2 files changed, 229 insertions, 0 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 4325b2502e..2a3e8f00cd 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 0000000000..18f0e62acd
--- /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;
+}