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2025-07-25doc: sframe: mention errata 1 of SFrame version 2Indu Bhagat1-9/+11
With the changes of an added flag SFRAME_F_FDE_FUNC_START_PCREL, s390x support and new section type SHT_GNU_SFRAME, indicate that this document specifies the errata 1 of SFrame version 2. This will help distinguish the document / specification better from previous releases. libsframe/doc/ * sframe-spec.texi: Mention errata 1 of SFrame version 2.
2025-07-11gas: elf: binutils: add new section type SHT_GNU_SFRAMEIndu Bhagat1-3/+4
So far, SFrame sections were of type SHT_PROGBITS. As per ELF specification, SHT_PROGBITS indicates that the section holds information defined by the program, whose format and meaning are determined solely by the program. On the linker side, SHT_PROGBITS should be reserved for the simple "cat contents after applying relocs" semantics. Currently, the only way to know that a section contains SFrame stack trace data is if consumer checks for section name. Such a check for section name is not quite conformant to ELF principles. Some of this was discussed here https://sourceware.org/pipermail/binutils/2025-March/140181.html With this change, the SFrame sections generated by gas, ld will have section type set to SHT_GNU_SFRAME. The new section type is defined in the SHT_LOOS/SHT_HIOS space. The SFrame parsing routine _bfd_elf_parse_sframe () now admits sections only when the the section type is SHT_GNU_SFRAME. No special handling / validation is done at the moment for the case of manual creation of SFrame sections via obj_elf_section (). Add function level comments for now to add a note about this. Although the default handling for (sh_type >= SHT_LOOS && sh_type <= SHT_HIOS) is sufficient when SHT_GNU_SFRAME is in that range, it makes sense to add it as a case of its own. bfd/ * elf-sframe.c (_bfd_elf_parse_sframe): Check if section type is SHT_GNU_SFRAME. (_bfd_elf_set_section_sframe): Set SHT_GNU_SFRAME for output SFrame section. * elflink.c (obj_elf_section): Use section type for check instead of section name. * elfxx-x86.c: Set SHT_GNU_SFRAME for SFrame sections for .plt* sections. * elf.c (bfd_section_from_shdr): Add case for SHT_GNU_SFRAME. binutils/ * readelf.c (get_os_specific_section_type_name): Add SHT_GNU_SFRAME. gas/ * NEWS: Announce emitted SFrame sections have SHT_GNU_SFRAME set. * config/obj-elf.c (obj_elf_attach_to_group): Add comments to indicate no special handling for SFrame yet. * dw2gencfi.c (cfi_finish): Set SHT_GNU_SFRAME for emitted SFrame section. ld/ * NEWS: Announce emitted SFrame sections have SHT_GNU_SFRAME set. gas/testsuite/ * gas/cfi-sframe/cfi-sframe.exp: Add new test. * gas/cfi-sframe/cfi-sframe-common-1b.d: New test. * gas/cfi-sframe/cfi-sframe-common-1b.s: New test. include/ * elf/common.h (SHT_GNU_SFRAME): Add new section type for SFrame stack trace information. libsframe/doc/ * sframe-spec.texi: Add expected ELF section type.
