Re: [PATCH v5 1/2] x86: Add Isolated Memory Regions for Quark X1000
From: Andy Shevchenko
Date: Wed Jan 28 2015 - 15:52:22 EST
On Wed, Jan 28, 2015 at 5:00 PM, Bryan O'Donoghue
<pure.logic@xxxxxxxxxxxxxxxxx> wrote:
> Intel's Quark X1000 SoC contains a set of registers called Isolated Memory
> Regions. IMRs are accessed over the IOSF mailbox interface. IMRs are areas
> carved out of memory that define read/write access rights to the various
> system agents within the Quark system. For a given agent in the system it is
> possible to specify if that agent may read or write an area of memory
> defined by an IMR with a granularity of 1 KiB.
>
> Quark_SecureBootPRM_330234_001.pdf section 4.5 details the concept of IMRs
> quark-x1000-datasheet.pdf section 12.7.4 details the implementation of IMRs
> in silicon.
>
> eSRAM flush, CPU Snoop write-only, CPU SMM Mode, CPU non-SMM mode, RMU and
> PCIe Virtual Channels (VC0 and VC1) can have individual read/write access
> masks applied to them for a given memory region in Quark X1000. This
> enables IMRs to treat each memory transaction type listed above on an
> individual basis and to filter appropriately based on the IMR access mask
> for the memory region. Quark supports eight IMRs.
>
> Since all of the DMA capable SoC components in the X1000 are mapped to VC0
> it is possible to define sections of memory as invalid for DMA write
> operations originating from Ethernet, USB, SD and any other DMA capable
> south-cluster component on VC0. Similarly it is possible to mark kernel
> memory as non-SMM mode read/write only or to mark BIOS runtime memory as SMM
> mode accessible only depending on the particular memory footprint on a given
> system.
>
> On an IMR violation Quark SoC X1000 systems are configured to reset the
> system, so ensuring that the IMR memory map is consistent with the EFI
> provided memory map is critical to ensure no IMR violations reset the
> system.
>
> The API for accessing IMRs is based on MTRR code but doesn't provide a /proc
> or /sys interface to manipulate IMRs. Defining the size and extent of IMRs
> is exclusively the domain of in-kernel code.
>
> Quark firmware sets up a series of locked IMRs around pieces of memory that
> firmware owns such as ACPI runtime data. During boot a series of unlocked
> IMRs are placed around items in memory to guarantee no DMA modification of
> those items can take place. Grub also places an unlocked IMR around the
> kernel boot params data structure and compressed kernel image. It is
> necessary for the kernel to tear down all unlocked IMRs in order to ensure
> that the kernel's view of memory passed via the EFI memory map is consistent
> with the IMR memory map. Without tearing down all unlocked IMRs on boot
> transitory IMRs such as those used to protect the compressed kernel image
> will cause IMR violations and system reboots.
>
> The IMR init code tears down all unlocked IMRs and sets a protective IMR
> around the kernel .text and .rodata as one contiguous block. This sanitizes
> the IMR memory map with respect to the EFI memory map and protects the
> read-only portions of the kernel from unwarranted DMA access.
>
> Signed-off-by: Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
Few generic comments:
- missed dots at the end of several sentences
- %zu is suitable for size_t in printk()
One optional (though I suppose not bad) idea is to split test to
separate module which might go as a separate patch in the series.
After addressing those comments:
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> ---
> arch/x86/Kconfig.debug | 12 +
> arch/x86/include/asm/imr.h | 60 +++
> arch/x86/platform/intel-quark/Makefile | 1 +
> arch/x86/platform/intel-quark/imr.c | 716 +++++++++++++++++++++++++++++++++
> drivers/platform/x86/Kconfig | 25 ++
> 5 files changed, 814 insertions(+)
> create mode 100644 arch/x86/include/asm/imr.h
> create mode 100644 arch/x86/platform/intel-quark/Makefile
> create mode 100644 arch/x86/platform/intel-quark/imr.c
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 61bd2ad..fcf5701 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -313,6 +313,18 @@ config DEBUG_NMI_SELFTEST
>
> If unsure, say N.
>
> +config DEBUG_IMR_SELFTEST
> + bool "Isolated Memory Region self test"
> + default n
> + depends on INTEL_IMR
> + ---help---
> + This option enables automated sanity testing of the IMR code.
