Quoting from https://gcc.gnu.org/pipermail/gcc/2021-July/236716.html:
--------------------------------------------------------------------
It was pointed out to me off-list that config/aarch64/value-unwind.h
is missing the runtime exception. It looks like a few other files
are too; a fuller list is:
libgcc/config/aarch64/value-unwind.h
libgcc/config/frv/frv-abi.h
libgcc/config/i386/value-unwind.h
libgcc/config/pa/pa64-hpux-lib.h
Certainly for the aarch64 file this was simply a mistake;
it seems to have been copied from the i386 version, both of which
reference the runtime exception but don't actually include it.
--------------------------------------------------------------------
Similarly, frv-abi.h referenced the exception but didn't include it.
pa64-hpux-lib.h was missing any reference to the exception.
The decision was that this was simply a mistake
[https://gcc.gnu.org/pipermail/gcc/2021-July/236717.html]:
--------------------------------------------------------------------
[…] It generally is
considered a textual omission. The runtime library components of GCC
are intended to be licensed under the runtime exception, which was
granted and approved at the time of introduction.
--------------------------------------------------------------------
and that we should simply change all of the files above
[https://gcc.gnu.org/pipermail/gcc/2021-July/236719.html]:
--------------------------------------------------------------------
Please correct the text in the files. The files in libgcc used in the
GCC runtime are intended to be licensed with the runtime exception and
GCC previously was granted approval for that licensing and purpose.
[…]
The runtime exception explicitly was intended for this purpose and
usage at the time that GCC received approval to apply the exception.
--------------------------------------------------------------------
libgcc/
* config/aarch64/value-unwind.h: Add missing runtime exception
paragraph.
* config/frv/frv-abi.h: Likewise.
* config/i386/value-unwind.h: Likewise.
* config/pa/pa64-hpux-lib.h: Likewise.
The libgcc HF support routines were being linked into libgcc_s.so,
but weren't being exported.
libgcc/
* config/aarch64/libgcc-softfp.ver: New file.
* config/aarch64/t-softfp (SHLIB_MAPFILES): Add it.
As mentioned in the PR, the fallback path when LSE is unavailable writes
incorrect registers to the memory if the previous content compares equal
to x0, x1 - it writes copy of x0, x1 from the start of function, but it
should write x2, x3.
2020-08-03 Jakub Jelinek <jakub@redhat.com>
PR target/96402
* config/aarch64/lse.S (__aarch64_cas16_acq_rel): Use x2, x3 instead
of x(tmp0), x(tmp1) in STXP arguments.
* gcc.target/aarch64/pr96402.c: New test.
This note is not used anywhere currently but it is supposed to mark
objects if the return address is protected with PAC on the stack.
Since lse.S only has leaf functions the return address is never
saved on the stack so we can add the note.
The note is only added if pac-ret is enabled because it can cause
problems with old linkers and we don't have checks for that. This
can be changed later to be unconditional, for now it is consistent
with how gcc generates the notes.
libgcc/ChangeLog:
* config/aarch64/lse.S: Add PAC property note.
Mangling, currently only used on AArch64 for return address signing,
is an internal representation that should not be exposed via
__builtin_return_address return value,
__builtin_eh_return handler argument,
_Unwind_DebugHook handler argument.
Note that a mangled address might not even fit into a void *, e.g.
with AArch64 ilp32 ABI the return address is stored as 64bit, so
the mangled return address cannot be accessed via _Unwind_GetPtr.
This patch changes the unwinder hooks as follows:
MD_POST_EXTRACT_ROOT_ADDR is removed: root address comes from
__builtin_return_address which is not mangled.
MD_POST_EXTRACT_FRAME_ADDR is renamed to MD_DEMANGLE_RETURN_ADDR,
it now operates on _Unwind_Word instead of void *, so the hook
should work when return address signing is enabled on AArch64 ilp32.
(But for that __builtin_aarch64_autia1716 should be fixed to operate
on 64bit input instead of a void *.)
MD_POST_FROB_EH_HANDLER_ADDR is removed: it is the responsibility of
__builtin_eh_return to do the mangling if necessary.
2020-07-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
PR target/94891
* config/aarch64/aarch64-unwind.h (MD_POST_EXTRACT_ROOT_ADDR): Remove.
(MD_POST_FROB_EH_HANDLER_ADDR): Remove.