2025-07-11s390: Store SFrame CFA offset adjusted and scaled downJens Remus1-9/+14
In SFrame V2 the size of the offsets following an SFrame FRE can be either signed 8-bit, 16-bit, or 32-bit integer, with the largest offset determining their size: 1. CFA offset from CFA base register 2. RA (stack save slot) offset from CFA, usually -48 on s390x if saved 3. FP (stack save slot) offset from CFA, usually -72 on s390x if saved The FP and RA offsets from CFA, when FP/RA saved on the stack, usually have fixed values that fit into signed 8-bit SFrame offsets. Likewise the DWARF register numbers on s390x of general registers (GR; 0-15) and floating-point registers (FPR; 16-31), when FP/RA saved in registers. With that the CFA offset from CFA base register has the greatest impact on the signed SFrame offset size. The s390x ELF ABI defines the stack pointer (SP) to be 8-byte aligned [1] and the CFA as SP at call site + 160 [2]. The CFA offset from CFA base register is therefore always a multiple of 8. On s390x store the SFrame CFA offset from CFA base register scaled down by the s390x-specific CFA alignment factor of 8, in addition to the adjustment by the s390x-specific CFA adjustment of -160, to further improve the use of signed 8-bit SFrame offsets. This is similar to the DWARF data alignment factor getting factored out from certain offsets stored in DWARF CFI. [1]: s390x ELF ABI, sections "Register Roles" and "Stack Frame Allocation", https://github.com/IBM/s390x-abi/releases [2]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"), https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88 include/ * sframe.h (SFRAME_S390X_CFA_OFFSET_ALIGNMENT_FACTOR): Define s390x-specific CFA offset alignment factor. (SFRAME_V2_S390X_CFA_OFFSET_ENCODE, SFRAME_V2_S390X_CFA_OFFSET_DECODE): Scale down/up by SFRAME_S390X_CFA_OFFSET_ALIGNMENT_FACTOR. libsframe/ * doc/sframe-spec.texi (s390x, SFRAME_S390X_CFA_OFFSET_ALIGNMENT_FACTOR): Document s390x- specific CFA offset alignment factor. Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-07-11s390: Store SFrame CFA offset adjustedJens Remus1-1/+15
In SFrame V2 the size of the offsets following an SFrame FRE can be either signed 8-bit, 16-bit, or 32-bit integer, with the largest offset determining their size: 1. CFA offset from CFA base register 2. RA (stack save slot) offset from CFA, usually -48 on s390x if saved 3. FP (stack save slot) offset from CFA, usually -72 on s390x if saved The FP and RA offsets from CFA, when FP/RA saved on the stack, usually have fixed values that fit into signed 8-bit SFrame offsets. Likewise the DWARF register numbers on s390x of general registers (GR; 0-15) and floating-point registers (FPR; 16-31), when FP/RA saved in registers. With that the CFA offset from CFA base register has the greatest impact on the signed SFrame offset size. The s390x ELF ABI [1] defines the CFA as stack pointer (SP) at call site +160. [2] Therefore the minimum CFA offset from CFA base register on s390x is 160. This does not fit into a signed 8-bit integer and therefore effectively prevents any use of signed 8-bit SFrame offsets on s390x. For s390x store the CFA offset from CFA base register adjusted by -160 to enable the use of signed 8-bit SFrame offsets. [1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases [2]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"), https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88 include/ * sframe.h (SFRAME_S390X_CFA_OFFSET_ADJUSTMENT): Define s390x-specific CFA offset adjustment. (SFRAME_V2_S390X_CFA_OFFSET_ENCODE, SFRAME_V2_S390X_CFA_OFFSET_DECODE): New s390x-specific macros. Use SFRAME_S390X_CFA_OFFSET_ADJUSTMENT to en-/decode CFA offset. bfd/ * elf64-s390.c (elf_s390x_sframe_plt_fre): Use SFRAME_V2_S390X_CFA_OFFSET_ENCODE on CFA offset to store it adjusted and switch to 8-bit offsets. gas/ * gen-sframe.c (sframe_fre_set_cfa_offset): For s390x use SFRAME_V2_S390X_CFA_OFFSET_ENCODE on CFA offset to store it adjusted. (sframe_fre_get_cfa_offset): New helper. For s390x use SFRAME_V2_S390X_CFA_OFFSET_DECODE on CFA