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#include <mlibc/thread-entry.hpp>
#include <mlibc/all-sysdeps.hpp>
#include <mlibc/thread.hpp>
#include <bits/ensure.h>
#include <sys/mman.h>
#include <stdint.h>
#include <stddef.h>
#include <errno.h>
extern "C" void __mlibc_enter_thread(void *entry, void *user_arg) {
// The linux kernel already sets the TCB in sys_clone().
auto tcb = mlibc::get_current_tcb();
// Wait until our parent sets up the TID.
while(!__atomic_load_n(&tcb->tid, __ATOMIC_RELAXED))
mlibc::sys_futex_wait(&tcb->tid, 0, nullptr);
tcb->invokeThreadFunc(entry, user_arg);
__atomic_store_n(&tcb->didExit, 1, __ATOMIC_RELEASE);
mlibc::sys_futex_wake(&tcb->didExit);
mlibc::sys_thread_exit();
}
namespace mlibc {
static constexpr size_t default_stacksize = 0x200000;
int sys_prepare_stack(void **stack, void *entry, void *user_arg, void *tcb, size_t *stack_size, size_t *guard_size, void **stack_base) {
(void)tcb;
if (!*stack_size)
*stack_size = default_stacksize;
uintptr_t map;
if (*stack) {
map = reinterpret_cast<uintptr_t>(*stack);
*guard_size = 0;
} else {
map = reinterpret_cast<uintptr_t>(
mmap(nullptr, *stack_size + *guard_size,
PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)
);
if (reinterpret_cast<void*>(map) == MAP_FAILED)
return EAGAIN;
int ret = mprotect(reinterpret_cast<void*>(map + *guard_size), *stack_size,
PROT_READ | PROT_WRITE);
if(ret)
return EAGAIN;
}
*stack_base = reinterpret_cast<void*>(map);
auto sp = reinterpret_cast<uintptr_t*>(map + *guard_size + *stack_size);
*--sp = reinterpret_cast<uintptr_t>(user_arg);
*--sp = reinterpret_cast<uintptr_t>(entry);
*stack = reinterpret_cast<void*>(sp);
return 0;
}
} // namespace mlibc
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