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arch/sh/kernel/dwarf.c
29.2 KB
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/* * 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. |
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* - Registers with DWARF_VAL_OFFSET rules aren't handled properly. |
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*/ /* #define DEBUG */ #include <linux/kernel.h> #include <linux/io.h> #include <linux/list.h> |
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#include <linux/mempool.h> |
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#include <linux/mm.h> |
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#include <linux/elf.h> |
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#include <linux/ftrace.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <asm/dwarf.h> #include <asm/unwinder.h> #include <asm/sections.h> |
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#include <asm/unaligned.h> |
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#include <asm/stacktrace.h> |
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/* Reserve enough memory for two stack frames */ #define DWARF_FRAME_MIN_REQ 2 /* ... with 4 registers per frame. */ #define DWARF_REG_MIN_REQ (DWARF_FRAME_MIN_REQ * 4) static struct kmem_cache *dwarf_frame_cachep; static mempool_t *dwarf_frame_pool; static struct kmem_cache *dwarf_reg_cachep; static mempool_t *dwarf_reg_pool; |
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static struct rb_root cie_root; |
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static DEFINE_SPINLOCK(dwarf_cie_lock); |
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static struct rb_root fde_root; |
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static DEFINE_SPINLOCK(dwarf_fde_lock); |
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static struct dwarf_cie *cached_cie; |
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static unsigned int dwarf_unwinder_ready; |
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/** * dwarf_frame_alloc_reg - allocate memory for a DWARF register * @frame: the DWARF frame whose list of registers we insert on * @reg_num: the register number * * Allocate space for, and initialise, a dwarf reg from * dwarf_reg_pool and insert it onto the (unsorted) linked-list of * dwarf registers for @frame. |
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* |
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* Return the initialised DWARF reg. |
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*/ |
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static struct dwarf_reg *dwarf_frame_alloc_reg(struct dwarf_frame *frame, unsigned int reg_num) |
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{ |
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struct dwarf_reg *reg; |
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reg = mempool_alloc(dwarf_reg_pool, GFP_ATOMIC); if (!reg) { printk(KERN_WARNING "Unable to allocate a DWARF register "); |
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/* * Let's just bomb hard here, we have no way to * gracefully recover. */ |
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UNWINDER_BUG(); |
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} |
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reg->number = reg_num; reg->addr = 0; reg->flags = 0; list_add(®->link, &frame->reg_list); return reg; } static void dwarf_frame_free_regs(struct dwarf_frame *frame) { struct dwarf_reg *reg, *n; list_for_each_entry_safe(reg, n, &frame->reg_list, link) { list_del(®->link); mempool_free(reg, dwarf_reg_pool); } } /** * dwarf_frame_reg - return a DWARF register * @frame: the DWARF frame to search in for @reg_num * @reg_num: the register number to search for * * Lookup and return the dwarf reg @reg_num for this frame. Return * NULL if @reg_num is an register invalid number. */ static struct dwarf_reg *dwarf_frame_reg(struct dwarf_frame *frame, unsigned int reg_num) { struct dwarf_reg *reg; list_for_each_entry(reg, &frame->reg_list, link) { if (reg->number == reg_num) return reg; |
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} |
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return NULL; |
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} /** * 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. */ |
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static inline int dwarf_read_addr(unsigned long *src, unsigned long *dst) |
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{ |
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u32 val = get_unaligned(src); put_unaligned(val, dst); |
