// SPDX-License-Identifier: GPL-2.0-only/* * arch/arm/kernel/unwind.c * * Copyright (C) 2008 ARM Limited * * Stack unwinding support for ARM * * An ARM EABI version of gcc is required to generate the unwind * tables. For information about the structure of the unwind tables, * see "Exception Handling ABI for the ARM Architecture" at: * * http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html */ #ifndef __CHECKER__#if !defined (__ARM_EABI__)#warning Your compiler does not have EABI support.#warning ARM unwind is known to compile only with EABI compilers.#warning Change compiler or disable ARM_UNWIND option.#endif#endif /* __CHECKER__ */ #include <linux/kernel.h>#include <linux/init.h>#include <linux/export.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/list.h>#include <linux/module.h> #include <asm/stacktrace.h>#include <asm/traps.h>#include <asm/unwind.h> #include "reboot.h" /* Dummy functions to avoid linker complaints */void __aeabi_unwind_cpp_pr0(void){};EXPORT_SYMBOL(__aeabi_unwind_cpp_pr0); void __aeabi_unwind_cpp_pr1(void){};EXPORT_SYMBOL(__aeabi_unwind_cpp_pr1); void __aeabi_unwind_cpp_pr2(void){};EXPORT_SYMBOL(__aeabi_unwind_cpp_pr2); struct unwind_ctrl_block { unsigned long vrs[16]; /* virtual register set */ const unsigned long *insn; /* pointer to the current instructions word */ unsigned long sp_high; /* highest value of sp allowed */ unsigned long *lr_addr; /* address of LR value on the stack */ /* * 1 : check for stack overflow for each register pop. * 0 : save overhead if there is plenty of stack remaining. */ int check_each_pop; int entries; /* number of entries left to interpret */ int byte; /* current byte number in the instructions word */}; enum regs {#ifdef CONFIG_THUMB2_KERNEL FP = 7,#else FP = 11,#endif SP = 13, LR = 14, PC = 15}; extern const struct unwind_idx __start_unwind_idx[];static const struct unwind_idx *__origin_unwind_idx;extern const struct unwind_idx __stop_unwind_idx[]; static DEFINE_RAW_SPINLOCK(unwind_lock);static LIST_HEAD(unwind_tables); /* Convert a prel31 symbol to an absolute address */#define prel31_to_addr(ptr) \({ \ /* sign-extend to 32 bits */ \ long offset = (((long)*(ptr)) << 1) >> 1; \ (unsigned long)(ptr) + offset; \}) /* * Binary search in the unwind index. The entries are * guaranteed to be sorted in ascending order by the linker. * * start = first entry * origin = first entry with positive offset (or stop if there is no such entry) * stop - 1 = last entry */static const struct unwind_idx *search_index(unsigned long addr, const struct unwind_idx *start, const struct unwind_idx *origin, const struct unwind_idx *stop){ unsigned long addr_prel31; pr_debug("%s(%08lx, %p, %p, %p)\n", __func__, addr, start, origin, stop); /* * only search in the section with the matching sign. This way the * prel31 numbers can be compared as unsigned longs. */ if (addr < (unsigned long)start) /* negative offsets: [start; origin) */ stop = origin; else /* positive offsets: [origin; stop) */ start = origin; /* prel31 for address relavive to start */ addr_prel31 = (addr - (unsigned long)start) & 0x7fffffff; while (start < stop - 1) { const struct unwind_idx *mid = start + ((stop - start) >> 1); /* * As addr_prel31 is relative to start an offset is needed to * make it relative to mid. */ if (addr_prel31 - ((unsigned long)mid - (unsigned long)start) < mid->addr_offset) stop = mid; else { /* keep addr_prel31 relative to start */ addr_prel31 -= ((unsigned long)mid - (unsigned long)start); start = mid; } } if (likely(start->addr_offset <= addr_prel31)) return start; else { pr_warn("unwind: Unknown symbol address %08lx\n", addr); return NULL; }} static const struct unwind_idx *unwind_find_origin( const struct unwind_idx *start, const struct unwind_idx *stop){ pr_debug("%s(%p, %p)\n", __func__, start, stop); while (start < stop) { const struct unwind_idx *mid = start + ((stop - start) >> 1); if (mid->addr_offset >= 0x40000000) /* negative offset */ start = mid + 1; else /* positive offset */ stop = mid; } pr_debug("%s -> %p\n", __func__, stop); return stop;} static const struct unwind_idx *unwind_find_idx(unsigned long addr){ const struct unwind_idx *idx = NULL; unsigned long flags; pr_debug("%s(%08lx)\n", __func__, addr); if (core_kernel_text(addr)) { if (unlikely(!__origin_unwind_idx)) __origin_unwind_idx = unwind_find_origin(__start_unwind_idx, __stop_unwind_idx); /* main unwind table */ idx = search_index(addr, __start_unwind_idx, __origin_unwind_idx, __stop_unwind_idx); } else { /* module unwind tables */ struct unwind_table *table; raw_spin_lock_irqsave(&unwind_lock, flags); list_for_each_entry(table, &unwind_tables, list) { if (addr >= table->begin_addr && addr < table->end_addr) { idx = search_index(addr, table->start, table->origin, table->stop); /* Move-to-front to exploit common traces */ list_move(&table->list, &unwind_tables); break; } } raw_spin_unlock_irqrestore(&unwind_lock, flags); } pr_debug("%s: idx = %p\n", __func__, idx); return idx;} static unsigned long unwind_get_byte(struct unwind_ctrl_block *ctrl){ unsigned long ret; if (ctrl->entries <= 0) { pr_warn("unwind: Corrupt unwind table\n"); return 0; } ret = (*ctrl->insn >> (ctrl->byte * 8)) & 0xff; if (ctrl->byte == 0) { ctrl->insn++; ctrl->entries--; ctrl->byte = 3; } else ctrl->byte--; return ret;} /* Before poping a register check whether it is feasible or not */static int unwind_pop_register(struct unwind_ctrl_block *ctrl, unsigned long **vsp, unsigned int reg){ if (unlikely(ctrl->check_each_pop)) if (*vsp >= (unsigned long *)ctrl->sp_high) return -URC_FAILURE; /* Use READ_ONCE_NOCHECK here to avoid this memory access * from being tracked by KASAN. */ ctrl->vrs[reg] = READ_ONCE_NOCHECK(*(*vsp)); if (reg == 14) ctrl->lr_addr = *vsp; (*vsp)++; return URC_OK;} /* Helper functions to execute the instructions */static int unwind_exec_pop_subset_r4_to_r13(struct unwind_ctrl_block *ctrl, unsigned long mask){ unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int load_sp, reg = 4; load_sp = mask & (1 << (13 - 4)); while (mask) { if (mask & 1) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; mask >>= 1; reg++; } if (!load_sp) { ctrl->vrs[SP] = (unsigned long)vsp; } return URC_OK;} static int unwind_exec_pop_r4_to_rN(struct unwind_ctrl_block *ctrl, unsigned long insn){ unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int reg; /* pop R4-R[4+bbb] */ for (reg = 4; reg <= 4 + (insn & 7); reg++) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; if (insn & 0x8) if (unwind_pop_register(ctrl, &vsp, 14)) return -URC_FAILURE; ctrl->vrs[SP] = (unsigned long)vsp; return URC_OK;} static int unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl, unsigned long mask){ unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int reg = 0; /* pop R0-R3 according to mask */ while (mask) { if (mask & 1) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; mask >>= 