This patch implements the following:
- Emit PACBTI-M build attributes in libunwind asm files
- Authenticate LR in DWARF32 using PACBTI
Use Armv8.1-M.Main PACBTI extension to authenticate the return address
(stored in the LR register) before moving it to the PC (IP) register.
The AUTG instruction is used with the candidate return address, the CFA,
and the authentication code that is retrieved from the saved
pseudo-register RA_AUTH_CODE.
- Authenticate LR in EHABI using PACBTI
Authenticate the contents of the LR register using Armv8.1-M.Main PACBTI
extension.
A new frame unwinding instruction is introduced (0xb4). This
instruction pops out of the stack the return address authentication
code, which is then used in conjunction with the SP and the next-to-be
instruction pointer to perform authentication.
This authentication code is popped into a new register,
UNW_ARM_PSEUDO_PAC, which is a pseudo-register.
This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:
https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension
The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:
https://developer.arm.com/documentation/ddi0553/latest
The following people contributed to this patch:
- Momchil Velikov
- Victor Campos
- Ties Stuij
Reviewed By: #libunwind, danielkiss, mstorsjo
Differential Revision: https://reviews.llvm.org/D112430
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
The original libunwind project defines UNW_AARCH64_* instead of UNW_ARM64_*.
Rename the enum members to match. This allows some applications with simple
`unw_init_local` usage to migrate to llvm-project libunwind.
Note: the canonical names of `UNW_ARM_D{0..31}` are now `UNW_AARCH64_V{0..31}`,
to match the original libunwind.
UNW_ARM64_* are kept for now for compatibility. Some may be unneeded and can be
cleaned up in the future.
Reviewed By: #libunwind, compnerd
Differential Revision: https://reviews.llvm.org/D107996
This change adds support for the dwarf PC register column in arm64, allowing
CFI directives to make use of it.
As of the last revision of the DWARF for ARM 64-bit architecture[0], the pc
register has been added as a valir register, with number 32.
This allows libunwinder to restore both pc and lr, which is useful
for stack switches and signal contexts.
[0]:
f52e1ad3f8/aadwarf64/aadwarf64.rst
Reviewed By: phosek, #libunwind
Differential Revision: https://reviews.llvm.org/D96901
Modify libunwind to support SjLj exception handling routines for VE.
In order to do that, we need to implement not only SjLj exception
handling routines but also a Registers_ve class. This implementation
of Registers_ve is incomplete. We will work on it later when we need
backtrace in libunwind.
Reviewed By: #libunwind, compnerd
Differential Revision: https://reviews.llvm.org/D94591
When built in SEH mode, UnwindCursor contains a CONTEXT struct,
which is aligned to 16 bytes in most configurations, causing the
whole UnwindCursor object to have 16 byte alignment.
This fixes backtraces using _Unwind_Backtrace on x86_64 mingw,
where an unw_cursor_t allocated on the stack was misaligned before.
This is an ABI break for this struct for this configuration, but very
few callers call libunwind directly (and even fewer directly allocate
an unw_cursor_t anyway).
Differential Revision: https://reviews.llvm.org/D86102
Summary:
Add unwinding support for 64-bit RISC-V.
This is from the FreeBSD implementation with the following minor
changes:
- Renamed and renumbered DWARF registers to match the RISC-V ABI [1]
- Use the ABI mneumonics in getRegisterName() instead of the exact
register names
- Include checks for __riscv_xlen == 64 to facilitate adding the 32-bit
ABI in the future.
[1] https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md
Patch by Mitchell Horne (mhorne)
Reviewers: lenary, luismarques, compnerd, phosek
Reviewed By: lenary, luismarques
Subscribers: arichardson, sameer.abuasal, abidh, asb, aprantl, krytarowski, simoncook, kito-cheng, christof, shiva0217, rogfer01, rkruppe, PkmX, psnobl, benna, lenary, s.egerton, luismarques, emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D68362
This is unfinished, unused and incomplete. This could be brought back in
the future if there's a desire to build a more complete implementation,
but at the moment it's just bitrotting.
Differential Revision: https://reviews.llvm.org/D57252
llvm-svn: 352965
The existing typedef of unw_fpreg_t to uint64_t might work and be
correct for the ARM_EHABI case, but for dwarf, some cases in e.g.
DwarfInstructions.hpp convert between double and unw_fpreg_t.
When converting implicitly between double and unw_fpreg_t (uint64_t),
the values get interpreted as integers and converted to float and vice
versa, while the correct thing would be to keep the same bit pattern.
Avoid the whole issue by using the same definition of unw_fpreg_t
as all other architectures, when using dwarf unwinding on ARM.
Change assembler functions to take a void pointer instead of
unw_fpreg_t pointer, to avoid having a different mangled symbol name
depending on the actual value of this typedef.