> + Some simple tests are run to verify IMR bounds checking, alignment
> + and overlapping. This option is really only useful if you are
> + debugging an IMR memory map or are modifying the IMR code and want to
> + test your changes.
> +
> + If unsure say N here.
> config X86_DEBUG_STATIC_CPU_HAS
> bool "Debug alternatives"
> depends on DEBUG_KERNEL
> diff --git a/arch/x86/include/asm/imr.h b/arch/x86/include/asm/imr.h
> new file mode 100644
> index 0000000..0542dc2
> --- /dev/null
> +++ b/arch/x86/include/asm/imr.h
> @@ -0,0 +1,60 @@
> +/*
> + * imr.h: Isolated Memory Region API
> + *
> + * Copyright(c) 2013 Intel Corporation.
> + * Copyright(c) 2015 Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
> + *
> + * 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 the Free Software Foundation; version 2
> + * of the License.
> + */
> +#ifndef _IMR_H
> +#define _IMR_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * IMR agent access mask bits
> + * See section 12.7.4.7 from quark-x1000-datasheet.pdf for register
> + * definitions.
> + */
> +#define IMR_ESRAM_FLUSH BIT(31)
> +#define IMR_CPU_SNOOP BIT(30) /* Applicable only to write */
> +#define IMR_RMU BIT(29)
> +#define IMR_VC1_SAI_ID3 BIT(15)
> +#define IMR_VC1_SAI_ID2 BIT(14)
> +#define IMR_VC1_SAI_ID1 BIT(13)
> +#define IMR_VC1_SAI_ID0 BIT(12)
> +#define IMR_VC0_SAI_ID3 BIT(11)
> +#define IMR_VC0_SAI_ID2 BIT(10)
> +#define IMR_VC0_SAI_ID1 BIT(9)
> +#define IMR_VC0_SAI_ID0 BIT(8)
> +#define IMR_CPU_0 BIT(1) /* SMM mode */
> +#define IMR_CPU BIT(0) /* Non SMM mode */
> +#define IMR_ACCESS_NONE 0
> +
> +/*
> + * Read/Write access-all bits here include some reserved bits
> + * These are the values firmware uses and are accepted by hardware.
> + * The kernel defines read/write access-all in the same way as firmware
> + * in order to have a consistent and crisp definition across firmware,
> + * bootloader and kernel.
> + */
> +#define IMR_READ_ACCESS_ALL 0xBFFFFFFF
> +#define IMR_WRITE_ACCESS_ALL 0xFFFFFFFF
> +
> +/* Number of IMRs provided by Quark X1000 SoC */
> +#define QUARK_X1000_IMR_MAX 0x08
> +#define QUARK_X1000_IMR_REGBASE 0x40
> +
> +/* IMR alignment bits - only bits 31:10 are checked for IMR validity */
> +#define IMR_ALIGN 0x400
> +#define IMR_MASK (IMR_ALIGN - 1)
> +
> +int imr_add_range(phys_addr_t base, size_t size,
> + unsigned int rmask, unsigned int wmask, bool lock);
> +
> +int imr_remove_range(int reg, phys_addr_t base, size_t size);
> +
> +#endif /* _IMR_H */
> diff --git a/arch/x86/platform/intel-quark/Makefile b/arch/x86/platform/intel-quark/Makefile
> new file mode 100644
> index 0000000..3180df5
> --- /dev/null
> +++ b/arch/x86/platform/intel-quark/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_INTEL_IMR) += imr.o
> diff --git a/arch/x86/platform/intel-quark/imr.c b/arch/x86/platform/intel-quark/imr.c
> new file mode 100644
> index 0000000..4e5be5c
> --- /dev/null
> +++ b/arch/x86/platform/intel-quark/imr.c
> @@ -0,0 +1,716 @@
> +/**
> + * imr.c
> + *
> + * Copyright(c) 2013 Intel Corporation.
> + * Copyright(c) 2015 Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>
> + *
> + * IMR registers define an isolated region of memory that can
> + * be masked to prohibit certain system agents from accessing memory.
> + * When a device behind a masked port performs an access - snooped or
> + * not, an IMR may optionally prevent that transaction from changing
> + * the state of memory or from getting correct data in response to the
> + * operation.
