* Add to list. */ + spin_lock_irqsave(&dwarf_fde_lock, flags); + list_add_tail(&fde->link, &dwarf_fde_list); + spin_unlock_irqrestore(&dwarf_fde_lock, flags); + + return 0; +} + +static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs, + unsigned long *sp, + const struct stacktrace_ops *ops, void *data) +{ + struct dwarf_frame *frame; + + frame = dwarf_unwind_stack(0, NULL); + + while (frame && frame->return_addr) { + ops->address(data, frame->return_addr, 1); + frame = frame->next; + } +} + +static struct unwinder dwarf_unwinder = { + .name = "dwarf-unwinder", + .dump = dwarf_unwinder_dump, + .rating = 150, +}; + +static void dwarf_unwinder_cleanup(void) +{ + struct dwarf_cie *cie, *m; + struct dwarf_fde *fde, *n; + unsigned long flags; + + /* + * Deallocate all the memory allocated for the DWARF unwinder. + * Traverse all the FDE/CIE lists and remove and free all the + * memory associated with those data structures. + */ + spin_lock_irqsave(&dwarf_cie_lock, flags); + list_for_each_entry_safe(cie, m, &dwarf_cie_list, link) + kfree(cie); + spin_unlock_irqrestore(&dwarf_cie_lock, flags); + + spin_lock_irqsave(&dwarf_fde_lock, flags); + list_for_each_entry_safe(fde, n, &dwarf_fde_list, link) + kfree(fde); + spin_unlock_irqrestore(&dwarf_fde_lock, flags); +} + +/** + * dwarf_unwinder_init - initialise the dwarf unwinder + * + * Build the data structures describing the .dwarf_frame section to + * make it easier to lookup CIE and FDE entries. Because the + * .eh_frame section is packed as tightly as possible it is not + * easy to lookup the FDE for a given PC, so we build a list of FDE + * and CIE entries that make it easier. + */ +void dwarf_unwinder_init(void) +{ + u32 entry_type; + void *p, *entry; + int count, err; + unsigned long len; + unsigned int c_entries, f_entries; + unsigned char *end; + INIT_LIST_HEAD(&dwarf_cie_list); + INIT_LIST_HEAD(&dwarf_fde_list); + + c_entries = 0; + f_entries = 0; + entry = &__start_eh_frame; + + while ((char *)entry < __stop_eh_frame) { + p = entry; + + count = dwarf_entry_len(p, &len); + if (count == 0) { + /* + * We read a bogus length field value. There is + * nothing we can do here apart from disabling + * the DWARF unwinder. We can't even skip this + * entry and move to the next one because 'len' + * tells us where our next entry is. + */ + goto out; + } else + p += count; + + /* initial length does not include itself */ + end = p + len; + + entry_type = get_unaligned((u32 *)p); + p += 4; + + if (entry_type == DW_EH_FRAME_CIE) { + err = dwarf_parse_cie(entry, p, len, end); + if (err < 0) + goto out; + else + c_entries++; + } else { + err = dwarf_parse_fde(entry, entry_type, p, len); + if (err < 0) + goto out; + else + f_entries++; + } + + entry = (char *)entry + len + 4; + } + + printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n", + c_entries, f_entries); + + err = unwinder_register(&dwarf_unwinder); + if (err) + goto out; + + return; + +out: + printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err); + dwarf_unwinder_cleanup(); +} diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S index fc26ccd8278..e63178fefb9 100644 --- a/arch/sh/kernel/entry-common.S +++ b/arch/sh/kernel/entry-common.S @@ -43,6 +43,7 @@ * syscall # * */ +#include <asm/dwarf.h> #if defined(CONFIG_PREEMPT) # define preempt_stop() cli ; TRACE_IRQS_OFF @@ -66,6 +67,11 @@ ENTRY(exception_error) .align 2 ret_from_exception: + CFI_STARTPROC simple + CFI_DEF_CFA r14, 0 + CFI_REL_OFFSET 17, 64 + CFI_REL_OFFSET 15, 0 + CFI_REL_OFFSET 14, 56 preempt_stop() ENTRY(ret_from_irq) ! @@ -240,6 +246,7 @@ debug_trap: nop bra __restore_all nop + CFI_ENDPROC .align 2 1: .long debug_trap_table @@ -285,6 +292,7 @@ ret_from_fork: * system calls and debug traps through their respective jump tables. */ ENTRY(system_call) + setup_frame_reg #if !defined(CONFIG_CPU_SH2) mov.l 1f, r9 mov.l @r9, r8 ! Read from TRA (Trap Address) Register diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c index 278c68c6048..2bb43dc74f2 100644 --- a/arch/sh/kernel/irq.c +++ b/arch/sh/kernel/irq.c @@ -14,6 +14,7 @@ #include <asm/processor.h> #include <asm/machvec.h> #include <asm/uaccess.h> +#include <asm/dwarf.h> #include <asm/thread_info.h> #include <cpu/mmu_context.h> @@ -261,6 +262,9 @@ void __init init_IRQ(void) sh_mv.mv_init_irq(); irq_ctx_init(smp_processor_id()); + + /* This needs to be early, but not too early.. */ + dwarf_unwinder_init(); } #ifdef CONFIG_SPARSE_IRQ diff --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S index 80dc9f8d941..1b7d9d541e0 100644 --- a/arch/sh/kernel/vmlinux.lds.S +++ b/arch/sh/kernel/vmlinux.lds.S @@ -12,7 +12,7 @@ OUTPUT_ARCH(sh) #include <asm/thread_info.h> #include <asm/cache.h> -#include <asm-generic/vmlinux.lds.h> +#include <asm/vmlinux.lds.h> ENTRY(_start) SECTIONS @@ -70,6 +70,8 @@ SECTIONS _edata = .; /* End of data section */ + DWARF_EH_FRAME + . = ALIGN(PAGE_SIZE); /* Init code and data */ __init_begin = .; INIT_TEXT_SECTION(PAGE_SIZE) |