diff options
Diffstat (limited to 'runtime/unwind.c')
| -rw-r--r-- | runtime/unwind.c | 895 |
1 files changed, 895 insertions, 0 deletions
diff --git a/runtime/unwind.c b/runtime/unwind.c new file mode 100644 index 00000000..9a5d61e8 --- /dev/null +++ b/runtime/unwind.c @@ -0,0 +1,895 @@ +/* + * Copyright (C) 2002-2006 Novell, Inc. + * Jan Beulich <jbeulich@novell.com> + * This code is released under version 2 of the GNU GPL. + * + * A simple API for unwinding kernel stacks. This is used for + * debugging and error reporting purposes. The kernel doesn't need + * full-blown stack unwinding with all the bells and whistles, so there + * is not much point in implementing the full Dwarf2 unwind API. + */ + +#include "unwind/unwind.h" + +struct eh_frame_hdr_table_entry { + unsigned long start, fde; +}; + +static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2) +{ + const struct eh_frame_hdr_table_entry *e1 = p1; + const struct eh_frame_hdr_table_entry *e2 = p2; + return (e1->start > e2->start) - (e1->start < e2->start); +} + +static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size) +{ + struct eh_frame_hdr_table_entry *e1 = p1; + struct eh_frame_hdr_table_entry *e2 = p2; + unsigned long v; + + v = e1->start; + e1->start = e2->start; + e2->start = v; + v = e1->fde; + e1->fde = e2->fde; + e2->fde = v; +} + +/* Build a binary-searchable unwind header. Also do some + * validity checks. In the future we might use */ +/* .eh_frame_hdr if it is already present. */ +static void _stp_create_unwind_hdr(struct _stp_module *m) +{ + const u8 *ptr; + unsigned long tableSize, hdrSize, last; + unsigned n = 0; + const u32 *fde; + int bad_order = 0; + struct { + u8 version; + u8 eh_frame_ptr_enc; + u8 fde_count_enc; + u8 table_enc; + unsigned long eh_frame_ptr; + unsigned int fde_count; + struct eh_frame_hdr_table_entry table[]; + } __attribute__ ((__packed__)) * header = NULL; + + /* already did this or no data? */ + if (m->unwind_hdr || m->unwind_data_len == 0) + return; + + tableSize = m->unwind_data_len; + if (tableSize & (sizeof(*fde) - 1)) { + dbug_unwind(1, "tableSize=0x%x not a multiple of 0x%x\n", (int)tableSize, (int)sizeof(*fde)); + goto bad; + } + + /* count the FDEs */ + for (fde = m->unwind_data; + tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; + tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { + signed ptrType; + const u32 *cie; + + /* check for extended length */ + if ((*fde & 0xfffffff0) == 0xfffffff0) { + dbug_unwind(1, "Module %s has extended-length CIE or FDE."); + dbug_unwind(1, "This is not supported at this time."); + goto bad; + } + cie = cie_for_fde(fde, m); + if (cie == ¬_fde) + continue; /* fde was a CIE. That's OK, just skip it. */ + if (cie == NULL || cie == &bad_cie || (ptrType = fde_pointer_type(cie)) < 0) + goto bad; + /* we have a real FDE */ + ptr = (const u8 *)(fde + 2); + if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType)) + goto bad; + ++n; + } + + if (tableSize || !n) { + dbug_unwind(1, "%s: tableSize=%ld, n=%d\n", m->name, tableSize, n); + goto bad; + } + + hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int) + 2 * n * sizeof(unsigned long); + header = _stp_kmalloc(hdrSize); + if (header == NULL) { + header = _stp_vmalloc(hdrSize); + if (header == NULL) + return; + m->allocated.unwind_hdr = 1; + } + + header->version = 1; + header->eh_frame_ptr_enc = DW_EH_PE_absptr; + header->fde_count_enc = DW_EH_PE_data4; + header->table_enc = DW_EH_PE_absptr; + _stp_put_unaligned((unsigned long)m->unwind_data, &header->eh_frame_ptr); + + BUILD_BUG_ON(offsetof(typeof(*header), fde_count) + % __alignof(typeof(header->fde_count))); + header->fde_count = n; + + BUILD_BUG_ON(offsetof(typeof(*header), table) % __alignof(typeof(*header->table))); + + n = 0; + last = 0; + tableSize = m->unwind_data_len; + for (fde = m->unwind_data; tableSize; tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { + const u32 *cie = cie_for_fde(fde, m); + if (cie == ¬_fde) + continue; + if (cie == NULL || cie == &bad_cie) + goto bad; + /* we have a real FDE */ + ptr = (const u8 *)(fde + 2); + header->table[n].start = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, fde_pointer_type(cie)); + header->table[n].fde = (unsigned long)fde; + if (header->table[n].start < last) + bad_order++; + last = header->table[n].start; + ++n; + } + WARN_ON(n != header->fde_count); + + /* Is sort ever necessary? */ + if (bad_order) + _stp_sort(header->table, n, sizeof(*header->table), cmp_eh_frame_hdr_table_entries, + swap_eh_frame_hdr_table_entries); + + m->unwind_hdr_len = hdrSize; + m->unwind_hdr = header; + return; + + /* unwind data is not acceptable. free it and return */ +bad: + dbug_unwind(1, "unwind data for %s is unacceptable. Freeing.", m->name); + if (header) { + if (m->allocated.unwind_hdr) { + m->allocated.unwind_hdr = 0; + _stp_vfree(header); + } else + _stp_kfree(header); + } + if (m->unwind_data) { + if (m->allocated.unwind_data) + _stp_vfree(m->unwind_data); + else + _stp_kfree(m->unwind_data); + m->unwind_data = NULL; + m->unwind_data_len = 0; + } + return; +} + +static uleb128_t get_uleb128(const u8 **pcur, const u8 *end) +{ + const u8 *cur = *pcur; + uleb128_t value = 0; + unsigned shift; + + for (shift = 0; cur < end; shift += 7) { + if (shift + 7 > 8 * sizeof(value) + && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { + cur = end + 1; + break; + } + value |= (uleb128_t)(*cur & 0x7f) << shift; + if (!(*cur++ & 0x80)) + break; + } + *pcur = cur; + + return value; +} + +static sleb128_t get_sleb128(const u8 **pcur, const u8 *end) +{ + const u8 *cur = *pcur; + sleb128_t value = 0; + unsigned shift; + + for (shift = 0; cur < end; shift += 7) { + if (shift + 7 > 8 * sizeof(value) + && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { + cur = end + 1; + break; + } + value |= (sleb128_t)(*cur & 0x7f) << shift; + if (!(*cur & 0x80)) { + value |= -(*cur++ & 0x40) << shift; + break; + } + } + *pcur = cur; + + return value; +} + +/* given an FDE, find its CIE */ +static const u32 *cie_for_fde(const u32 *fde, const struct _stp_module *m) +{ + const u32 *cie; + + /* check that length is proper */ + if (!*fde || (*fde & (sizeof(*fde) - 1))) + return &bad_cie; + + /* CIE id for eh_frame is 0, otherwise 0xffffffff */ + if (m->unwind_is_ehframe && fde[1] == 0) + return ¬_fde; + else if (fde[1] == 0xffffffff) + return ¬_fde; + + /* OK, must be an FDE. Now find its CIE. */ + + /* CIE_pointer must be a proper offset */ + if ((fde[1] & (sizeof(*fde) - 1)) || fde[1] > (unsigned long)(fde + 1) - (unsigned long)m->unwind_data) { + dbug_unwind(1, "fde[1]=%lx fde+1=%lx, unwind_data=%lx %lx\n", + (unsigned long)fde[1], (unsigned long)(fde + 1), + (unsigned long)m->unwind_data, (unsigned long)(fde + 1) - (unsigned long)m->unwind_data); + return NULL; /* this is not a valid FDE */ + } + + /* cie pointer field is different in eh_frame vs debug_frame */ + if (m->unwind_is_ehframe) + cie = fde + 1 - fde[1] / sizeof(*fde); + else + cie = m->unwind_data + fde[1]; + + if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde) + || (*cie & (sizeof(*cie) - 1)) + || (cie[1] != 0xffffffff && cie[1] != 0)) { + dbug_unwind(1, "cie is not valid %lx %x %x %x\n", cie, *cie, fde[1], cie[1]); + return NULL; /* this is not a (valid) CIE */ + } + + return cie; +} + +/* read an encoded pointer */ +static unsigned long read_pointer(const u8 **pLoc, const void *end, signed ptrType) +{ + unsigned long value = 0; + union { + const u8 *p8; + const u16 *p16u; + const s16 *p16s; + const u32 *p32u; + const s32 *p32s; + const unsigned long *pul; + } ptr; + + if (ptrType < 0 || ptrType == DW_EH_PE_omit) + return 0; + + ptr.p8 = *pLoc; + switch (ptrType & DW_EH_PE_FORM) { + case DW_EH_PE_data2: + if (end < (const void *)(ptr.p16u + 1)) + return 0; + if (ptrType & DW_EH_PE_signed) + value = _stp_get_unaligned(ptr.p16s++); + else + value = _stp_get_unaligned(ptr.p16u++); + break; + case DW_EH_PE_data4: +#ifdef CONFIG_64BIT + if (end < (const void *)(ptr.p32u + 1)) + return 0; + if (ptrType & DW_EH_PE_signed) + value = _stp_get_unaligned(ptr.p32s++); + else + value = _stp_get_unaligned(ptr.p32u++); + break; + case DW_EH_PE_data8: + BUILD_BUG_ON(sizeof(u64) != sizeof(value)); +#else + BUILD_BUG_ON(sizeof(u32) != sizeof(value)); +#endif + case DW_EH_PE_absptr: + if (end < (const void *)(ptr.pul + 1)) + return 0; + value = _stp_get_unaligned(ptr.pul++); + break; + case DW_EH_PE_leb128: + BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value)); + value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end) + : get_uleb128(&ptr.p8, end); + if ((const void *)ptr.p8 > end) + return 0; + break; + default: + return 0; + } + switch (ptrType & DW_EH_PE_ADJUST) { + case DW_EH_PE_absptr: + break; + case DW_EH_PE_pcrel: + value += (unsigned long)*pLoc; + break; + default: + return 0; + } + if ((ptrType & DW_EH_PE_indirect) + && __stp_get_user(value, (unsigned long *)value)) + return 0; + *pLoc = ptr.p8; + + return value; +} + +static signed fde_pointer_type(const u32 *cie) +{ + const u8 *ptr = (const u8 *)(cie + 2); + unsigned version = *ptr; + + if (version != 1) + return -1; /* unsupported */ + if (*++ptr) { + const char *aug; + const u8 *end = (const u8 *)(cie + 1) + *cie; + uleb128_t len; + + /* check if augmentation size is first (and thus present) */ + if (*ptr != 'z') + return -1; + /* check if augmentation string is nul-terminated */ + if ((ptr = memchr(aug = (const void *)ptr, 0, end - ptr)) == NULL) + return -1; + ++ptr; /* skip terminator */ + get_uleb128(&ptr, end); /* skip code alignment */ + get_sleb128(&ptr, end); /* skip data alignment */ + /* skip return address column */ + version <= 1 ? (void)++ptr : (void)get_uleb128(&ptr, end); + len = get_uleb128(&ptr, end); /* augmentation length */ + if (ptr + len < ptr || ptr + len > end) + return -1; + end = ptr + len; + while (*++aug) { + if (ptr >= end) + return -1; + switch (*aug) { + case 'L': + ++ptr; + break; + case 'P':{ + signed ptrType = *ptr++; + + if (!read_pointer(&ptr, end, ptrType) || ptr > end) + return -1; + } + break; + case 'R': + return *ptr; + default: + return -1; + } + } + } + return DW_EH_PE_absptr; +} + +static int advance_loc(unsigned long delta, struct unwind_state *state) +{ + state->loc += delta * state->codeAlign; + dbug_unwind(1, "state->loc=%lx\n", state->loc); + return delta > 0; +} + +static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value, struct unwind_state *state) +{ + dbug_unwind(1, "reg=%d, where=%d, value=%lx\n", reg, where, value); + if (reg < ARRAY_SIZE(state->regs)) { + state->regs[reg].where = where; + state->regs[reg].value = value; + } +} + +static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, signed ptrType, struct unwind_state *state) +{ + union { + const u8 *p8; + const u16 *p16; + const u32 *p32; + } ptr; + int result = 1; + + if (start != state->cieStart) { + state->loc = state->org; + result = processCFI(state->cieStart, state->cieEnd, 0, ptrType, state); + if (targetLoc == 0 && state->label == NULL) + return result; + } + + for (ptr.p8 = start; result && ptr.p8 < end;) { + switch (*ptr.p8 >> 6) { + uleb128_t value; + case 0: + switch (*ptr.p8++) { + case DW_CFA_nop: + dbug_unwind(1, "DW_CFA_nop\n"); + break; + case DW_CFA_set_loc: + if ((state->loc = read_pointer(&ptr.p8, end, ptrType)) == 0) + result = 0; + dbug_unwind(1, "DW_CFA_set_loc %lx (result=%d)\n", state->loc, result); + break; + case DW_CFA_advance_loc1: + result = ptr.p8 < end && advance_loc(*ptr.p8++, state); + dbug_unwind(1, "DW_CFA_advance_loc1 %d\n", result); + break; + case DW_CFA_advance_loc2: + result = ptr.p8 <= end + 2 && advance_loc(*ptr.p16++, state); + dbug_unwind(1, "DW_CFA_advance_loc2 %d\n", result); + break; + case DW_CFA_advance_loc4: + result = ptr.p8 <= end + 4 && advance_loc(*ptr.p32++, state); + dbug_unwind(1, "DW_CFA_advance_loc4 %d\n", result); + break; + case DW_CFA_offset_extended: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Memory, get_uleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_offset_extended\n"); + break; + case DW_CFA_val_offset: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Value, get_uleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_val_offset\n"); + break; + case DW_CFA_offset_extended_sf: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Memory, get_sleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_offset_extended_sf\n"); + break; + case DW_CFA_val_offset_sf: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Value, get_sleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_val_offset_sf\n"); + break; + case DW_CFA_restore_extended: + case DW_CFA_undefined: + case DW_CFA_same_value: + set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, state); + dbug_unwind(1, "DW_CFA_undefined\n"); + break; + case DW_CFA_register: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Register, get_uleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_register\n"); + break; + case DW_CFA_remember_state: + dbug_unwind(1, "DW_CFA_remember_state\n"); + if (ptr.p8 == state->label) { + state->label = NULL; + return 1; + } + if (state->stackDepth >= MAX_STACK_DEPTH) + return 0; + state->stack[state->stackDepth++] = ptr.p8; + break; + case DW_CFA_restore_state: + dbug_unwind(1, "DW_CFA_restore_state\n"); + if (state->stackDepth) { + const uleb128_t loc = state->loc; + const u8 *label = state->label; + + state->label = state->stack[state->stackDepth - 1]; + memcpy(&state->cfa, &badCFA, sizeof(state->cfa)); + memset(state->regs, 0, sizeof(state->regs)); + state->stackDepth = 0; + result = processCFI(start, end, 0, ptrType, state); + state->loc = loc; + state->label = label; + } else + return 0; + break; + case DW_CFA_def_cfa: + state->cfa.reg = get_uleb128(&ptr.p8, end); + dbug_unwind(1, "DW_CFA_def_cfa reg=%ld\n", state->cfa.reg); + /*nobreak */ + case DW_CFA_def_cfa_offset: + state->cfa.offs = get_uleb128(&ptr.p8, end); + dbug_unwind(1, "DW_CFA_def_cfa_offset offs=%lx\n", state->cfa.offs); + break; + case DW_CFA_def_cfa_sf: + state->cfa.reg = get_uleb128(&ptr.p8, end); + dbug_unwind(1, "DW_CFA_def_cfa_sf reg=%ld\n", state->cfa.reg); + /*nobreak */ + case DW_CFA_def_cfa_offset_sf: + state->cfa.offs = get_sleb128(&ptr.p8, end) * state->dataAlign; + dbug_unwind(1, "DW_CFA_def_cfa_offset_sf offs=%lx\n", state->cfa.offs); + break; + case DW_CFA_def_cfa_register: + state->cfa.reg = get_uleb128(&ptr.p8, end); + dbug_unwind(1, "DW_CFA_def_cfa_register reg=%ld\n", state->cfa.reg); + break; + /*todo case DW_CFA_def_cfa_expression: */ + /*todo case DW_CFA_expression: */ + /*todo case DW_CFA_val_expression: */ + case DW_CFA_GNU_args_size: + get_uleb128(&ptr.p8, end); + dbug_unwind(1, "DW_CFA_GNU_args_size\n"); + break; + case DW_CFA_GNU_negative_offset_extended: + value = get_uleb128(&ptr.p8, end); + set_rule(value, Memory, (uleb128_t)0 - get_uleb128(&ptr.p8, end), state); + dbug_unwind(1, "DW_CFA_GNU_negative_offset_extended\n"); + break; + case DW_CFA_GNU_window_save: + default: + dbug_unwind(1, "unimplemented call frame instruction: 0x%x\n", *(ptr.p8 - 1)); + result = 0; + break; + } + break; + case 1: + result = advance_loc(*ptr.p8++ & 0x3f, state); + dbug_unwind(1, "case 1\n"); + break; + case 2: + value = *ptr.p8++ & 0x3f; + set_rule(value, Memory, get_uleb128(&ptr.p8, end), state); + dbug_unwind(1, "case 2\n"); + break; + case 3: + set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state); + dbug_unwind(1, "case 3\n"); + break; + } + if (ptr.p8 > end) + result = 0; + if (result && targetLoc != 0 && targetLoc < state->loc) + return 1; + } + return result && ptr.p8 == end && (targetLoc == 0 || state->label == NULL); +} + +/* If we previously created an unwind header, then use it now to binary search */ +/* for the FDE corresponding to pc. */ + +static u32 *_stp_search_unwind_hdr(unsigned long pc, struct _stp_module *m) +{ + const u8 *ptr, *end, *hdr = m->unwind_hdr; + unsigned long startLoc; + u32 *fde = NULL; + unsigned num, tableSize, t2; + + /* TOTO: only really need to test hdr == NULL */ + /* The rest should be validated at load time */ + + if (hdr == NULL || hdr[0] != 1) + return NULL; + + dbug_unwind(1, "search for %lx", pc); + + /* table_enc */ + switch (hdr[3] & DW_EH_PE_FORM) { + case DW_EH_PE_absptr: + tableSize = sizeof(unsigned long); + break; + case DW_EH_PE_data2: + tableSize = 2; + break; + case DW_EH_PE_data4: + tableSize = 4; + break; + case DW_EH_PE_data8: + tableSize = 8; + break; + default: + dbug_unwind(1, "bad table encoding"); + return NULL; + } + ptr = hdr + 4; + end = hdr + m->unwind_hdr_len; + + if (read_pointer(&ptr, end, hdr[1]) != (unsigned long)m->unwind_data) { + dbug_unwind(1, "eh_frame_ptr not valid"); + return NULL; + } + + num = read_pointer(&ptr, end, hdr[2]); + if (num == 0 || num != (end - ptr) / (2 * tableSize) || (end - ptr) % (2 * tableSize)) { + dbug_unwind(1, "Bad num=%d end-ptr=%ld 2*tableSize=%d", num, end - ptr, 2 * tableSize); + return NULL; + } + + do { + const u8 *cur = ptr + (num / 2) * (2 * tableSize); + startLoc = read_pointer(&cur, cur + tableSize, hdr[3]); + if (pc < startLoc) + num /= 2; + else { + ptr = cur - tableSize; + num = (num + 1) / 2; + } + } while (startLoc && num > 1); + + if (num == 1 && (startLoc = read_pointer(&ptr, ptr + tableSize, hdr[3])) != 0 && pc >= startLoc) + fde = (void *)read_pointer(&ptr, ptr + tableSize, hdr[3]); + + dbug_unwind(1, "returning %lx", fde); + return fde; +} + +/* Unwind to previous to frame. Returns 0 if successful, negative + * number in case of an error. */ +int unwind(struct unwind_frame_info *frame) +{ +#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs]) + const u32 *fde, *cie = NULL; + const u8 *ptr = NULL, *end = NULL; + unsigned long pc = UNW_PC(frame) - frame->call_frame; + unsigned long tableSize, startLoc = 0, endLoc = 0, cfa; + unsigned i; + signed ptrType = -1; + uleb128_t retAddrReg = 0; + struct _stp_module *m; + struct unwind_state state; + + dbug_unwind(1, "pc=%lx, %lx", pc, UNW_PC(frame)); + + if (UNW_PC(frame) == 0) + return -EINVAL; + + m = _stp_get_unwind_info(pc); + if (unlikely(m == NULL)) { + dbug_unwind(1, "No module found for pc=%lx", pc); + return -EINVAL; + } + + if (unlikely(m->unwind_data_len == 0 || m->unwind_data_len & (sizeof(*fde) - 1))) { + dbug_unwind(1, "Module %s: unwind_data_len=%d", m->name, m->unwind_data_len); + goto done; + } + + fde = _stp_search_unwind_hdr(pc, m); + dbug_unwind(1, "%s: fde=%lx\n", m->name, fde); + + if (fde != NULL) { + cie = cie_for_fde(fde, m); + ptr = (const u8 *)(fde + 2); + if (cie != NULL + && cie != &bad_cie + && cie != ¬_fde + && (ptrType = fde_pointer_type(cie)) >= 0 + && read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType) == startLoc) { + if (!