> + *
> + * Write data will be dropped and reads will return 0xFFFFFFFF, the
> + * system will reset and system BIOS will print out an error message to
> + * inform the user that an IMR has been violated.
> + *
> + * This code is based on the Linux MTRR code and reference code from
> + * Intel's Quark BSP EFI, Linux and grub code.
> + *
> + * See quark-x1000-datasheet.pdf for register definitions.
> + * http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/quark-x1000-datasheet.pdf
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <asm-generic/sections.h>
> +#include <asm/cpu_device_id.h>
> +#include <asm/imr.h>
> +#include <asm/iosf_mbi.h>
> +#include <linux/debugfs.h>
> +#include <linux/init.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +
> +struct imr_device {
> + struct dentry *file;
> + bool init;
> + struct mutex lock;
> + int max_imr;
> + int reg_base;
> +};
> +
> +static struct imr_device imr_dev;
> +
> +/*
> + * IMR read/write mask control registers.
> + * See quark-x1000-datasheet.pdf sections 12.7.4.5 and 12.7.4.6 for
> + * bit definitions.
> + *
> + * addr_hi
> + * 31 Lock bit
> + * 30:24 Reserved
> + * 23:2 1 KiB aligned lo address
> + * 1:0 Reserved
> + *
> + * addr_hi
> + * 31:24 Reserved
> + * 23:2 1 KiB aligned hi address
> + * 1:0 Reserved
> + */
> +#define IMR_LOCK BIT(31)
> +
> +struct imr_regs {
> + u32 addr_lo;
> + u32 addr_hi;
> + u32 rmask;
> + u32 wmask;
> +};
> +
> +#define IMR_NUM_REGS (sizeof(struct imr_regs)/sizeof(u32))
> +#define IMR_SHIFT 8
> +#define imr_to_phys(x) ((x) << IMR_SHIFT)
> +#define phys_to_imr(x) ((x) >> IMR_SHIFT)
> +
> +/**
> + * imr_is_enabled - true if an IMR is enabled false otherwise
> + *
> + * Determines if an IMR is enabled based on address range and read/write
> + * mask. An IMR set with an address range set to zero and a read/write
> + * access mask set to all is considered to be disabled. An IMR in any
> + * other state - for example set to zero but without read/write access
> + * all is considered to be enabled. This definition of disabled is how
> + * firmware switches off an IMR and is maintained in kernel for
> + * consistency.
> + *
> + * @imr: pointer to IMR descriptor
> + * @return: true if IMR enabled false if disabled
> + */
> +static inline int imr_is_enabled(struct imr_regs *imr)
> +{
> + return !(imr->rmask == IMR_READ_ACCESS_ALL &&
> + imr->wmask == IMR_WRITE_ACCESS_ALL &&
> + imr_to_phys(imr->addr_lo) == 0 &&
> + imr_to_phys(imr->addr_hi) == 0);
> +}
> +
> +/**
> + * imr_read - read an IMR at a given index.
> + *
> + * Requires caller to hold imr mutex
> + *
> + * @idev: pointer to imr_device structure
> + * @imr_id: IMR entry to read
> + * @imr: IMR structure representing address and access masks
> + * @return: 0 on success or error code passed from mbi_iosf on failure
> + */
> +static int imr_read(struct imr_device *idev, u32 imr_id, struct imr_regs *imr)
> +{
> + u32 reg = imr_id * IMR_NUM_REGS + idev->reg_base;
> + int ret;
> +
> + ret = iosf_mbi_read(QRK_MBI_UNIT_MM, QRK_MBI_MM_READ,
> + reg++, &imr->addr_lo);
> + if (ret)
> + return ret;
> +
> + ret = iosf_mbi_read(QRK_MBI_UNIT_MM, QRK_MBI_MM_READ,
> + reg++, &imr->addr_hi);
> + if (ret)
> + return ret;
> +
> + ret = iosf_mbi_read(QRK_MBI_UNIT_MM, QRK_MBI_MM_READ,
> + reg++, &imr->rmask);
> + if (ret)
> + return ret;
> +
> + ret = iosf_mbi_read(QRK_MBI_UNIT_MM, QRK_MBI_MM_READ,
> + reg++, &imr->wmask);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +/**
> + * imr_write - write an IMR at a given index.
