diff options
Diffstat (limited to 'linux-user/host/arm/safe-syscall.inc.S')
| -rw-r--r-- | linux-user/host/arm/safe-syscall.inc.S | 90 |
1 files changed, 0 insertions, 90 deletions
diff --git a/linux-user/host/arm/safe-syscall.inc.S b/linux-user/host/arm/safe-syscall.inc.S deleted file mode 100644 index 88c4958504..0000000000 --- a/linux-user/host/arm/safe-syscall.inc.S +++ /dev/null @@ -1,90 +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 - - .cfi_sections .debug_frame - - .text - .syntax unified - .arm - .align 2 - - /* 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'). - * We return a long which is the syscall's return value, which - * may be negative-errno on failure. Conversion to the - * -1-and-errno-set convention is done by the calling wrapper. - */ -safe_syscall_base: - .fnstart - .cfi_startproc - mov r12, sp /* save entry stack */ - push { r4, r5, r6, r7, r8, lr } - .save { r4, r5, r6, r7, r8, lr } - .cfi_adjust_cfa_offset 24 - .cfi_rel_offset r4, 0 - .cfi_rel_offset r5, 4 - .cfi_rel_offset r6, 8 - .cfi_rel_offset r7, 12 - .cfi_rel_offset r8, 16 - .cfi_rel_offset lr, 20 - - /* The syscall calling convention isn't the same as the C one: - * we enter with r0 == *signal_pending - * r1 == syscall number - * r2, r3, [sp+0] ... [sp+12] == syscall arguments - * and return the result in r0 - * and the syscall instruction needs - * r7 == syscall number - * r0 ... r6 == syscall arguments - * and returns the result in r0 - * Shuffle everything around appropriately. - * Note the 16 bytes that we pushed to save registers. - */ - mov r8, r0 /* copy signal_pending */ - mov r7, r1 /* syscall number */ - mov r0, r2 /* syscall args */ - mov r1, r3 - ldm r12, { r2, r3, r4, r5, r6 } - - /* 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 */ - ldr r12, [r8] /* signal_pending */ - tst r12, r12 - bne 1f - swi 0 -safe_syscall_end: - /* code path for having successfully executed the syscall */ - pop { r4, r5, r6, r7, r8, pc } - -1: - /* code path when we didn't execute the syscall */ - ldr r0, =-TARGET_ERESTARTSYS - pop { r4, r5, r6, r7, r8, pc } - .fnend - .cfi_endproc - - .size safe_syscall_base, .-safe_syscall_base |