offset to undo its adjustment. (sframe_xlate_do_def_cfa_register): Use new helper sframe_fre_get_cfa_offset. libsframe/ * sframe.c (sframe_fre_get_cfa_offset): For s390x use SFRAME_V2_S390X_CFA_OFFSET_DECODE on CFA offset to undo its adjustment. * doc/sframe-spec.texi (s390x, SFRAME_S390X_CFA_OFFSET_ADJUSTMENT, SFRAME_V2_S390X_CFA_OFFSET_ENCODE, SFRAME_V2_S390X_CFA_OFFSET_DECODE): Document s390x-specific adjustment of CFA offset. libsframe/testsuite/ * libsframe.find/plt-findfre-2.c (add_plt0_fde, add_pltn_fde): Use SFRAME_V2_S390X_CFA_OFFSET_ENCODE to enable use of 1-byte SFrame offsets. Suggested-by: Indu Bhagat <indu.bhagat@oracle.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-07-11s390: Represent FP without RA saved in SFrameJens Remus1-6/+11
If an architecture uses both SFrame RA and FP tracking SFrame assumes that the RA offset is the 2nd offset and the FP offset is the 3rd offset following a SFrame FRE. An architecture does not necessarily need to save both on the stack (or in register) at the same time or even at all. SFrame cannot represent FP without RA saved on stack (or in a register), since it cannot distinguish whether the 2nd offset is the RA or FP offset. For s390x use an invalid SFrame RA offset from CFA value of zero as padding to represent the FP being saved when the RA is not saved. This aligns with the existing invalid SFrame fixed RA offset from CFA value of zero. In a stack tracer this then also naturally falls into place, as it can skip restoring the RA in the topmost frame, if both the fixed RA offset (from SFrame header) and the RA offset (from FDE) are zero, without any need to test architecture-specific flags. include/ * sframe.h (SFRAME_FRE_RA_OFFSET_INVALID): New define. Used as padding offset. * sframe-api.h (sframe_fre_get_ra_offset): Add comment that for s390x an offset value of SFRAME_FRE_RA_OFFSET_INVALID indicates that the RA is not saved. gas/ * gen-sframe.c (get_fre_num_offsets): For s390x account padding RA offset, if FP without RA saved. (sframe_get_fre_offset_size): Likewise. (output_sframe_row_entry): For s390x write a padding RA offset, if FP without RA needs to be represented. (sframe_do_fde): Enable FP without RA saved to be represented on s390x. libsframe/ * sframe.c (sframe_fre_get_ra_offset): Add comment that for s390x an offset value of SFRAME_FRE_RA_OFFSET_INVALID indicates that the RA is not saved. * sframe-dump.c (dump_sframe_func_with_fres): Treat invalid RA offsets as if they were undefined. Display them as "U" to distinguish them. * doc/sframe-spec.texi (s390x): Document s390x-specific use of SFRAME_FRE_RA_OFFSET_INVALID to represent FP without RA saved. gas/testsuite/ * gas/cfi-sframe/cfi-sframe.exp: Rename s390x-specific tests. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.s: Rename to ... * cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-2.s: This. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-2.d: Likewise. Update test verification pattern accordingly. * cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.s: Rename to ... * cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-2.s: This. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-2.d: Likewise. Update test verification pattern accordingly. Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-07-11s390: Represent FP/RA saved in register in SFrameJens Remus1-9/+30
GCC on s390x, when in a leaf function, can be observed to save the frame pointer (FP) and/or return address (RA) register in a floating- point registers (FPR) instead of on the stack. This is declared using the following CFI directive: .cfi_register <fp/ra-regnum>, <fpr-regnum> SFrame cannot represent the FP and/or RA being saved in another register. It does only track the CFA base register (SP/FP), CFA offset from CFA base register, and FP and RA save area offsets from CFA. On s390x the FP and/or RA are only saved in another FPR when in a leaf function. That is a function that does not call any other function. Therefore it can ever only be the topmost function in a call chain. An unwinder by