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wine-winehq
Commit 4ec770a1 authored by Brendan Shanks's avatar Brendan Shanks Committed by Alexandre Julliard
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loader: Add comments to 'start' in macOS preloader.

parent 57ce3b91
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Showing with 91 additions and 38 deletions
loader/preloader_mac.c
View file @ 4ec770a1
......@@ -101,6 +101,47 @@ void *__stack_chk_guard = 0;
void __stack_chk_fail_local(void) { return; }
void __stack_chk_fail(void) { return; }
/*
* When 'start' is called, stack frame looks like:
*
* :
* | STRING AREA |
* +-------------+
* | 0 |
* +-------------+
* | exec_path | extra "apple" parameters start after NULL terminating env array
* +-------------+
* | 0 |
* +-------------+
* | env[n] |
* +-------------+
* :
* :
* +-------------+
* | env[0] |
* +-------------+
* | 0 |
* +-------------+
* | arg[argc-1] |
* +-------------+
* :
* :
* +-------------+
* | arg[0] |
* +-------------+
* | argc | argc is always 4 bytes long, even in 64-bit architectures
* +-------------+ <- sp
*
* Where arg[i] and env[i] point into the STRING AREA
*
* See also:
* macOS C runtime 'start':
* <https://github.com/apple-oss-distributions/Csu/blob/Csu-88/start.s>
*
* macOS dyld '__dyld_start' (pre-dyld4):
* <https://github.com/apple-oss-distributions/dyld/blob/dyld-852.2/src/dyldStartup.s>
*/
#ifdef __i386__
static const size_t page_size = 0x1000;
......@@ -132,13 +173,14 @@ static const size_t page_mask = 0xfff;
__ASM_GLOBAL_FUNC( start,
__ASM_CFI("\t.cfi_undefined %eip\n")
/* The first 16 bytes are used as a function signature on i386 */
"\t.byte 0x6a,0x00\n" /* pushl $0 */
"\t.byte 0x89,0xe5\n" /* movl %esp,%ebp */
"\t.byte 0x83,0xe4,0xf0\n" /* andl $-16,%esp */
"\t.byte 0x83,0xec,0x10\n" /* subl $16,%esp */
"\t.byte 0x8b,0x5d,0x04\n" /* movl 4(%ebp),%ebx */
"\t.byte 0x89,0x5c,0x24,0x00\n" /* movl %ebx,0(%esp) */
"\t.byte 0x6a,0x00\n" /* pushl $0: push a zero for debugger end of frames marker */
"\t.byte 0x89,0xe5\n" /* movl %esp,%ebp: pointer to base of kernel frame */
"\t.byte 0x83,0xe4,0xf0\n" /* andl $-16,%esp: force SSE alignment */
"\t.byte 0x83,0xec,0x10\n" /* subl $16,%esp: room for new argc, argv, & envp, SSE aligned */
"\t.byte 0x8b,0x5d,0x04\n" /* movl 4(%ebp),%ebx: pickup argc in %ebx */
"\t.byte 0x89,0x5c,0x24,0x00\n" /* movl %ebx,0(%esp): argc to reserved stack word */
/* call wld_start(stack, &is_unix_thread) */
"\tleal 4(%ebp),%eax\n"
"\tmovl %eax,0(%esp)\n" /* stack */
"\tleal 8(%esp),%eax\n"
......@@ -146,16 +188,21 @@ __ASM_GLOBAL_FUNC( start,
"\tmovl $0,(%eax)\n"
"\tcall _wld_start\n"
/* argc/argv need to be fixed to remove argv[0].
* With LC_MAIN, pointers to argv/env/apple are passed so this is easy.
* With LC_UNIXTHREAD, argv[1] to the end of apple[] need to be moved.
