diff options
Diffstat (limited to 'linux-user/host/i386/safe-syscall.inc.S')
| -rw-r--r-- | linux-user/host/i386/safe-syscall.inc.S | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/linux-user/host/i386/safe-syscall.inc.S b/linux-user/host/i386/safe-syscall.inc.S deleted file mode 100644 index 1fb031d228..0000000000 --- a/linux-user/host/i386/safe-syscall.inc.S +++ /dev/null @@ -1,115 +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) 2016 Red Hat, 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 - - /* 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 - push %ebp - .cfi_adjust_cfa_offset 4 - .cfi_rel_offset ebp, 0 - push %esi - .cfi_adjust_cfa_offset 4 - .cfi_rel_offset esi, 0 - push %edi - .cfi_adjust_cfa_offset 4 - .cfi_rel_offset edi, 0 - push %ebx - .cfi_adjust_cfa_offset 4 - .cfi_rel_offset ebx, 0 - - /* The syscall calling convention isn't the same as the C one: - * we enter with 0(%esp) == return address - * 4(%esp) == &signal_pending - * 8(%esp) == syscall number - * 12(%esp) ... 32(%esp) == syscall arguments - * and return the result in eax - * and the syscall instruction needs - * eax == syscall number - * ebx, ecx, edx, esi, edi, ebp == syscall arguments - * and returns the result in eax - * Shuffle everything around appropriately. - * Note the 16 bytes that we pushed to save registers. - */ - mov 12+16(%esp), %ebx /* the syscall arguments */ - mov 16+16(%esp), %ecx - mov 20+16(%esp), %edx - mov 24+16(%esp), %esi - mov 28+16(%esp), %edi - mov 32+16(%esp), %ebp - - /* 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 */ - mov 4+16(%esp), %eax /* signal_pending */ - cmpl $0, (%eax) - jnz 2f - mov 8+16(%esp), %eax /* syscall number */ - int $0x80 -safe_syscall_end: - /* code path for having successfully executed the syscall */ - cmp $-4095, %eax - jae 0f - pop %ebx - .cfi_remember_state - .cfi_adjust_cfa_offset -4 - .cfi_restore ebx - pop %edi - .cfi_adjust_cfa_offset -4 - .cfi_restore edi - pop %esi - .cfi_adjust_cfa_offset -4 - .cfi_restore esi - pop %ebp - .cfi_adjust_cfa_offset -4 - .cfi_restore ebp - ret - .cfi_restore_state - -0: neg %eax - jmp 1f - - /* code path when we didn't execute the syscall */ -2: mov $QEMU_ERESTARTSYS, %eax - - /* code path setting errno */ -1: pop %ebx - .cfi_adjust_cfa_offset -4 - .cfi_restore ebx - pop %edi - .cfi_adjust_cfa_offset -4 - .cfi_restore edi - pop %esi - .cfi_adjust_cfa_offset -4 - .cfi_restore esi - pop %ebp - .cfi_adjust_cfa_offset -4 - .cfi_restore ebp - jmp safe_syscall_set_errno_tail - - .cfi_endproc - .size safe_syscall_base, .-safe_syscall_base |