1; reg++; } ctrl->vrs[SP] = (unsigned long)vsp; return URC_OK;} static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl){ unsigned long bytes = 0; unsigned long insn; unsigned long result = 0; /* * unwind_get_byte() will advance `ctrl` one instruction at a time, so * loop until we get an instruction byte where bit 7 is not set. * * Note: This decodes a maximum of 4 bytes to output 28 bits data where * max is 0xfffffff: that will cover a vsp increment of 1073742336, hence * it is sufficient for unwinding the stack. */ do { insn = unwind_get_byte(ctrl); result |= (insn & 0x7f) << (bytes * 7); bytes++; } while (!!(insn & 0x80) && (bytes != sizeof(result))); return result;} /* * Execute the current unwind instruction. */static int unwind_exec_insn(struct unwind_ctrl_block *ctrl){ unsigned long insn = unwind_get_byte(ctrl); int ret = URC_OK; pr_debug("%s: insn = %08lx\n", __func__, insn); if ((insn & 0xc0) == 0x00) ctrl->vrs[SP] += ((insn & 0x3f) << 2) + 4; else if ((insn & 0xc0) == 0x40) { ctrl->vrs[SP] -= ((insn & 0x3f) << 2) + 4; } else if ((insn & 0xf0) == 0x80) { unsigned long mask; insn = (insn << 8) | unwind_get_byte(ctrl); mask = insn & 0x0fff; if (mask == 0) { pr_warn("unwind: 'Refuse to unwind' instruction %04lx\n", insn); return -URC_FAILURE; } ret = unwind_exec_pop_subset_r4_to_r13(ctrl, mask); if (ret) goto error; } else if ((insn & 0xf0) == 0x90 && (insn & 0x0d) != 0x0d) { ctrl->vrs[SP] = ctrl->vrs[insn & 0x0f]; } else if ((insn & 0xf0) == 0xa0) { ret = unwind_exec_pop_r4_to_rN(ctrl, insn); if (ret) goto error; } else if (insn == 0xb0) { if (ctrl->vrs[PC] == 0) ctrl->vrs[PC] = ctrl->vrs[LR]; /* no further processing */ ctrl->entries = 0; } else if (insn == 0xb1) { unsigned long mask = unwind_get_byte(ctrl); if (mask == 0 || mask & 0xf0) { pr_warn("unwind: Spare encoding %04lx\n", (insn << 8) | mask); return -URC_FAILURE; } ret = unwind_exec_pop_subset_r0_to_r3(ctrl, mask); if (ret) goto error; } else if (insn == 0xb2) { unsigned long uleb128 = unwind_decode_uleb128(ctrl); ctrl->vrs[SP] += 0x204 + (uleb128 << 2); } else { pr_warn("unwind: Unhandled instruction %02lx\n", insn); return -URC_FAILURE; } pr_debug("%s: fp = %08lx sp = %08lx lr = %08lx pc = %08lx\n", __func__, ctrl->vrs[FP], ctrl->vrs[SP], ctrl->vrs[LR], ctrl->vrs[PC]); error: return ret;} /* * Unwind a single frame starting with *sp for the symbol at *pc. It * updates the *pc and *sp with the new values. */int unwind_frame(struct stackframe *frame){ const struct unwind_idx *idx; struct unwind_ctrl_block ctrl; unsigned long sp_low; /* store the highest address on the stack to avoid crossing it*/ sp_low = frame->sp; ctrl.sp_high = ALIGN(sp_low - THREAD_SIZE, THREAD_ALIGN) + THREAD_SIZE; pr_debug("%s(pc = %08lx lr = %08lx sp = %08lx)\n", __func__, frame->pc, frame->lr, frame->sp); idx = unwind_find_idx(frame->pc); if (!idx) { if (frame->pc && kernel_text_address(frame->pc)) { if (in_module_plt(frame->pc) && frame->pc != frame->lr) { /* * Quoting Ard: Veneers only set PC using a * PC+immediate LDR, and so they don't affect * the state of the stack or the register file */ frame->pc = frame->lr; return URC_OK; } pr_warn("unwind: Index not found %08lx\n", frame->pc); } return -URC_FAILURE; } ctrl.vrs[FP] = frame->fp; ctrl.vrs[SP] = frame->sp; ctrl.vrs[LR] = frame->lr; ctrl.vrs[PC] = 0; if (idx->insn == 1) /* can't unwind */ return -URC_FAILURE; else if (frame->pc == prel31_to_addr(&idx->addr_offset)) { /* * Unwinding