default has access to all registers of the function that is the topmost on the call stack. Therefore no further information is required to restore FP/RA from the FPR. Represent FP/RA saved in another register on s390x, by encoding the DWARF register number shifted by one to the left with the least- significant bit set in the offset as follows: offset = (regnum << 1) | 1 The use of the least-significant bit of the offset as indication is possible, as the stack pointer (SP), the CFA, and any register save area slots are 8-byte aligned according to the s390x ELF ABI: - The stack pointer (SP) "shall maintain an 8-byte alignment". [1] - The CFA is defined as SP at call site +160. [2] - Pointers and 8-byte integers, such as general register values, must be 8-byte aligned. [3] SFrame FP and RA stack offsets must therefore always be a multiple of 8 on s390x. Note that for the same reason the DWARF data alignment factor is -8 on s390x (see DWARF2_CIE_DATA_ALIGNMENT). Add s390x-specific SFrame (error) tests for FP/RA saved in FPRs in leaf function. [1]: s390x ELF ABI, sections "Register Roles" and "Stack Frame Allocation", https://github.com/IBM/s390x-abi/releases [2]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"), https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88 [3]: s390x ELF ABI, section "Fundamental Types", table "Scalar types", https://github.com/IBM/s390x-abi/releases include/ * sframe.h (SFRAME_V2_S390X_OFFSET_IS_REGNUM): New s390x- specific macro to test whether an SFrame FP/RA offset is a DWARF register number. (SFRAME_V2_S390X_OFFSET_ENCODE_REGNUM): New s390x-specific macro to encode a DWARF register number into an SFrame FP/RA offset. (SFRAME_V2_S390X_OFFSET_DECODE_REGNUM): New s390x-specific macro to decode an SFrame FP/RA offset into a DWARF register number. * sframe-api.h (sframe_fre_get_fp_offset, sframe_fre_get_fp_offset): Add comment that for s390x the offset may be an encoded register number. gas/ * gen-sframe.c (s390_sframe_xlate_do_register): New S390- specific function. Uses SFRAME_V2_S390X_OFFSET_ENCODE_REGNUM to represent FP/RA saved in another register on s390x. (sframe_xlate_do_register): Invoke s390_sframe_xlate_do_register on s390x. libsframe/ * sframe.c (sframe_fre_get_fp_offset, sframe_fre_get_fp_offset): Add comment that for s390x the offset may be an encoded register number. * sframe-dump.c (is_sframe_abi_arch_s390x): New helper to test whether ABI/arch is s390x. (dump_sframe_func_with_fres): Use SFRAME_V2_S390X_OFFSET_IS_REGNUM and SFRAME_V2_S390X_OFFSET_DECODE_REGNUM to dump FP/RA saved in another register on s390x. * doc/sframe-spec.texi (s390x): Document s390x-specific representation of FP/RA saved in another register. gas/testsuite/ * gas/cfi-sframe/cfi-sframe.exp: Update s390x-specific SFrame (error) tests. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.s: Rename to ... * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-1.s: This. Test no longer triggers a warning, as SFrame can represent FP and RA saved in registers. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-1.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: Test now triggers a different warning, as SFrame can represent FP and RA saved in registers, but not FP without RA saved in register. Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-07-11s390: Initial support to generate .sframe from CFI directives in assemblerJens Remus1-3/+60
This introduces initial support to generate .sframe from CFI directives in assembler on s390 64-bit (s390x). Due to SFrame V2 format limitations it has the following limitations, some of them getting addressed by subsequent patches, which cause generation of SFrame FDE to be skipped: - SFrame FP/RA tracking only supports register contents being saved on the stack (i.e. .cfi_offset). It does not support FP/RA register contents being saved in other registers (i.e. .cfi_register). GCC on s390x can be observed to save the FP/RA register contents in floating- point registers, but only in leaf functions. This issue is detailed further and resolved in the