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/*
* 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 <asm/cpu.h>
#include <linux/compiler.h>
DECLARE_GLOBAL_DATA_PTR;
/* 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);
}
cpu_enable_paging_pae((ulong)pdpt);
}
/* Disable paging and PAE mode. */
static void x86_phys_exit_paging(void)
{
cpu_disable_paging_pae();
}
/*
* 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;
}
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