Differential Revision: https://reviews.llvm.org/D57001
llvm-svn: 352461
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351648
Summary:
Adds the register class implementation for Sparc.
Adds support for DW_CFA_GNU_window_save.
Adds save and restore context functionality.
Adds getArch() function to each Registers_ class to be able to separate
between DW_CFA_AARCH64_negate_ra_state and DW_CFA_GNU_window_save which
are both represented by the same constant.
On Sparc the return address is the address of the call instruction, so
an offset needs to be added when returning to skip the call instruction
and its delay slot. If the function returns a struct it is also necessary
to skip one extra instruction on Sparc V8.
Reviewers: jyknight, mclow.lists, mstorsjo, compnerd
Reviewed By: jyknight, compnerd
Subscribers: jgorbe, mgorny, christof, llvm-commits, fedor.sergeev, JDevlieghere, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D55763
llvm-svn: 351044
Summary:
Adds the register class implementation for Sparc.
Adds support for DW_CFA_GNU_window_save.
Adds save and restore context functionality.
On Sparc the return address is the address of the call instruction,
so an offset needs to be added when returning to skip the call instruction
and its delay slot. If the function returns a struct it is also necessary
to skip one extra instruction.
Reviewers: jyknight, mclow.lists, mstorsjo, compnerd
Reviewed By: compnerd
Subscribers: fedor.sergeev, JDevlieghere, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D55763
llvm-svn: 350705
- Follow up to revision r342895
- gcc would not build libunwind with the earlier patch as the autia1716
instruction wasn't allowed to be assembled for pre armv8.3a targets
- The autia1716 instruction lives in the hint space encodings so is a valid
instruction for all armv8a targets
- To work around this I have swapped out the autia1716 instruction for the hint
instruction
Differential Revision: https://reviews.llvm.org/D55700
llvm-svn: 349140
- When return address signing is enabled, the LR may be signed on function entry
- When an exception is thrown the return address is inspected used to unwind the call stack
- Before this happens, the return address must be correctly authenticated to avoid causing an abort by dereferencing the signed pointer
Differential Revision: https://reviews.llvm.org/D51432
llvm-svn: 342895
This makes it possible to unwind hardware exception stack frames,
which necessarily save every register and so need an extra column
for storing the return address. CFI for the exception handler could
then look as follows:
.globl exception_vector
exception_vector:
.cfi_startproc
.cfi_signal_frame
.cfi_return_column 32
l.addi r1, r1, -0x100
.cfi_def_cfa_offset 0x100
l.sw 0x00(r1), r2
.cfi_offset 2, 0x00-0x100
l.sw 0x04(r1), r3
.cfi_offset 3, 0x04-0x100
l.sw 0x08(r1), r4
.cfi_offset 4, 0x08-0x100
l.mfspr r3, r0, SPR_EPCR_BASE
l.sw 0x78(r1), r3
.cfi_offset 32, 0x78-0x100
l.jal exception_handler
l.nop
l.lwz r2, 0x00(r1)
l.lwz r3, 0x04(r1)
l.lwz r4, 0x08(r1)
l.jr r9
l.nop
.cfi_endproc
This register could, of course, also be accessed by the trace
callback or personality function, if so desired.
llvm-svn: 332513
Summary:
For MIPS ABIs with 64-bit floating point registers including newabi
and O32 with 64-bit floating point registers, just save and restore the
32 floating-point registers as doubles.
For O32 MIPS with 32-bit floating-point registers, save and restore the
individual floating-point registers as "plain" registers. These registers
are encoded as floats rather than doubles, but the DWARF unwinder
assumes that floating-point registers are stored as doubles when reading
them from memory (via AddressSpace::getDouble()). Treating the
registers as "normal" registers instead causes the DWARF unwinder to
fetch them from memory as a 32-bit register. This does mean that for
O32 with 32-bit floating-point registers unw_get_fpreg() and
unw_set_fpreg() do not work. One would have to use unw_get_reg()
and unw_set_reg() instead. However, DWARF unwinding works
correctly as the DWARF CFI emits records for individual 32-bit
floating-point registers even when they are treated as doubles stored
in paired registers. If the lack of unw_get/set_fpreg() becomes a pressing
need in the future for O32 MIPS we could add in special handling to
make it work.
Reviewers: sdardis, compnerd
Reviewed By: sdardis
Differential Revision: https://reviews.llvm.org/D41968
llvm-svn: 332414
The Registers_ppc64 class needed a couple of changes, both to accommodate the
new registers as well as to handle the overlaps of VS register set
without wasting space.
The save/restore code of V and VS registers was added.
As VS registers depend on the VMX extension, they are processed only if
VMX support is detected (_ARCH_PWR8 for now).
Patch by Leandro Lupori!
