| /* |
| * Early initialization code for riscv virtual memory |
| * |
| * Copyright 2015 Google Inc. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as |
| * published by the Free Software Foundation; version 2 of |
| * the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <arch/barrier.h> |
| #include <arch/encoding.h> |
| #include <arch/sbi.h> |
| #include <atomic.h> |
| #include <console/console.h> |
| #include <stdint.h> |
| #include <vm.h> |
| #include <symbols.h> |
| |
| pte_t* root_page_table; |
| |
| /* Indent the following text by 2*level spaces */ |
| static void indent(int level) |
| { |
| int i; |
| for (i = 0; i < level; i++) |
| printk(BIOS_DEBUG, " "); |
| } |
| |
| /* |
| * Convert a page table index at a given page table level to a virtual address |
| * offset |
| */ |
| static uintptr_t index_to_virt_addr(int index, int level) |
| { |
| /* |
| * Index is at most RISCV_PGLEVEL_BITS bits wide (not considering the |
| * leading zeroes. If level==0, the below expression thus shifts index |
| * into the highest bits of a 64-bit number, and then shifts it down |
| * with sign extension. |
| * |
| * If level>0, then the expression should work as expected, without any |
| * magic. |
| */ |
| return ((intptr_t)index) |
| << (64 - RISCV_PGLEVEL_BITS - level * RISCV_PGLEVEL_BITS) |
| >> (64 - VA_BITS); |
| } |
| |
| /* Dump the page table structures to the console -- helper function */ |
| static void print_page_table_at(pte_t *pt, intptr_t virt_addr, int level) |
| { |
| int i; |
| |
| indent(level); |
| printk(BIOS_DEBUG, "Level %d page table at 0x%p\n", level, pt); |
| |
| for (i = 0; i < RISCV_PGSIZE / sizeof(pte_t); i++) { |
| char urwx[8]; |
| uintptr_t pointer; |
| intptr_t next_virt_addr; |
| |
| if (!(pt[i] & PTE_V)) |
| continue; |
| |
| urwx[0] = (pt[i] & PTE_U)? 'u' : '-'; |
| urwx[1] = (pt[i] & PTE_R)? 'r' : '-'; |
| urwx[2] = (pt[i] & PTE_W)? 'w' : '-'; |
| urwx[3] = (pt[i] & PTE_X)? 'x' : '-'; |
| urwx[4] = '\0'; |
| |
| next_virt_addr = virt_addr + index_to_virt_addr(i, level); |
| |
| pointer = ((uintptr_t)pt[i] >> 10) << RISCV_PGSHIFT; |
| |
| indent(level + 1); |
| printk(BIOS_DEBUG, "Valid PTE at index %d (0x%016zx -> 0x%zx), ", |
| i, (size_t) next_virt_addr, (size_t) pointer); |
| if (PTE_TABLE(pt[i])) |
| printk(BIOS_DEBUG, "page table\n"); |
| else |
| printk(BIOS_DEBUG, "protections %s\n", urwx); |
| |
| if (PTE_TABLE(pt[i])) { |
| print_page_table_at((pte_t *)pointer, next_virt_addr, level + 1); |
| } |
| } |
| } |
| |
| /* Print the page table structures to the console */ |
| void print_page_table(void) { |
| print_page_table_at((void *)(read_csr(sptbr) << RISCV_PGSHIFT), 0, 0); |
| } |
| |
| void flush_tlb(void) |
| { |
| asm volatile("sfence.vm"); |
| } |
| |
| size_t pte_ppn(pte_t pte) |
| { |
| return pte >> PTE_PPN_SHIFT; |
| } |
| |
| pte_t ptd_create(uintptr_t ppn) |
| { |
| return (ppn << PTE_PPN_SHIFT) | PTE_V; |
| } |
| |
| pte_t pte_create(uintptr_t ppn, int prot, int user) |
| { |
| pte_t pte = (ppn << PTE_PPN_SHIFT) | PTE_R | PTE_V; |
| if (prot & PTE_W) |
| pte |= PTE_W; |
| if (prot & PTE_X) |
| pte |= PTE_X; |
| if (user) |
| pte |= PTE_U; |
| return pte; |
| } |
| |
| void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, pte_t *sbi_pt) |
| { |
| memset(sbi_pt, 0, RISCV_PGSIZE); |
| // need to leave room for sbi page |
| uintptr_t memorySize = 0x7F000000; // 0xFFF... - 0xFFFFFFFF81000000 - RISCV_PGSIZE |
| |
| // middle page table |
| pte_t* middle_pt = (void*)sbi_pt + RISCV_PGSIZE; |
| size_t num_middle_pts = 2; // 3 level page table, 39 bit virtual address space for now |
| |
| // root page table |
| pte_t* root_pt = (void*)middle_pt + num_middle_pts * RISCV_PGSIZE; |