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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 ", (encoding & 0x70)); |
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UNWINDER_BUG(); |
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} if ((encoding & 0x07) == 0x00) encoding |= DW_EH_PE_udata4; switch (encoding & 0x0f) { case DW_EH_PE_sdata4: case DW_EH_PE_udata4: count += 4; |
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decoded_addr += get_unaligned((u32 *)addr); |
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__raw_writel(decoded_addr, val); break; default: pr_debug("encoding=0x%x ", encoding); |
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UNWINDER_BUG(); |
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} 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; |
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initial_len = get_unaligned((u32 *)addr); |
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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) { |
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*len = get_unaligned((u64 *)addr + 4); |
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count = 12; } else { printk(KERN_WARNING "Unknown DWARF extension "); 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) { |
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struct rb_node **rb_node = &cie_root.rb_node; struct dwarf_cie *cie = NULL; |
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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; } |
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while (*rb_node) { struct dwarf_cie *cie_tmp; cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); BUG_ON(!cie_tmp); if (cie_ptr == cie_tmp->cie_pointer) { cie = cie_tmp; cached_cie = cie_tmp; goto out; } else { if (cie_ptr < cie_tmp->cie_pointer) rb_node = &(*rb_node)->rb_left; else rb_node = &(*rb_node)->rb_right; |
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} } |
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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) { |
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struct rb_node **rb_node = &fde_root.rb_node; struct dwarf_fde *fde = NULL; |
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unsigned long flags; |
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spin_lock_irqsave(&dwarf_fde_lock, flags); |
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while (*rb_node) { struct dwarf_fde *fde_tmp; unsigned long tmp_start, tmp_end; |
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fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); BUG_ON(!fde_tmp); |
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tmp_start = fde_tmp->initial_location; tmp_end = fde_tmp->initial_location + fde_tmp->address_range; |
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if (pc < tmp_start) { rb_node = &(*rb_node)->rb_left; } else { if (pc < tmp_end) { fde = fde_tmp; goto out; } else rb_node = &(*rb_node)->rb_right; } } |
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out: |
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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 * * 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, |
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unsigned long pc) |
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{ unsigned char insn; unsigned char *current_insn; unsigned int count, delta, reg, expr_len, offset; |
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struct dwarf_reg *regp; |
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current_insn = insn_start; |
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while (current_insn < insn_end && frame->pc <= pc) { |
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insn = __raw_readb(current_insn++); /* * 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; |
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regp = dwarf_frame_alloc_reg(frame, reg); regp->addr = offset; regp->flags |= DWARF_REG_OFFSET; |
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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: |
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delta = get_unaligned((u16 *)current_insn); |
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current_insn += 2; frame->pc += delta * cie->code_alignment_factor; break; case DW_CFA_advance_loc4: |
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delta = get_unaligned((u32 *)current_insn); |
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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; |
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regp = dwarf_frame_alloc_reg(frame, reg); regp->flags |= DWARF_UNDEFINED; |