Differential Revision: https://reviews.llvm.org/D41906
llvm-svn: 322596
Initial working version of libunwind for PowerPC 64. Tested on
little-endian ppc64 host only.
Based on the existing PowerPC 32 code.
It supports:
- context save/restore (unw_getcontext, unw_init_local, unw_resume)
- read/write from/to saved registers
- backtrace (unw_step)
Patch by Leandro Lupori!
Differential Revision: https://reviews.llvm.org/D41386
Now builds with LIBUNWIND_ENABLE_CROSS_UNWINDING=ON should
work.
llvm-svn: 321680
Initial working version of libunwind for PowerPC 64. Tested on
little-endian ppc64 host only.
Based on the existing PowerPC 32 code.
It supports:
- context save/restore (unw_getcontext, unw_init_local, unw_resume)
- read/write from/to saved registers
- backtrace (unw_step)
Patch by Leandro Lupori!
Differential Revision: https://reviews.llvm.org/D41386
llvm-svn: 321667
This supports the soft-float ABI only and has been tested with both clang
and gcc on FreeBSD.
Reviewed By: sdardis, compnerd
Differential Revision: https://reviews.llvm.org/D38110
llvm-svn: 320528
The previous definition of _LIBUNWIND_HIGHEST_DWARF_REGISTER seems
to be a copy of the ARM64 value (introduced in SVN r276128); since
the code actually hasn't compiled properly for arm in dwarf mode
before, this hasn't actually been used. Set it to the correct value
based on the UNW_ARM_* enum values.
The iwmmx control variables have to be made mutable, since they are
touched from within getRegister (which previously wasn't const), and
getRegister is used on a const Registers object in DwarfInstructions.hpp.
Differential Revision: https://reviews.llvm.org/D39251
llvm-svn: 317192
This matches the original libunwind API. This also unifies the
type between ARM EHABI and the other configurations, and allows
getting rid of a number of casts in log messages.
The cursor size updates for ppc and or1k are untested, but
unw_proc_info_t shrinks by 4 uint64_t units on i386 at least.
Differential Revision: https://reviews.llvm.org/D39365
llvm-svn: 316942
Clang doesn't currently support building for windows/x86_64 with
dwarf by setting command line parameters, but if manually modified
to use dwarf, we can make libunwind work in this configuration
as well.
Also include i386 in the docs when adding this as a supported
configuration; libunwind already works for i386 windows, but
can fail due to an issue unrelated to windows itself.
Differential Revision: https://reviews.llvm.org/D38819
llvm-svn: 316747
Restore the `libunwind.h` enumeration values back to the inverted
values. This diverges from the DWARF definition of the register values.
However, this allows our header to be compatible with other unwind
implementations (e.g. HP, GNU Savannah, GCC).
The register IDs are only swapped in the header and need to be unswapped
when accessing the unwind register file. The flipped EBP and ESP only
applies on non-Apple x86 targets.
When optimizations were enabled, EBP and ESP would no longer be
equivalent. As a result, the incorrect access on Linux would manifest
as a failure to unwind the stack. We can now unwind the stack with and
without FPO on Linux x86.
Resolves PR30879!
llvm-svn: 292723
For historical reasons i386 has ebp and esp swapped in the eh_frame
register numbering on at least Darwin. That is:
Darwin FreeBSD
Reg # eh_frame eh_frame DWARF
===== ======== ======== =====
4 ebp esp esp
5 esp ebp ebp
Although the UNW_X86_* constants are not intended to be coupled with
DWARF / eh_frame numbering they are currently conflated in libunwind.
Differential Revision: https://reviews.llvm.org/D22508
llvm-svn: 280099
Currently libunwind is built to support cross-unwinding [1] by default, which
requires the buffers unw_context_t and unw_cursor_t to be large enough to hold
the vritual register set (VRS) of any supported architecture. This is not
desirable for some platforms where the stack usage of the unwinder needs
to be kept to a minimum (e.g. bare-metal targets). The current patch introduces
a native-only (-DLIBUNWIND_ENABLE_CROSS_UNWINDING=OFF) unwinder variant that
adopts strict sizes for the buffers unw_context_t and unw_cursor_t depending
on the target architecture.
[1] http://www.nongnu.org/libunwind/man/libunwind(3).html#section_4
Change-Id: I380fff9a56c16a0fc520e3b1d8454a34b4a48373
llvm-svn: 270692
This patch makes no assumptions on ABI past the ABI defined in
the OpenRISC 1000 spec except that the DWARF register numbers will
be 0-31 for registers r0-r31, which is true for both gcc and
clang at the moment.
llvm-svn: 246413
This moves the majority of the unwind sources into the new project layout for
libunwind. This was previously discussed on llvmdev at [1]. This is a
purely movement related change, with the build infrastructure currently still
residing in the libc++abi repository.
[1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-January/081507.html
llvm-svn: 235758
Ties Stuij