Patch set updated for coreboot: soc/apollolake: Only allow mmaped accesses to IFD BIOS region

[Alexandru Gagniuc]

Alexandru Gagniuc ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13326

-gerrit

commit 042c0da31046ca3acc287567d53b382e125b9952
Author: Alexandru Gagniuc 
Date:   Wed Oct 28 12:28:41 2015 -0700

soc/apollolake: Only allow mmaped accesses to IFD BIOS region

Only the BIOS region is memory-mapped by the hardware. Anything below
    that is invisible via MMIO. Also, the 256 KiB right below 4G are being
    decoded by readonly SRAM. Fail accesses to those regions, rather than
    returning false data.

Change-Id: I34779109ffce50a1c5a4842d7bf75870b8b4dff8
    Signed-off-by: Alexandru Gagniuc 
---
 src/soc/intel/apollolake/Kconfig     |  2 +-
 src/soc/intel/apollolake/mmap_boot.c | 32 ++++++++++++++++++++------------
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig
index 4a4efa4..317a439 100644
--- a/src/soc/intel/apollolake/Kconfig
+++ b/src/soc/intel/apollolake/Kconfig
@@ -78,7 +78,7 @@ config IFD_BIOS_START
      The starting address of flash region 1 (BIOS), as declared in the
      firmware descriptor. This can be obtained via 'ifdtool -d'.

-config IFD_BIOS_SIZE
+config IFD_BIOS_END
    hex
    default ROM_SIZE
    help
diff --git a/src/soc/intel/apollolake/mmap_boot.c b/src/soc/intel/apollolake/mmap_boot.c
index 7e9080b..60f7c1a 100644
--- a/src/soc/intel/apollolake/mmap_boot.c
+++ b/src/soc/intel/apollolake/mmap_boot.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2015 Intel Corp.
  * (Written by Andrey Petrov  for Intel Corp.)
+ * (Written by Alexandru Gagniuc  for Intel Corp.)
  *
  * 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
@@ -11,31 +12,38 @@
  */

#include <boot_device.h>
-#include <console/console.h>
 #include <cbfs.h>
-#include <endian.h>
-#include <stdlib.h>
 #include <commonlib/region.h>
+#include <console/console.h>
 #include <fmap.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* The 256 KiB right below 4G are decoded by readonly SRAM, not boot media */
+#define IFD_BIOS_MAX_MAPPED	(CONFIG_IFD_BIOS_END - 256 * KiB)
+#define IFD_MAPPED_SIZE		(IFD_BIOS_MAX_MAPPED - CONFIG_IFD_BIOS_START)
+#define IFD_BIOS_SIZE		(CONFIG_IFD_BIOS_END - CONFIG_IFD_BIOS_START)

/*
  *  If Apollo Lake is configured to boot from SPI flash "BIOS" region
  *  (as defined in descriptor) is mapped below 4GiB.  Form a pointer for
  *  the base.
  */
-#define ROM_BASE ((void *)(uintptr_t)(0x100000000ULL - CONFIG_IFD_BIOS_SIZE))
+#define VIRTUAL_ROM_BASE ((uintptr_t)(0x100000000ULL - IFD_BIOS_SIZE))

-static const struct mem_region_device boot_dev = {
-	.base = (void *) ROM_BASE,
-	/* typically not whole flash is memory mapped */
-	.rdev = REGION_DEV_INIT(&mem_rdev_ops, CONFIG_IFD_BIOS_START,
-							CONFIG_IFD_BIOS_SIZE)
-};
+static const struct mem_region_device shadow_dev = MEM_REGION_DEV_INIT(
+	VIRTUAL_ROM_BASE, IFD_BIOS_MAX_MAPPED
+);
+
+static const struct xlate_region_device real_dev = XLATE_REGION_INIT(
+		&shadow_dev.rdev, CONFIG_IFD_BIOS_START,
+		IFD_MAPPED_SIZE, CONFIG_ROM_SIZE
+);

const struct region_device *boot_device_ro(void)
 {
-	return &boot_dev.rdev;
-}
+	return &real_dev.rdev;
+};

static int iafw_boot_region_properties(struct cbfs_props *props)
 {