is tricky when we're halfway through the prologue, * since the stack frame that the unwinder expects may not be * fully set up yet. However, one thing we do know for sure is * that if we are unwinding from the very first instruction of * a function, we are still effectively in the stack frame of * the caller, and the unwind info has no relevance yet. */ if (frame->pc == frame->lr) return -URC_FAILURE; frame->pc = frame->lr; return URC_OK; } else if ((idx->insn & 0x80000000) == 0) /* prel31 to the unwind table */ ctrl.insn = (unsigned long *)prel31_to_addr(&idx->insn); else if ((idx->insn & 0xff000000) == 0x80000000) /* only personality routine 0 supported in the index */ ctrl.insn = &idx->insn; else { pr_warn("unwind: Unsupported personality routine %08lx in the index at %p\n", idx->insn, idx); return -URC_FAILURE; } /* check the personality routine */ if ((*ctrl.insn & 0xff000000) == 0x80000000) { ctrl.byte = 2; ctrl.entries = 1; } else if ((*ctrl.insn & 0xff000000) == 0x81000000) { ctrl.byte = 1; ctrl.entries = 1 + ((*ctrl.insn & 0x00ff0000) >> 16); } else { pr_warn("unwind: Unsupported personality routine %08lx at %p\n", *ctrl.insn, ctrl.insn); return -URC_FAILURE; } ctrl.check_each_pop = 0; if (prel31_to_addr(&idx->addr_offset) == (u32)&call_with_stack) { /* * call_with_stack() is the only place where we permit SP to * jump from one stack to another, and since we know it is * guaranteed to happen, set up the SP bounds accordingly. */ sp_low = frame->fp; ctrl.sp_high = ALIGN(frame->fp, THREAD_SIZE); } while (ctrl.entries > 0) { int urc; if ((ctrl.sp_high - ctrl.vrs[SP]) < sizeof(ctrl.vrs)) ctrl.check_each_pop = 1; urc = unwind_exec_insn(&ctrl); if (urc < 0)Lines 1–500 of 610. 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// SPDX-License-Identifier: GPL-2.0-only /* * arch/arm/kernel/unwind.c * * Copyright (C) 2008 ARM Limited * * Stack unwinding support for ARM * * An ARM EABI version of gcc is required to generate the unwind * tables. For information about the structure of the unwind tables, * see "Exception Handling ABI for the ARM Architecture" at: * * http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html */ #ifndef __CHECKER__ #if !defined (__ARM_EABI__) #warning Your compiler does not have EABI support. #warning ARM unwind is known to compile only with EABI compilers. #warning Change compiler or disable ARM_UNWIND option. #endif #endif /* __CHECKER__ */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/list.h> #include <linux/module.h> #include <asm/stacktrace.h> #include <asm/traps.h> #include <asm/unwind.h> #include "reboot.h" /* Dummy functions to avoid linker complaints */ void __aeabi_unwind_cpp_pr0(void) { }; EXPORT_SYMBOL(__aeabi_unwind_cpp_pr0); void __aeabi_unwind_cpp_pr1(void) { }; EXPORT_SYMBOL(__aeabi_unwind_cpp_pr1); void __aeabi_unwind_cpp_pr2(void) { }; EXPORT_SYMBOL(__aeabi_unwind_cpp_pr2); struct unwind_ctrl_block { unsigned long vrs[16]; /* virtual register set */ const unsigned long *insn; /* pointer to the current instructions word */ unsigned long sp_high; /* highest value of sp allowed */ unsigned long *lr_addr; /* address of LR value on the stack */ /* * 1 : check for stack overflow for each register pop. * 0 : save overhead if there is plenty of stack remaining. */ int check_each_pop; int entries; /* number of entries left to interpret */ int byte; /* current byte number in the instructions word */ }; enum regs { #ifdef CONFIG_THUMB2_KERNEL