(ptrType & DW_EH_PE_indirect)) + ptrType &= DW_EH_PE_FORM | DW_EH_PE_signed; + endLoc = startLoc + read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType); + if (pc >= endLoc) + fde = NULL; + } else + fde = NULL; + } + if (fde == NULL) { + for (fde = m->unwind_data, tableSize = m->unwind_data_len; cie = NULL, tableSize > sizeof(*fde) + && tableSize - sizeof(*fde) >= *fde; tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) { + // dbug_unwind(1,"fde=%lx tableSize=%d\n", (long)*fde, (int)tableSize); + cie = cie_for_fde(fde, m); + if (cie == &bad_cie) { + cie = NULL; + break; + } + if (cie == NULL || cie == ¬_fde || (ptrType = fde_pointer_type(cie)) < 0) + continue; + + ptr = (const u8 *)(fde + 2); + startLoc = read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType); + // dbug_unwind(1,"startLoc=%p\n",(u64)startLoc); + if (!startLoc) + continue; + if (!(ptrType & DW_EH_PE_indirect)) + ptrType &= DW_EH_PE_FORM | DW_EH_PE_signed; + endLoc = startLoc + read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType); + // dbug_unwind(1,"endLoc=%p\n",(u64)endLoc); + if (pc >= startLoc && pc < endLoc) + break; + } + } + + dbug_unwind(1, "cie=%lx fde=%lx startLoc=%lx endLoc=%lx\n", cie, fde, startLoc, endLoc); + if (cie == NULL || fde == NULL) + goto done; + + /* found the CIE and FDE */ + + memset(&state, 0, sizeof(state)); + state.cieEnd = ptr; /* keep here temporarily */ + ptr = (const u8 *)(cie + 2); + end = (const u8 *)(cie + 1) + *cie; + frame->call_frame = 1; + if ((state.version = *ptr) != 1) { + dbug_unwind(1, "CIE version number is %d. 1 is supported.\n", state.version); + goto done; /* unsupported version */ + } + if (*++ptr) { + /* check if augmentation size is first (and thus present) */ + if (*ptr == 'z') { + while (++ptr < end && *ptr) { + switch (*ptr) { + /* check for ignorable (or already handled) + * nul-terminated augmentation string */ + case 'L': + case 'P': + case 'R': + continue; + case 'S': + frame->call_frame = 0; + continue; + default: + break; + } + break; + } + } + if (ptr >= end || *ptr) { + dbug_unwind(1, "Problem parsing the augmentation string.\n"); + goto done; + } + } + ++ptr; + + /* get code aligment factor */ + state.codeAlign = get_uleb128(&ptr, end); + /* get data aligment factor */ + state.dataAlign = get_sleb128(&ptr, end); + if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end) + goto done;; + + retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end); + + /* skip augmentation */ + if (((const char *)(cie + 2))[1] == 'z') { + uleb128_t augSize = get_uleb128(&ptr, end); + ptr += augSize; + } + if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info) + || REG_INVALID(retAddrReg) + || reg_info[retAddrReg].width != sizeof(unsigned long)) + goto done; + + state.cieStart = ptr; + ptr = state.cieEnd; + state.cieEnd = end; + end = (const u8 *)(fde + 1) + *fde; + + /* skip augmentation */ + if (((const char *)(cie + 2))[1] == 'z') { + uleb128_t augSize = get_uleb128(&ptr, end); + if ((ptr += augSize) > end) + goto done; + } + + state.org = startLoc; + memcpy(&state.cfa, &badCFA, sizeof(state.cfa)); + /* process