> + *
> + * Requires caller to hold imr mutex
> + * Note lock bits need to be written independently of address bits
> + *
> + * @idev: pointer to imr_device structure
> + * @imr_id: IMR entry to write
> + * @imr: IMR structure representing address and access masks
> + * @lock: indicates if the IMR lock bit should be applied
> + * @return: 0 on success or error code passed from mbi_iosf on failure
> + */
> +static int imr_write(struct imr_device *idev, u32 imr_id,
> + struct imr_regs *imr, bool lock)
> +{
> + unsigned long flags;
> + u32 reg = imr_id * IMR_NUM_REGS + idev->reg_base;
> + int ret;
> +
> + local_irq_save(flags);
> +
> + ret = iosf_mbi_write(QRK_MBI_UNIT_MM, QRK_MBI_MM_WRITE, reg++,
> + imr->addr_lo);
> + if (ret)
> + goto done;
> +
> + ret = iosf_mbi_write(QRK_MBI_UNIT_MM, QRK_MBI_MM_WRITE,
> + reg++, imr->addr_hi);
> + if (ret)
> + goto done;
> +
> + ret = iosf_mbi_write(QRK_MBI_UNIT_MM, QRK_MBI_MM_WRITE,
> + reg++, imr->rmask);
> + if (ret)
> + goto done;
> +
> + ret = iosf_mbi_write(QRK_MBI_UNIT_MM, QRK_MBI_MM_WRITE,
> + reg++, imr->wmask);
> + if (ret)
> + goto done;
> +
> + /* Lock bit must be set separately to addr_lo address bits */
> + if (lock) {
> + imr->addr_lo |= IMR_LOCK;
> + ret = iosf_mbi_write(QRK_MBI_UNIT_MM, QRK_MBI_MM_WRITE,
> + reg - IMR_NUM_REGS, imr->addr_lo);
> + if (ret)
> + goto done;
> + }
> +
> + local_irq_restore(flags);
> + return 0;
> +done:
> + /*
> + * If writing to the IOSF failed then we're in an unknown state,
> + * likely a very bad state. An IMR in an invalid state will almost
> + * certainly lead to a memory access violation.
> + */
> + local_irq_restore(flags);
> + WARN(ret, "IOSF-MBI write fail range 0x%08x-0x%08x unreliable\n",
> + imr_to_phys(imr->addr_lo), imr_to_phys(imr->addr_hi) + IMR_MASK);
> +
> + return ret;
> +}
> +
> +/**
> + * imr_dbgfs_state_show
> + * Print state of IMR registers
> + *
> + * @s: pointer to seq_file for output
> + * @unused: unused parameter
> + * @return: 0 on success or error code passed from mbi_iosf on failure
> + */
> +static int imr_dbgfs_state_show(struct seq_file *s, void *unused)
> +{
> + phys_addr_t base;
> + phys_addr_t end;
> + int i;
> + struct imr_device *idev = s->private;
> + struct imr_regs imr;
> + size_t size;
> + int ret = -ENODEV;
> +
> + mutex_lock(&idev->lock);
> +
> + for (i = 0; i < idev->max_imr; i++) {
> +
> + ret = imr_read(idev, i, &imr);
> + if (ret)
> + break;
> +
> + /*
> + * Remember to add IMR_ALIGN bytes to size to indicate the
> + * inherent IMR_ALIGN size bytes contained in the masked away
> + * lower ten bits
> + */
> + if (imr_is_enabled(&imr)) {
> + base = imr_to_phys(imr.addr_lo);
> + end = imr_to_phys(imr.addr_hi) + IMR_MASK;
> + } else {
> + base = 0;
> + end = 0;
> + }
> + size = end - base;
> + seq_printf(s, "imr%02i: base=%pa, end=%pa, size=0x%08x "
> + "rmask=0x%08x, wmask=0x%08x, %s, %s\n", i,
> + &base, &end, size, imr.rmask, imr.wmask,
> + imr_is_enabled(&imr) ? "enabled " : "disabled",
> + imr.addr_lo & IMR_LOCK ? "locked" : "unlocked");
> + }
> +
> + mutex_unlock(&idev->lock);
> +
> + return ret;
> +}
> +
> +/**
> + * imr_state_open - debugfs open callback
> + *
> + * @inode: pointer to struct inode
> + * @file: pointer to struct file
> + * @return: result of single open
> + */
> +static int imr_state_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, imr_dbgfs_state_show, inode->i_private);
> +}
> +
> +static const struct file_operations imr_state_ops = {
> + .open = imr_state_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