(MD_POST_EXTRACT_FRAME_ADDR): Rename to ...
(MD_DEMANGLE_RETURN_ADDR): This.
(aarch64_post_extract_frame_addr): Rename to ...
(aarch64_demangle_return_addr): This.
(aarch64_post_frob_eh_handler_addr): Remove.
* unwind-dw2.c (uw_update_context): Demangle return address.
(uw_frob_return_addr): Remove.
lse.S did not have the GNU property note markup and the BTI c
instructions that are necessary when it is built with branch
protection.
The notes are only added when libgcc is built with branch
protection, because old linkers mishandle the note (merge
them incorrectly or emit warnings), the BTI instructions
are added unconditionally.
Note: BTI c is only necessary at function entry if the function
may be called indirectly, currently lse functions are not called
indirectly, but BTI is added for ABI reasons e.g. to allow
linkers later to emit stub code with indirect jump.
2020-07-09 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
PR target/96001
* config/aarch64/lse.S: Add BTI marking and related definitions,
and add BTI c to function entries.
lse.S did not have GNU stack note, this may cause missing
PT_GNU_STACK in binaries on Linux and FreeBSD.
2020-07-09 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
* config/aarch64/lse.S: Add stack note.
This version of the fix uses __getauxval instead of getauxval.
The whole thing is guarded simply on __gnu_linux__.
__getauxval was introduced in 2.16 but the aarch64 port was added in 2.17 so in practice I expect all aarch64 glibcs to support __getauxval.
Bootstrapped and tested on aarch64-none-linux-gnu.
Also tested on aarch64-none-elf.
2020-05-06 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
* config/aarch64/lse-init.c (init_have_lse_atomics): Use __getauxval
instead of getauxval.
(AT_HWCAP): Define.
(HWCAP_ATOMICS): Define.
Guard detection on __gnu_linux__.
With -mbranch-protection=pac-ret the debug info toggles the
signedness state of the return address so the unwinder knows when
the return address needs pointer authentication.
The unwind context flags were not updated according to the dwarf
frame info.
This causes unwinding across frames that were built without pac-ret
to incorrectly authenticate the return address wich corrupts the
return address on a system where PAuth is enabled.
Note: This even affects systems where all code use pac-ret because
unwinding across a signal frame the return address is not signed.
gcc/testsuite/ChangeLog:
PR target/94514
* g++.target/aarch64/pr94514.C: New test.
* gcc.target/aarch64/pr94514.c: New test.
libgcc/ChangeLog:
PR target/94514
* config/aarch64/aarch64-unwind.h (aarch64_frob_update_context):
Update context->flags accroding to the frame state.
As reported in the PR, GCC 10 (and also 9.3.1 but not 9.3.0) fails to build
when using older binutils which lack LSE support, because those instructions
are used in libgcc.
Thanks to Kyrylo's hint, the following patches (hopefully) allow it to build
even with older binutils by using .inst directive if LSE support isn't
available in the assembler.
2020-04-15 Jakub Jelinek <jakub@redhat.com>
PR target/93053
* configure.ac (LIBGCC_CHECK_AS_LSE): Add HAVE_AS_LSE checking.
* config/aarch64/lse.S: Include auto-target.h, if HAVE_AS_LSE
is not defined, use just .arch armv8-a.
(B, M, N, OPN): Define.
(COMMENT): New .macro.
(CAS, CASP, SWP, LDOP): Use .inst directive if HAVE_AS_LSE is not
defined. Otherwise, move the operands right after the glue? and
comment out operands where the macros are used.
* configure: Regenerated.
* config.in: Regenerated.
The DCache clean & ICache invalidation requirements for instructions
to be data coherence are discoverable through new fields in CTR_EL0.
Let's support the two bits if they are enabled, the CPU core will
not execute the unnecessary DCache clean or Icache Invalidation
instructions.
2019-09-25 Shaokun Zhang <zhangshaokun@hisilicon.com>
* config/aarch64/sync-cache.c (__aarch64_sync_cache_range): Add support for
CTR_EL0.IDC and CTR_EL0.DIC.
From-SVN: r276122
This is the libgcc part of the interface -- providing the functions.
Rationale is provided at the top of libgcc/config/aarch64/lse.S.
* config/aarch64/lse-init.c: New file.
* config/aarch64/lse.S: New file.
