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Kernel+LibPthread+LibC: Create secondary thread stacks in userspace

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Have pthread_create() allocate a stack and passing it to the kernel
instead of this work happening in the kernel. The more of this we can
do in userspace, the better.

This patch also unexposes the raw create_thread() and exit_thread()
syscalls since they are now only used by LibPthread anyway.
This commit is contained in:
Andreas Kling 2019-11-17 17:28:17 +01:00
parent 6685be36a0
commit e34ed04d1e
7 changed files with 30 additions and 33 deletions
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23
Libraries/LibPthread/pthread.cpp
View file

@ -1,18 +1,36 @@
#include <AK/Assertions.h>
#include <AK/Atomic.h>
#include <AK/StdLibExtras.h>
#include <Kernel/Syscall.h>
#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
extern "C" {
static int create_thread(void* (*entry)(void*), void* argument, void* stack)
{
int rc = syscall(SC_create_thread, entry, argument, stack);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
static void exit_thread(void* code)
{
syscall(SC_exit_thread, code);
ASSERT_NOT_REACHED();
}
int pthread_create(pthread_t* thread, pthread_attr_t* attributes, void* (*start_routine)(void*), void* argument_to_start_routine)
{
if (!thread)
return -EINVAL;
UNUSED_PARAM(attributes);
int rc = create_thread(start_routine, argument_to_start_routine);
const size_t stack_size = 4 * MB;
auto* stack = (u8*)mmap_with_name(nullptr, stack_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, 0, 0, "Thread stack");
if (!stack)
return -1;
int rc = create_thread(start_routine, argument_to_start_routine, stack + stack_size);
if (rc < 0)
return rc;
*thread = rc;
@ -55,5 +73,4 @@ int pthread_mutex_unlock(pthread_mutex_t* mutex)
atomic->store(false, AK::memory_order_release);
return 0;
}
}