diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lib/physmem.c | 228 |
2 files changed, 229 insertions, 0 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 4325b25..2a3e8f0 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -47,6 +47,7 @@ COBJS-$(CONFIG_SYS_GENERIC_TIMER) += pcat_timer.o COBJS-$(CONFIG_PCI) += pci.o COBJS-$(CONFIG_PCI) += pci_type1.o COBJS-y += relocate.o +COBJS-y += physmem.o COBJS-y += string.o COBJS-$(CONFIG_SYS_X86_ISR_TIMER) += timer.o COBJS-$(CONFIG_VIDEO) += video.o diff --git a/arch/x86/lib/physmem.c b/arch/x86/lib/physmem.c new file mode 100644 index 0000000..18f0e62 --- /dev/null +++ b/arch/x86/lib/physmem.c @@ -0,0 +1,228 @@ +/* + * Copyright (c) 2012 The Chromium OS Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + * + * Alternatively, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2 as published by the Free + * Software Foundation. + */ + +#include <common.h> +#include <physmem.h> +#include <linux/compiler.h> + +/* Large pages are 2MB. */ +#define LARGE_PAGE_SIZE ((1 << 20) * 2) + +/* + * Paging data structures. + */ + +struct pdpe { + uint64_t p:1; + uint64_t mbz_0:2; + uint64_t pwt:1; + uint64_t pcd:1; + uint64_t mbz_1:4; + uint64_t avl:3; + uint64_t base:40; + uint64_t mbz_2:12; +}; + +typedef struct pdpe pdpt_t[512]; + +struct pde { + uint64_t p:1; /* present */ + uint64_t rw:1; /* read/write */ + uint64_t us:1; /* user/supervisor */ + uint64_t pwt:1; /* page-level writethrough */ + uint64_t pcd:1; /* page-level cache disable */ + uint64_t a:1; /* accessed */ + uint64_t d:1; /* dirty */ + uint64_t ps:1; /* page size */ + uint64_t g:1; /* global page */ + uint64_t avl:3; /* available to software */ + uint64_t pat:1; /* page-attribute table */ + uint64_t mbz_0:8; /* must be zero */ + uint64_t base:31; /* base address */ +}; + +typedef struct pde pdt_t[512]; + +static pdpt_t pdpt __aligned(4096); +static pdt_t pdts[4] __aligned(4096); + +/* + * Map a virtual address to a physical address and optionally invalidate any + * old mapping. + * + * @param virt The virtual address to use. + * @param phys The physical address to use. + * @param invlpg Whether to use invlpg to clear any old mappings. + */ +static void x86_phys_map_page(uintptr_t virt, phys_addr_t phys, int invlpg) +{ + /* Extract the two bit PDPT index and the 9 bit PDT index. */ + uintptr_t pdpt_idx = (virt >> 30) & 0x3; + uintptr_t pdt_idx = (virt >> 21) & 0x1ff; + + /* Set up a handy pointer to the appropriate PDE. */ + struct pde *pde = &(pdts[pdpt_idx][pdt_idx]); + + memset(pde, 0, sizeof(struct pde)); + pde->p = 1; + pde->rw = 1; + pde->us = 1; + pde->ps = 1; + pde->base = phys >> 21; + + if (invlpg) { + /* Flush any stale mapping out of the TLBs. */ + __asm__ __volatile__( + "invlpg %0\n\t" + : + : "m" (*(uint8_t *)virt) + ); + } +} + +/* Identity map the lower 4GB and turn on paging with PAE. */ +static void x86_phys_enter_paging(void) +{ + phys_addr_t page_addr; + unsigned i; + + /* Zero out the page tables. */ + memset(pdpt, 0, sizeof(pdpt)); + memset(pdts, 0, sizeof(pdts)); + + /* Set up the PDPT. */ + for (i = 0; i < ARRAY_SIZE(pdts); i++) { + pdpt[i].p = 1; + pdpt[i].base = ((uintptr_t)&pdts[i]) >> 12; + } + + /* Identity map everything up to 4GB. */ + for (page_addr = 0; page_addr < (1ULL << 32); + page_addr += LARGE_PAGE_SIZE) { + /* There's no reason to invalidate the TLB with paging off. */ + x86_phys_map_page(page_addr, page_addr, 0); + } + + /* Turn on paging */ + __asm__ __volatile__( + /* Load the page table address */ + "movl %0, %%cr3\n\t" + /* Enable pae */ + "movl %%cr4, %%eax\n\t" + "orl $0x00000020, %%eax\n\t" + "movl %%eax, %%cr4\n\t" + /* Enable paging */ + "movl %%cr0, %%eax\n\t" + "orl $0x80000000, %%eax\n\t" + "movl %%eax, %%cr0\n\t" + : + : "r" (pdpt) + : "eax" + ); +} + +/* Disable paging and PAE mode. */ +static void x86_phys_exit_paging(void) +{ + /* Turn off paging */ + __asm__ __volatile__ ( + /* Disable paging */ + "movl %%cr0, %%eax\n\t" + "andl $0x7fffffff, %%eax\n\t" + "movl %%eax, %%cr0\n\t" + /* Disable pae */ + "movl %%cr4, %%eax\n\t" + "andl $0xffffffdf, %%eax\n\t" + "movl %%eax, %%cr4\n\t" + : + : + : "eax" + ); +} + +/* + * Set physical memory to a particular value when the whole region fits on one + * page. + * + * @param map_addr The address that starts the physical page. + * @param offset How far into that page to start setting a value. + * @param c The value to set memory to. + * @param size The size in bytes of the area to set. + */ +static void x86_phys_memset_page(phys_addr_t map_addr, uintptr_t offset, int c, + unsigned size) +{ + /* + * U-Boot should be far away from the beginning of memory, so that's a + * good place to map our window on top of. + */ + const uintptr_t window = LARGE_PAGE_SIZE; + + /* Make sure the window is below U-Boot. */ + assert(window + LARGE_PAGE_SIZE < + gd->relocaddr - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_STACK_SIZE); + /* Map the page into the window and then memset the appropriate part. */ + x86_phys_map_page(window, map_addr, 1); + memset((void *)(window + offset), c, size); +} + +/* + * A physical memory anologue to memset with matching parameters and return + * value. + */ +phys_addr_t arch_phys_memset(phys_addr_t start, int c, phys_size_t size) +{ + const phys_addr_t max_addr = (phys_addr_t)~(uintptr_t)0; + const phys_addr_t orig_start = start; + + if (!size) + return orig_start; + + /* Handle memory below 4GB. */ + if (start <= max_addr) { + phys_size_t low_size = MIN(max_addr + 1 - start, size); + void *start_ptr = (void *)(uintptr_t)start; + + assert(((phys_addr_t)(uintptr_t)start) == start); + memset(start_ptr, c, low_size); + start += low_size; + size -= low_size; + } + + /* Use paging and PAE to handle memory above 4GB up to 64GB. */ + if (size) { + phys_addr_t map_addr = start & ~(LARGE_PAGE_SIZE - 1); + phys_addr_t offset = start - map_addr; + + x86_phys_enter_paging(); + + /* Handle the first partial page. */ + if (offset) { + phys_addr_t end = + MIN(map_addr + LARGE_PAGE_SIZE, start + size); + phys_size_t cur_size = end - start; + x86_phys_memset_page(map_addr, offset, c, cur_size); + size -= cur_size; + map_addr += LARGE_PAGE_SIZE; + } + /* Handle the complete pages. */ + while (size > LARGE_PAGE_SIZE) { + x86_phys_memset_page(map_addr, 0, c, LARGE_PAGE_SIZE); + size -= LARGE_PAGE_SIZE; + map_addr += LARGE_PAGE_SIZE; + } + /* Handle the last partial page. */ + if (size) + x86_phys_memset_page(map_addr, 0, c, size); + + x86_phys_exit_paging(); + } + return orig_start; +} |