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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; |
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regp = dwarf_frame_alloc_reg(frame, reg); regp->flags |= DWARF_REG_OFFSET; regp->addr = offset; |
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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; |
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regp = dwarf_frame_alloc_reg(frame, reg); |
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regp->flags |= DWARF_VAL_OFFSET; |
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regp->addr = offset; |
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break; |
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case DW_CFA_GNU_args_size: count = dwarf_read_uleb128(current_insn, &offset); current_insn += count; break; case DW_CFA_GNU_negative_offset_extended: count = dwarf_read_uleb128(current_insn, ®); current_insn += count; count = dwarf_read_uleb128(current_insn, &offset); offset *= cie->data_alignment_factor; |
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regp = dwarf_frame_alloc_reg(frame, reg); regp->flags |= DWARF_REG_OFFSET; regp->addr = -offset; |
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break; |
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default: pr_debug("unhandled DWARF instruction 0x%x ", insn); |
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UNWINDER_BUG(); |
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break; } } return 0; } /** |
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* dwarf_free_frame - free the memory allocated for @frame * @frame: the frame to free */ void dwarf_free_frame(struct dwarf_frame *frame) { dwarf_frame_free_regs(frame); mempool_free(frame, dwarf_frame_pool); } |
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extern void ret_from_irq(void); |
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/** |
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* dwarf_unwind_stack - unwind the stack * |
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* @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. */ |
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struct dwarf_frame *dwarf_unwind_stack(unsigned long pc, struct dwarf_frame *prev) |
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{ struct dwarf_frame *frame; struct dwarf_cie *cie; struct dwarf_fde *fde; |
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struct dwarf_reg *reg; |
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unsigned long addr; |
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/* |
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* If we've been called in to before initialization has * completed, bail out immediately. */ if (!dwarf_unwinder_ready) return NULL; /* |
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* If we're starting at the top of the stack we need get the * contents of a physical register to get the CFA in order to * begin the virtual unwinding of the stack. |
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* |
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* NOTE: the return address is guaranteed to be setup by the * time this function makes its first function call. |
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*/ |
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if (!pc || !prev) |
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pc = (unsigned long)current_text_addr(); |
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER /* * If our stack has been patched by the function graph tracer * then we might see the address of return_to_handler() where we * expected to find the real return address. */ if (pc == (unsigned long)&return_to_handler) { int index = current->curr_ret_stack; /* * We currently have no way of tracking how many * return_to_handler()'s we've seen. If there is more * than one patched return address on our stack, * complain loudly. */ WARN_ON(index > 0); pc = current->ret_stack[index].ret; } #endif |
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frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC); if (!frame) { printk(KERN_ERR "Unable to allocate a dwarf frame "); |
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UNWINDER_BUG(); |
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} |
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INIT_LIST_HEAD(&frame->reg_list); frame->flags = 0; |
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frame->prev = prev; |
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frame->return_addr = 0; |
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fde = dwarf_lookup_fde(pc); if (!fde) { /* |
