[coreboot-gerrit] Patch set updated for coreboot: riscv-virtual-memory: Add virtual memory setup
Thaminda Edirisooriya (thaminda@google.com)
gerrit at coreboot.org
Thu Aug 27 19:26:06 CEST 2015
Thaminda Edirisooriya (thaminda at google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/11369
-gerrit
commit 587dd02af82b3ce005086a23ee3891da3023a4eb
Author: Thaminda Edirisooriya <thaminda at google.com>
Date: Wed Aug 26 15:28:04 2015 -0700
riscv-virtual-memory: Add virtual memory setup
Execution in supervisor level code in RISCV requires early setup of
virtual memory. Add initialization calls in
src/arch/riscv/virtual_memory.c to implement the required page table
setup, and helper functions to use when jumping to the payload correctly
in riscv.
Change-Id: I46e080e0ee8dc13277d567dcd4bf0f61a4507b76
Signed-off-by: Thaminda Edirisooriya <thaminda at google.com>
---
src/arch/riscv/include/vm.h | 74 +++++++++++++++++++++
src/arch/riscv/virtual_memory.c | 142 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 216 insertions(+)
diff --git a/src/arch/riscv/include/vm.h b/src/arch/riscv/include/vm.h
new file mode 100644
index 0000000..f9ffc40
--- /dev/null
+++ b/src/arch/riscv/include/vm.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2013, The Regents of the University of California (Regents).
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Regents nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+ * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
+ * OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
+ * BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
+ * HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
+ * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#ifndef _VM_H
+#define _VM_H
+
+#include <string.h>
+#include <stdint.h>
+
+#define SUPERPAGE_SIZE ((uintptr_t)(RISCV_PGSIZE << RISCV_PGLEVEL_BITS))
+#define VM_CHOICE VM_SV39
+#define VA_BITS 39
+#define MEGAPAGE_SIZE (SUPERPAGE_SIZE << RISCV_PGLEVEL_BITS)
+
+#define PROT_READ 1
+#define PROT_WRITE 2
+#define PROT_EXEC 4
+
+#define MAP_PRIVATE 0x2
+#define MAP_FIXED 0x10
+#define MAP_ANONYMOUS 0x20
+#define MAP_POPULATE 0x8000
+#define MREMAP_FIXED 0x2
+
+#define EXTRACT_FIELD(val, which) (((val) & (which)) / ((which) & ~((which)-1)))
+#define INSERT_FIELD(val, which, fieldval) (((val) & ~(which)) | ((fieldval) * ((which) & ~((which)-1))))
+
+#define supervisor_paddr_valid(start, length) \
+ ((uintptr_t)(start) >= current.first_user_vaddr + current.bias \
+ && (uintptr_t)(start) + (length) < mem_size \
+ && (uintptr_t)(start) + (length) >= (uintptr_t)(start))
+
+typedef uintptr_t pte_t;
+extern pte_t* root_page_table;
+
+void enter_supervisor(void);
+void initVirtualMemory(void);
+
+size_t pte_ppn(pte_t pte);
+pte_t ptd_create(uintptr_t ppn);
+pte_t pte_create(uintptr_t ppn, int prot, int user);
+
+void walk_page_table(void);
+
+void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, uintptr_t pageTableStart);
+void mstatus_init(void); // need to setup mstatus so we know we have virtual memory
+
+void flush_tlb(void);
+
+#endif
diff --git a/src/arch/riscv/virtual_memory.c b/src/arch/riscv/virtual_memory.c
new file mode 100644
index 0000000..78405dd
--- /dev/null
+++ b/src/arch/riscv/virtual_memory.c
@@ -0,0 +1,142 @@
+/*
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <vm.h>
+#include <arch/encoding.h>
+#include <atomic.h>
+#include <stdint.h>
+#include <console/console.h>
+
+pte_t* root_page_table;
+
+void walk_page_table(void) {
+ // TODO: implement a full walk to make sure memory was set up
+ //const size_t pte_per_page = RISCV_PGSIZE/sizeof(void*);
+ pte_t* t = root_page_table;
+ printk(BIOS_DEBUG, "root_page_table: %p\n", t);
+}
+
+void enter_supervisor(void) {
+ // enter supervisor mode
+ asm volatile("la t0, 1f; csrw mepc, t0; eret; 1:" ::: "t0");
+}
+
+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_TYPE_TABLE;
+}
+
+pte_t pte_create(uintptr_t ppn, int prot, int user)
+{
+ pte_t pte = (ppn << PTE_PPN_SHIFT) | PTE_V;
+ if (prot & PROT_WRITE) pte |= PTE_TYPE_URW_SRW;
+ if (prot & PROT_EXEC) pte |= PTE_TYPE_URX_SRX;
+ if (!user) pte |= PTE_TYPE_SR;
+ return pte;
+}
+
+void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, uintptr_t pageTableStart) {
+ pte_t* sbi_pt = (pte_t*) pageTableStart;
+ 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 < 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, PROT_READ|PROT_WRITE|PROT_EXEC, 0);
+ }
+
+ // map SBI at top of vaddr space
+ uintptr_t num_sbi_pages = 1; // only need to map a single page for sbi interface
+ uintptr_t sbiStartAddress = 0x2000; // the start of the sbi mapping
+ 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, PROT_READ|PROT_EXEC, 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);
+
+ mb();
+ root_page_table = root_pt;
+ write_csr(sptbr, root_pt);
+}
+
+void initVirtualMemory(void) {
+ printk(BIOS_DEBUG, "Initializing virtual memory...\n");
+ uintptr_t physicalStart = 0x1000000; // TODO: Figure out how to grab this from cbfs
+ uintptr_t virtualStart = 0xffffffff81000000;
+ uintptr_t pageTableStart = 0x1f0000;
+ init_vm(virtualStart, physicalStart, pageTableStart);
+ mb();
+ printk(BIOS_DEBUG, "Finished initializing virtual memory, starting walk...\n");
+ walk_page_table();
+}
+
+void mstatus_init(void)
+{
+ // supervisor support is required
+
+ uintptr_t ms = 0;
+ ms = INSERT_FIELD(ms, MSTATUS_PRV, PRV_M);
+ ms = INSERT_FIELD(ms, MSTATUS_PRV1, PRV_S);
+ ms = INSERT_FIELD(ms, MSTATUS_PRV2, PRV_U);
+ ms = INSERT_FIELD(ms, MSTATUS_IE2, 1);
+ ms = INSERT_FIELD(ms, MSTATUS_VM, VM_CHOICE);
+ ms = INSERT_FIELD(ms, MSTATUS_FS, 3);
+ ms = INSERT_FIELD(ms, MSTATUS_XS, 3);
+ 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");
+ } else {
+ printk(BIOS_DEBUG, "-----------------------------\n");
+ printk(BIOS_DEBUG, "virtual memory status enabled\n");
+ printk(BIOS_DEBUG, "-----------------------------\n");
+ }
+
+ clear_csr(mip, MIP_MSIP);
+ set_csr(mie, MIP_MSIP);
+}
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