* config/aarch64/t-lse: New file.
* config.host: Add t-lse to all aarch64 tuples.
From-SVN: r275967
This patch adds support for unwinding frames that use the SVE
pseudo VG register. We want this register to act like a normal
register if the CFI explicitly sets it, but want to provide a
default value otherwise. Computing the default value requires
an SVE target, so we only want to compute it on demand.
aarch64_vg uses a hard-coded .inst in order to avoid a build
dependency on binutils 2.28 or later.
2018-01-13 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* doc/tm.texi.in (DWARF_LAZY_REGISTER_VALUE): Document.
* doc/tm.texi: Regenerate.
libgcc/
* config/aarch64/value-unwind.h (aarch64_vg): New function.
(DWARF_LAZY_REGISTER_VALUE): Define.
* unwind-dw2.c (_Unwind_GetGR): Use DWARF_LAZY_REGISTER_VALUE
to provide a fallback register value.
gcc/testsuite/
* g++.target/aarch64/sve/aarch64-sve.exp: New harness.
* g++.target/aarch64/sve/catch_1.C: New test.
* g++.target/aarch64/sve/catch_2.C: Likewise.
* g++.target/aarch64/sve/catch_3.C: Likewise.
* g++.target/aarch64/sve/catch_4.C: Likewise.
* g++.target/aarch64/sve/catch_5.C: Likewise.
* g++.target/aarch64/sve/catch_6.C: Likewise.
Reviewed-by: James Greenhalgh <james.greenhalgh@arm.com>
From-SVN: r256615
Current glibc no longer gives the ucontext_t type the tag struct
ucontext, to conform with POSIX namespace rules. This requires
various linux-unwind.h files in libgcc, that were previously using
struct ucontext, to be fixed to use ucontext_t instead. This is
similar to the removal of the struct siginfo tag from siginfo_t some
years ago.
This patch changes those files to use ucontext_t instead. As the
standard name that should be unconditionally safe, so this is not
restricted to architectures supported by glibc, or conditioned on the
glibc version.
Tested compilation together with current glibc with glibc's
build-many-glibcs.py.
* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state),
config/alpha/linux-unwind.h (alpha_fallback_frame_state),
config/bfin/linux-unwind.h (bfin_fallback_frame_state),
config/i386/linux-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state), config/m68k/linux-unwind.h (struct
uw_ucontext), config/nios2/linux-unwind.h (struct nios2_ucontext),
config/pa/linux-unwind.h (pa32_fallback_frame_state),
config/riscv/linux-unwind.h (riscv_fallback_frame_state),
config/sh/linux-unwind.h (sh_fallback_frame_state),
config/tilepro/linux-unwind.h (tile_fallback_frame_state),
config/xtensa/linux-unwind.h (xtensa_fallback_frame_state): Use
ucontext_t instead of struct ucontext.
From-SVN: r249731
libgcc/
* config/aarch64/aarch64-unwind.h: New file.
(DWARF_REGNUM_AARCH64_RA_STATE): Define.
(MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64.
(MD_POST_EXTRACT_FRAME_ADDR): Likewise.
(MD_POST_FROB_EH_HANDLER_ADDR): Likewise.
(MD_FROB_UPDATE_CONTEXT): Define it on AArch64.
(aarch64_post_extract_frame_addr): New function.
(aarch64_post_frob_eh_handler_addr): New function.
(aarch64_frob_update_context): New function.
* config/aarch64/linux-unwind.h: Include aarch64-unwind.h
* config.host (aarch64*-*-elf, aarch64*-*-rtems*,
aarch64*-*-freebsd*):
Initialize md_unwind_header to include aarch64-unwind.h.
* unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT".
(execute_cfa_program): Multiplex DW_CFA_GNU_window_save for
__aarch64__.
(uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR.
(uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR.
(uw_frob_return_addr): New function.
(uw_install_context): Use uw_frob_return_addr.