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* This is our normal exit path. There are two reasons * why we might exit here, |
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* * 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. */ |
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goto bail; |
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} cie = dwarf_lookup_cie(fde->cie_pointer); frame->pc = fde->initial_location; /* CIE initial instructions */ dwarf_cfa_execute_insns(cie->initial_instructions, |
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cie->instructions_end, cie, fde, |
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frame, pc); |
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/* FDE instructions */ dwarf_cfa_execute_insns(fde->instructions, fde->end, cie, |
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fde, frame, pc); |
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/* Calculate the CFA */ switch (frame->flags) { case DWARF_FRAME_CFA_REG_OFFSET: if (prev) { |
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reg = dwarf_frame_reg(prev, frame->cfa_register); |
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UNWINDER_BUG_ON(!reg); UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET); |
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addr = prev->cfa + reg->addr; |
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frame->cfa = __raw_readl(addr); } else { /* |
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* Again, we're starting from the top of the * stack. We need to physically read * the contents of a register in order to get * the Canonical Frame Address for this |
bd353861c
|
679 680 681 682 683 684 685 686 |
* function. */ frame->cfa = dwarf_read_arch_reg(frame->cfa_register); } frame->cfa += frame->cfa_offset; break; default: |
b344e24a8
|
687 |
UNWINDER_BUG(); |
bd353861c
|
688 |
} |
fb3f3e7fc
|
689 |
reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG); |
5580e9044
|
690 691 692 693 694 695 696 697 |
/* * If we haven't seen the return address register or the return * address column is undefined then we must assume that this is * the end of the callstack. */ if (!reg || reg->flags == DWARF_UNDEFINED) goto bail; |
b344e24a8
|
698 |
UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET); |
bd353861c
|
699 |
|
fb3f3e7fc
|
700 |
addr = frame->cfa + reg->addr; |
bd353861c
|
701 |
frame->return_addr = __raw_readl(addr); |
944a34386
|
702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 |
/* * Ah, the joys of unwinding through interrupts. * * Interrupts are tricky - the DWARF info needs to be _really_ * accurate and unfortunately I'm seeing a lot of bogus DWARF * info. For example, I've seen interrupts occur in epilogues * just after the frame pointer (r14) had been restored. The * problem was that the DWARF info claimed that the CFA could be * reached by using the value of the frame pointer before it was * restored. * * So until the compiler can be trusted to produce reliable * DWARF info when it really matters, let's stop unwinding once * we've calculated the function that was interrupted. */ if (prev && prev->pc == (unsigned long)ret_from_irq) frame->return_addr = 0; |
bd353861c
|
719 |
return frame; |
fb3f3e7fc
|
720 721 |
bail: |
ed4fe7f48
|
722 |
dwarf_free_frame(frame); |
fb3f3e7fc
|
723 |
return NULL; |
bd353861c
|
724 725 726 |
} static int dwarf_parse_cie(void *entry, void *p, unsigned long len, |
a6a2f2ad6
|
727 |
unsigned char *end, struct module *mod) |
bd353861c
|
728 |
{ |
858918b77
|
729 |
struct rb_node **rb_node = &cie_root.rb_node; |
4e1a25940
|
730 |
struct rb_node *parent = *rb_node; |
bd353861c
|
731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 |
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++; |
b344e24a8
|
750 |
UNWINDER_BUG_ON(cie->version != 1); |
bd353861c
|
751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 |
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; |
b344e24a8
|
779 |
UNWINDER_BUG_ON((unsigned char *)p > end); |
bd353861c
|
780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 |
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. */ |
b344e24a8
|
807 |
UNWINDER_BUG(); |
bd353861c
|
808 |
} else if (*cie->augmentation == 'S') { |
b344e24a8
|
809 |
UNWINDER_BUG(); |
bd353861c
|
810 811 812 813 814 815 |
} else { /* * Unknown augmentation. Assume * 'z' augmentation. */ p = cie->initial_instructions; |
b344e24a8
|
816 |
UNWINDER_BUG_ON(!p); |
bd353861c
|
817 818 819 820 821 822 823 824 825 |
break; } } cie->initial_instructions = p; cie->instructions_end = end; /* Add to list */ spin_lock_irqsave(&dwarf_cie_lock, flags); |
858918b77
|
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 |
