glibc/sysdeps/aarch64/__longjmp.S
Florian Weimer 88f4b6929c Introduce <pointer_guard.h>, extracted from <sysdep.h>
This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE.  In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.

In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>.  <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-18 17:03:55 +02:00

120 lines
3.5 KiB
ArmAsm

/* Copyright (C) 1997-2022 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 Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <pointer_guard.h>
#include <jmpbuf-offsets.h>
#include <stap-probe.h>
/* __longjmp(jmpbuf, val) */
ENTRY (__longjmp)
cfi_def_cfa(x0, 0)
cfi_offset(x19, JB_X19<<3)
cfi_offset(x20, JB_X20<<3)
cfi_offset(x21, JB_X21<<3)
cfi_offset(x22, JB_X22<<3)
cfi_offset(x23, JB_X23<<3)
cfi_offset(x24, JB_X24<<3)
cfi_offset(x25, JB_X25<<3)
cfi_offset(x26, JB_X26<<3)
cfi_offset(x27, JB_X27<<3)
cfi_offset(x28, JB_X28<<3)
cfi_offset(x29, JB_X29<<3)
cfi_offset(x30, JB_LR<<3)
cfi_offset( d8, JB_D8<<3)
cfi_offset( d9, JB_D9<<3)
cfi_offset(d10, JB_D10<<3)
cfi_offset(d11, JB_D11<<3)
cfi_offset(d12, JB_D12<<3)
cfi_offset(d13, JB_D13<<3)
cfi_offset(d14, JB_D14<<3)
cfi_offset(d15, JB_D15<<3)
PTR_ARG (0)
ldp x19, x20, [x0, #JB_X19<<3]
ldp x21, x22, [x0, #JB_X21<<3]
ldp x23, x24, [x0, #JB_X23<<3]
ldp x25, x26, [x0, #JB_X25<<3]
ldp x27, x28, [x0, #JB_X27<<3]
#ifdef PTR_DEMANGLE
ldp x29, x4, [x0, #JB_X29<<3]
PTR_DEMANGLE (30, 4, 3, 2)
#else
ldp x29, x30, [x0, #JB_X29<<3]
#endif
/* longjmp probe takes 3 arguments, address of jump buffer as
first argument (8@x0), return value as second argument (-4@x1),
and target address (8@x30), respectively. */
LIBC_PROBE (longjmp, 3, 8@x0, -4@x1, 8@x30)
ldp d8, d9, [x0, #JB_D8<<3]
ldp d10, d11, [x0, #JB_D10<<3]
ldp d12, d13, [x0, #JB_D12<<3]
ldp d14, d15, [x0, #JB_D14<<3]
/* Originally this was implemented with a series of
.cfi_restore() directives.
The theory was that cfi_restore should revert to previous
frame value is the same as the current value. In practice
this doesn't work, even after cfi_restore() gdb continues
to try to recover a previous frame value offset from x0,
which gets stuffed after a few more instructions. The
cfi_same_value() mechanism appears to work fine. */
cfi_same_value(x19)
cfi_same_value(x20)
cfi_same_value(x21)
cfi_same_value(x22)
cfi_same_value(x23)
cfi_same_value(x24)
cfi_same_value(x25)
cfi_same_value(x26)
cfi_same_value(x27)
cfi_same_value(x28)
cfi_same_value(x29)
cfi_same_value(x30)
cfi_same_value(d8)
cfi_same_value(d9)
cfi_same_value(d10)
cfi_same_value(d11)
cfi_same_value(d12)
cfi_same_value(d13)
cfi_same_value(d14)
cfi_same_value(d15)
#ifdef PTR_DEMANGLE
ldr x4, [x0, #JB_SP<<3]
PTR_DEMANGLE (5, 4, 3, 2)
#else
ldr x5, [x0, #JB_SP<<3]
#endif
mov sp, x5
/* longjmp_target probe takes 3 arguments, address of jump buffer
as first argument (8@x0), return value as second argument (-4@x1),
and target address (8@x30), respectively. */
LIBC_PROBE (longjmp_target, 3, 8@x0, -4@x1, 8@x30)
cmp x1, #0
mov x0, #1
csel x0, x1, x0, ne
/* Use br instead of ret because ret is guaranteed to mispredict */
br x30
END (__longjmp)