From-SVN: r244673
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Also define
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__,
__LIBGCC_EH_FRAME_SECTION_NAME__, __LIBGCC_JCR_SECTION_NAME__,
__LIBGCC_CTORS_SECTION_ASM_OP__, __LIBGCC_DTORS_SECTION_ASM_OP__,
__LIBGCC_TEXT_SECTION_ASM_OP__, __LIBGCC_INIT_SECTION_ASM_OP__,
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__,
__LIBGCC_STACK_GROWS_DOWNWARD__,
__LIBGCC_DONT_USE_BUILTIN_SETJMP__,
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__,
__LIBGCC_DWARF_FRAME_REGISTERS__,
__LIBGCC_EH_RETURN_STACKADJ_RTX__, __LIBGCC_JMP_BUF_SIZE__,
__LIBGCC_STACK_POINTER_REGNUM__ and
__LIBGCC_VTABLE_USES_DESCRIPTORS__ for -fbuilding-libgcc.
(builtin_define_with_value): Handle backslash-escaping in string
macro values.
libgcc:
* Makefile.in (CRTSTUFF_CFLAGS): Add -fbuilding-libgcc.
* config/aarch64/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/alpha/vms-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change use to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/cr16/unwind-cr16.c (STACK_GROWS_DOWNWARD): Change all
uses to __LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* config/cr16/unwind-dw2.h (DWARF_FRAME_REGISTERS): Change use to
__LIBGCC_DWARF_FRAME_REGISTERS__. Remove conditional definition.
* config/i386/cygming-crtbegin.c (EH_FRAME_SECTION_NAME): Change
use to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__.
* config/i386/cygming-crtend.c (EH_FRAME_SECTION_NAME): Change use
to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__
* config/mips/linux-unwind.h (STACK_POINTER_REGNUM): Change use to
__LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/nios2/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/pa/hpux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/pa/linux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/rs6000/aix-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
(STACK_POINTER_REGNUM): Change all uses to
__LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/darwin-fallback.c (STACK_POINTER_REGNUM): Change
use to __LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
* config/sparc/linux-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/sparc/sol2-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/tilepro/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/xtensa/unwind-dw2-xtensa.h (DWARF_FRAME_REGISTERS):
Remove conditional definition.
* crtstuff.c (TEXT_SECTION_ASM_OP): Change all uses to
__LIBGCC_TEXT_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
(EH_TABLES_CAN_BE_READ_ONLY): Change all uses to
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__.
(CTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_CTORS_SECTION_ASM_OP__.
(DTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_DTORS_SECTION_ASM_OP__.
(JCR_SECTION_NAME): Change all uses to
__LIBGCC_JCR_SECTION_NAME__.
(INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
* generic-morestack.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
* libgcc2.c (INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
* libgcov-profiler.c (VTABLE_USES_DESCRIPTORS): Remove conditional
definitions. Change all uses to
__LIBGCC_VTABLE_USES_DESCRIPTORS__.
* unwind-dw2.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* unwind-dw2.h (DWARF_FRAME_REGISTERS): Remove conditional
definition. Change use to __LIBGCC_DWARF_FRAME_REGISTERS__.
* unwind-sjlj.c (DONT_USE_BUILTIN_SETJMP): Change all uses to
__LIBGCC_DONT_USE_BUILTIN_SETJMP__.
(JMP_BUF_SIZE): Change use to __LIBGCC_JMP_BUF_SIZE__.
From-SVN: r214954
2013-11-26 Matthew Leach <matthew.leach@arm.com>
* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state): Check
for correct opcodes on BE.
From-SVN: r205479
libgcc/
* config/aarch64/sfp-machine.h (_FP_W_TYPE): Change to define
as 'unsigned long long' instead of 'unsigned long'.
(_FP_WS_TYPE): Change to define as 'signed long long' instead of
'signed long'.
From-SVN: r198090
2013-01-17 Yufeng Zhang <yufeng.zhang@arm.com>
* config/aarch64/sync-cache.c (__aarch64_sync_cache_range): Cast the
results of (dcache_lsize - 1) and (icache_lsize - 1) to the type
__UINTPTR_TYPE__; also cast 'base' to the same type before the
alignment operation.
From-SVN: r195266
Jakub Jelinek
Richard Sandiford
Wei Wentao
Szabolcs Nagy
Kyrylo Tkachov
Jakub Jelinek
Richard Henderson
Shaokun Zhang
Sam Tebbs
Richard Sandiford
Tom de Vries
Joseph Myers
John Marino
Andrew Pinski
Jiong Wang
Jiong Wang
James Greenhalgh
Marcus Shawcroft
Richard Sandiford
Matthew Leach
Maxim Kuvyrkov
Yufeng Zhang
Sofiane Naci
Marcus Shawcroft