diff options
Diffstat (limited to 'sysdeps/generic/sframe-read.c')
| -rw-r--r-- | sysdeps/generic/sframe-read.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/sysdeps/generic/sframe-read.c b/sysdeps/generic/sframe-read.c new file mode 100644 index 0000000..d536575 --- /dev/null +++ b/sysdeps/generic/sframe-read.c @@ -0,0 +1,566 @@ +/* Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include <stdio.h> +#include <stdlib.h> +#include <stdarg.h> +#include <string.h> +#include <assert.h> +#include <sframe-read.h> + +/* Get the SFrame header size. */ + +static inline uint32_t +sframe_get_hdr_size (sframe_header *sfh) +{ + return SFRAME_V1_HDR_SIZE (*sfh); +} + +/* Access functions for frame row entry data. */ + +static inline uint8_t +sframe_fre_get_offset_count (uint8_t fre_info) +{ + return SFRAME_V1_FRE_OFFSET_COUNT (fre_info); +} + +static inline uint8_t +sframe_fre_get_offset_size (uint8_t fre_info) +{ + return SFRAME_V1_FRE_OFFSET_SIZE (fre_info); +} + +static inline bool +sframe_get_fre_ra_mangled_p (uint8_t fre_info) +{ + return SFRAME_V1_FRE_MANGLED_RA_P (fre_info); +} + +/* Access functions for info from function descriptor entry. */ + +static uint32_t +sframe_get_fre_type (sframe_func_desc_entry *fdep) +{ + uint32_t fre_type = 0; + if (fdep != NULL) + fre_type = SFRAME_V1_FUNC_FRE_TYPE (fdep->sfde_func_info); + return fre_type; +} + +static uint32_t +sframe_get_fde_type (sframe_func_desc_entry *fdep) +{ + uint32_t fde_type = 0; + if (fdep != NULL) + fde_type = SFRAME_V1_FUNC_FDE_TYPE (fdep->sfde_func_info); + return fde_type; +} + +/* Check if SFrame header has valid data. Only consider SFrame type + 2. */ + +static bool +sframe_header_sanity_check_p (sframe_header *hp) +{ + uint8_t all_flags = SFRAME_F_FDE_SORTED | SFRAME_F_FRAME_POINTER; + /* Check preamble is valid. */ + if ((hp->sfh_preamble.sfp_magic != SFRAME_MAGIC) + || (hp->sfh_preamble.sfp_version != SFRAME_VERSION_2) + || ((hp->sfh_preamble.sfp_flags | all_flags) != all_flags)) + return false; + + /* Check offsets are valid. */ + if (hp->sfh_fdeoff > hp->sfh_freoff) + return false; + + return true; +} + +/* Get the FRE start address size. */ + +static size_t +sframe_fre_start_addr_size (uint32_t fre_type) +{ + size_t addr_size = 0; + switch (fre_type) + { + case SFRAME_FRE_TYPE_ADDR1: + addr_size = 1; + break; + case SFRAME_FRE_TYPE_ADDR2: + addr_size = 2; + break; + case SFRAME_FRE_TYPE_ADDR4: + addr_size = 4; + break; + default: + break; + } + return addr_size; +} + +/* Check if the FREP has valid data. */ + +static bool +sframe_fre_sanity_check_p (sframe_frame_row_entry *frep) +{ + uint8_t offset_size, offset_cnt; + uint8_t fre_info; + + if (frep == NULL) + return false; + + fre_info = frep->fre_info; + offset_size = sframe_fre_get_offset_size (fre_info); + + if (offset_size != SFRAME_FRE_OFFSET_1B + && offset_size != SFRAME_FRE_OFFSET_2B + && offset_size != SFRAME_FRE_OFFSET_4B) + return false; + + offset_cnt = sframe_fre_get_offset_count (fre_info); + if (offset_cnt > MAX_NUM_STACK_OFFSETS) + return false; + + return true; +} + +/* Get FRE_INFO's offset size in bytes. */ + +static size_t +sframe_fre_offset_bytes_size (uint8_t fre_info) +{ + uint8_t offset_size, offset_cnt; + + offset_size = sframe_fre_get_offset_size (fre_info); + + offset_cnt = sframe_fre_get_offset_count (fre_info); + + if (offset_size == SFRAME_FRE_OFFSET_2B + || offset_size == SFRAME_FRE_OFFSET_4B) /* 2 or 4 bytes. */ + return (offset_cnt * (offset_size * 2)); + + return (offset_cnt); +} + +/* Get total size in bytes to represent FREP in the binary format. This + includes the