diff options
Diffstat (limited to 'src/kernel/mm')
| -rw-r--r-- | src/kernel/mm/vm.cc | 299 |
1 files changed, 260 insertions, 39 deletions
diff --git a/src/kernel/mm/vm.cc b/src/kernel/mm/vm.cc index 8a7068e..a38ee84 100644 --- a/src/kernel/mm/vm.cc +++ b/src/kernel/mm/vm.cc @@ -1,26 +1,62 @@ #include "kernel/mm.h" #include "kernel/pmm.h" +#include "kernel/riscv.h" #include "drivers/uart.h" #include "common/types.h" #include "kernel/config.h" -extern "C" char text_start[]; -extern "C" char text_end[]; -extern "C" char rodata_start[]; -extern "C" char rodata_end[]; -extern "C" char data_start[]; -extern "C" char kernel_end[]; +void *memset(void *dst, int c, uint n) +{ + char *cdst = (char *)dst; + for (uint i = 0; i < n; i++) + cdst[i] = c; + return dst; +} -namespace VM +void *memmove(void *dst, const void *src, uint n) { - pagetable_t kernel_pagetable; + const char *s = (const char *)src; + char *d = (char *)dst; + if (s < d && s + n > d) + { + s += n; + d += n; + while (n-- > 0) + *--d = *--s; + } + else + { + while (n-- > 0) + *d++ = *s++; + } + return dst; +} + +extern char text_start[]; +extern char text_end[]; +extern char rodata_start[]; +extern char rodata_end[]; +extern char data_start[]; +extern char data_end[]; +extern char bss_start[]; +extern char bss_end[]; +extern char kernel_end[]; - #define PX(level, va) ((((uint64)va) >> (12 + 9 * (level))) & 0x1FF) - #define PA2PTE(pa) ((((uint64)pa) >> 12) << 10) - #define PTE2PA(pte) (((pte) >> 10) << 12) +extern char uservec[]; +extern char userret[]; +extern char trampoline[]; + +VM::pagetable_t kernel_pagetable; + +namespace VM +{ + // pagetable_t kernel_pagetable; pte_t *walk(pagetable_t pagetable, uint64 va, int alloc) { + if (va >= MAXVA) + return 0; + for (int level = 2; level > 0; level--) { pte_t *pte = &pagetable[PX(level, va)]; @@ -31,13 +67,10 @@ namespace VM } else { - if (!alloc) + if (!alloc || (pagetable = (pagetable_t)PMM::alloc_page()) == 0) return 0; - + memset(pagetable, 0, PGSIZE); pagetable = (pagetable_t)PMM::alloc_page(); - if (!pagetable) - return 0; - *pte = PA2PTE(pagetable) | PTE_V; } } @@ -49,8 +82,8 @@ namespace VM uint64 a, last; pte_t *pte; - a = (va / PGSIZE) * PGSIZE; - last = ((va + size - 1) / PGSIZE) * PGSIZE; + a = PGROUNDDOWN(va); + last = PGROUNDDOWN(va + size - 1); for(;;) { @@ -59,7 +92,9 @@ namespace VM if (*pte & PTE_V) { - Drivers::uart_puts("Remap error\n"); + Drivers::uart_puts("Remap panic: "); + Drivers::print_hex(a); + Drivers::uart_puts("\n"); return -1; } @@ -73,42 +108,228 @@ namespace VM return 0; } + void kvmmap(uint64 va, uint64 pa, uint64 sz, int perm) + { + if (mappages(kernel_pagetable, va, sz, pa, perm) != 0) + { + Drivers::uart_puts("kvmmap: failed to map\n"); + } + } + void kvminit() { kernel_pagetable = (pagetable_t)PMM::alloc_page(); + memset(kernel_pagetable, 0, PGSIZE); + + kvmmap(g_uart_base, g_uart_base, PGSIZE, PTE_R | PTE_W); + + kvmmap(g_plic_base, g_plic_base, 0x400000, PTE_R | PTE_W); + + // kvmmap(g_clint_base, g_clint_base, 0x10000, PTE_R | PTE_W); + + kvmmap((uint64)text_start, (uint64)text_start, + (uint64)text_end - (uint64)text_start, PTE_R | PTE_X); + + kvmmap((uint64)rodata_start, (uint64)rodata_start, + (uint64)rodata_end - (uint64)rodata_start, PTE_R); + + kvmmap((uint64)data_start, (uint64)data_start, + (uint64)kernel_end - (uint64)data_start, PTE_R | PTE_W); - if (g_uart_base != 0) + kvmmap((uint64)kernel_end, (uint64)kernel_end, + (uint64)PHYSTOP - (uint64)kernel_end, PTE_R | PTE_W); + + kvmmap(TRAMPOLINE, (uint64)trampoline, PGSIZE, PTE_R | PTE_X); + } + void kvminithart() + { + w_satp(MAKE_SATP(kernel_pagetable)); + sfence_vma(); + } + + + pagetable_t uvmcreate() + { + pagetable_t pagetable = (pagetable_t)PMM::alloc_page(); + if (pagetable == 0) + return 0; + memset(pagetable, 0, PGSIZE); + + if (mappages(pagetable, TRAMPOLINE, PGSIZE, (uint64)trampoline, PTE_R | PTE_X) < 0) { - mappages(kernel_pagetable, g_uart_base, PGSIZE, g_uart_base, PTE_R | PTE_W); + return 0; } - // if (g_clint_base != 0) - // { - // mappages(kernel_pagetable, g_clint_base, 