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rt-thread-official/libcpu/risc-v/t-head/c906/mmu.c

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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-01-30 lizhirui first version
* 2022-12-13 WangXiaoyao Port to new mm
* 2023-10-12 Shell Add permission control API
*/
#include <rtthread.h>
#include <stddef.h>
#include <stdint.h>
#define DBG_TAG "hw.mmu"
#define DBG_LVL DBG_WARNING
#include <rtdbg.h>
#include <cache.h>
#include <mm_aspace.h>
#include <mm_page.h>
#include <mmu.h>
#include <riscv_mmu.h>
#include <tlb.h>
#ifdef RT_USING_SMART
#include <board.h>
#include <ioremap.h>
#include <lwp_user_mm.h>
#endif
#ifndef RT_USING_SMART
#define USER_VADDR_START 0
#endif
static size_t _unmap_area(struct rt_aspace *aspace, void *v_addr, size_t size);
static void *current_mmu_table = RT_NULL;
volatile __attribute__((aligned(4 * 1024)))
rt_ubase_t MMUTable[__SIZE(VPN2_BIT)];
static rt_uint8_t ASID_BITS = 0;
static rt_uint32_t next_asid;
static rt_uint64_t global_asid_generation;
#define ASID_MASK ((1 << ASID_BITS) - 1)
#define ASID_FIRST_GENERATION (1 << ASID_BITS)
#define MAX_ASID ASID_FIRST_GENERATION
static void _asid_init()
{
unsigned int satp_reg = read_csr(satp);
satp_reg |= (((rt_uint64_t)0xffff) << PPN_BITS);
write_csr(satp, satp_reg);
unsigned short valid_asid_bit = ((read_csr(satp) >> PPN_BITS) & 0xffff);
// The maximal value of ASIDLEN, is 9 for Sv32 or 16 for Sv39, Sv48, and Sv57
for (unsigned i = 0; i < 16; i++)
{
if (!(valid_asid_bit & 0x1))
{
break;
}
valid_asid_bit >>= 1;
ASID_BITS++;
}
global_asid_generation = ASID_FIRST_GENERATION;
next_asid = 1;
}
static rt_uint64_t _asid_check_switch(rt_aspace_t aspace)
{
if ((aspace->asid ^ global_asid_generation) >> ASID_BITS) // not same generation
{
if (next_asid != MAX_ASID)
{
aspace->asid = global_asid_generation | next_asid;
next_asid++;
}
else
{
// scroll to next generation
global_asid_generation += ASID_FIRST_GENERATION;
next_asid = 1;
rt_hw_tlb_invalidate_all_local();
aspace->asid = global_asid_generation | next_asid;
next_asid++;
}
}
return aspace->asid & ASID_MASK;
}
void rt_hw_aspace_switch(rt_aspace_t aspace)
{
uintptr_t page_table = (uintptr_t)rt_kmem_v2p(aspace->page_table);
current_mmu_table = aspace->page_table;
rt_uint64_t asid = _asid_check_switch(aspace);
write_csr(satp, (((size_t)SATP_MODE) << SATP_MODE_OFFSET) |
(asid << PPN_BITS) |
((rt_ubase_t)page_table >> PAGE_OFFSET_BIT));
asm volatile("sfence.vma x0,%0"::"r"(asid):"memory");
}
void *rt_hw_mmu_tbl_get()
{
return current_mmu_table;
}
static int _map_one_page(struct rt_aspace *aspace, void *va, void *pa,
size_t attr)
{
rt_size_t l1_off, l2_off, l3_off;
rt_size_t *mmu_l1, *mmu_l2, *mmu_l3;
l1_off = GET_L1((size_t)va);
l2_off = GET_L2((size_t)va);
l3_off = GET_L3((size_t)va);
mmu_l1 = ((rt_size_t *)aspace->page_table) + l1_off;
if (PTE_USED(*mmu_l1))
{
mmu_l2 = (rt_size_t *)PPN_TO_VPN(GET_PADDR(*mmu_l1), PV_OFFSET);
}
else
{
mmu_l2 = (rt_size_t *)rt_pages_alloc(0);
