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/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2022-12-06 WangXiaoyao the first version
* 2023-08-19 Shell Support PRIVATE mapping and COW
*/
#include <rtthread.h>
#ifdef RT_USING_SMART
#define DBG_TAG "mm.fault"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#include <lwp.h>
#include <lwp_syscall.h>
#include "mm_aspace.h"
#include "mm_fault.h"
#include "mm_flag.h"
#include "mm_private.h"
#include <mmu.h>
#include <tlb.h>
static int _fetch_page(rt_varea_t varea, struct rt_aspace_fault_msg *msg)
{
int err = MM_FAULT_FIXABLE_FALSE;
if (varea->mem_obj && varea->mem_obj->on_page_fault)
{
varea->mem_obj->on_page_fault(varea, msg);
err = rt_varea_map_with_msg(varea, msg);
err = (err == RT_EOK ? MM_FAULT_FIXABLE_TRUE : MM_FAULT_FIXABLE_FALSE);
}
return err;
}
static int _read_fault(rt_varea_t varea, void *pa, struct rt_aspace_fault_msg *msg)
{
int err = MM_FAULT_FIXABLE_FALSE;
if (msg->fault_type == MM_FAULT_TYPE_PAGE_FAULT)
{
RT_ASSERT(pa == ARCH_MAP_FAILED);
RT_ASSERT(!(varea->flag & MMF_PREFETCH));
err = _fetch_page(varea, msg);
}
else
{
/* signal a fault to user? */
}
return err;
}
static int _write_fault(rt_varea_t varea, void *pa, struct rt_aspace_fault_msg *msg)
{
rt_aspace_t aspace = varea->aspace;
int err = MM_FAULT_FIXABLE_FALSE;
if (rt_varea_is_private_locked(varea))
{
if (VAREA_IS_WRITABLE(varea) && (
msg->fault_type == MM_FAULT_TYPE_ACCESS_FAULT ||
msg->fault_type == MM_FAULT_TYPE_PAGE_FAULT))
{
RDWR_LOCK(aspace);
err = rt_varea_fix_private_locked(varea, pa, msg, RT_FALSE);
RDWR_UNLOCK(aspace);
if (err == MM_FAULT_FIXABLE_FALSE)
LOG_I("%s: fix private failure", __func__);
}
else
{
LOG_I("%s: No permission on %s(attr=0x%lx)", __func__, VAREA_NAME(varea), varea->attr);
}
}
else if (msg->fault_type == MM_FAULT_TYPE_PAGE_FAULT)
{
RT_ASSERT(pa == ARCH_MAP_FAILED);
RT_ASSERT(!(varea->flag & MMF_PREFETCH));
err = _fetch_page(varea, msg);
if (err == MM_FAULT_FIXABLE_FALSE)
LOG_I("%s: page fault failure", __func__);
}
else
{
LOG_D("%s: can not fix", __func__);
/* signal a fault to user? */
}
return err;
}
static int _exec_fault(rt_varea_t varea, void *pa, struct rt_aspace_fault_msg *msg)
{
int err = MM_FAULT_FIXABLE_FALSE;
if (msg->fault_type == MM_FAULT_TYPE_PAGE_FAULT)
{
RT_ASSERT(pa == ARCH_MAP_FAILED);
RT_ASSERT(!(varea->flag & MMF_PREFETCH));
err = _fetch_page(varea, msg);
}
return err;
}
int rt_aspace_fault_try_fix(rt_aspace_t aspace, struct rt_aspace_fault_msg *msg)
{
int err = MM_FAULT_FIXABLE_FALSE;
uintptr_t va = (uintptr_t)msg->fault_vaddr;
va &= ~ARCH_PAGE_MASK;
msg->fault_vaddr = (void *)va;
rt_mm_fault_res_init(&msg->response);
RT_DEBUG_SCHEDULER_AVAILABLE(1);
if (aspace)
{
rt_varea_t varea;
RD_LOCK(aspace);
varea = _aspace_bst_search(aspace, msg->fault_vaddr);
if (varea)
{
void *pa = rt_hw_mmu_v2p(aspace, msg->fault_vaddr);
if (pa != ARCH_MAP_FAILED && msg->fault_type == MM_FAULT_TYPE_PAGE_FAULT)
{
LOG_D("%s(fault=%p) has already fixed", __func__, msg->fault_vaddr);
err = MM_FAULT_FIXABLE_TRUE;
}
else
{
LOG_D("%s(varea=%s,fault=%p,fault_op=%d,phy=%p)", __func__, VAREA_NAME(varea), msg->fault_vaddr, msg->fault_op, pa);
msg->off = varea->offset + ((long)msg->fault_vaddr - (long)varea->start) / ARCH_PAGE_SIZE;
/* permission checked by fault op */
switch (msg->fault_op)
{
case MM_FAULT_OP_READ:
err = _read_fault(varea, pa, msg);
break;
case MM_FAULT_OP_WRITE:
err = _write_fault(varea, pa, msg);
break;
case MM_FAULT_OP_EXECUTE:
err = _exec_fault(varea, pa, msg);
break;
}
}
}
else
{
LOG_I("%s: varea not found at 0x%lx", __func__, msg->fault_vaddr);
}
RD_UNLOCK(aspace);
}
return err;
}
#endif /* RT_USING_SMART */
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