103 lines
2.2 KiB
C++
103 lines
2.2 KiB
C++
/*
|
|
* Copyright 2018, Jérôme Duval, jerome.duval@gmail.com.
|
|
* Copyright 2014, Paweł Dziepak, pdziepak@quarnos.org.
|
|
* Distributed under the terms of the MIT License.
|
|
*/
|
|
#ifndef _KERNEL_ARCH_GENERIC_USER_MEMORY_H
|
|
#define _KERNEL_ARCH_GENERIC_USER_MEMORY_H
|
|
|
|
|
|
#include <atomic>
|
|
|
|
#include <setjmp.h>
|
|
#include <string.h>
|
|
|
|
#include <thread.h>
|
|
|
|
|
|
namespace {
|
|
|
|
|
|
struct FaultHandlerGuard {
|
|
FaultHandlerGuard()
|
|
{
|
|
old_handler = thread_get_current_thread()->fault_handler;
|
|
if (old_handler != nullptr) {
|
|
memcpy(old_handler_state,
|
|
thread_get_current_thread()->fault_handler_state,
|
|
sizeof(jmp_buf));
|
|
}
|
|
thread_get_current_thread()->fault_handler = HandleFault;
|
|
std::atomic_signal_fence(std::memory_order_acq_rel);
|
|
}
|
|
|
|
|
|
~FaultHandlerGuard()
|
|
{
|
|
std::atomic_signal_fence(std::memory_order_acq_rel);
|
|
thread_get_current_thread()->fault_handler = old_handler;
|
|
if (old_handler != nullptr) {
|
|
memcpy(thread_get_current_thread()->fault_handler_state,
|
|
old_handler_state,
|
|
sizeof(jmp_buf));
|
|
}
|
|
|
|
}
|
|
|
|
|
|
[[noreturn]] static void HandleFault()
|
|
{
|
|
longjmp(thread_get_current_thread()->fault_handler_state, 1);
|
|
}
|
|
|
|
void (*old_handler)(void);
|
|
jmp_buf old_handler_state;
|
|
};
|
|
|
|
|
|
template<typename Function>
|
|
bool user_access(Function function)
|
|
{
|
|
FaultHandlerGuard guard;
|
|
// TODO: try { } catch (...) { } would be much nicer, wouldn't it?
|
|
// And faster... And world wouldn't end in a terrible disaster if function()
|
|
// or anything it calls created on stack an object with non-trivial
|
|
// destructor.
|
|
auto fail = setjmp(thread_get_current_thread()->fault_handler_state);
|
|
if (fail == 0) {
|
|
set_ac();
|
|
function();
|
|
clear_ac();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
|
|
inline status_t
|
|
arch_cpu_user_memcpy(void* src, const void* dst, size_t n)
|
|
{
|
|
return user_access([=] { memcpy(src, dst, n); }) ? B_OK : B_ERROR;
|
|
}
|
|
|
|
|
|
inline status_t
|
|
arch_cpu_user_memset(void* src, char v, size_t n)
|
|
{
|
|
return user_access([=] { memset(src, v, n); }) ? B_OK : B_ERROR;
|
|
}
|
|
|
|
|
|
inline ssize_t
|
|
arch_cpu_user_strlcpy(char* src, const char* dst, size_t n)
|
|
{
|
|
ssize_t result;
|
|
return user_access([=, &result] { result = strlcpy(src, dst, n); })
|
|
? result : B_ERROR;
|
|
}
|
|
|
|
}
|
|
|
|
#endif // _KERNEL_ARCH_GENERIC_USER_MEMORY_H
|
|
|