diff options
Diffstat (limited to 'linux-user/host/i386/safe-syscall.inc.S')
| -rw-r--r-- | linux-user/host/i386/safe-syscall.inc.S | 158 |
1 files changed, 79 insertions, 79 deletions
diff --git a/linux-user/host/i386/safe-syscall.inc.S b/linux-user/host/i386/safe-syscall.inc.S index 9e58fc6504..e425aa54d8 100644 --- a/linux-user/host/i386/safe-syscall.inc.S +++ b/linux-user/host/i386/safe-syscall.inc.S @@ -10,91 +10,91 @@ * 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 + .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'). - * 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. - */ + /* 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: - .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 + .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 + /* 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. - */ + /* 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 1f - mov 8+16(%esp), %eax /* syscall number */ - int $0x80 + /* if signal_pending is non-zero, don't do the call */ + mov 4+16(%esp), %eax /* signal_pending */ + cmpl $0, (%eax) + jnz 1f + mov 8+16(%esp), %eax /* syscall number */ + int $0x80 safe_syscall_end: - /* code path for having successfully executed the syscall */ - 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 + /* code path for having successfully executed the syscall */ + 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 1: - /* code path when we didn't execute the syscall */ - .cfi_restore_state - mov $-TARGET_ERESTARTSYS, %eax - jmp safe_syscall_end - .cfi_endproc + /* code path when we didn't execute the syscall */ + .cfi_restore_state + mov $-TARGET_ERESTARTSYS, %eax + jmp safe_syscall_end + .cfi_endproc - .size safe_syscall_base, .-safe_syscall_base + .size safe_syscall_base, .-safe_syscall_base |