diff options
Diffstat (limited to 'payloads/libpayload/arch/x86/exec.S')
| -rw-r--r-- | payloads/libpayload/arch/x86/exec.S | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/x86/exec.S b/payloads/libpayload/arch/x86/exec.S new file mode 100644 index 0000000000..9a44196e6b --- /dev/null +++ b/payloads/libpayload/arch/x86/exec.S @@ -0,0 +1,99 @@ +/* + * This file is part of the libpayload project. + * + * Copyright (C) 2008 Advanced Micro Devices, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* calling syntax: i386_do_exec(long addr, int argc, char **argv, int *ret) */ + +/* This implements the payload API detailed here: + * http://www.coreboot.org/Payload_API + */ + +.align 4 +.text + +.global i386_do_exec + .type i386_do_exec,@function + +i386_do_exec: + pushl %ebp + movl %esp, %ebp + pushl %eax + + /* Put the run address in %eax */ + movl 8(%ebp), %eax + + /* Save off the rest of the registers */ + + pushl %esi + pushl %ecx + pushl %ebp + + /* Push the argc and argv pointers on to the stack */ + + movl 12(%ebp), %esi + movl 16(%ebp), %ecx + + pushl %esi + pushl %ecx + + /* Move a "magic" number on the stack - the other + * payload will use this as a clue that the argc + * and argv are sane + */ + + movl $12345678, %ecx + pushl %ecx + + /* Jump to the code */ + call *%eax + + /* %eax has the return value */ + + /* Skip over the argc/argv stuff still on the stack */ + addl $12, %esp + + /* Get back %ebp */ + popl %ebp + + /* Get the pointer to the return value + * and save the return value in it + */ + + movl 20(%ebp), %ecx + movl %eax, (%eax) + + /* Get the rest of the saved registers */ + popl %ecx + popl %esi + popl %eax + + /* Restore the stack pointer */ + movl %ebp,%esp + popl %ebp + ret + |