3 files changed, 188 insertions, 0 deletions
diff --git a/util/pgtblgen/Makefile.inc b/util/pgtblgen/Makefile.inc
new file mode 100644
index 0000000000..c4f3ef37b6
--- /dev/null
+++ b/util/pgtblgen/Makefile.inc
@@ -0,0 +1,19 @@
+ifeq ($(CONFIG_ARCH_BOOTBLOCK_X86_64),y)
+
+PGTBLGEN:= $(obj)/pgtblgen
+
+cbfs-files-y += pagetables
+pagetables-file := $(obj)/mainboard/$(MAINBOARDDIR)/pagetables
+pagetables-type := raw
+pagetables-compression := none
+pagetables-COREBOOT-position := $(CONFIG_ARCH_X86_64_PGTBL_LOC)
+
+$(obj)/mainboard/$(MAINBOARDDIR)/pagetables: $(PGTBLGEN) $(obj)/config.h
+	printf "    TOOL       Creating page tables\n"
+	$(PGTBLGEN) -b $(CONFIG_ARCH_X86_64_PGTBL_LOC) -a x86_64 -o $@
+
+$(PGTBLGEN): util/pgtblgen/pgtblgen.c
+	printf "    MAKE       Creating PGTBLGEN tool\n"
+	$(HOSTCC) $< -I$(obj) -o $@
+
+endif
diff --git a/util/pgtblgen/description.md b/util/pgtblgen/description.md
new file mode 100644
index 0000000000..f2e4763d75
--- /dev/null
+++ b/util/pgtblgen/description.md
@@ -0,0 +1 @@
+Generates page tables based on fixed physical address. `C`
diff --git a/util/pgtblgen/pgtblgen.c b/util/pgtblgen/pgtblgen.c
new file mode 100644
index 0000000000..efbad55204
--- /dev/null
+++ b/util/pgtblgen/pgtblgen.c
@@ -0,0 +1,168 @@
+/*
+ * This file is part of pgtblgen.
+ *
+ * Copyright (c) 2019 Patrick Rudolph <siro@das-labor.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <inttypes.h>
+
+static void usage(char *argv[])
+{
+	printf("usage: %s -b <addr> -a <arch> -o <file>\n", argv[0]);
+	printf("  -a\t architecure. Supported: x86_64\n");
+	printf("  -b\t base address\n");
+	printf("  -b\t the file to write to\n");
+	printf("  -h\t show this help text\n");
+}
+
+/*
+ * For reference see "AMD64 ArchitectureProgrammer's Manual Volume 2",
+ * Document 24593-Rev. 3.31-July 2019 Chapter 5.3.4
+ *
+ * Page table attributes: WB, User+Supervisor, Present, Writeable
+ */
+#define PRES (1ULL << 0)
+#define RW   (1ULL << 1)
+#define US   (1ULL << 2)
+#define PS   (1ULL << 7)
+#define _GEN_DIR(a) (PRES | RW | US | (a))
+#define _GEN_PAGE(a) (PRES | RW | US | PS | (a))
+
+/*
+ * Generate x86_64 page tables.
+ * The page tables needs to be placed at @base_address, and identity map
+ * the first @size_gib GiB of physical memory.
+ */
+static int gen_pgtbl_x86_64(const uint64_t base_address,
+			    const size_t size_gib,
+			    void **out_buf,
+			    size_t *out_size)
+{
+	uint64_t *entry;
+
+	if (!out_size || !out_buf)
+		return 1;
+
+	*out_size = (size_gib + 2) * 4096;
+	*out_buf = malloc(*out_size);
+	if (!*out_buf)
+		return 1;
+
+	memset(*out_buf, 0, *out_size);
+	entry = (uint64_t *)*out_buf;
+
+	/* Generate one PM4LE entry - point to PDPE */
+	entry[0] = _GEN_DIR(base_address + 4096);
+	entry += 512;
+
+	/* PDPE table - point to PDE */
+	for (size_t i = 0; i < size_gib; i++)
+		entry[i] = _GEN_DIR(base_address + 4096 * (i + 2));
+	entry += 512;
+
+	/* PDE tables - identity map 2MiB pages */
+	for (size_t g = 0; g < size_gib; g++) {
+		for (size_t i = 0; i < 512; i++) {
+			uint64_t addr = ((1ULL << (12 + 9)) * i) | ((1ULL << (12 + 9 + 9)) * g);
+			entry[i] = _GEN_PAGE(addr);
+		}
+		entry += 512;
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret = 1;
+	uint64_t base_address = 0;
+	char *filename = NULL;
+	char *arch = NULL;
+	void *buf = NULL;
+	size_t buf_size = 0;
+	int c;
+
+	while ((c = getopt(argc, argv, "ho:a:b:")) != -1)
+		switch (c) {
+		case '?': /* falltrough */
+		case 'h':
+			usage(argv);
+			return 0;
+		case 'o':
+			filename = optarg;
+			break;
+		case 'a':
+			arch = optarg;
+			break;
+		case 'b':
+			base_address = strtoull(optarg, NULL, 0);
+			break;
+		default:
+			break;
+		}
+
+	if (!filename) {
+		fprintf(stderr, "E: Missing filename.\n");
+		goto done;
+	}
+	if (!arch) {
+		fprintf(stderr, "E: Missing architecture.\n");
+		goto done;
+	} else if (strcmp(arch, "x86_64") != 0) {
+		fprintf(stderr, "E: Unsupported architecture.\n");
+		goto done;
+	}
+	if (base_address & 4095) {
+		fprintf(stderr, "E: Base address not 4 KiB aligned\n");
+		goto done;
+	}
+
+	/* FIXME: Identity map 4GiB for now, increase if necessary */
+	if (strcmp(arch, "x86_64") == 0)
+		ret = gen_pgtbl_x86_64(base_address, 4, &buf, &buf_size);
+
+	if (ret) {
+		fprintf(stderr, "Failed to generate page tables\n");
+		goto done;
+	}
+
+	// write the table
+	FILE *fd = fopen(filename, "wb");
+	if (!fd) {
+		fprintf(stderr, "%s open failed: %s\n", filename, strerror(errno));
+		goto done;
+	}
+
+	if (fwrite(buf, 1, buf_size, fd) != buf_size) {
+		fprintf(stderr, "%s write failed: %s\n", filename, strerror(errno));
+		fclose(fd);
+		goto done;
+	}
+
+	if (fclose(fd)) {
+		fprintf(stderr, "%s close failed: %s\n", filename, strerror(errno));
+		goto done;
+	}
+
+	ret = 0;
+done:
+	free(buf);
+	return ret;
+}