> +
> +/**
> + * imr_debugfs_register - register debugfs hooks
> + *
> + * @idev: pointer to imr_device structure
> + * @return: 0 on success - errno on failure
> + */
> +static int imr_debugfs_register(struct imr_device *idev)
> +{
> + idev->file = debugfs_create_file("imr_state", S_IFREG | S_IRUGO, NULL,
> + idev, &imr_state_ops);
> + if (!idev->file)
> + return -ENOMEM;
> +
> + return 0;
> +}
> +
> +/**
> + * imr_debugfs_unregister - unregister debugfs hooks
> + *
> + * @idev: pointer to imr_device structure
> + * @return:
> + */
> +static void imr_debugfs_unregister(struct imr_device *idev)
> +{
> + debugfs_remove(idev->file);
> +}
> +
> +/**
> + * imr_check_range - checks passed address range for an IMR is aligned
> + *
> + * @base: base address of intended IMR
> + * @size: size of intended IMR
> + * @return: zero on valid range -EINVAL on unaligned base/size
> + */
> +static int imr_check_range(phys_addr_t base, size_t size)
> +{
> + if ((base & IMR_MASK) || (size & IMR_MASK)) {
> + pr_warn("base %pa size 0x%08x must align to 1KiB\n",
> + &base, size);
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> +/**
> + * imr_fixup_size - account for the IMR_ALIGN bytes that addr_hi appends
> + *
> + * IMR addr_hi has a built in offset of plus IMR_ALIGN (0x400) bytes from the
> + * value in the register. We need to subtract IMR_ALIGN bytes from input sizes
> + * as a result.
> + *
> + * @size: input size bytes
> + * @return: reduced size
> + */
> +static inline size_t imr_fixup_size(size_t size)
> +{
> + return size - IMR_ALIGN;
> +}
> +
> +/**
> + * imr_address_overlap - detects an address overlap
> + *
> + * @addr: address to check against an existing IMR
> + * @imr: imr being checked
> + * @return: true for overlap false for no overlap
> + */
> +static inline int imr_address_overlap(phys_addr_t addr, struct imr_regs *imr)
> +{
> + return addr >= imr_to_phys(imr->addr_lo) && addr <= imr_to_phys(imr->addr_hi);
> +}
> +
> +/**
> + * imr_add_range - add an Isolated Memory Region
> + *
> + * @base: physical base address of region aligned to 1KiB
> + * @size: physical size of region in bytes must be aligned to 1KiB
> + * @read_mask: read access mask
> + * @write_mask: write access mask
> + * @lock: indicates whether or not to permanently lock this region
> + * @return: index of the IMR allocated or negative value indicating error
> + */
> +int imr_add_range(phys_addr_t base, size_t size,
> + unsigned int rmask, unsigned int wmask, bool lock)
> +{
> + phys_addr_t end;
> + unsigned int i;
> + struct imr_device *idev = &imr_dev;
> + struct imr_regs imr;
> + int reg;
> + int ret;
> +
> + if (idev->init == false)
> + return -ENODEV;
> +
> + ret = imr_check_range(base, size);
> + if (ret)
> + return ret;
> +
> + if (size == 0)
> + return -EINVAL;
> +
> + /* Tweak the size value */
> + size = imr_fixup_size(size);
> + end = base + size;
> +
> + /*
> + * Check for reserved IMR value common to firmware, kernel and grub
> + * indicating a disabled IMR
> + */
> + imr.addr_lo = phys_to_imr(base);
> + imr.addr_hi = phys_to_imr(end);
> + imr.rmask = rmask;
> + imr.wmask = wmask;
> + if (!imr_is_enabled(&imr))
> + return -EINVAL;
> +
> + mutex_lock(&idev->lock);
> +
> + /*
> + * Find a free IMR while checking for an existing overlapping range.
> + * Note there's no restriction in silicon to prevent IMR overlaps.
> + * For the sake of simplicity and ease in defining/debugging an IMR
> + * memory map we exclude IMR overlaps.