instructions */ + if (!processCFI(ptr, end, pc, ptrType, &state) + || state.loc > endLoc || state.regs[retAddrReg].where == Nowhere || state.cfa.reg >= ARRAY_SIZE(reg_info) + || reg_info[state.cfa.reg].width != sizeof(unsigned long) + || state.cfa.offs % sizeof(unsigned long)) + goto done; + + /* update frame */ + dbug_unwind(1, "cie=%lx fde=%lx\n", cie, fde); +#ifndef CONFIG_AS_CFI_SIGNAL_FRAME + if (frame->call_frame && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign)) + frame->call_frame = 0; +#endif + cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs; + startLoc = min((unsigned long)UNW_SP(frame), cfa); + endLoc = max((unsigned long)UNW_SP(frame), cfa); + dbug_unwind(1, "cfa=%lx SP startLoc=%lx, endLoc=%lx\n", cfa, startLoc, endLoc); + if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) { + startLoc = min(STACK_LIMIT(cfa), cfa); + endLoc = max(STACK_LIMIT(cfa), cfa); + dbug_unwind(1, "SP startLoc=%p, endLoc=%p\n", (u64)startLoc, (u64)endLoc); + } +#ifndef CONFIG_64BIT +# define CASES CASE(8); CASE(16); CASE(32) +#else +# define CASES CASE(8); CASE(16); CASE(32); CASE(64) +#endif + dbug_unwind(1, "cie=%p fde=%p\n", (u64)cie, (u64)fde); + for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { + if (REG_INVALID(i)) { + if (state.regs[i].where == Nowhere) + continue; + dbug_unwind(1, "REG_INVALID %d\n", i); + goto done; + } + dbug_unwind(1, "register %d. where=%d\n", i, state.regs[i].where); + switch (state.regs[i].where) { + default: + break; + case Register: + if (state.regs[i].value >= ARRAY_SIZE(reg_info) + || REG_INVALID(state.regs[i].value) + || reg_info[i].width > reg_info[state.regs[i].value].width) { + dbug_unwind(1, "case Register bad\n"); + goto done; + } + switch (reg_info[state.regs[i].value].width) { +#define CASE(n) \ + case sizeof(u##n): \ + state.regs[i].value = FRAME_REG(state.regs[i].value, \ + const u##n); \ + break + CASES; +#undef CASE + default: + dbug_unwind(1, "default\n"); + goto done; + } + break; + } + } + for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { + dbug_unwind(1, "register %d. invalid=%d\n", i, REG_INVALID(i)); + if (REG_INVALID(i)) + continue; + dbug_unwind(1, "register %d. where=%d\n", i, state.regs[i].where); + switch (state.regs[i].where) { + case Nowhere: + if (reg_info[i].width != sizeof(UNW_SP(frame)) + || &FRAME_REG(i, __typeof__(UNW_SP(frame))) + != &UNW_SP(frame)) + continue; + UNW_SP(frame) = cfa; + break; + case Register: + switch (reg_info[i].width) { +#define CASE(n) case sizeof(u##n): \ + FRAME_REG(i, u##n) = state.regs[i].value; \ + break + CASES; +#undef CASE + default: + dbug_unwind(1, "default\n"); + goto done; + } + break; + case Value: + if (reg_info[i].width != sizeof(unsigned long)) { + dbug_unwind(1, "Value\n"); + goto done; + } + FRAME_REG(i, unsigned long) = cfa + state.regs[i].value * state.dataAlign; + break; + case Memory:{ + unsigned long addr = cfa + state.regs[i].value * state.dataAlign; + dbug_unwind(1, "addr=%lx width=%d\n", addr, reg_info[i].width); + switch (reg_info[i].width) { +#define CASE(n) case sizeof(u##n): \ + if (unlikely(__stp_get_user(FRAME_REG(i, u##n), (u##n *)addr))) \ + goto copy_failed;\ + dbug_unwind(1, "set register %d to %lx\n", i, (long)FRAME_REG(i,u##n));\ + break + CASES; +#undef CASE + default: + dbug_unwind(1, "default\n"); + goto done; + } + } + break; + } + } + read_unlock(&m->lock); + dbug_unwind(1, "returning 0 (%lx)\n", UNW_PC(frame)); + return 0; + +copy_failed: + dbug_unwind(1, "_stp_get_user failed to access memory\n"); +done: + read_unlock(&m->lock); + return -EIO; +#undef CASES +#undef FRAME_REG +} |