subsequent commit "s390: Represent FP/RA saved in register in SFrame". - SFrame FP/RA tracking cannot represent FP without RA saved. This is because the format assumes SFrame FDE offset2 to be the RA offset, if there are two offsets, and offset3 to be the FP offset, if there are three offsets. There is no mean to distinguish whether offset2 is the RA or FP offset, if there are only two offsets. This issue is detailed further and resolved in the subsequent commit "s390: Represent FP without RA saved in SFrame". - SFrame assumes a dedicated FP register number. The s390x ELF ABI [1] does only designate register 11 as preferred FP register number. In general GCC and Clang on s390x use register 11 as frame pointer. GCC on s390x can be observed to use register 14 as frame pointer in the stack clash protector in the function prologue. glibc on s390x contains hand-written assembler code that uses register 12 as frame pointer. This s390x support is largely based on the AArch64 support from commit b52c4ee46657 ("gas: generate .sframe from CFI directives"). The SFrame ABI/arch identifier SFRAME_ABI_S390X_ENDIAN_BIG is introduced for s390x and added to the SFrame format specification. The s390x ELF ABI [1] specifies the following C calling conventions for s390x architecture: - Register 15 is the stack pointer (SP). - Register 14 contains the return address (RA) at function entry. - There is no dedicated frame pointer register. Register 11 is the preferred frame pointer (FP). [2] GCC and Clang in general use register 11 as frame pointer. - The CFA is defined as SP at call site +160. [3] The SP at call site can therefore be derived from the CFA using a SP value offset from CFA of -160. The s390x ELF ABI [1] does not assign any standard save slot to each register in the register save area of a stack frame. Neither the return address (RA, r14) nor preferred frame pointer (FP, r11) necessarily need to be saved. Therefore SFrame RA and FP tracking is used. Support for SFrame on s390 is only enabled for the 64-bit s390x ELF ABI (z/Architecture with 64-bit addressing mode). It is disabled for the 32-bit s390 ELF ABI (ESA/390 or z/Architecture with 32-bit addressing mode). s390x-specific SFrame assembler and linker tests are added, including error tests for use of a non-preferred frame pointer (FP) register and specification of a non-default return address (RA) register. [1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases [2]: s390x ELF ABI, commit f00421825979 ("Add information about the frame pointer register"), https://github.com/IBM/s390x-abi/commit/f00421825979 [3]: s390x ELF ABI, commit 4e38ad9c8a88 ("Document the CFA"), https://github.com/IBM/s390x-abi/commit/4e38ad9c8a88 include/ * sframe.h: Add reference to s390x architecture in comments. (SFRAME_ABI_S390X_ENDIAN_BIG): Define SFrame ABI/arch identifier for s390x. (SFRAME_S390X_SP_VAL_OFFSET): Define s390x-specific SP value offset from CFA. libsframe/ * sframe.c (need_swapping): Add SFRAME_ABI_S390X_ENDIAN_BIG. * doc/sframe-spec.texi (SFRAME_ABI_S390X_ENDIAN_BIG, s390x, SFRAME_S390X_SP_VAL_OFFSET): Document SFrame ABI/arch identifier for s390x, add references to s390x architecture, and document s390x-specifics, such as the SP value offset from CFA of -160. gas/ * config/tc-s390.h: s390x support to generate .sframe from CFI directives in assembler. (support_sframe_p): Define. (SFRAME_CFA_SP_REG, SFRAME_CFA_FP_REG, SFRAME_CFA_RA_REG): Define. (sframe_ra_tracking_p): Define. (sframe_cfa_ra_offset): Define. (sframe_get_abi_arch): Define. * config/tc-s390.c: s390x support to generate .sframe from CFI directives in assembler. (s390_sframe_cfa_sp_reg, s390_sframe_cfa_fp_reg, s390_sframe_cfa_ra_reg): New. Initialize to DWARF register numbers of stack pointer (SP, r15), preferred frame pointer (FP, r11), and return address (RA, r14) registers. (s390_support_sframe_p): New function. Return true if s390x. (s390_sframe_ra_tracking_p): New function. Return true. (s390_sframe_cfa_ra_offset): New function. Return SFRAME_CFA_FIXED_RA_INVALID. (s390_sframe_get_abi_arch): New function. Return SFRAME_ABI_S390X_ENDIAN_BIG if s390x, otherwise zero. * gen-sframe.c: Add reference to s390x architecture in comments. (sframe_xlate_do_val_offset): Add support for s390x-specific SFRAME_S390X_SP_VAL_OFFSET. * NEWS: Add news entry. gas/testsuite/ * gas/cfi-sframe/cfi-sframe.exp: Enable common SFrame tests for s390x. Add s390x-specific SFrame (error) tests. * gas/cfi-sframe/cfi-sframe-s390x-1.d: New s390x-specific SFrame test. * gas/cfi-sframe/cfi-sframe-s390x-1.