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/* Architecture specific bits for cancellation handling.
Copyright (C) 2023 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
<http://www.gnu.org/licenses/>. */
#ifndef _NPTL_CANCELLATION_PC_CHECK
#define _NPTL_CANCELLATION_PC_CHECK 1
/* Check if the program counter (PC) from ucontext CTX is within the start and
then end boundary from the __syscall_cancel_arch bridge. Return TRUE if
the PC is within the boundary, meaning the syscall does not have any side
effects; or FALSE otherwise. */
static bool
cancellation_pc_check (void *ctx)
{
/* Both are defined in syscall_cancel.S for each architecture. */
extern const char __syscall_cancel_arch_start[1];
extern const char __syscall_cancel_arch_end[1];
uintptr_t sc_ip = ((struct sigcontext *) (ctx))->sc_ip;
uintptr_t cr_iip = sc_ip & ~0x3ull;
uintptr_t ri = sc_ip & 0x3ull;
/* IA64 __syscall_cancel_arch issues the 'break 0x100000' on its own bundle,
and __syscall_cancel_arch_end points to end of the previous bundle.
To check if the syscall had any side-effects we need to check the slot
number. */
if (cr_iip == (uintptr_t) __syscall_cancel_arch_end)
return ri == 0;
return cr_iip >= (uintptr_t) __syscall_cancel_arch_start
&& cr_iip < (uintptr_t) __syscall_cancel_arch_end;
}
#endif
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