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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /arch/x86/platform/intel-quark/imr.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/platform/intel-quark/imr.c')
-rw-r--r--arch/x86/platform/intel-quark/imr.c597
1 files changed, 597 insertions, 0 deletions
diff --git a/arch/x86/platform/intel-quark/imr.c b/arch/x86/platform/intel-quark/imr.c
new file mode 100644
index 000000000..0286fe1b1
--- /dev/null
+++ b/arch/x86/platform/intel-quark/imr.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/**
+ * imr.c -- Intel Isolated Memory Region driver
+ *
+ * Copyright(c) 2013 Intel Corporation.
+ * Copyright(c) 2015 Bryan O'Donoghue <pure.logic@nexus-software.ie>
+ *
+ * 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 <asm/io.h>
+
+#include <linux/debugfs.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/types.h>
+
+struct imr_device {
+ 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, MBI_REG_READ, reg++, &imr->addr_lo);
+ if (ret)
+ return ret;
+
+ ret = iosf_mbi_read(QRK_MBI_UNIT_MM, MBI_REG_READ, reg++, &imr->addr_hi);
+ if (ret)
+ return ret;
+
+ ret = iosf_mbi_read(QRK_MBI_UNIT_MM, MBI_REG_READ, reg++, &imr->rmask);
+ if (ret)
+ return ret;
+
+ return iosf_mbi_read(QRK_MBI_UNIT_MM, MBI_REG_READ, reg++, &imr->wmask);
+}
+
+/**
+ * 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.
+ * @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)
+{
+ 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, MBI_REG_WRITE, reg++, imr->addr_lo);
+ if (ret)
+ goto failed;
+
+ ret = iosf_mbi_write(QRK_MBI_UNIT_MM, MBI_REG_WRITE, reg++, imr->addr_hi);
+ if (ret)
+ goto failed;
+
+ ret = iosf_mbi_write(QRK_MBI_UNIT_MM, MBI_REG_WRITE, reg++, imr->rmask);
+ if (ret)
+ goto failed;
+
+ ret = iosf_mbi_write(QRK_MBI_UNIT_MM, MBI_REG_WRITE, reg++, imr->wmask);
+ if (ret)
+ goto failed;
+
+ local_irq_restore(flags);
+ return 0;
+failed:
+ /*
+ * 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;
+ size = end - base + 1;
+ } else {
+ base = 0;
+ end = 0;
+ size = 0;
+ }
+ seq_printf(s, "imr%02i: base=%pa, end=%pa, size=0x%08zx "
+ "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;
+}
+DEFINE_SHOW_ATTRIBUTE(imr_dbgfs_state);
+
+/**
+ * imr_debugfs_register - register debugfs hooks.
+ *
+ * @idev: pointer to imr_device structure.
+ */
+static void imr_debugfs_register(struct imr_device *idev)
+{
+ debugfs_create_file("imr_state", 0444, NULL, idev,
+ &imr_dbgfs_state_fops);
+}
+
+/**
+ * imr_check_params - check passed address range IMR alignment and non-zero size
+ *
+ * @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_params(phys_addr_t base, size_t size)
+{
+ if ((base & IMR_MASK) || (size & IMR_MASK)) {
+ pr_err("base %pa size 0x%08zx must align to 1KiB\n",
+ &base, size);
+ return -EINVAL;
+ }
+ if (size == 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * imr_raw_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_raw_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.
+ * @return: zero on success or negative value indicating error.
+ */
+int imr_add_range(phys_addr_t base, size_t size,
+ unsigned int rmask, unsigned int wmask)
+{
+ phys_addr_t end;
+ unsigned int i;
+ struct imr_device *idev = &imr_dev;
+ struct imr_regs imr;
+ size_t raw_size;
+ int reg;
+ int ret;
+
+ if (WARN_ONCE(idev->init == false, "driver not initialized"))
+ return -ENODEV;
+
+ ret = imr_check_params(base, size);
+ if (ret)
+ return ret;
+
+ /* Tweak the size value. */
+ raw_size = imr_raw_size(size);
+ end = base + raw_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 -ENOTSUPP;
+
+ 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 failed;
+
+ /* Find overlap @ base or end of requested range. */
+ ret = -EINVAL;
+ if (imr_is_enabled(&imr)) {
+ if (imr_address_overlap(base, &imr))
+ goto failed;
+ if (imr_address_overlap(end, &imr))
+ goto failed;
+ } else {
+ reg = i;
+ }
+ }
+
+ /* Error out if we have no free IMR entries. */
+ if (reg == -1) {
+ ret = -ENOMEM;
+ goto failed;
+ }
+
+ pr_debug("add %d phys %pa-%pa size %zx mask 0x%08x wmask 0x%08x\n",
+ reg, &base, &end, raw_size, rmask, wmask);
+
+ /* Enable IMR at specified range and access mask. */
+ 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);
+ if (ret < 0) {
+ /*
+ * In the highly unlikely event iosf_mbi_write failed
+ * attempt to rollback the IMR setup skipping the trapping
+ * of further IOSF write failures.