if (mmu_l2)
{
rt_memset(mmu_l2, 0, PAGE_SIZE);
rt_hw_cpu_dcache_clean(mmu_l2, PAGE_SIZE);
*mmu_l1 = COMBINEPTE((rt_size_t)VPN_TO_PPN(mmu_l2, PV_OFFSET),
PAGE_DEFAULT_ATTR_NEXT);
rt_hw_cpu_dcache_clean(mmu_l1, sizeof(*mmu_l1));
}
else
{
return -1;
}
}
if (PTE_USED(*(mmu_l2 + l2_off)))
{
RT_ASSERT(!PAGE_IS_LEAF(*(mmu_l2 + l2_off)));
mmu_l3 =
(rt_size_t *)PPN_TO_VPN(GET_PADDR(*(mmu_l2 + l2_off)), PV_OFFSET);
}
else
{
mmu_l3 = (rt_size_t *)rt_pages_alloc(0);
if (mmu_l3)
{
rt_memset(mmu_l3, 0, PAGE_SIZE);
rt_hw_cpu_dcache_clean(mmu_l3, PAGE_SIZE);
*(mmu_l2 + l2_off) =
COMBINEPTE((rt_size_t)VPN_TO_PPN(mmu_l3, PV_OFFSET),
PAGE_DEFAULT_ATTR_NEXT);
rt_hw_cpu_dcache_clean(mmu_l2, sizeof(*mmu_l2));
// declares a reference to parent page table
rt_page_ref_inc((void *)mmu_l2, 0);
}
else
{
return -1;
}
}
RT_ASSERT(!PTE_USED(*(mmu_l3 + l3_off)));
// declares a reference to parent page table
rt_page_ref_inc((void *)mmu_l3, 0);
*(mmu_l3 + l3_off) = COMBINEPTE((rt_size_t)pa, attr);
rt_hw_cpu_dcache_clean(mmu_l3 + l3_off, sizeof(*(mmu_l3 + l3_off)));
return 0;
}
/** rt_hw_mmu_map will never override existed page table entry */
void *rt_hw_mmu_map(struct rt_aspace *aspace, void *v_addr, void *p_addr,
size_t size, size_t attr)
{
int ret = -1;
void *unmap_va = v_addr;
size_t npages = size >> ARCH_PAGE_SHIFT;
// TODO trying with HUGEPAGE here
while (npages--)
{
MM_PGTBL_LOCK(aspace);
ret = _map_one_page(aspace, v_addr, p_addr, attr);
MM_PGTBL_UNLOCK(aspace);
if (ret != 0)
{
/* error, undo map */
while (unmap_va != v_addr)
{
MM_PGTBL_LOCK(aspace);
_unmap_area(aspace, unmap_va, ARCH_PAGE_SIZE);
MM_PGTBL_UNLOCK(aspace);
unmap_va += ARCH_PAGE_SIZE;
}
break;
}
v_addr += ARCH_PAGE_SIZE;
p_addr += ARCH_PAGE_SIZE;
}
if (ret == 0)
{
return unmap_va;
}
return NULL;
}
static void _unmap_pte(rt_size_t *pentry, rt_size_t *lvl_entry[], int level)
{
int loop_flag = 1;
while (loop_flag)
{
loop_flag = 0;
*pentry = 0;
rt_hw_cpu_dcache_clean(pentry, sizeof(*pentry));
// we don't handle level 0, which is maintained by caller
if (level > 0)
{
void *page = (void *)((rt_ubase_t)pentry & ~ARCH_PAGE_MASK);
// decrease reference from child page to parent
rt_pages_free(page, 0);
int free = rt_page_ref_get(page, 0);
if (free == 1)
{
rt_pages_free(page, 0);
pentry = lvl_entry[--level];
loop_flag = 1;
}
}
}
}
static size_t _unmap_area(struct rt_aspace *aspace, void *v_addr, size_t size)
{
rt_size_t loop_va = __UMASKVALUE((rt_size_t)v_addr, PAGE_OFFSET_MASK);
size_t unmapped = 0;
int i = 0;
rt_size_t lvl_off[3];
rt_size_t *lvl_entry[3];
lvl_off[0] = (rt_size_t)GET_L1(loop_va);
lvl_off[1] = (rt_size_t)GET_L2(loop_va);
lvl_off[2] = (rt_size_t)GET_L3(loop_va);
unmapped = 1 << (ARCH_PAGE_SHIFT + ARCH_INDEX_WIDTH * 2ul);
rt_size_t *pentry;
lvl_entry[i] = ((rt_size_t *)aspace->page_table + lvl_off[i]);
pentry = lvl_entry[i];
// find leaf page table entry
while (PTE_USED(*pentry) && !PAGE_IS_LEAF(*pentry))
{
i += 1;
lvl_entry[i] = ((rt_size_t *)PPN_TO_VPN(GET_PADDR(*pentry), PV_OFFSET) +