while (*rb_node) { struct dwarf_cie *cie_tmp; cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); parent = *rb_node; if (cie->cie_pointer < cie_tmp->cie_pointer) rb_node = &parent->rb_left; else if (cie->cie_pointer >= cie_tmp->cie_pointer) rb_node = &parent->rb_right; else WARN_ON(1); } rb_link_node(&cie->node, parent, rb_node); rb_insert_color(&cie->node, &cie_root); |
d8252d627
|
844 |
#ifdef CONFIG_MODULES |
858918b77
|
845 846 |
if (mod != NULL) list_add_tail(&cie->link, &mod->arch.cie_list); |
d8252d627
|
847 |
#endif |
858918b77
|
848 |
|
bd353861c
|
849 850 851 852 853 854 |
spin_unlock_irqrestore(&dwarf_cie_lock, flags); return 0; } static int dwarf_parse_fde(void *entry, u32 entry_type, |
5480675dc
|
855 |
void *start, unsigned long len, |
a6a2f2ad6
|
856 |
unsigned char *end, struct module *mod) |
bd353861c
|
857 |
{ |
858918b77
|
858 |
struct rb_node **rb_node = &fde_root.rb_node; |
4e1a25940
|
859 |
struct rb_node *parent = *rb_node; |
bd353861c
|
860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 |
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; |
5480675dc
|
905 |
fde->end = end; |
bd353861c
|
906 907 908 |
/* Add to list. */ spin_lock_irqsave(&dwarf_fde_lock, flags); |
858918b77
|
909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 |
while (*rb_node) { struct dwarf_fde *fde_tmp; unsigned long tmp_start, tmp_end; unsigned long start, end; fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); start = fde->initial_location; end = fde->initial_location + fde->address_range; tmp_start = fde_tmp->initial_location; tmp_end = fde_tmp->initial_location + fde_tmp->address_range; parent = *rb_node; if (start < tmp_start) rb_node = &parent->rb_left; else if (start >= tmp_end) rb_node = &parent->rb_right; else WARN_ON(1); } rb_link_node(&fde->node, parent, rb_node); rb_insert_color(&fde->node, &fde_root); |
d8252d627
|
935 |
#ifdef CONFIG_MODULES |
858918b77
|
936 937 |
if (mod != NULL) list_add_tail(&fde->link, &mod->arch.fde_list); |
d8252d627
|
938 |
#endif |
858918b77
|
939 |
|
bd353861c
|
940 941 942 943 |
spin_unlock_irqrestore(&dwarf_fde_lock, flags); return 0; } |
b344e24a8
|
944 945 |
static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs, |
bd353861c
|
946 |
unsigned long *sp, |
b344e24a8
|
947 948 |
const struct stacktrace_ops *ops, void *data) |
bd353861c
|
949 |
{ |
fb3f3e7fc
|
950 951 952 953 954 |
struct dwarf_frame *frame, *_frame; unsigned long return_addr; _frame = NULL; return_addr = 0; |
bd353861c
|
955 |
|
fb3f3e7fc
|
956 957 |
while (1) { frame = dwarf_unwind_stack(return_addr, _frame); |
ed4fe7f48
|
958 959 |
if (_frame) dwarf_free_frame(_frame); |
fb3f3e7fc
|
960 961 962 963 964 |
_frame = frame; if (!frame || !frame->return_addr) break; |
bd353861c
|
965 |
|
fb3f3e7fc
|
966 967 |
return_addr = frame->return_addr; ops->address(data, return_addr, 1); |
bd353861c
|
968 |
} |
ed4fe7f48
|
969 970 971 |
if (frame) dwarf_free_frame(frame); |
bd353861c
|
972 973 974 975 976 977 978 979 980 981 |
} static struct unwinder dwarf_unwinder = { .name = "dwarf-unwinder", .dump = dwarf_unwinder_dump, .rating = 150, }; static void dwarf_unwinder_cleanup(void) { |
e376ed7c8
|
982 983 |
struct dwarf_fde *fde, *next_fde; struct dwarf_cie *cie, *next_cie; |
bd353861c
|
984 985 986 987 988 989 |
/* * 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. */ |
e376ed7c8
|
990 |
rbtree_postorder_for_each_entry_safe(fde, next_fde, &fde_root, node) |
bd353861c
|
991 |
kfree(fde); |
858918b77
|
992 |
|
e376ed7c8
|
993 |
rbtree_postorder_for_each_entry_safe(cie, next_cie, &cie_root, node) |
858918b77
|
994 |
kfree(cie); |
fb3f3e7fc
|
995 996 997 |
kmem_cache_destroy(dwarf_reg_cachep); kmem_cache_destroy(dwarf_frame_cachep); |
bd353861c
|
998 999 1000 |
} /** |
a6a2f2ad6
|
1001 1002 1003 1004 |
* dwarf_parse_section - parse DWARF section * @eh_frame_start: start address of the .eh_frame section * @eh_frame_end: end address of the .eh_frame section * @mod: the kernel module containing the .eh_frame section |
bd353861c
|
1005 |
* |
a6a2f2ad6
|
1006 |
* Parse the information in a .eh_frame section. |
bd353861c
|
1007 |
*/ |
5a3abba77
|
1008 1009 |
static int dwarf_parse_section(char *eh_frame_start, char *eh_frame_end, struct module *mod) |
bd353861c
|
1010 1011 1012 |
{ u32 entry_type; void *p, *entry; |
2f6dafc5f
|
1013 |
int count, err = 0; |
eca28e376
|
1014 |
unsigned long len = 0; |
bd353861c
|
1015 1016 |
unsigned int c_entries, f_entries; unsigned char *end; |
bd353861c
|
1017 1018 1019 |
c_entries = 0; f_entries = 0; |
a6a2f2ad6
|
1020 |
entry = eh_frame_start; |
fb3f3e7fc
|
1021 |
|
a6a2f2ad6
|
1022 |
while ((char *)entry < eh_frame_end) { |
bd353861c
|
1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 |
