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https://github.com/jart/cosmopolitan.git
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f7780de24b
Cosmopolitan now supports mremap(), which is only supported on Linux and NetBSD. First, it allows memory mappings to be relocated without copying them; this can dramatically speed up data structures like std::vector if the array size grows larger than 256kb. The mremap() system call is also 10x faster than munmap() when shrinking large memory mappings. There's now two functions, getpagesize() and getgransize() which help to write portable code that uses mmap(MAP_FIXED). Alternative sysconf() may be called with our new _SC_GRANSIZE. The madvise() system call now has a better wrapper with improved documentation.
111 lines
4.3 KiB
C
111 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2024 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/maps.h"
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#include "ape/sections.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/dll.h"
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#include "libc/intrin/maps.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/stack.h"
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#include "libc/sysv/consts/auxv.h"
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#include "libc/sysv/consts/prot.h"
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#ifdef __x86_64__
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__static_yoink("_init_maps");
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#endif
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struct Maps __maps;
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void __maps_add(struct Map *map) {
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tree_insert(&__maps.maps, &map->tree, __maps_compare);
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++__maps.count;
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}
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static void __maps_adder(struct Map *map, int pagesz) {
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__maps.pages += ((map->size + pagesz - 1) & -pagesz) / pagesz;
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__maps_add(map);
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}
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void __maps_stack(char *stackaddr, int pagesz, int guardsize, size_t stacksize,
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int stackprot, intptr_t stackhand) {
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__maps.stack.addr = stackaddr + guardsize;
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__maps.stack.size = stacksize - guardsize;
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__maps.stack.prot = stackprot;
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__maps.stack.hand = -1;
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__maps_adder(&__maps.stack, pagesz);
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if (guardsize) {
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__maps.guard.addr = stackaddr;
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__maps.guard.size = guardsize;
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__maps.guard.prot = PROT_NONE;
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__maps.guard.hand = stackhand;
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__maps_adder(&__maps.guard, pagesz);
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}
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}
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void __maps_init(void) {
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int pagesz = getpagesize();
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// record _start() stack mapping
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if (!IsWindows()) {
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struct AddrSize stack;
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stack = __get_main_stack();
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__maps_stack(stack.addr, pagesz, 0, stack.size, (uintptr_t)ape_stack_prot,
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0);
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}
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// record .text and .data mappings
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static struct Map text, data;
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text.addr = (char *)__executable_start;
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text.size = _etext - __executable_start;
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text.prot = PROT_READ | PROT_EXEC;
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uintptr_t ds = ((uintptr_t)_etext + pagesz - 1) & -pagesz;
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if (ds < (uintptr_t)_end) {
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data.addr = (char *)ds;
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data.size = (uintptr_t)_end - ds;
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data.prot = PROT_READ | PROT_WRITE;
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__maps_adder(&data, pagesz);
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}
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__maps_adder(&text, pagesz);
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}
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privileged bool __maps_lock(void) {
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struct CosmoTib *tib;
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if (!__tls_enabled)
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return false;
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tib = __get_tls_privileged();
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if (tib->tib_relock_maps++)
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return true;
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while (atomic_exchange_explicit(&__maps.lock, 1, memory_order_acquire)) {
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#if defined(__GNUC__) && defined(__aarch64__)
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__asm__ volatile("yield");
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#elif defined(__GNUC__) && (defined(__x86_64__) || defined(__i386__))
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__asm__ volatile("pause");
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#endif
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}
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return false;
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}
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privileged void __maps_unlock(void) {
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struct CosmoTib *tib;
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if (!__tls_enabled)
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return;
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tib = __get_tls_privileged();
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if (!--tib->tib_relock_maps)
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atomic_store_explicit(&__maps.lock, 0, memory_order_release);
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}
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