common-user: Move safe-syscall.* from linux-user

Move linux-user safe-syscall.S and safe-syscall-error.c to common-user
so that bsd-user can also use it.  Also move safe-syscall.h to
include/user/.  Since there is nothing here that is related to the guest,
as opposed to the host, build it once.

Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 0 insertions, 79 deletions

diff --git a/linux-user/host/riscv/safe-syscall.inc.S b/linux-user/host/riscv/safe-syscall.inc.S
deleted file mode 100644
index ca456d8a46..0000000000
--- a/linux-user/host/riscv/safe-syscall.inc.S
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * safe-syscall.inc.S : host-specific assembly fragment
- * to handle signals occurring at the same time as system calls.
- * This is intended to be included by linux-user/safe-syscall.S
- *
- * Written by Richard Henderson <rth@twiddle.net>
- * Copyright (C) 2018 Linaro, Inc.
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- */
-
-        .global safe_syscall_base
-        .global safe_syscall_start
-        .global safe_syscall_end
-        .type   safe_syscall_base, @function
-        .type   safe_syscall_start, @function
-        .type   safe_syscall_end, @function
-
-        /*
-         * This is the entry point for making a system call. The calling
-         * convention here is that of a C varargs function with the
-         * first argument an 'int *' to the signal_pending flag, the
-         * second one the system call number (as a 'long'), and all further
-         * arguments being syscall arguments (also 'long').
-         */
-safe_syscall_base:
-        .cfi_startproc
-        /*
-         * The syscall calling convention is nearly the same as C:
-         * we enter with a0 == &signal_pending
-         *               a1 == syscall number
-         *               a2 ... a7 == syscall arguments
-         *               and return the result in a0
-         * and the syscall instruction needs
-         *               a7 == syscall number
-         *               a0 ... a5 == syscall arguments
-         *               and returns the result in a0
-         * Shuffle everything around appropriately.
-         */
-        mv      t0, a0          /* signal_pending pointer */
-        mv      t1, a1          /* syscall number */
-        mv      a0, a2          /* syscall arguments */
-        mv      a1, a3
-        mv      a2, a4
-        mv      a3, a5
-        mv      a4, a6
-        mv      a5, a7
-        mv      a7, t1
-
-        /*
-         * This next sequence of code works in conjunction with the
-         * rewind_if_safe_syscall_function(). If a signal is taken
-         * and the interrupted PC is anywhere between 'safe_syscall_start'
-         * and 'safe_syscall_end' then we rewind it to 'safe_syscall_start'.
-         * The code sequence must therefore be able to cope with this, and
-         * the syscall instruction must be the final one in the sequence.
-         */
-safe_syscall_start:
-        /* If signal_pending is non-zero, don't do the call */
-        lw      t1, 0(t0)
-        bnez    t1, 2f
-        scall
-safe_syscall_end:
-        /* code path for having successfully executed the syscall */
-        li      t2, -4096
-        bgtu    a0, t2, 0f
-        ret
-
-        /* code path setting errno */
-0:      neg     a0, a0
-        j       safe_syscall_set_errno_tail
-
-        /* code path when we didn't execute the syscall */
-2:      li      a0, QEMU_ERESTARTSYS
-        j       safe_syscall_set_errno_tail
-
-        .cfi_endproc
-        .size   safe_syscall_base, .-safe_syscall_base