> + */
> + reg = -1;
> + for (i = 0; i < idev->max_imr; i++) {
> + ret = imr_read(idev, i, &imr);
> + if (ret)
> + goto done;
> +
> + /* Find overlap @ base or end of requested range */
> + if (imr_is_enabled(&imr)) {
> + if (imr_address_overlap(base, &imr)) {
> + ret = -EINVAL;
> + goto done;
> + }
> + if (imr_address_overlap(end, &imr)) {
> + ret = -EINVAL;
> + goto done;
> + }
> + } else {
> + reg = i;
> + }
> + }
> +
> + /* Error out if we have no free IMR entries */
> + if (reg == -1) {
> + ret = -ENODEV;
> + goto done;
> + }
> +
> + pr_debug("IMR %d phys %pa-%pa rmask 0x%08x wmask 0x%08x\n",
> + reg, &base, &end, rmask, wmask);
> +
> + /* Allocate IMR */
> + imr.addr_lo = phys_to_imr(base);
> + imr.addr_hi = phys_to_imr(end);
> + imr.rmask = rmask;
> + imr.wmask = wmask;
> +
> + ret = imr_write(idev, reg, &imr, lock);
> +
> +done:
> + mutex_unlock(&idev->lock);
> + return ret == 0 ? reg : ret;
> +}
> +EXPORT_SYMBOL(imr_add_range);
> +
> +/**
> + * imr_remove_range - delete an Isolated Memory Region
> + *
> + * This function allows you to delete an IMR by its index specified by reg or
> + * by address range specified by base and size respectively. If you specify an
> + * index on its own the base and size parameters are ignored.
> + * imr_remove_range(0, size, base); delete IMR at index 0 base/size ignored
> + * imr_remove_range(-1, base, size); delete IMR from base to base+size
> + *
> + * @reg: imr index to remove
> + * @base: physical base address of region aligned to 1 KiB
> + * @size: physical size of region in bytes aligned to 1 KiB
> + * @return: -EINVAL on invalid range or out or range id
> + * -ENODEV if reg is valid but no IMR exists or is locked
> + * 0 on success
> + */
> +int imr_remove_range(int reg, phys_addr_t base, size_t size)
> +{
> + phys_addr_t end;
> + bool found = false;
> + unsigned int i;
> + struct imr_device *idev = &imr_dev;
> + struct imr_regs imr;
> + int ret = 0;
> +
> + if (idev->init == false)
> + return -ENODEV;
> +
> + if (imr_check_range(base, size))
> + return -EINVAL;
> +
> + if (reg >= idev->max_imr)
> + return -EINVAL;
> +
> + /* Tweak the size value */
> + size = imr_fixup_size(size);
> + end = base + size;
> +
> + mutex_lock(&idev->lock);
> +
> + if (reg >= 0) {
> + /* If a specific IMR is given try to use it */
> + ret = imr_read(idev, reg, &imr);
> + if (ret)
> + goto done;
> +
> + if (!imr_is_enabled(&imr) || imr.addr_lo & IMR_LOCK) {
> + ret = -ENODEV;
> + goto done;
> + }
> + found = true;
> + } else {
> + /* Search for match based on address range */
> + for (i = 0; i < idev->max_imr; i++) {
> + ret = imr_read(idev, i, &imr);
> + if (ret)
> + goto done;
> +
> + if (!imr_is_enabled(&imr) || imr.addr_lo & IMR_LOCK)
> + continue;
> +
> + if ((imr_to_phys(imr.addr_lo) == base) &&
> + (imr_to_phys(imr.addr_hi) == end)) {
> + found = true;
> + reg = i;
> + break;
> + }
> + }
> + }
> +
> + if (found == false) {
> + ret = -ENODEV;
> + goto done;
> + }
> +
> + /* Tear down the IMR */
> + imr.addr_lo = 0;
> + imr.addr_hi = 0;
> + imr.rmask = IMR_READ_ACCESS_ALL;
> + imr.wmask = IMR_WRITE_ACCESS_ALL;
> +
> + ret = imr_write(idev, reg, &imr, false);
> +
> +done:
> + mutex_unlock(&idev->lock);
> + return ret;
> +}
> +EXPORT_SYMBOL(imr_remove_range);
> +
> +#ifdef CONFIG_DEBUG_IMR_SELFTEST
> +#define SELFTEST KBUILD_MODNAME ": self_test "
> +
> +/**
> + * imr_self_test_result - Print result string for self test
> + *
> + * @res: result code - true if test passed false otherwise
> + * @fmt: format string
> + * ... variadic argument list
> + */
> +static void __init imr_self_test_result(int res, const char *fmt, ...)
