cosmopolitan/libc/runtime/cosmo.S
Justine Tunney 791f79fcb3
Make improvements
- We now serialize the file descriptor table when spawning / executing
  processes on Windows. This means you can now inherit more stuff than
  just standard i/o. It's needed by bash, which duplicates the console
  to file descriptor #255. We also now do a better job serializing the
  environment variables, so you're less likely to encounter E2BIG when
  using your bash shell. We also no longer coerce environ to uppercase

- execve() on Windows now remotely controls its parent process to make
  them spawn a replacement for itself. Then it'll be able to terminate
  immediately once the spawn succeeds, without having to linger around
  for the lifetime as a shell process for proxying the exit code. When
  process worker thread running in the parent sees the child die, it's
  given a handle to the new child, to replace it in the process table.

- execve() and posix_spawn() on Windows will now provide CreateProcess
  an explicit handle list. This allows us to remove handle locks which
  enables better fork/spawn concurrency, with seriously correct thread
  safety. Other codebases like Go use the same technique. On the other
  hand fork() still favors the conventional WIN32 inheritence approach
  which can be a little bit messy, but is *controlled* by guaranteeing
  perfectly clean slates at both the spawning and execution boundaries

- sigset_t is now 64 bits. Having it be 128 bits was a mistake because
  there's no reason to use that and it's only supported by FreeBSD. By
  using the system word size, signal mask manipulation on Windows goes
  very fast. Furthermore @asyncsignalsafe funcs have been rewritten on
  Windows to take advantage of signal masking, now that it's much more
  pleasant to use.

- All the overlapped i/o code on Windows has been rewritten for pretty
  good signal and cancelation safety. We're now able to ensure overlap
  data structures are cleaned up so long as you don't longjmp() out of
  out of a signal handler that interrupted an i/o operation. Latencies
  are also improved thanks to the removal of lots of "busy wait" code.
  Waits should be optimal for everything except poll(), which shall be
  the last and final demon we slay in the win32 i/o horror show.

- getrusage() on Windows is now able to report RUSAGE_CHILDREN as well
  as RUSAGE_SELF, thanks to aggregation in the process manager thread.
2023-10-08 08:59:53 -07:00

147 lines
4.8 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
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.
*/
#include "libc/macros.internal.h"
#include "libc/notice.inc"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/map.h"
#include "libc/intrin/strace.internal.h"
#include "libc/sysv/consts/map.h"
#include "libc/dce.h"
#ifdef __x86_64__
.text.startup
// Cosmopolitan runtime.
//
// @param edi is argc
// @param rsi is argv
// @param rdx is environ
// @param rcx is auxv
// @noreturn
cosmo: push %rbp
mov %rsp,%rbp
mov %edi,%r12d
mov %rsi,%r13
mov %rdx,%r14
mov %rcx,%r15
#ifdef SYSDEBUG
call __strace_init
mov %eax,%r12d
#endif /* SYSDEBUG */
#ifndef NOX87
// Windows always initializes FPU to douuble precision.
// WSL breaks Linux ABI by initializing FPU to double precision.
// This code makes long double long again.
//
// @see System V Application Binary Interface NexGen32e Architecture
// Processor Supplement, Version 1.0, December 5th, 2018
// Section 3.4.1: Initial Stack and Register State
fldcw 1f(%rip)
.rodata
.balign 2
// 8087 FPU Control Word
// IM: Invalid Operation
// DM: Denormal Operand
// ZM: Zero Divide
// OM: Overflow
// UM: Underflow
// PM: Precision
// PC: Precision Control
// {float,,double,long double}
// RC: Rounding Control
// {even, -, +, 0}
//
// drr
1: .short 0b00000000000000000001101111111
.previous
#endif
#ifdef __FAST_MATH__
push %rax
stmxcsr (%rsp)
orl $0x8040,(%rsp)
ldmxcsr (%rsp)
pop %rax
#endif
// run assembly init
call _init
// call constructors
ezlea __init_array_end,ax // static ctors in forward order
.weak __init_array_end // could be called multiple times
ezlea __init_array_start,cx // idempotency recommended
.weak __init_array_start // @see ape/ape.lds
1: cmp %rax,%rcx
je 2f
sub $8,%rax
push %rax
push %rcx
call .Largs
call *(%rax)
pop %rcx
pop %rax
jmp 1b
// call main()
2: call .Largs
.weak main
call main
xchg %eax,%edi
call exit
.Largs: mov %r12d,%edi
mov %r13,%rsi
mov %r14,%rdx
mov %r15,%rcx
ret
.endfn cosmo,weak
// Enables Thread Local Storage.
.init.start 304,_init_tls
push %rdi
push %rsi
call __enable_tls
pop %rsi
pop %rdi
.init.end 304,_init_tls
#if IsAsan()
.init.start 305,_init_symbols
push %rdi
push %rsi
call __init_symbols
pop %rsi
pop %rdi
.init.end 305,_init_symbols
#endif
#ifdef FTRACE
.init.start 306,_init_ftrace
push %rdi
push %rsi
call ftrace_init
mov %eax,%r12d
pop %rsi
pop %rdi
.init.end 306,_init_ftrace
#endif
#endif /* __x86_64__ */