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#!/usr/bin/env perl
# Copyright (c) 2019, Google Inc.
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# This file defines helper functions for crypto/test/abi_test.h on 32-bit
# ARM. See that header for details on how to use this.
#
# For convenience, this file is linked into libcrypto, where consuming builds
# already support architecture-specific sources. The static linker should drop
# this code in non-test binaries. This includes a shared library build of
# libcrypto, provided --gc-sections (ELF), -dead_strip (iOS), or equivalent is
# used.
#
# References:
#
# AAPCS: http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042f/IHI0042F_aapcs.pdf
# iOS ARMv6: https://developer.apple.com/library/archive/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARMv6FunctionCallingConventions.html
# iOS ARMv7: https://developer.apple.com/library/archive/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARMv7FunctionCallingConventions.html
# Linux: http://sourcery.mentor.com/sgpp/lite/arm/portal/kbattach142/arm_gnu_linux_%20abi.pdf
use strict;
my $flavour = shift;
my $output = shift;
if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
$0 =~ m/(.*[\/\\])[^\/\\]+$/;
my $dir = $1;
my $xlate;
( $xlate="${dir}arm-xlate.pl" and -f $xlate ) or
( $xlate="${dir}../../perlasm/arm-xlate.pl" and -f $xlate) or
die "can't locate arm-xlate.pl";
open OUT, "| \"$^X\" \"$xlate\" $flavour \"$output\"";
*STDOUT = *OUT;
my ($func, $state, $argv, $argc) = ("r0", "r1", "r2", "r3");
my $code = <<____;
.syntax unified
.arch armv7-a
.fpu vfp
.text
@ abi_test_trampoline loads callee-saved registers from |state|, calls |func|
@ with |argv|, then saves the callee-saved registers into |state|. It returns
@ the result of |func|. The |unwind| argument is unused.
@ uint32_t abi_test_trampoline(void (*func)(...), CallerState *state,
@ const uint32_t *argv, size_t argc,
@ int unwind);
.type abi_test_trampoline, %function
.globl abi_test_trampoline
.align 4
abi_test_trampoline:
.Labi_test_trampoline_begin:
@ Save parameters and all callee-saved registers. For convenience, we
@ save r9 on iOS even though it's volatile.
vstmdb sp!, {d8-d15}
stmdb sp!, {r0-r11,lr}
@ Reserve stack space for six (10-4) stack parameters, plus an extra 4
@ bytes to keep it 8-byte-aligned (see AAPCS, section 5.3).
sub sp, sp, #28
@ Every register in AAPCS is either non-volatile or a parameter (except
@ r9 on iOS), so this code, by the actual call, loses all its scratch
@ registers. First fill in stack parameters while there are registers
@ to spare.
cmp $argc, #4
bls .Lstack_args_done
mov r4, sp @ r4 is the output pointer.
add r5, $argv, $argc, lsl #2 @ Set r5 to the end of argv.
add $argv, $argv, #16 @ Skip four arguments.
.Lstack_args_loop:
ldr r6, [$argv], #4
cmp $argv, r5
str r6, [r4], #4
bne .Lstack_args_loop
.Lstack_args_done:
@ Load registers from |$state|.
vldmia $state!, {d8-d15}
#if defined(__APPLE__)
@ r9 is not volatile on iOS.
ldmia $state!, {r4-r8,r10-r11}
#else
ldmia $state!, {r4-r11}
#endif
@ Load register parameters. This uses up our remaining registers, so we
@ repurpose lr as scratch space.
ldr $argc, [sp, #40] @ Reload argc.
ldr lr, [sp, #36] @ Load argv into lr.
cmp $argc, #3
bhi .Larg_r3
beq .Larg_r2
cmp $argc, #1
bhi .Larg_r1
beq .Larg_r0
b .Largs_done
.Larg_r3:
ldr r3, [lr, #12] @ argv[3]
.Larg_r2:
ldr r2, [lr, #8] @ argv[2]
.Larg_r1:
ldr r1, [lr, #4] @ argv[1]
.Larg_r0:
ldr r0, [lr] @ argv[0]
.Largs_done:
@ With every other register in use, load the function pointer into lr
@ and call the function.
ldr lr, [sp, #28]
blx lr
@ r1-r3 are free for use again. The trampoline only supports
@ single-return functions. Pass r4-r11 to the caller.
ldr $state, [sp, #32]
vstmia $state!, {d8-d15}
#if defined(__APPLE__)
@ r9 is not volatile on iOS.
stmia $state!, {r4-r8,r10-r11}
#else
stmia $state!, {r4-r11}
#endif
@ Unwind the stack and restore registers.
add sp, sp, #44 @ 44 = 28+16
ldmia sp!, {r4-r11,lr} @ Skip r0-r3 (see +16 above).
vldmia sp!, {d8-d15}
bx lr
.size abi_test_trampoline,.-abi_test_trampoline
____
# abi_test_clobber_* zeros the corresponding register. These are used to test
# the ABI-testing framework.
foreach (0..12) {
# This loop skips r13 (sp), r14 (lr, implicitly clobbered by every call), and
# r15 (pc).
$code .= <<____;
.type abi_test_clobber_r$_, %function
.globl abi_test_clobber_r$_
.align 4
abi_test_clobber_r$_:
mov r$_, #0
bx lr
.size abi_test_clobber_r$_,.-abi_test_clobber_r$_
____
}
foreach (0..15) {
my $lo = "s".(2*$_);
my $hi = "s".(2*$_+1);
$code .= <<____;
.type abi_test_clobber_d$_, %function
.globl abi_test_clobber_d$_
.align 4
abi_test_clobber_d$_:
mov r0, #0
vmov $lo, r0
vmov $hi, r0
bx lr
.size abi_test_clobber_d$_,.-abi_test_clobber_d$_
____
}
print $code;
close STDOUT;
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