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-2.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-2.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-err-1.d: New s390x-specific SFrame error test that uses a non-default frame-pointer register as CFA base register. * gas/cfi-sframe/cfi-sframe-s390x-err-1.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-err-2.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-err-2.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-err-3.d: New s390x-specific SFrame error test that uses a non-default return address register. * gas/cfi-sframe/cfi-sframe-s390x-err-3.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-1.d: New s390x- specific SFrame test that saves RA and FP individually on the stack. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-1.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.d: New s390x-specific SFrame error test that saves FP and RA individually, to trigger FP without RA saved. * gas/cfi-sframe/cfi-sframe-s390x-fpra-offset-err-1.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.d: New s390x-specific SFrame error test that saves FP and RA individually in registers. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-1.s: Likewise. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.d: New s390x-specific SFrame error test that saves RA and FP individually in registers. * gas/cfi-sframe/cfi-sframe-s390x-fpra-register-err-2.s: Likewise. ld/testsuite/ * ld-s390/s390.exp: Add simple SFrame test. * ld-s390/sframe-simple-1.d: New simple SFrame test. * ld-s390/sframe-bar.s: Likewise. * ld-s390/sframe-foo.s: Likewise. Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-07-06include: sframe: doc: define new flag SFRAME_F_FDE_FUNC_START_PCRELIndu Bhagat1-6/+26
Add a new flag SFRAME_F_FDE_FUNC_START_PCREL to SFrame stack trace format. If set, this flag indicates that the function start address field (sfde_func_start_address) is the offset to the function start address from the SFrame FDE function start address field itself. Such an encoding is friendlier to the exisitng PC-REL relocations available in the ABIs supported in SFrame: AMD64 (R_X86_64_PC32) and AArch64 (R_AARCH64_PREL32). In subsequent patches, we will make the implementation in gas and ld to both: - emit the values in the same (above-mentioned) encoding uniformly. - set the flag SFRAME_F_FDE_FUNC_START_PCREL in the SFrame header for consumers to be able to distinguish. Define SFRAME_V2_F_ALL_FLAGS in sframe.h to help keep the implementation less error-prone by keeping a set of all defined flags at a central place. Adjust the check in sframe_header_sanity_check_p () to use the SFRAME_V2_F_ALL_FLAGS instead. Add documentation for SFRAME_F_FDE_FUNC_START_PCREL. Update the documentation about the encoding of the sfde_func_start_address field. Also, update the section "Changes from Version 1 to Version 2" to include the specification of the new flag SFRAME_F_FDE_FUNC_START_PCREL as an erratum to the SFrame Version 2 specification. include/ * sframe.h (SFRAME_F_FDE_FUNC_START_PCREL): New definition. (SFRAME_V2_F_ALL_FLAGS): Likewise. libsframe/ * sframe-dump.c (dump_sframe_header_flags): Update to include the new flag SFRAME_F_FDE_FUNC_START_PCREL. * sframe.c (sframe_header_sanity_check_p): Use SFRAME_V2_F_ALL_FLAGS. libsframe/doc/ * sframe-spec.texi: Add details about the new flag. Also update the defails about the sfde_func_start_address encoding.
2025-06-03sframe: doc: add date to the pdf outputIndu Bhagat1-0/+2
libsframe/doc/ * sframe-spec.texi: Include date with each publication.
