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