FP = 7, #else FP = 11, #endif SP = 13, LR = 14, PC = 15 }; extern const struct unwind_idx __start_unwind_idx[]; static const struct unwind_idx *__origin_unwind_idx; extern const struct unwind_idx __stop_unwind_idx[]; static DEFINE_RAW_SPINLOCK(unwind_lock); static LIST_HEAD(unwind_tables); /* Convert a prel31 symbol to an absolute address */ #define prel31_to_addr(ptr) \ ({ \ /* sign-extend to 32 bits */ \ long offset = (((long)*(ptr)) << 1) >> 1; \ (unsigned long)(ptr) + offset; \ }) /* * Binary search in the unwind index. The entries are * guaranteed to be sorted in ascending order by the linker. * * start = first entry * origin = first entry with positive offset (or stop if there is no such entry) * stop - 1 = last entry */ static const struct unwind_idx *search_index(unsigned long addr, const struct unwind_idx *start, const struct unwind_idx *origin, const struct unwind_idx *stop) { unsigned long addr_prel31; pr_debug("%s(%08lx, %p, %p, %p)\n", __func__, addr, start, origin, stop); /* * only search in the section with the matching sign. This way the * prel31 numbers can be compared as unsigned longs. */ if (addr < (unsigned long)start) /* negative offsets: [start; origin) */ stop = origin; else /* positive offsets: [origin; stop) */ start = origin; /* prel31 for address relavive to start */ addr_prel31 = (addr - (unsigned long)start) & 0x7fffffff; while (start < stop - 1) { const struct unwind_idx *mid = start + ((stop - start) >> 1); /* * As addr_prel31 is relative to start an offset is needed to * make it relative to mid. */ if (addr_prel31 - ((unsigned long)mid - (unsigned long)start) < mid->addr_offset) stop = mid; else { /* keep addr_prel31 relative to start */ addr_prel31 -= ((unsigned long)mid - (unsigned long)start); start = mid; } } if (likely(start->addr_offset <= addr_prel31)) return start; else { pr_warn("unwind: Unknown symbol address %08lx\n", addr); return NULL; } } static const struct unwind_idx *unwind_find_origin( const struct unwind_idx *start, const struct unwind_idx *stop) { pr_debug("%s(%p, %p)\n", __func__, start, stop); while (start < stop) { const struct unwind_idx *mid = start + ((stop - start) >> 1); if (mid->addr_offset >= 0x40000000) /* negative offset */ start = mid + 1; else /* positive offset */ stop = mid; } pr_debug("%s -> %p\n", __func__, stop); return stop; } static const struct unwind_idx *unwind_find_idx(unsigned long addr) { const struct unwind_idx *idx = NULL; unsigned long flags; pr_debug("%s(%08lx)\n", __func__, addr); if (core_kernel_text(addr)) { if (unlikely(!__origin_unwind_idx)) __origin_unwind_idx = unwind_find_origin(__start_unwind_idx, __stop_unwind_idx); /* main unwind table */ idx = search_index(addr, __start_unwind_idx, __origin_unwind_idx, __stop_unwind_idx); } else { /* module unwind tables */ struct unwind_table *table; raw_spin_lock_irqsave(&unwind_lock, flags); list_for_each_entry(table, &unwind_tables, list) { if (addr >= table->begin_addr && addr < table->end_addr) { idx = search_index(addr, table->start, table->origin, table->stop); /* Move-to-front to exploit common traces */ list_move(&table->list, &unwind_tables); break; } } raw_spin_unlock_irqrestore(&unwind_lock, flags); } pr_debug("%s: idx = %p\n", __func__, idx); return idx; } static unsigned long unwind_get_byte(struct unwind_ctrl_block *ctrl) { unsigned long ret; if (ctrl->entries <= 0) { pr_warn("unwind: Corrupt unwind table\n"); return 0; } ret = (*ctrl->insn >> (ctrl->byte * 8)) & 0xff; if (ctrl->byte == 0) { ctrl->insn++; ctrl->entries--; ctrl->byte = 3; } else ctrl->byte--; return ret; } /* Before poping a register check whether it is feasible or not */ static int unwind_pop_register(struct unwind_ctrl_block *ctrl, unsigned long **vsp, unsigned int reg) { if (unlikely(ctrl->check_each_pop)) if (*vsp >= (unsigned long *)ctrl->sp_high) return -URC_FAILURE; /* Use READ_ONCE_NOCHECK here to avoid this memory access * from being tracked by KASAN. */ ctrl->vrs[reg] = READ_ONCE_NOCHECK(*(*vsp)); if (reg == 14) ctrl->lr_addr = *vsp; (*vsp)++; return URC_OK; } /* Helper functions to execute the instructions */ static int unwind_exec_pop_subset_r4_to_r13(struct unwind_ctrl_block *ctrl, unsigned long mask) { unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int load_sp, reg = 4; load_sp = mask & (1 << (13 - 4)); while (mask) { if (mask & 1) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; mask >>= 1; reg++; } if (!load_sp) { ctrl->vrs[SP] = (unsigned long)vsp; } return URC_OK; } static int unwind_exec_pop_r4_to_rN(struct unwind_ctrl_block *ctrl, unsigned long insn) { unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int reg; /* pop R4-R[4+bbb] */ for (reg = 4; reg <= 4 + (insn & 7); reg++) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; if (insn & 0x8) if (unwind_pop_register(ctrl, &vsp, 14)) return -URC_FAILURE; ctrl->vrs[SP] = (unsigned long)vsp; return URC_OK; } static int unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl, unsigned long mask) { unsigned long *vsp = (unsigned long *)ctrl->vrs[SP]; int reg = 0; /* pop R0-R3 according to mask */ while (mask) { if (mask & 1) if (unwind_pop_register(ctrl, &vsp, reg)) return -URC_FAILURE; mask >>= 1; reg++; } ctrl->vrs[SP] = (unsigned long)vsp; return URC_OK; } static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl) { unsigned long bytes = 0; unsigned long insn; unsigned long result = 0; /* * unwind_get_byte() will advance `ctrl` one instruction at a time, so * loop until we get an instruction byte where bit 7 is not set. * * Note: This decodes a maximum of 4 bytes to output 28 bits data where * max is 0xfffffff: that will cover a vsp increment of 1073742336, hence * it is sufficient for unwinding the stack. */ do { insn = unwind_get_byte(ctrl); result |= (insn & 0x7f) << (bytes * 7); bytes++; } while (!!(insn & 0x80) && (bytes != sizeof(result))); return result; } /* * Execute the current unwind instruction. */ static int unwind_exec_insn(struct unwind_ctrl_block *ctrl) { unsigned long insn = unwind_get_byte(ctrl); int ret = URC_OK; pr_debug("%s: insn = %08lx\n", __func__, insn); if ((insn & 0xc0) == 0x00) ctrl->vrs[SP] += ((insn & 0x3f) << 2) + 4; else if ((insn & 0xc0) == 0x40) { ctrl->vrs[SP] -= ((insn & 0x3f) << 2) + 4; } else if ((insn & 0xf0) == 0x80) { unsigned long mask; insn = (insn << 8) | unwind_get_byte(ctrl); mask = insn & 0x0fff; if (mask == 0) { pr_warn("unwind: 'Refuse to unwind' instruction %04lx\n", insn); return -URC_FAILURE; } ret = unwind_exec_pop_subset_r4_to_r13(ctrl, mask); if (ret) goto error; } else if ((insn & 0xf0) == 0x90 && (insn & 0x0d) != 0x0d) { ctrl->vrs[SP] = ctrl->vrs[insn & 0x0f]; } else if ((insn & 0xf0) == 0xa0) { ret = unwind_exec_pop_r4_to_rN(ctrl, insn); if (ret) goto error; } else if (insn == 0xb0) { if (ctrl->vrs[PC] == 0) ctrl->vrs[PC] = ctrl->vrs[LR]; /* no further processing */ ctrl->entries = 0; } else if (insn == 0xb1) { unsigned long mask = unwind_get_byte(ctrl); if (mask == 0 || mask & 0xf0) { pr_warn("unwind: Spare encoding %04lx\n", (insn << 8) | mask); return -URC_FAILURE; } ret = unwind_exec_pop_subset_r0_to_r3(ctrl, mask); if (ret) goto error; } else if (insn == 0xb2) { unsigned long uleb128 = unwind_decode_uleb128(ctrl); ctrl->vrs[SP] += 0x204 + (uleb128 << 2); } else { pr_warn("unwind: Unhandled instruction %02lx\n", insn); return -URC_FAILURE; } pr_debug("%s: fp = %08lx sp = %08lx lr = %08lx pc = %08lx\n", __func__, ctrl->vrs[FP], ctrl->vrs[SP], ctrl->vrs[LR], ctrl->vrs[PC]); error: return ret; } /* * Unwind a single frame starting with *sp for the symbol at *pc. It * updates the *pc and *sp with the new values. */ int unwind_frame(struct stackframe *frame) { const struct unwind_idx *idx; struct unwind_ctrl_block ctrl; unsigned long sp_low; /* store the highest address on the stack to avoid crossing it*/ sp_low = frame->sp; ctrl.sp_high = ALIGN(sp_low - THREAD_SIZE, THREAD_ALIGN) + THREAD_SIZE; pr_debug("%s(pc = %08lx lr = %08lx sp = %08lx)\n", __func__, frame->pc, frame->lr, frame->sp); idx = unwind_find_idx(frame->pc); if (!idx) { if (frame->pc && kernel_text_address(frame->pc)) { if (in_module_plt(frame->pc) && frame->pc != frame->lr) { /* * Quoting Ard: Veneers only set PC using a * PC+immediate LDR, and so they don't affect * the state of the stack or the register file */ frame->pc = frame->lr; return URC_OK; } pr_warn("unwind: Index not found %08lx\n", frame->pc); } return -URC_FAILURE; } ctrl.vrs[FP] = frame->fp; ctrl.vrs[SP] = frame->sp; ctrl.vrs[LR] = frame->lr; ctrl.vrs[PC] = 0; if (idx->insn == 1) /* can't unwind */ return -URC_FAILURE; else if (frame->pc == prel31_to_addr(&idx->addr_offset)) { /* * Unwinding is tricky when we're halfway through the prologue, * since the stack frame that the unwinder expects may not be * fully set up yet. However, one thing we do know for sure is * that if we are unwinding from the very first instruction of * a function, we are still effectively in the stack frame of * the caller, and the unwind info has no relevance yet. */ if (frame->pc == frame->lr) return -URC_FAILURE; frame->pc = frame->lr; return URC_OK; } else if ((idx->insn & 0x80000000) == 0) /* prel31 to the unwind table */ ctrl.insn = (unsigned long *)prel31_to_addr(&idx->insn); else if ((idx->insn & 0xff000000) == 0x80000000) /* only personality routine 0 supported in the index */ ctrl.insn = &idx->insn; else { pr_warn("unwind: Unsupported personality routine %08lx in the index at %p\n", idx->insn, idx); return -URC_FAILURE; } /* check the personality routine */ if ((*ctrl.insn & 0xff000000) == 0x80000000) { ctrl.byte = 2; ctrl.entries = 1; } else if ((*ctrl.insn & 0xff000000) == 0x81000000) { ctrl.byte = 1; ctrl.entries = 1 + ((*ctrl.insn & 0x00ff0000) >> 16); } else { pr_warn("unwind: Unsupported personality routine %08lx at %p\n", *ctrl.insn, ctrl.insn); return -URC_FAILURE; } ctrl.check_each_pop = 0; if (prel31_to_addr(&idx->addr_offset) == (u32)&call_with_stack) { /* * call_with_stack() is the only place where we permit SP to * jump from one stack to another, and since we know it is * guaranteed to happen, set up the SP bounds accordingly. */ sp_low = frame->fp; ctrl.sp_high = ALIGN(frame->fp, THREAD_SIZE); } while (ctrl.entries > 0) { int urc; if ((ctrl.sp_high - ctrl.vrs[SP]) < sizeof(ctrl.vrs)) ctrl.check_each_pop = 1; urc = unwind_exec_insn(&ctrl); if (urc < 0)