lvl_off[i]);
pentry = lvl_entry[i];
unmapped >>= ARCH_INDEX_WIDTH;
}
// clear PTE & setup its
if (PTE_USED(*pentry))
{
_unmap_pte(pentry, lvl_entry, i);
}
return unmapped;
}
/** unmap is different from map that it can handle multiple pages */
void rt_hw_mmu_unmap(struct rt_aspace *aspace, void *v_addr, size_t size)
{
// caller guarantee that v_addr & size are page aligned
if (!aspace->page_table)
{
return;
}
size_t unmapped = 0;
while (size > 0)
{
MM_PGTBL_LOCK(aspace);
unmapped = _unmap_area(aspace, v_addr, size);
MM_PGTBL_UNLOCK(aspace);
// when unmapped == 0, region not exist in pgtbl
if (!unmapped || unmapped > size)
break;
size -= unmapped;
v_addr += unmapped;
}
}
#ifdef RT_USING_SMART
static inline void _init_region(void *vaddr, size_t size)
{
rt_ioremap_start = vaddr;
rt_ioremap_size = size;
rt_mpr_start = rt_ioremap_start - rt_mpr_size;
LOG_D("rt_ioremap_start: %p, rt_mpr_start: %p", rt_ioremap_start, rt_mpr_start);
}
#else
static inline void _init_region(void *vaddr, size_t size)
{
rt_mpr_start = vaddr - rt_mpr_size;
}
#endif
int rt_hw_mmu_map_init(rt_aspace_t aspace, void *v_address, rt_size_t size,
rt_size_t *vtable, rt_size_t pv_off)
{
size_t l1_off, va_s, va_e;
rt_base_t level;
if ((!aspace) || (!vtable))
{
return -1;
}
va_s = (rt_size_t)v_address;
va_e = ((rt_size_t)v_address) + size - 1;
if (va_e < va_s)
{
return -1;
}
// convert address to PPN2 index
va_s = GET_L1(va_s);
va_e = GET_L1(va_e);
if (va_s == 0)
{
return -1;
}
// vtable initialization check
for (l1_off = va_s; l1_off <= va_e; l1_off++)
{
size_t v = vtable[l1_off];
if (v)
{
return -1;
}
}
rt_aspace_init(&rt_kernel_space, (void *)0x1000, USER_VADDR_START - 0x1000,
vtable);
_init_region(v_address, size);
return 0;
}
const static int max_level =
(ARCH_VADDR_WIDTH - ARCH_PAGE_SHIFT) / ARCH_INDEX_WIDTH;
static inline uintptr_t _get_level_size(int level)
{
return 1ul << (ARCH_PAGE_SHIFT + (max_level - level) * ARCH_INDEX_WIDTH);
}
static rt_size_t *_query(struct rt_aspace *aspace, void *vaddr, int *level)
{
rt_size_t l1_off, l2_off, l3_off;
rt_size_t *mmu_l1, *mmu_l2, *mmu_l3;
rt_size_t pa;
l1_off = GET_L1((rt_size_t)vaddr);
l2_off = GET_L2((rt_size_t)vaddr);
l3_off = GET_L3((rt_size_t)vaddr);
if (!aspace)
{
LOG_W("%s: no aspace", __func__);
return RT_NULL;
}
mmu_l1 = ((rt_size_t *)aspace->page_table) + l1_off;
if (PTE_USED(*mmu_l1))
{
if (*mmu_l1 & PTE_XWR_MASK)
{
*level = 1;
return mmu_l1;
}
mmu_l2 = (rt_size_t *)PPN_TO_VPN(GET_PADDR(*mmu_l1), PV_OFFSET);
if (PTE_USED(*(mmu_l2 + l2_off)))
{
if (*(mmu_l2 + l2_off) & PTE_XWR_MASK)
{
*level = 2;
return mmu_l2 + l2_off;
}
mmu_l3 = (rt_size_t *)PPN_TO_VPN(GET_PADDR(*(mmu_l2 + l2_off)),
PV_OFFSET);
if (PTE_USED(*(mmu_l3 + l3_off)))
{
*level = 3;
return mmu_l3 + l3_off;
}
}
}
return RT_NULL;
}
void *rt_hw_mmu_v2p(struct rt_aspace *aspace, void *vaddr)
{
int level;
uintptr_t *pte = _query(aspace, vaddr, &level);
uintptr_t paddr;
if (pte)
{
paddr = GET_PADDR(*pte);
paddr |= ((intptr_t)vaddr & (_get_level_size(level) - 1));
