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.
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.
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.
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
Jakub Jelinek
Szabolcs Nagy
Jakub Jelinek
Richard Henderson