*/
"\tmovl 4(%ebp),%edi\n"
"\tdecl %edi\n" /* argc */
"\tleal 12(%ebp),%esi\n" /* argv */
"\tleal 4(%esi,%edi,4),%edx\n" /* env */
"\tmovl %edx,%ecx\n" /* apple data */
"\tdecl %edi\n" /* %edi = argc (decremented) */
"\tleal 12(%ebp),%esi\n" /* %esi = &argv[1] */
"\tleal 4(%esi,%edi,4),%edx\n" /* %edx = env */
"\tmovl %edx,%ecx\n"
"1:\tmovl (%ecx),%ebx\n"
"\tadd $4,%ecx\n"
"\torl %ebx,%ebx\n"
"\tjnz 1b\n"
"\torl %ebx,%ebx\n" /* look for the NULL ending the env[] array */
"\tjnz 1b\n" /* %ecx = apple data */
/* jmp based on is_unix_thread */
"\tcmpl $0,8(%esp)\n"
"\tjne 2f\n"
......@@ -164,16 +211,16 @@ __ASM_GLOBAL_FUNC( start,
"\tmovl %esi,4(%esp)\n" /* argv */
"\tmovl %edx,8(%esp)\n" /* env */
"\tmovl %ecx,12(%esp)\n" /* apple data */
"\tcall *%eax\n"
"\tmovl %eax,(%esp)\n"
"\tcall _wld_exit\n"
"\tcall *%eax\n" /* call main(argc,argv,env,apple) */
"\tmovl %eax,(%esp)\n" /* pass result from main() to exit() */
"\tcall _wld_exit\n" /* need to use call to keep stack aligned */
"\thlt\n"
/* LC_UNIXTHREAD */
"2:\tmovl (%ecx),%ebx\n"
"\tadd $4,%ecx\n"
"\torl %ebx,%ebx\n"
"\tjnz 2b\n"
"\torl %ebx,%ebx\n" /* look for the NULL ending the apple[] array */
"\tjnz 2b\n" /* %ecx = end of apple[] */
"\tsubl %ebp,%ecx\n"
"\tsubl $8,%ecx\n"
......@@ -186,8 +233,8 @@ __ASM_GLOBAL_FUNC( start,
"\tcld\n"
"\trep; movsd\n" /* argv, ... */
"\tmovl $0,%ebp\n"
"\tjmpl *%eax\n" )
"\tmovl $0,%ebp\n" /* restore ebp back to zero */
"\tjmpl *%eax\n" ) /* jump to the entry point */
#elif defined(__x86_64__)
......@@ -221,41 +268,47 @@ static const size_t page_mask = 0xfff;
__ASM_GLOBAL_FUNC( start,
__ASM_CFI("\t.cfi_undefined %rip\n")
"\tpushq $0\n"
"\tmovq %rsp,%rbp\n"
"\tandq $-16,%rsp\n"
"\tsubq $16,%rsp\n"
"\tpushq $0\n" /* push a zero for debugger end of frames marker */
"\tmovq %rsp,%rbp\n" /* pointer to base of kernel frame */
"\tandq $-16,%rsp\n" /* force SSE alignment */
"\tsubq $16,%rsp\n" /* room for local variables */
/* call wld_start(stack, &is_unix_thread) */
"\tleaq 8(%rbp),%rdi\n" /* stack */
"\tmovq %rsp,%rsi\n" /* &is_unix_thread */
"\tmovq $0,(%rsi)\n"
"\tcall _wld_start\n"
/* argc/argv need to be fixed to remove argv[0].
* With LC_MAIN, pointers to argv/env/apple are passed so this is easy.
* With LC_UNIXTHREAD, argv[1] to the end of apple[] need to be moved.
*/
"\tmovq 8(%rbp),%rdi\n"
"\tdec %rdi\n" /* argc */
"\tleaq 24(%rbp),%rsi\n" /* argv */
"\tleaq 8(%rsi,%rdi,8),%rdx\n" /* env */
"\tmovq %rdx,%rcx\n" /* apple data */
"\tdec %rdi\n" /* %rdi = argc (decremented) */
"\tleaq 24(%rbp),%rsi\n" /* %rsi = &argv[1] */
"\tleaq 8(%rsi,%rdi,8),%rdx\n" /* %rdx = env */
"\tmovq %rdx,%rcx\n"
"1:\tmovq (%rcx),%r8\n"
"\taddq $8,%rcx\n"
"\torq %r8,%r8\n"
"\tjnz 1b\n"
"\torq %r8,%r8\n" /* look for the NULL ending the env[] array */
"\tjnz 1b\n" /* %rcx = apple data */
/* jmp based on is_unix_thread */
"\tcmpl $0,0(%rsp)\n"
"\tjne 2f\n"
/* LC_MAIN */
"\taddq $16,%rsp\n"
"\tcall *%rax\n"
"\tmovq %rax,%rdi\n"
"\tcall _wld_exit\n"
"\taddq $16,%rsp\n" /* remove local variables */
"\tcall *%rax\n" /* call main(argc,argv,env,apple) */
"\tmovq %rax,%rdi\n" /* pass result from main() to exit() */
"\tcall _wld_exit\n" /* need to use call to keep stack aligned */
"\thlt\n"
/* LC_UNIXTHREAD */
"2:\tmovq (%rcx),%r8\n"
"\taddq $8,%rcx\n"
"\torq %r8,%r8\n"
"\tjnz 2b\n"
"\torq %r8,%r8\n" /* look for the NULL ending the apple[] array */
"\tjnz 2b\n" /* %rcx = end of apple[] */
"\tsubq %rbp,%rcx\n"
"\tsubq $16,%rcx\n"
......@@ -268,8 +321,8 @@ __ASM_GLOBAL_FUNC( start,
"\tcld\n"
"\trep; movsq\n" /* argv, ... */
"\tmovq $0,%rbp\n"
"\tjmpq *%rax\n" )
"\tmovq $0,%rbp\n" /* restore ebp back to zero */
"\tjmpq *%rax\n" ) /* jump to the entry point */
#else
#error preloader not implemented for this CPU
......
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