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/* Install given context.
Copyright (C) 2008-2023 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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <sys/trap.h>
#include "ucontext_i.h"
/* int __setcontext (const ucontext_t *ucp)
Restores the machine context in UCP and thereby resumes execution
in that context.
This implementation is intended to be used for *synchronous* context
switches only. Therefore, it does not have to restore anything
other than the PRESERVED state. */
ENTRY(__setcontext)
save %sp, -112, %sp
mov SIG_SETMASK, %o0
add %i0, UC_SIGMASK, %o1
clr %o2
mov 8, %o3
mov __NR_rt_sigprocmask, %g1
ta 0x10
/* This is a bit on the expensive side, and we could optimize
the unwind similar to how the 32-bit sparc longjmp code
does if performance of this routine really matters. */
ta ST_FLUSH_WINDOWS
ldub [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_EN], %g1
cmp %g1, 0
be 1f
nop
ld [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_FSR], %fsr
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D0], %f0
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D2], %f2
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D4], %f4
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D6], %f6
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D8], %f8
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D10], %f10
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D12], %f12
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D14], %f14
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D16], %f16
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D18], %f18
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D20], %f20
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D22], %f22
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D24], %f24
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D26], %f26
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D28], %f28
ldd [%i0 + UC_MCONTEXT + MC_FPREGS + FPU_D30], %f30
1:
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_Y], %g1
wr %g1, 0x0, %y
/* We specifically do not restore %g1 since we need it here as
a temporary. */
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G2], %g2
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G3], %g3
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G4], %g4
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G5], %g5
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G6], %g6
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_G7], %g7
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O1], %i1
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O2], %i2
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O3], %i3
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O4], %i4
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O5], %i5
ld [%i0 + UC_MCONTEXT + MC_GREGS + GREG_O6], %i6
restore
ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_O7], %o7
ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_PC], %g1
jmpl %g1, %g0
ld [%o0 + UC_MCONTEXT + MC_GREGS + GREG_O0], %o0
END(__setcontext)
weak_alias (__setcontext, setcontext)
/* We add an NOP here to separate between __setcontext/__startcontext. The
wanted behavior that happens is: when unwinding from a function called
inside a makecontext() context, FDE lookup will use '&__startcontext - 1',
then returns NULL for no FDE found, and immediately ends the unwind, in
a normal fashion.
If this NOP word does not exist, FDE lookup just repeatedly finds
__setcontext's FDE in an infinite loop, due to the convention of using
'address - 1' for FDE lookup. Modifying/deleting the below
__startcontext's FDE has no help on this. */
nop
/* This is the helper code which gets called if a function which is
registered with 'makecontext' returns. In this case we have to
install the context listed in the uc_link element of the context
'makecontext' manipulated at the time of the 'makecontext' call.
If the pointer is NULL the process must terminate. */
ENTRY(__start_context)
ld [%sp + (16 * 4)], %g1
cmp %g1, 0
be,a 1f
clr %o0
call __setcontext
mov %g1, %o0
/* If this returns (which can happen if the syscall fails) we'll
exit the program with the return error value (-1). */
1: call HIDDEN_JUMPTARGET(exit)
nop
/* The 'exit' call should never return. In case it does cause
the process to terminate. */
unimp
END(__start_context)
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