0x10000, g_clint_base, PTE_R | PTE_W); - // } + return pagetable; + } + + void uvminit(pagetable_t pagetable, uchar *src, uint sz) + { + char *mem; - if (g_plic_base != 0) + if (sz >= PGSIZE) { - mappages(kernel_pagetable, g_plic_base, 0x400000, g_plic_base, PTE_R | PTE_W); + Drivers::uart_puts("uvminit: initcode too big\n"); + return; } - mappages(kernel_pagetable, (uint64)text_start, (uint64)text_end - (uint64)text_start, - (uint64)text_start, PTE_R | PTE_X); + mem = (char*)PMM::alloc_page(); + memset(mem, 0, PGSIZE); - mappages(kernel_pagetable, (uint64)data_start, PHYSTOP - (uint64)data_start, - (uint64)data_start, PTE_R | PTE_W); + mappages(pagetable, 0, PGSIZE, (uint64)mem, PTE_W|PTE_R|PTE_X|PTE_U); - mappages(kernel_pagetable, (uint64)rodata_start, (uint64)rodata_end - (uint64)rodata_start, - (uint64)rodata_start, PTE_R); - + memmove(mem, src, sz); + + uint64 trap_pa = (uint64)uservec; + uint64 trap_page_start = PGROUNDDOWN(trap_pa); + + mappages(pagetable, trap_page_start, PGSIZE, trap_page_start, PTE_R | PTE_X); + + mappages(pagetable, trap_page_start + PGSIZE, PGSIZE, trap_page_start + PGSIZE, PTE_R | PTE_X); } - void kvminithart() + + void uvmunmap(pagetable_t pagetable, uint64 va, uint64 npages, int do_free) + { + uint64 a; + pte_t *pte; + + if ((va % PGSIZE) != 0) + { + Drivers::uart_puts("uvmunmap: not aligned\n"); + return; + } + + for(a = va; a < va + npages * PGSIZE; a += PGSIZE) + { + if ((pte = walk(pagetable, a, 0)) == 0) + continue; + + if((*pte & PTE_V) == 0) + continue; + + if (PTE_FLAGS(*pte) == PTE_V) + { + Drivers::uart_puts("uvmunmap: not a leaf\n"); + } + + if (do_free) + { + uint64 pa = PTE2PA(*pte); + PMM::free_page((void *)pa); + } + *pte = 0; + } + } + + void uvmfree(pagetable_t pagetable, uint64 sz) + { + if(sz > 0) + uvmunmap(pagetable, 0, PGROUNDDOWN(sz)/PGSIZE, 1); + + PMM::free_page((void *)pagetable); + } + + int uvmcopy(pagetable_t oldpt, pagetable_t newpt, uint64 sz) + { + pte_t *pte; + uint64 pa, i; + uint flags; + char *mem; + + for(i = 0; i < sz; i += PGSIZE) + { + if((pte = walk(oldpt, i, 0)) == 0) + continue; + if ((*pte & PTE_V) == 0) + continue; + + pa = PTE2PA(*pte); + flags = PTE_FLAGS(*pte); + + if ((mem = (char *)PMM::alloc_page()) == 0) + goto err; + + memmove(mem, (char *)pa, PGSIZE); + + if (mappages(newpt, i, PGSIZE, (uint64)mem, flags) != 0) + { + PMM::free_page(mem); + goto err; + } + } + return 0; + err: + uvmunmap(newpt, 0, i / PGSIZE, 1); + return -1; + } + + uint64 uvmalloc(pagetable_t pagetable, uint64 oldsz, uint64 newsz) { - asm volatile("sfence.vma zero, zero"); + char *mem; + uint64 a; - uint64 satp_val = MAKE_SATP(kernel_pagetable); - asm volatile("csrw satp, %0" : : "r"(satp_val)); + if (newsz < oldsz) + return oldsz; - asm volatile("sfence.vma zero, zero"); + oldsz = PGROUNDUP(oldsz); + for (a = oldsz; a < newsz; a += PGSIZE) + { + mem = (char *)PMM::alloc_page(); + if (mem == 0) + { + uvmdealloc(pagetable, a, oldsz); + return 0; + } + memset(mem, 0, PGSIZE); + if (mappages(pagetable, a, PGSIZE, (uint64)mem, PTE_W | PTE_X | PTE_R | PTE_U) != 0) + { + PMM::free_page(mem); + uvmdealloc(pagetable, a, oldsz); + return 0; + } + } + return newsz; + } + + uint64 uvmdealloc(pagetable_t pagetable, uint64 oldsz, uint64 newsz) + { + if (newsz >= oldsz) + return oldsz; + + if (PGROUNDUP(newsz) < PGROUNDUP(oldsz)) + { + int npages = (PGROUNDUP(oldsz) - PGROUNDUP(newsz)) / PGSIZE; + uvmunmap(pagetable, PGROUNDUP(newsz), npages, 1); + } + + return newsz; + } + + int copyin(pagetable_t pagetable, char *dst, uint64 srcva, uint64 len) + { + uint64 n, va0, pa0; + pte_t *pte; + + while (len > 0) + { + va0 = PGROUNDDOWN(srcva); + pte = walk(pagetable, va0, 0); + if(pte == 0 || (*pte & PTE_V) == 0 || (*pte & PTE_U) == 0) + { + return -1; + } + pa0 = PTE2PA(*pte); + n = PGSIZE - (srcva - va0); + if(n > len) + n = len; + + memmove(dst, (void*)(pa0 + (srcva - va0)), n); + + len -= n; + dst += n; + srcva = va0 + PGSIZE; + } + return 0; + } }
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