| memset(middle_pt, 0, (num_middle_pts + 1) * RISCV_PGSIZE); // 0's out middle_pt and root_pt |
| for (size_t i = 0; i < num_middle_pts; i++) |
| root_pt[(1<<RISCV_PGLEVEL_BITS)-num_middle_pts+i] = ptd_create(((uintptr_t)middle_pt >> RISCV_PGSHIFT) + i); |
| |
| // fill the middle page table |
| for (uintptr_t vaddr = virtMemStart, paddr = physMemStart; |
| paddr < physMemStart + memorySize; |
| vaddr += SUPERPAGE_SIZE, paddr += SUPERPAGE_SIZE) { |
| int l2_shift = RISCV_PGLEVEL_BITS + RISCV_PGSHIFT; |
| size_t l2_idx = (virtMemStart >> l2_shift) & ((1 << RISCV_PGLEVEL_BITS)-1); |
| l2_idx += ((vaddr - virtMemStart) >> l2_shift); |
| middle_pt[l2_idx] = pte_create(paddr >> RISCV_PGSHIFT, |
| PTE_U|PTE_R|PTE_W|PTE_X, 0); |
| } |
| |
| // map SBI at top of vaddr space |
| // only need to map a single page for sbi interface |
| uintptr_t num_sbi_pages = 1; |
| uintptr_t sbiStartAddress = (uintptr_t) &sbi_page; |
| uintptr_t sbiAddr = sbiStartAddress; |
| for (uintptr_t i = 0; i < num_sbi_pages; i++) { |
| uintptr_t idx = (1 << RISCV_PGLEVEL_BITS) - num_sbi_pages + i; |
| sbi_pt[idx] = pte_create(sbiAddr >> RISCV_PGSHIFT, |
| PTE_R|PTE_X, 0); |
| sbiAddr += RISCV_PGSIZE; |
| } |
| pte_t* sbi_pte = middle_pt + ((num_middle_pts << RISCV_PGLEVEL_BITS)-1); |
| *sbi_pte = ptd_create((uintptr_t)sbi_pt >> RISCV_PGSHIFT); |
| |
| // IO space. |
| root_pt[0] = pte_create(0, PTE_W|PTE_R, 0); |
| root_pt[1] = pte_create(0x40000000>>RISCV_PGSHIFT, |
| PTE_W|PTE_R, 0); |
| |
| // Start of RAM |
| root_pt[2] = pte_create(0x80000000>>RISCV_PGSHIFT, |
| PTE_W|PTE_R, 0); |
| mb(); |
| root_page_table = root_pt; |
| uintptr_t ptbr = ((uintptr_t) root_pt) >> RISCV_PGSHIFT; |
| write_csr(sptbr, ptbr); |
| } |
| |
| void initVirtualMemory(void) { |
| uintptr_t ms; |
| |
| ms = read_csr(mstatus); |
| ms = INSERT_FIELD(ms, MSTATUS_VM, VM_CHOICE); |
| write_csr(mstatus, ms); |
| ms = read_csr(mstatus); |
| |
| if (EXTRACT_FIELD(ms, MSTATUS_VM) != VM_CHOICE) { |
| printk(BIOS_DEBUG, "We don't have virtual memory...\n"); |
| return; |
| } else { |
| printk(BIOS_DEBUG, "-----------------------------\n"); |
| printk(BIOS_DEBUG, "Virtual memory status enabled\n"); |
| printk(BIOS_DEBUG, "-----------------------------\n"); |
| } |
| |
| // TODO: Figure out how to grab this from cbfs |
| printk(BIOS_DEBUG, "Initializing virtual memory...\n"); |
| uintptr_t physicalStart = 0x81000000; |
| uintptr_t virtualStart = 0xffffffff81000000; |
| init_vm(virtualStart, physicalStart, (pte_t *)_pagetables); |
| mb(); |
| flush_tlb(); |
| |
| #if IS_ENABLED(CONFIG_DEBUG_PRINT_PAGE_TABLES) |
| printk(BIOS_DEBUG, "Finished initializing virtual memory, starting walk...\n"); |
| print_page_table(); |
| #else |
| printk(BIOS_DEBUG, "Finished initializing virtual memory\n"); |
| #endif |
| } |
| |
| void mstatus_init(void) |
| { |
| uintptr_t ms = 0; |
| ms = INSERT_FIELD(ms, MSTATUS_FS, 3); |
| ms = INSERT_FIELD(ms, MSTATUS_XS, 3); |
| write_csr(mstatus, ms); |
| |
| clear_csr(mip, MIP_MSIP); |
| set_csr(mie, MIP_MSIP); |
| |
| /* Configure which exception causes are delegated to supervisor mode */ |
| set_csr(medeleg, (1 << CAUSE_MISALIGNED_FETCH) |
| | (1 << CAUSE_FAULT_FETCH) |
| | (1 << CAUSE_ILLEGAL_INSTRUCTION) |
| | (1 << CAUSE_BREAKPOINT) |
| | (1 << CAUSE_FAULT_LOAD) |
| | (1 << CAUSE_FAULT_STORE) |
| | (1 << CAUSE_USER_ECALL) |
| ); |
| |
| |
| /* Enable all user/supervisor-mode counters */ |
| /* We'll turn these on once lowrisc gets their bitstream up to |
| * 1.9. Right now there's no agreement on the values for these |
| * architectural registers. |
| */ |
| //write_csr(mscounteren, 0b111); |
| //write_csr(mucounteren, 0b111); |
| } |