2025-02-04doc: sframe: Clarify FDE/FRE function/range start address fieldsJens Remus1-4/+6
The function start address in a SFrame FDE (sfde_func_start_address) is encoded as a signed offset to the function start address from the SFrame section. The PC range start address in a SFrame FRE (sfre_start_address) is encoded as an unsigned offset to the range from the function start address. Signed-off-by: Jens Remus <jremus@linux.ibm.com>
2025-01-01Update year range in copyright notice of binutils filesAlan Modra2-2/+2
2024-07-09doc: sframe: add appendix for generating stack tracesIndu Bhagat1-0/+84
Add an appendix to provide a rough outline to show how to generate stack traces using the SFrame format. Such content should hopefully aid the reader assimmilate the information in the specification. libsframe/ * doc/sframe-spec.texi: Add new appendix.
2024-07-09doc: sframe: segregate the ABI/arch-specific componentsIndu Bhagat1-28/+110
The recipe to interpret the SFrame FRE stack offsets is ABI/arch-specific. Although, there is other information in the specification that is ABI-specific (like pauth_key usage in AArch64), those pieces of information are now assimmilated in the SFrame specification in a way that it is fairly difficult to carve then out into a ABI/arch-specific section without confusing the readers. For future though, the specification must strive to keep the generic parts and ABI/arch-specific parts clearly laid out in separate sections. libsframe/ * doc/sframe-spec.texi: Reorder and adapt the contents.
2024-06-25doc: sframe: small improvements for readabilityIndu Bhagat1-130/+183
Update some of the content to make the specification document hopefully clearer: - Fix some typos. - Use Title case consistently for headings. - Update text around detection of foreign endianness. - Split the structure field "Name" in each table to two separate colunms for additional attention: "Type" and "Name". - Rename "SFrame endianness" section to "SFrame magic number and endianness" - Update text around provisions for extending SFrame for future ABIs/architectures. Make it clear by tagging all provisions with an explicit index item "Provisions for future ABIs". - Add a paragraph on sort order of SFrame FDEs. - Add a statement for SFRAME_F_FRAME_POINTER flag. - Add a statement to assert that SFrame version 1 is now obsolete and should not be used. libsframe/ * doc/sframe-spec.texi: Small improvements for readability.
2024-01-04Update year range in copyright notice of binutils filesAlan Modra2-2/+2
Adds two new external authors to etc/update-copyright.py to cover bfd/ax_tls.m4, and adds gprofng to dirs handled automatically, then updates copyright messages as follows: 1) Update cgen/utils.scm emitted copyrights. 2) Run "etc/update-copyright.py --this-year" with an extra external author I haven't committed, 'Kalray SA.', to cover gas testsuite files (which should have their copyright message removed). 3) Build with --enable-maintainer-mode --enable-cgen-maint=yes. 4) Check out */po/*.pot which we don't update frequently.
2023-06-29doc: sframe: update specification for SFRAME_VERSION_2Indu Bhagat1-10/+74
Add details for the changes made from Version 1 to Version 2 of the format. Also add details about alignment in the SFrame format. A portion of the SFrame stack trace format has an unaligned on-disk representation. Add description at relevant points in the specificatin to clarify the alignment related details.
2023-06-29libsframe: fix sframe_find_fre for pltN entriesIndu Bhagat1-2/+4
For a toy application on x86_64, for example, following is the SFrame stack trace information for the 3 pltN entries of 16 bytes each: func idx [1]: pc = 0x401030, size = 48 bytes STARTPC[m] CFA FP RA 0000000000000000 sp+8 u u 000000000000000b sp+16 u u The data in first column is the start_ip_offset. Also note that the FDE is of type SFRAME_FDE_TYPE_PCMASK (denoted by the [m] on LHS). Where each pltN (note: excluding plt0 entry) entry looks like: 401030: jmp *0x2fca(%rip) 401036: push $0x0 40103b: jmp 401020<_init+0x20> 401040: jmp *0x2fc2(%rip) 401046: push $0x1 40104b: jmp 401020<_init+0x20> 401050: jmp *0x2fba(%rip) 401056: push $0x2 40105b: jmp 401020<_init+0x20> Now, to find SFrame stack trace information from an FDE of type SFRAME_FDE_TYPE_PCMASK, sframe_find_fre () was doing an operation like, (start_ip_offset & 0xf) >= (pc & 0xf) This works for pltN entry of size, say, less than 16 bytes. But if the pltN entries or similar code stubs (for which SFrame FDE of type SFRAME_FDE_TYPE_PCMASK may be used), evolve to be of size > 16 bytes, this will cease to work. To match the range covered by the SFrame FRE, one should instead perform a modulo operation. The constant for the modulo operation must be the size of the pltN entry. Further, this constant should ideally be encoded in the format, as it may be different for each ABI. In SFrame Version 2 of the format, we will move towards encoding it explicitly in the SFrame FDE. For now, fix up the logic to at least move towards modulo operation. libsframe/ * sframe.c (sframe_fre_check_range_p): New definition. (sframe_find_fre): Refactor a bit and use the new definition above. include/ * sframe.h (SFRAME_FDE_TYPE_PCMASK): Update comment. libsframe/doc/ * sframe-spec.texi: Fix the text for SFRAME_FDE_TYPE_PCMASK FDE type.