> +{
> + va_list vlist;
> +
> + va_start(vlist, fmt);
> + if (res)
> + printk(KERN_INFO SELFTEST "pass ");
> + else
> + printk(KERN_ERR SELFTEST "fail ");
> + vprintk(fmt, vlist);
> + va_end(vlist);
> + WARN(res == 0, "test failed");
> +}
> +#undef SELFTEST
> +
> +/**
> + * imr_self_test
> + *
> + * Verify IMR self_test with some simple tests to verify overlap,
> + * zero sized allocations and 1 KiB sized areas.
> + *
> + */
> +static void __init imr_self_test(void)
> +{
> + phys_addr_t base = virt_to_phys(&_text);
> + size_t size = virt_to_phys(&__end_rodata) - base;
> + const char *fmt_over = "overlapped IMR @ (0x%08lx - 0x%08lx)\n";
> + int idx;
> +
> + /* Test zero zero */
> + idx = imr_add_range(0, 0, 0, 0, false);
> + imr_self_test_result(idx < 0, "zero sized IMR\n");
> +
> + /* Test exact overlap */
> + idx = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
> + imr_self_test_result(idx < 0, fmt_over, __va(base), __va(base + size));
> +
> + /* Test overlap with base inside of existing */
> + base += size - IMR_ALIGN;
> + idx = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
> + imr_self_test_result(idx < 0, fmt_over, __va(base), __va(base + size));
> +
> + /* Test overlap with end inside of existing */
> + base -= size + IMR_ALIGN * 2;
> + idx = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
> + imr_self_test_result(idx < 0, fmt_over, __va(base), __va(base + size));
> +
> + /* Test that a 1 KiB IMR @ zero with read/write all will bomb out */
> + idx = imr_add_range(0, IMR_ALIGN, IMR_READ_ACCESS_ALL,
> + IMR_WRITE_ACCESS_ALL, false);
> + imr_self_test_result(idx < 0, "1KiB IMR @ 0x00000000 - access-all\n");
> +
> + /* Test that a 1 KiB IMR @ zero with CPU only will work */
> + idx = imr_add_range(0, IMR_ALIGN, IMR_CPU, IMR_CPU, false);
> + imr_self_test_result(idx >= 0, "1KiB IMR @ 0x00000000 - cpu access\n");
> + if (idx >= 0) {
> + /* For an index removal address doesn't matter */
> + idx = imr_remove_range(idx, 0, 0);
> + imr_self_test_result(idx == 0, "index-teardown - cpu access\n");
> + }
> +
> + /* Test 2 KiB works - remove based on index */
> + size = IMR_ALIGN * 2;
> + idx = imr_add_range(0, size, IMR_READ_ACCESS_ALL,
> + IMR_WRITE_ACCESS_ALL, false);
> + imr_self_test_result(idx >= 0, "2KiB IMR @ 0x00000000\n");
> + if (idx >= 0) {
> + /* For an index removal address doesn't matter */
> + idx = imr_remove_range(idx, 0, 0);
> + imr_self_test_result(idx == 0, "index-teardown 2KiB\n");
> + }
> +
> + /* Test 1 KiB - remove based on address range */
> + idx = imr_add_range(0, size, IMR_READ_ACCESS_ALL,
> + IMR_WRITE_ACCESS_ALL, false);
> + imr_self_test_result(idx >= 0, "2KiB IMR @ 0x00000000\n");
> + if (idx >= 0) {
> + idx = imr_remove_range(-1, 0, size);
> + imr_self_test_result(idx == 0, "addr-teardown 2KiB\n");
> + }
> +}
> +#endif /* CONFIG_DEBUG_IMR_SELFTEST */
> +
> +/**
> + * imr_fixup_memmap - Tear down IMRs used during bootup.
> + *
> + * BIOS and Grub both setup IMRs around compressed kernel, initrd memory
> + * that need to be removed before the kernel hands out one of the IMR
> + * encased addresses to a downstream DMA agent such as the SD or Ethernet.