+ */
+ imr.addr_lo = 0;
+ imr.addr_hi = 0;
+ imr.rmask = IMR_READ_ACCESS_ALL;
+ imr.wmask = IMR_WRITE_ACCESS_ALL;
+ imr_write(idev, reg, &imr);
+ }
+failed:
+ mutex_unlock(&idev->lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(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, base, size); 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.
+ */
+static 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;
+ size_t raw_size;
+ int ret = 0;
+
+ if (WARN_ONCE(idev->init == false, "driver not initialized"))
+ return -ENODEV;
+
+ /*
+ * Validate address range if deleting by address, else we are
+ * deleting by index where base and size will be ignored.
+ */
+ if (reg == -1) {
+ ret = imr_check_params(base, size);
+ if (ret)
+ return ret;
+ }
+
+ /* Tweak the size value. */
+ raw_size = imr_raw_size(size);
+ end = base + raw_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 failed;
+
+ if (!imr_is_enabled(&imr) || imr.addr_lo & IMR_LOCK) {
+ ret = -ENODEV;
+ goto failed;
+ }
+ 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 failed;
+
+ 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) {
+ ret = -ENODEV;
+ goto failed;
+ }
+
+ pr_debug("remove %d phys %pa-%pa size %zx\n", reg, &base, &end, raw_size);
+
+ /* 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);
+
+failed:
+ mutex_unlock(&idev->lock);
+ return ret;
+}
+
+/**
+ * imr_remove_range - delete an Isolated Memory Region by address
+ *
+ * This function allows you to delete an IMR by an address range specified
+ * by base and size respectively.
+ * imr_remove_range(base, size); delete IMR from base to base+size.
+ *
+ * @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(phys_addr_t base, size_t size)
+{
+ return __imr_remove_range(-1, base, size);
+}
+EXPORT_SYMBOL_GPL(imr_remove_range);
+
+/**
+ * imr_clear - delete an Isolated Memory Region by index
+ *
+ * This function allows you to delete an IMR by an address range specified
+ * by the index of the IMR. Useful for initial sanitization of the IMR
+ * address map.
+ * imr_ge(base, size); delete IMR from base to base+size.
+ *
+ * @reg: imr index to remove.
+ * @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.
+ */
+static inline int imr_clear(int reg)
+{
+ return __imr_remove_range(reg, 0, 0);
+}
+
+/**
+ * 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;
+ unsigned long start, end;
+ int i;
+ int ret;
+
+ /* Tear down all existing unlocked IMRs. */
+ for (i = 0; i < idev->max_imr; i++)
+ imr_clear(i);
+
+ start = (unsigned long)_text;
+ end = (unsigned long)__end_rodata - 1;
+
+ /*
+ * Setup an unlocked 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.
+ *
+ * We don't round up @size since it is already PAGE_SIZE aligned.
+ * See vmlinux.lds.S for details.
+ */
+ ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
+ if (ret < 0) {
+ pr_err("unable to setup IMR for kernel: %zu KiB (%lx - %lx)\n",
+ size / 1024, start, end);
+ } else {
+ pr_info("protecting kernel .text - .rodata: %zu KiB (%lx - %lx)\n",
+ size / 1024, start, end);
+ }
+
+}
+
+static const struct x86_cpu_id imr_ids[] __initconst = {
+ X86_MATCH_VENDOR_FAM_MODEL(INTEL, 5, INTEL_FAM5_QUARK_X1000, NULL),
+ {}
+};
+
+/**
+ * imr_init - 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;
+
+ 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);
+ imr_debugfs_register(idev);
+ imr_fixup_memmap(idev);
+ return 0;
+}
+device_initcall(imr_init);