2023-05-25sframe/doc: minor improvements for readabilityIndu Bhagat1-10/+10
libsframe/ * sframe-spec.texi: Cosmetic fixes.
2023-02-02libsframe/doc: use "stack trace" instead of "unwind" for SFrameIndu Bhagat1-18/+19
SFrame format is meant for generating stack traces only. libsframe/ * doc/sframe-spec.texi: Use "stack trace" instead of "unwind".
2023-01-24libsframe/doc: fix some warningsIndu Bhagat1-9/+17
'make pdf' in libsframe shows some warnings, some of which (especially the Overfull warnings) are causing undesirable effects on the rendered output. Few examples of the warnings: Underfull \hbox (badness 10000) in paragraph at lines 406--407 @texttt pauth_ Underfull \hbox (badness 10000) in paragraph at lines 407--410 @textrm Specify which key is used for signing the return ... Overfull \hbox (2.0987pt too wide) in paragraph at lines 412--413 @texttt fdetype[]| ... Overfull \hbox (28.87212pt too wide) in paragraph at lines 446--447 @textrm SFRAME[]FDE[]TYPE[]PCMASK| ... This patch adjusts column widths of the affected cells to fix a subset of these warnings. For the rest of the warnings, use explicit newline command to fix them. libsframe/ * doc/sframe-spec.texi: Fix various underfull and overfull warnings.
2023-01-01Update year range in copyright notice of binutils filesAlan Modra2-2/+2
The newer update-copyright.py fixes file encoding too, removing cr/lf on binutils/bfdtest2.c and ld/testsuite/ld-cygwin/exe-export.exp, and embedded cr in binutils/testsuite/binutils-all/ar.exp string match.
2022-12-22sframe: doc: update documentation for pauth key in SFrame FDEIndu Bhagat1-1/+7
ChangeLog: * libsframe/doc/sframe-spec.texi
2022-12-16sframe: doc: update spec for the mangled-RA bit in FREIndu Bhagat1-2/+2
ChangeLog: * libsframe/doc/sframe-spec.texi
2022-11-24sframe/doc: remove usage of xrefautomaticsectiontitleIndu Bhagat1-5/+2
xrefautomaticsectiontitle appears to be available from texinfo 5.0 or greater. As such, it is not worthwhile to add requirement for a minimum necessary makeinfo version. So remove the usage of it. Also align node name with section title where possible. ChangeLog: * libsframe/doc/sframe-spec.texi: Remove usage of xrefautomaticsectiontitle.
2022-11-15doc: add SFrame spec fileIndu Bhagat2-0/+659
ChangeLog: * libsframe/Makefile.am: Add info-in-builddir to AUTOMAKE_OPTIONS. Include doc/local.mk. * libsframe/Makefile.in: Regenerated. * libsframe/configure: Likewise. * libsframe/configure.ac: Check for makeinfo and set BUILD_INFO. * libsframe/doc/local.mk: New file. * libsframe/doc/sframe-spec.texi: Likewise.
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