starting address, FRE info, and all the offsets. */ + +static size_t +sframe_fre_entry_size (sframe_frame_row_entry *frep, size_t addr_size) +{ + if (frep == NULL) + return 0; + + uint8_t fre_info = frep->fre_info; + + return (addr_size + sizeof (frep->fre_info) + + sframe_fre_offset_bytes_size (fre_info)); +} + +/* Check whether for the given FDEP, the SFrame Frame Row Entry identified via + the START_IP_OFFSET and the END_IP_OFFSET, provides the stack trace + information for the PC. */ + +static bool +sframe_fre_check_range_p (sframe_func_desc_entry *fdep, + uint32_t start_ip_offset, uint32_t end_ip_offset, + int32_t pc) +{ + int32_t func_start_addr; + uint8_t rep_block_size; + uint32_t fde_type; + uint32_t pc_offset; + bool mask_p; + + if (fdep == NULL) + return false; + + func_start_addr = fdep->sfde_func_start_address; + fde_type = sframe_get_fde_type (fdep); + mask_p = (fde_type == SFRAME_FDE_TYPE_PCMASK); + rep_block_size = fdep->sfde_func_rep_size; + + if (func_start_addr > pc) + return false; + + /* Given func_start_addr <= pc, pc - func_start_addr must be positive. */ + pc_offset = pc - func_start_addr; + /* For SFrame FDEs encoding information for repetitive pattern of insns, + masking with the rep_block_size is necessary to find the matching FRE. */ + if (mask_p) + pc_offset = pc_offset % rep_block_size; + + return (start_ip_offset <= pc_offset) && (end_ip_offset >= pc_offset); +} + +/* The SFrame Decoder. */ + +/* Get SFrame header from the given decoder context DCTX. */ + +static inline sframe_header * +sframe_decoder_get_header (sframe_decoder_ctx *dctx) +{ + sframe_header *hp = NULL; + if (dctx != NULL) + hp = &dctx->sfd_header; + return hp; +} + +/* Get IDX'th offset from FRE. Set ERRP as applicable. */ + +static int32_t +sframe_get_fre_offset (sframe_frame_row_entry *fre, + int idx, + _Unwind_Reason_Code *errp) +{ + uint8_t offset_cnt, offset_size; + + if (!sframe_fre_sanity_check_p (fre)) + { + *errp = _URC_END_OF_STACK; + return 0; + } + + offset_cnt = sframe_fre_get_offset_count (fre->fre_info); + offset_size = sframe_fre_get_offset_size (fre->fre_info); + + if (offset_cnt < (idx + 1)) + { + *errp = _URC_END_OF_STACK; + return 0; + } + *errp = _URC_NO_REASON; + + if (offset_size == SFRAME_FRE_OFFSET_1B) + { + int8_t *sp = (int8_t *)fre->fre_offsets; + return sp[idx]; + } + else if (offset_size == SFRAME_FRE_OFFSET_2B) + { + int16_t *sp = (int16_t *)fre->fre_offsets; + return sp[idx]; + } + else + { + int32_t *ip = (int32_t *)fre->fre_offsets; + return ip[idx]; + } +} + +/* Decode the SFrame FRE start address offset value from FRE_BUF in on-disk + binary format, given the FRE_TYPE. Updates the FRE_START_ADDR. */ + +static void +sframe_decode_fre_start_address (const char *fre_buf, + uint32_t *fre_start_addr, + uint32_t fre_type) +{ + uint32_t saddr = 0; + + if (fre_type == SFRAME_FRE_TYPE_ADDR1) + { + uint8_t *uc = (uint8_t *)fre_buf; + saddr = (uint32_t)*uc; + } + else if (fre_type == SFRAME_FRE_TYPE_ADDR2) + { + uint16_t *ust = (uint16_t *)fre_buf; + saddr = (uint32_t)*ust; + } + else if (fre_type == SFRAME_FRE_TYPE_ADDR4) + { + uint32_t *uit = (uint32_t *)fre_buf; + saddr = (uint32_t)*uit; + } + else + return; + + *fre_start_addr = saddr; +} + +/* Find the function descriptor entry starting which contains the specified + address ADDR. */ + +static sframe_func_desc_entry * +sframe_get_funcdesc_with_addr_internal (sframe_decoder_ctx *ctx, int32_t addr, + int *errp) +{ + sframe_header *dhp; + sframe_func_desc_entry *fdp; + int low, high; + + if (ctx == NULL) + return NULL; + + dhp = sframe_decoder_get_header (ctx); + + if (dhp == NULL || dhp->sfh_num_fdes == 0 || ctx->sfd_funcdesc == NULL) + return NULL; + /* If the FDE sub-section is not sorted on PCs, skip the lookup because + binary search cannot be used. */ + if ((dhp->sfh_preamble.sfp_flags & SFRAME_F_FDE_SORTED) == 0) + return NULL; + + /* Do the binary search. */ + fdp = (sframe_func_desc_entry *) ctx->sfd_funcdesc; + low = 0; + high = dhp->sfh_num_fdes; + while (low <= high) + { + int mid = low + (high - low) / 2; + + /* Given sfde_func_start_address <= addr, + addr - sfde_func_start_address must be positive. */ + if (fdp[mid].sfde_func_start_address <= addr + && ((uint32_t)(addr - fdp[mid].sfde_func_start_address) + < fdp[mid].sfde_func_size)) + return fdp + mid; + + if (fdp[mid].sfde_func_start_address < addr) + low = mid + 1; + else + high = mid - 1; + } + + return NULL; +} + +/* Get the end IP offset for the FRE at index i in the FDEP. The buffer FRES + is the starting location for the FRE. */ + +static uint32_t +sframe_fre_get_end_ip_offset (sframe_func_desc_entry *fdep, unsigned int i, + const char *fres) +{ + uint32_t end_ip_offset = 0; + uint32_t fre_type; + + fre_type = sframe_get_fre_type (fdep); + + /* Get the start address of the next FRE in sequence. */ + if (i < fdep->sfde_func_num_fres - 1) + { + sframe_decode_fre_start_address (fres, &end_ip_offset, fre_type); + end_ip_offset -= 1; + } + else + /* The end IP offset for the FRE needs to be deduced from the function + size. */ + end_ip_offset = fdep->sfde_func_size - 1; + + return end_ip_offset; +} + +/* Get the SFrame's fixed FP offset given the decoder context CTX. */ + +static int8_t +sframe_decoder_get_fixed_fp_offset (sframe_decoder_ctx *ctx) +{ + sframe_header *dhp; + dhp = sframe_decoder_get_header (ctx); + return dhp->sfh_cfa_fixed_fp_offset; +} + +/* Get the SFrame's fixed RA offset given the decoder context CTX. */ + +static int8_t +sframe_decoder_get_fixed_ra_offset (sframe_decoder_ctx *ctx) +{ + sframe_header *dhp; + dhp = sframe_decoder_get_header (ctx); + return dhp->sfh_cfa_fixed_ra_offset; +} + +/* Get the base reg id from the FRE info. Set errp if failure. */ + +uint8_t +__sframe_fre_get_base_reg_id (sframe_frame_row_entry *fre) +{ + uint8_t fre_info = fre->fre_info; + return SFRAME_V1_FRE_CFA_BASE_REG_ID (fre_info); +} + +/* Get the CFA offset from the FRE. If the offset is unavailable, + sets errp. */ + +int32_t +__sframe_fre_get_cfa_offset (sframe_decoder_ctx *dctx __attribute__ ((__unused__)), + sframe_frame_row_entry *fre, + _Unwind_Reason_Code *errp) +{ + return sframe_get_fre_offset (fre, SFRAME_FRE_CFA_OFFSET_IDX, errp); +} + +/* Get the FP offset from the FRE. If the offset is unavailable, sets + errp. */ + +int32_t +__sframe_fre_get_fp_offset (sframe_decoder_ctx *dctx, + sframe_frame_row_entry *fre, + _Unwind_Reason_Code *errp) +{ + uint32_t fp_offset_idx = 0; + int8_t fp_offset = sframe_decoder_get_fixed_fp_offset (dctx); + + *errp = _URC_NO_REASON; + /* If the FP offset is not being tracked, return the fixed FP offset + from the SFrame header. */ + if (fp_offset != SFRAME_CFA_FIXED_FP_INVALID) + return fp_offset; + + /* In some ABIs, the stack offset to recover RA (using the CFA) from is + fixed (like AMD64). In such cases, the stack offset to recover FP will + appear at the second index. */ + fp_offset_idx = ((sframe_decoder_get_fixed_ra_offset (dctx) + != SFRAME_CFA_FIXED_RA_INVALID) + ? SFRAME_FRE_RA_OFFSET_IDX + : SFRAME_FRE_FP_OFFSET_IDX); + return sframe_get_fre_offset (fre, fp_offset_idx, errp); +} + +/* Get the RA offset from the FRE. If the offset is unavailable, sets + errp. */ + +int32_t +__sframe_fre_get_ra_offset (sframe_decoder_ctx *dctx, + sframe_frame_row_entry *fre, + _Unwind_Reason_Code *errp) +{ + int8_t ra_offset = sframe_decoder_get_fixed_ra_offset (dctx); + *errp = _URC_NO_REASON; + + /* If the RA offset was not being tracked, return the fixed RA offset + from the SFrame header. */ + if (ra_offset != SFRAME_CFA_FIXED_RA_INVALID) + return ra_offset; + + /* Otherwise, get the RA offset from the FRE. */ + return sframe_get_fre_offset (fre, SFRAME_FRE_RA_OFFSET_IDX, errp); +} + +/* Decode the specified SFrame buffer SF_BUF and return the new SFrame + decoder context. */ + +_Unwind_Reason_Code +__sframe_decode (sframe_decoder_ctx *dctx, const char *sf_buf) +{ + const sframe_preamble *sfp; + size_t hdrsz; + sframe_header *sfheaderp; + char *frame_buf; + + int fidx_size; + uint32_t fre_bytes; + + if (sf_buf == NULL) + return _URC_END_OF_STACK; + + sfp = (const sframe_preamble *) sf_buf; + + /* Check for foreign endianness. */ + if (sfp->sfp_magic != SFRAME_MAGIC) + return _URC_END_OF_STACK; + + frame_buf = (char *)sf_buf; + + /* Handle the SFrame header. */ + dctx->sfd_header = *(sframe_header *) frame_buf; + + /* Validate the contents of SFrame header. */ + sfheaderp = &dctx->sfd_header; + if (!sframe_header_sanity_check_p (sfheaderp)) + return _URC_END_OF_STACK; + + hdrsz = sframe_get_hdr_size (sfheaderp); + frame_buf += hdrsz; + + /* Handle the SFrame Function Descriptor Entry section. */ + fidx_size + = sfheaderp->sfh_num_fdes * sizeof (sframe_func_desc_entry); + dctx->sfd_funcdesc = (sframe_func_desc_entry *)frame_buf; + frame_buf += (fidx_size); + + dctx->sfd_fres = frame_buf; + fre_bytes = sfheaderp->sfh_fre_len; + dctx->sfd_fre_nbytes = fre_bytes; + + return _URC_NO_REASON; +} + +/* Find the SFrame Row Entry which contains the PC. Returns + _URC_END_OF_STACK if failure. */ + +_Unwind_Reason_Code +__sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc, + sframe_frame_row_entry *frep) +{ + sframe_func_desc_entry *fdep; + uint32_t fre_type, i; + uint32_t start_ip_offset; + int32_t func_start_addr; + uint32_t end_ip_offset; + const char *fres; + size_t size = 0; + int err = 0; + + if ((ctx == NULL) || (frep == NULL)) + return _URC_END_OF_STACK; + + /* Find the FDE which contains the PC, then scan its fre entries. */ + fdep = sframe_get_funcdesc_with_addr_internal (ctx, pc, &err); + if (fdep == NULL || ctx->sfd_fres == NULL) + return _URC_END_OF_STACK; + + fre_type = sframe_get_fre_type (fdep); + + fres = ctx->sfd_fres + fdep->sfde_func_start_fre_off; + func_start_addr = fdep->sfde_func_start_address; + + for (i = 0; i < fdep->sfde_func_num_fres; i++) + { + size_t addr_size; + + /* Partially decode the FRE. */ + sframe_decode_fre_start_address (fres, &frep->fre_start_addr, fre_type); + + addr_size = sframe_fre_start_addr_size (fre_type); + if (addr_size == 0) + return _URC_END_OF_STACK; + + frep->fre_info = *(uint8_t *)(fres + addr_size); + size = sframe_fre_entry_size (frep, addr_size); + + start_ip_offset = frep->fre_start_addr; + end_ip_offset = sframe_fre_get_end_ip_offset (fdep, i, fres + size); + + /* Stop search if FRE's start_ip is greater than pc. Given + func_start_addr <= pc, pc - func_start_addr must be positive. */ + if (start_ip_offset > (uint32_t) (pc - func_start_addr)) + return _URC_END_OF_STACK; + + if (sframe_fre_check_range_p (fdep, start_ip_offset, end_ip_offset, pc)) + { + /* Decode last FRE bits: offsets size. */ + frep->fre_offsets = fres + addr_size + sizeof (frep->fre_info); + return _URC_NO_REASON; + } + + fres += size; + } + return _URC_END_OF_STACK; +} |