SPARC M7 and newer processors utilize ADI to version and
protect memory. This driver is capable of reading/writing
ADI/MCD versions from privileged user space processes.
Addresses in the adi file are mapped linearly to physical
memory at a ratio of 1:adi_blksz. Thus, a read (or write)
of offset K in the file operates upon the ADI version at
physical address K * adi_blksz. The version information
is encoded as one version per byte. Intended consumers
are makedumpfile and crash.
Signed-off-by: Tom Hromatka <tom.hroma...@oracle.com>
Reviewed-by: Khalid Aziz <khalid.a...@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nel...@oracle.com>
Reviewed-by: Anthony Yznaga <anthony.yzn...@oracle.com>
Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/char/Kconfig | 12 +++
drivers/char/Makefile | 1 +
drivers/char/adi.c | 239 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 252 insertions(+)
create mode 100644 drivers/char/adi.c
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 40947a796666..5ecddc95a698 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -540,5 +540,17 @@ source "drivers/s390/char/Kconfig"
source "drivers/char/xillybus/Kconfig"
+config ADI
+ tristate "SPARC Privileged ADI driver"
+ depends on SPARC64
+ default m
+ help
+ SPARC M7 and newer processors utilize ADI (Application Data
+ Integrity) to version and protect memory. This driver provides
+ read/write access to the ADI versions for privileged processes.
+ This feature is also known as MCD (Memory Corruption Detection)
+ and SSM (Silicon Secured Memory). Intended consumers of this
+ driver include crash and makedumpfile.
+
endmenu
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index c97c768cd1dd..b8d42b4e979b 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -57,3 +57,4 @@ js-rtc-y = rtc.o
obj-$(CONFIG_XILLYBUS) += xillybus/
obj-$(CONFIG_POWERNV_OP_PANEL) += powernv-op-panel.o
+obj-$(CONFIG_ADI) += adi.o
diff --git a/drivers/char/adi.c b/drivers/char/adi.c
new file mode 100644
index 000000000000..751d7cc0da1b
--- /dev/null
+++ b/drivers/char/adi.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Privileged ADI driver for sparc64
+ *
+ * Author: Tom Hromatka <tom.hroma...@oracle.com>
+ */
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <asm/asi.h>
+
+#define MAX_BUF_SZ PAGE_SIZE
+
+static int adi_open(struct inode *inode, struct file *file)
+{
+ file->f_mode |= FMODE_UNSIGNED_OFFSET;
+ return 0;
+}
+
+static int read_mcd_tag(unsigned long addr)
+{
+ long err;
+ int ver;
+
+ __asm__ __volatile__(
+ "1: ldxa [%[addr]] %[asi], %[ver]\n"
+ " mov 0, %[err]\n"
+ "2:\n"
+ " .section .fixup,#alloc,#execinstr\n"
+ " .align 4\n"
+ "3: sethi %%hi(2b), %%g1\n"
+ " jmpl %%g1 + %%lo(2b), %%g0\n"
+ " mov %[invalid], %[err]\n"
+ " .previous\n"
+ " .section __ex_table, \"a\"\n"
+ " .align 4\n"
+ " .word 1b, 3b\n"
+ " .previous\n"
+ : [ver] "=r" (ver), [err] "=r" (err)
+ : [addr] "r" (addr), [invalid] "i" (EFAULT),
+ [asi] "i" (ASI_MCD_REAL)
+ : "memory", "g1"
+ );
+
+ if (err)
+ return -EFAULT;
+ else
+ return ver;
+}
+
+static ssize_t adi_read(struct file *file, char __user *buf,
+ size_t count, loff_t *offp)
+{
+ size_t ver_buf_sz, bytes_read = 0;
+ int ver_buf_idx = 0;
+ loff_t offset;
+ u8 *ver_buf;
+ ssize_t ret;
+
+ ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
+ ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
+ if (!ver_buf)
+ return -ENOMEM;
+
+ offset = (*offp) * adi_blksize();
+
+ while (bytes_read < count) {
+ ret = read_mcd_tag(offset);
+ if (ret < 0)
+ goto out;
+
+ ver_buf[ver_buf_idx] = (u8)ret;
+ ver_buf_idx++;
+ offset += adi_blksize();
+
+ if (ver_buf_idx >= ver_buf_sz) {
+ if (copy_to_user(buf + bytes_read, ver_buf,
+ ver_buf_sz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ bytes_read += ver_buf_sz;
+ ver_buf_idx = 0;
+
+ ver_buf_sz = min(count - bytes_read,
+ (size_t)MAX_BUF_SZ);
+ }
+ }
+
+ (*offp) += bytes_read;
+ ret = bytes_read;
+out:
+ kfree(ver_buf);
+ return ret;
+}
+
+static int set_mcd_tag(unsigned long addr, u8 ver)
+{
+ long err;
+
+ __asm__ __volatile__(
+ "1: stxa %[ver], [%[addr]] %[asi]\n"
+ " mov 0, %[err]\n"
+ "2:\n"
+ " .section .fixup,#alloc,#execinstr\n"
+ " .align 4\n"
+ "3: sethi %%hi(2b), %%g1\n"
+ " jmpl %%g1 + %%lo(2b), %%g0\n"
+ " mov %[invalid], %[err]\n"
+ " .previous\n"
+ " .section __ex_table, \"a\"\n"
+ " .align 4\n"
+ " .word 1b, 3b\n"
+ " .previous\n"
+ : [err] "=r" (err)
+ : [ver] "r" (ver), [addr] "r" (addr),
+ [invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL)
+ : "memory", "g1"
+ );
+
+ if (err)
+ return -EFAULT;
+ else
+ return ver;
+}
+
+static ssize_t adi_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ size_t ver_buf_sz, bytes_written = 0;
+ loff_t offset;
+ u8 *ver_buf;
+ ssize_t ret;
+ int i;
+
+ if (count <= 0)
+ return -EINVAL;
+
+ ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
+ ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
+ if (!ver_buf)
+ return -ENOMEM;
+
+ offset = (*offp) * adi_blksize();
+
+ do {
+ if (copy_from_user(ver_buf, &buf[bytes_written],
+ ver_buf_sz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ for (i = 0; i < ver_buf_sz; i++) {
+ ret = set_mcd_tag(offset, ver_buf[i]);
+ if (ret < 0)
+ goto out;
+
+ offset += adi_blksize();
+ }
+
+ bytes_written += ver_buf_sz;
+ ver_buf_sz = min(count - bytes_written, (size_t)MAX_BUF_SZ);
+ } while (bytes_written < count);
+
+ (*offp) += bytes_written;
+ ret = bytes_written;
+out:
+ __asm__ __volatile__("membar #Sync");
+ kfree(ver_buf);
+ return ret;
+}
+
+static loff_t adi_llseek(struct file *file, loff_t offset, int whence)
+{
+ loff_t ret = -EINVAL;
+
+ switch (whence) {
+ case SEEK_END:
+ case SEEK_DATA:
+ case SEEK_HOLE:
+ /* unsupported */
+ return -EINVAL;
+ case SEEK_CUR:
+ if (offset == 0)
+ return file->f_pos;
+
+ offset += file->f_pos;
+ break;
+ case SEEK_SET:
+ break;
+ }
+
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ ret = offset;
+ }
+
+ return ret;
+}
+
+static const struct file_operations adi_fops = {
+ .owner = THIS_MODULE,
+ .llseek = adi_llseek,
+ .open = adi_open,
+ .read = adi_read,
+ .write = adi_write,
+};
+
+static struct miscdevice adi_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = KBUILD_MODNAME,
+ .fops = &adi_fops,
+};
+
+static int __init adi_init(void)
+{
+ if (!adi_capable())
+ return -EPERM;
+
+ return misc_register(&adi_miscdev);
+}
+
+static void __exit adi_exit(void)
+{
+ misc_deregister(&adi_miscdev);
+}
+
+module_init(adi_init);
+module_exit(adi_exit);
+
+MODULE_AUTHOR("Tom Hromatka <tom.hroma...@oracle.com>");
+MODULE_DESCRIPTION("Privileged interface to ADI");
+MODULE_VERSION("1.0");
+MODULE_LICENSE("GPL v2");
--
2.15.0