}
else
{
LOG_I("%s: failed at %p", __func__, vaddr);
paddr = (uintptr_t)ARCH_MAP_FAILED;
}
return (void *)paddr;
}
static int _noncache(uintptr_t *pte)
{
return 0;
}
static int _cache(uintptr_t *pte)
{
return 0;
}
static int (*control_handler[MMU_CNTL_DUMMY_END])(uintptr_t *pte) = {
[MMU_CNTL_CACHE] = _cache,
[MMU_CNTL_NONCACHE] = _noncache,
};
int rt_hw_mmu_control(struct rt_aspace *aspace, void *vaddr, size_t size,
enum rt_mmu_cntl cmd)
{
int level;
int err = -RT_EINVAL;
void *vend = vaddr + size;
int (*handler)(uintptr_t * pte);
if (cmd >= 0 && cmd < MMU_CNTL_DUMMY_END)
{
handler = control_handler[cmd];
while (vaddr < vend)
{
uintptr_t *pte = _query(aspace, vaddr, &level);
void *range_end = vaddr + _get_level_size(level);
RT_ASSERT(range_end <= vend);
if (pte)
{
err = handler(pte);
RT_ASSERT(err == RT_EOK);
}
vaddr = range_end;
}
}
else
{
err = -RT_ENOSYS;
}
return err;
}
/**
* @brief setup Page Table for kernel space. It's a fixed map
* and all mappings cannot be changed after initialization.
*
* Memory region in struct mem_desc must be page aligned,
* otherwise is a failure and no report will be
* returned.
*
* @param aspace
* @param mdesc
* @param desc_nr
*/
void rt_hw_mmu_setup(rt_aspace_t aspace, struct mem_desc *mdesc, int desc_nr)
{
void *err;
for (size_t i = 0; i < desc_nr; i++)
{
size_t attr;
switch (mdesc->attr)
{
case NORMAL_MEM:
attr = MMU_MAP_K_RWCB;
break;
case NORMAL_NOCACHE_MEM:
attr = MMU_MAP_K_RWCB;
break;
case DEVICE_MEM:
attr = MMU_MAP_K_DEVICE;
break;
default:
attr = MMU_MAP_K_DEVICE;
}
struct rt_mm_va_hint hint = {.flags = MMF_MAP_FIXED,
.limit_start = aspace->start,
.limit_range_size = aspace->size,
.map_size = mdesc->vaddr_end -
mdesc->vaddr_start + 1,
.prefer = (void *)mdesc->vaddr_start};
if (mdesc->paddr_start == (rt_size_t)ARCH_MAP_FAILED)
mdesc->paddr_start = mdesc->vaddr_start + PV_OFFSET;
rt_aspace_map_phy_static(aspace, &mdesc->varea, &hint, attr,
mdesc->paddr_start >> MM_PAGE_SHIFT, &err);
mdesc++;
}
_asid_init();
rt_hw_aspace_switch(&rt_kernel_space);
rt_page_cleanup();
}
void rt_hw_mmu_kernel_map_init(rt_aspace_t aspace, rt_size_t vaddr_start, rt_size_t size)
{
rt_size_t paddr_start =
__UMASKVALUE(VPN_TO_PPN(vaddr_start, PV_OFFSET), PAGE_OFFSET_MASK);
rt_size_t va_s = GET_L1(vaddr_start);
rt_size_t va_e = GET_L1(vaddr_start + size - 1);
rt_size_t i;
for (i = va_s; i <= va_e; i++)
{
MMUTable[i] =
COMBINEPTE(paddr_start, PAGE_ATTR_RWX | PTE_G | PTE_V | PTE_CACHE |
PTE_SHARE | PTE_BUF | PTE_A | PTE_D);
paddr_start += L1_PAGE_SIZE;
}
rt_hw_tlb_invalidate_all_local();
}
void *rt_hw_mmu_pgtbl_create(void)
{
size_t *mmu_table;
mmu_table = (rt_ubase_t *)rt_pages_alloc_ext(0, PAGE_ANY_AVAILABLE);
if (!mmu_table)
{
return RT_NULL;
}
rt_memcpy(mmu_table, rt_kernel_space.page_table, ARCH_PAGE_SIZE);
rt_hw_cpu_dcache_ops(RT_HW_CACHE_FLUSH, mmu_table, ARCH_PAGE_SIZE);
return mmu_table;
}
void rt_hw_mmu_pgtbl_delete(void *pgtbl)
{
rt_pages_free(pgtbl, 0);
}
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