> + * IMRs on Galileo are setup to immediately reset the system on violation.
> + * As a result if you're running a root filesystem from SD - you'll need
> + * the boot-time IMRs torn down or you'll find seemingly random resets when
> + * using your filesystem.
> + *
> + * @idev: pointer to imr_device structure
> + * @return:
> + */
> +static void __init imr_fixup_memmap(struct imr_device *idev)
> +{
> + phys_addr_t base = virt_to_phys(&_text);
> + size_t size = virt_to_phys(&__end_rodata) - base;
> + int i;
> + int ret;
> +
> + /* Tear down all existing unlocked IMRs */
> + for (i = 0; i < idev->max_imr; i++)
> + imr_remove_range(i, 0, 0);
> +
> + /*
> + * Setup a locked IMR around the physical extent of the kernel
> + * from the beginning of the .text secton to the end of the
> + * .rodata section as one physically contiguous block.
> + */
> + ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, true);
> + if (ret < 0)
> + pr_err("unable to setup IMR for kernel: (%p - %p)\n",
> + &_text, &__end_rodata);
> + else
> + pr_info("protecting kernel .text - .rodata: %d KiB (%p - %p)\n",
> + size / 1024, &_text, &__end_rodata);
> +
> +}
> +
> +static const struct x86_cpu_id imr_ids[] __initconst = {
> + { X86_VENDOR_INTEL, 5, 9 }, /* Intel Quark SoC X1000 */
> + {}
> +};
> +MODULE_DEVICE_TABLE(x86cpu, imr_ids);
> +
> +/**
> + * imr_probe - entry point for IMR driver
> + *
> + * return: -ENODEV for no IMR support 0 if good to go
> + */
> +static int __init imr_init(void)
> +{
> + struct imr_device *idev = &imr_dev;
> + int ret;
> +
> + if (!x86_match_cpu(imr_ids) || !iosf_mbi_available())
> + return -ENODEV;
> +
> + idev->max_imr = QUARK_X1000_IMR_MAX;
> + idev->reg_base = QUARK_X1000_IMR_REGBASE;
> + idev->init = true;
> +
> + mutex_init(&idev->lock);
> + ret = imr_debugfs_register(idev);
> + if (ret != 0)
> + pr_warn("debugfs register failed!\n");
> + imr_fixup_memmap(idev);
> +
> +#ifdef CONFIG_DEBUG_IMR_SELFTEST
> + /* Run optional self test */
> + imr_self_test();
> +#endif
> + return 0;
> +}
> +
> +/**
> + * imr_exit - exit point for IMR code
> + *
> + * Deregisters debugfs, leave IMR state as-is.
> + *
> + * return:
> + */
> +static void __exit imr_exit(void)
> +{
> + imr_debugfs_unregister(&imr_dev);
> +}
> +
> +module_init(imr_init);
> +module_exit(imr_exit);
> +
> +MODULE_AUTHOR("Bryan O'Donoghue <pure.logic@xxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Intel Isolated Memory Region driver");
> +MODULE_LICENSE("Dual BSD/GPL");
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 638e7970..9752761 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -735,6 +735,31 @@ config INTEL_IPS
> functionality. If in doubt, say Y here; it will only load on
> supported platforms.
>
> +config INTEL_IMR
> + bool "Intel Isolated Memory Region support"
> + default n
> + depends on X86_INTEL_QUARK && IOSF_MBI
> + ---help---
> + This option provides a means to manipulate Isolated Memory Regions.
> + IMRs are a set of registers that define read and write access masks
> + to prohibit certain system agents from accessing memory with 1 KiB
> + granularity.
> +
> + IMRs make it possible to control read/write access to an address
> + by hardware agents inside the SoC. Read and write masks can be
> + defined for:
> + - eSRAM flush
> + - Dirty CPU snoop (write only)
> + - RMU access
> + - PCI Virtual Channel 0/Virtual Channel 1
> + - SMM mode
> + - Non SMM mode
> +
> + Quark contains a set of eight IMR registers and makes use of those
> + registers during its bootup process.
> +
> + If you are running on a Galileo/Quark say Y here.
> +
> config IBM_RTL
> tristate "Device driver to enable PRTL support"
> depends on X86 && PCI
> --
> 1.9.1
>
--
With Best Regards,
Andy Shevchenko
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