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. */ |
a6a2f2ad6
|
1034 |
err = -EINVAL; |
bd353861c
|
1035 1036 1037 1038 1039 1040 |
goto out; } else p += count; /* initial length does not include itself */ end = p + len; |
3497447f1
|
1041 |
entry_type = get_unaligned((u32 *)p); |
bd353861c
|
1042 1043 1044 |
p += 4; if (entry_type == DW_EH_FRAME_CIE) { |
a6a2f2ad6
|
1045 |
err = dwarf_parse_cie(entry, p, len, end, mod); |
bd353861c
|
1046 1047 1048 1049 1050 |
if (err < 0) goto out; else c_entries++; } else { |
a6a2f2ad6
|
1051 1052 |
err = dwarf_parse_fde(entry, entry_type, p, len, end, mod); |
bd353861c
|
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 |
if (err < 0) goto out; else f_entries++; } entry = (char *)entry + len + 4; } printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs ", c_entries, f_entries); |
a6a2f2ad6
|
1065 1066 1067 1068 1069 |
return 0; out: return err; } |
5a3abba77
|
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 |
#ifdef CONFIG_MODULES int module_dwarf_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) { unsigned int i, err; unsigned long start, end; char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; start = end = 0; for (i = 1; i < hdr->e_shnum; i++) { /* Alloc bit cleared means "ignore it." */ if ((sechdrs[i].sh_flags & SHF_ALLOC) && !strcmp(secstrings+sechdrs[i].sh_name, ".eh_frame")) { start = sechdrs[i].sh_addr; end = start + sechdrs[i].sh_size; break; } } /* Did we find the .eh_frame section? */ if (i != hdr->e_shnum) { |
858918b77
|
1092 1093 |
INIT_LIST_HEAD(&me->arch.cie_list); INIT_LIST_HEAD(&me->arch.fde_list); |
5a3abba77
|
1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 |
err = dwarf_parse_section((char *)start, (char *)end, me); if (err) { printk(KERN_WARNING "%s: failed to parse DWARF info ", me->name); return err; } } return 0; } |
a6a2f2ad6
|
1105 |
/** |
5a3abba77
|
1106 |
* module_dwarf_cleanup - remove FDE/CIEs associated with @mod |
a6a2f2ad6
|
1107 1108 1109 1110 1111 |
* @mod: the module that is being unloaded * * Remove any FDEs and CIEs from the global lists that came from * @mod's .eh_frame section because @mod is being unloaded. */ |
5a3abba77
|
1112 |
void module_dwarf_cleanup(struct module *mod) |
a6a2f2ad6
|
1113 |
{ |
858918b77
|
1114 1115 |
struct dwarf_fde *fde, *ftmp; struct dwarf_cie *cie, *ctmp; |
a6a2f2ad6
|
1116 1117 1118 |
unsigned long flags; spin_lock_irqsave(&dwarf_cie_lock, flags); |
858918b77
|
1119 |
list_for_each_entry_safe(cie, ctmp, &mod->arch.cie_list, link) { |
a6a2f2ad6
|
1120 |
list_del(&cie->link); |
858918b77
|
1121 |
rb_erase(&cie->node, &cie_root); |
a6a2f2ad6
|
1122 |
kfree(cie); |
a6a2f2ad6
|
1123 1124 1125 1126 1127 |
} spin_unlock_irqrestore(&dwarf_cie_lock, flags); spin_lock_irqsave(&dwarf_fde_lock, flags); |
858918b77
|
1128 |
list_for_each_entry_safe(fde, ftmp, &mod->arch.fde_list, link) { |
a6a2f2ad6
|
1129 |
list_del(&fde->link); |
858918b77
|
1130 |
rb_erase(&fde->node, &fde_root); |
a6a2f2ad6
|
1131 |
kfree(fde); |
a6a2f2ad6
|
1132 1133 1134 1135 |
} spin_unlock_irqrestore(&dwarf_fde_lock, flags); } |
5a3abba77
|
1136 |
#endif /* CONFIG_MODULES */ |
a6a2f2ad6
|
1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 |
/** * 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. */ static int __init dwarf_unwinder_init(void) { |
8a37f5205
|
1149 |
int err = -ENOMEM; |
a6a2f2ad6
|
1150 1151 |
dwarf_frame_cachep = kmem_cache_create("dwarf_frames", |
8ec006c58
|
1152 1153 |
sizeof(struct dwarf_frame), 0, SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); |
a6a2f2ad6
|
1154 |
dwarf_reg_cachep = kmem_cache_create("dwarf_regs", |
8ec006c58
|
1155 1156 |
sizeof(struct dwarf_reg), 0, SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); |
a6a2f2ad6
|
1157 1158 1159 1160 1161 |
dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ, mempool_alloc_slab, mempool_free_slab, dwarf_frame_cachep); |
8a37f5205
|
1162 1163 |
if (!dwarf_frame_pool) goto out; |
a6a2f2ad6
|
1164 1165 1166 1167 1168 |
dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ, mempool_alloc_slab, mempool_free_slab, dwarf_reg_cachep); |
8a37f5205
|
1169 1170 |
if (!dwarf_reg_pool) goto out; |
a6a2f2ad6
|
1171 1172 1173 1174 |
err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL); if (err) goto out; |
bd353861c
|
1175 1176 1177 |
err = unwinder_register(&dwarf_unwinder); if (err) goto out; |
8a37f5205
|
1178 |
dwarf_unwinder_ready = 1; |
97f361e24
|
1179 |
return 0; |
bd353861c
|
1180 1181 1182 1183 1184 |
out: printk(KERN_ERR "Failed to initialise DWARF unwinder: %d ", err); dwarf_unwinder_cleanup(); |
8a37f5205
|
1185 |
return err; |
bd353861c
|
1186 |
} |
97f361e24
|
1187 |
early_initcall(dwarf_unwinder_init); |