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/*
* Copyright (C) 2019-2025 Intel Corporation
*
* SPDX-License-Identifier: MIT
*
*/
#include "shared/source/page_fault_manager/linux/cpu_page_fault_manager_linux.h"
#include "shared/source/debug_settings/debug_settings_manager.h"
#include "shared/source/device/device.h"
#include "shared/source/execution_environment/root_device_environment.h"
#include "shared/source/memory_manager/memory_operations_handler.h"
#include "shared/source/page_fault_manager/linux/tbx_page_fault_manager_linux.h"
#include <algorithm>
#include <sys/mman.h>
namespace NEO {
std::unique_ptr<CpuPageFaultManager> CpuPageFaultManager::create() {
auto pageFaultManager = [&]() -> std::unique_ptr<CpuPageFaultManager> {
if (debugManager.isTbxPageFaultManagerEnabled()) {
return TbxPageFaultManager::create();
}
return std::make_unique<PageFaultManagerLinux>();
}();
pageFaultManager->selectGpuDomainHandler();
return pageFaultManager;
}
std::function<void(int signal, siginfo_t *info, void *context)> PageFaultManagerLinux::pageFaultHandler = nullptr;
PageFaultManagerLinux::PageFaultManagerLinux() {
PageFaultManagerLinux::registerFaultHandler();
UNRECOVERABLE_IF(pageFaultHandler == nullptr);
}
PageFaultManagerLinux::~PageFaultManagerLinux() {
if (!previousHandlerRestored) {
auto retVal = sigaction(SIGSEGV, &previousPageFaultHandlers[0], nullptr);
UNRECOVERABLE_IF(retVal != 0);
previousPageFaultHandlers.clear();
}
}
bool PageFaultManagerLinux::checkFaultHandlerFromPageFaultManager() {
struct sigaction currentPageFaultHandler = {};
sigaction(SIGSEGV, NULL, ¤tPageFaultHandler);
return (currentPageFaultHandler.sa_sigaction == pageFaultHandlerWrapper);
}
void PageFaultManagerLinux::registerFaultHandler() {
struct sigaction previousPageFaultHandler = {};
auto retVal = sigaction(SIGSEGV, nullptr, &previousPageFaultHandler);
UNRECOVERABLE_IF(retVal != 0);
auto compareHandler = [&ph = previousPageFaultHandler](const struct sigaction &h) -> bool {
return (h.sa_flags & SA_SIGINFO) ? (h.sa_sigaction == ph.sa_sigaction) : (h.sa_handler == ph.sa_handler);
};
if (std::find_if(previousPageFaultHandlers.begin(),
previousPageFaultHandlers.end(),
compareHandler) == previousPageFaultHandlers.end()) {
previousPageFaultHandlers.push_back(previousPageFaultHandler);
}
pageFaultHandler = [&](int signal, siginfo_t *info, void *context) {
if (!this->verifyAndHandlePageFault(info->si_addr, this->handlerIndex == 0)) {
callPreviousHandler(signal, info, context);
}
};
struct sigaction pageFaultManagerHandler = {};
pageFaultManagerHandler.sa_flags = SA_SIGINFO;
pageFaultManagerHandler.sa_sigaction = pageFaultHandlerWrapper;
retVal = sigaction(SIGSEGV, &pageFaultManagerHandler, &previousPageFaultHandler);
UNRECOVERABLE_IF(retVal != 0);
}
void PageFaultManagerLinux::pageFaultHandlerWrapper(int signal, siginfo_t *info, void *context) {
pageFaultHandler(signal, info, context);
}
void PageFaultManagerLinux::allowCPUMemoryAccess(void *ptr, size_t size) {
auto retVal = mprotect(ptr, size, PROT_READ | PROT_WRITE);
UNRECOVERABLE_IF(retVal != 0);
}
void PageFaultManagerLinux::protectCPUMemoryAccess(void *ptr, size_t size) {
auto retVal = mprotect(ptr, size, PROT_NONE);
UNRECOVERABLE_IF(retVal != 0);
}
void PageFaultManagerLinux::protectCpuMemoryFromWrites(void *ptr, size_t size) {
auto retVal = mprotect(ptr, size, PROT_READ);
UNRECOVERABLE_IF(retVal != 0);
}
void PageFaultManagerLinux::callPreviousHandler(int signal, siginfo_t *info, void *context) {
handlerIndex++;
UNRECOVERABLE_IF(handlerIndex < 0 && handlerIndex >= static_cast<int>(previousPageFaultHandlers.size()));
auto previousPageFaultHandler = previousPageFaultHandlers[previousPageFaultHandlers.size() - handlerIndex];
if (previousPageFaultHandler.sa_flags & SA_SIGINFO) {
previousPageFaultHandler.sa_sigaction(signal, info, context);
} else {
if (previousPageFaultHandler.sa_handler == SIG_DFL) {
auto retVal = sigaction(SIGSEGV, &previousPageFaultHandler, nullptr);
UNRECOVERABLE_IF(retVal != 0);
previousHandlerRestored = true;
previousPageFaultHandlers.clear();
} else if (previousPageFaultHandler.sa_handler != SIG_IGN) {
previousPageFaultHandler.sa_handler(signal);
}
}
handlerIndex--;
}
void PageFaultManagerLinux::allowCPUMemoryEvictionImpl(bool evict, void *ptr, CommandStreamReceiver &csr, OSInterface *osInterface) {}
} // namespace NEO
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