Merge branch 'x86-acpi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 ACPI update from Peter Anvin:
 "This is a patchset which didn't make the last merge window.  It adds a
  debugging capability to feed ACPI tables via the initramfs.

  On a grander scope, it formalizes using the initramfs protocol for
  feeding arbitrary blobs which need to be accessed early to the kernel:
  they are fed first in the initramfs blob (lots of bootloaders can
  concatenate this at boot time, others can use a single file) in an
  uncompressed cpio archive using filenames starting with "kernel/".

  The ACPI maintainers requested that this patchset be fed via the x86
  tree rather than the ACPI tree as the footprint in the general x86
  code is much bigger than in the ACPI code proper."

* 'x86-acpi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  X86 ACPI: Use #ifdef not #if for CONFIG_X86 check
  ACPI: Fix build when disabled
  ACPI: Document ACPI table overriding via initrd
  ACPI: Create acpi_table_taint() function to avoid code duplication
  ACPI: Implement physical address table override
  ACPI: Store valid ACPI tables passed via early initrd in reserved memblock areas
  x86, acpi: Introduce x86 arch specific arch_reserve_mem_area() for e820 handling
  lib: Add early cpio decoder

2 files changed, 147 insertions, 1 deletions

diff --git a/lib/Makefile b/lib/Makefile
index e3723c7527da..e2152fa7ff4d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -12,7 +12,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
          idr.o int_sqrt.o extable.o \
          sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
          proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
-         is_single_threaded.o plist.o decompress.o kobject_uevent.o
+         is_single_threaded.o plist.o decompress.o kobject_uevent.o \
+         earlycpio.o
 
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/earlycpio.c b/lib/earlycpio.c
new file mode 100644
index 000000000000..8078ef49cb79
--- /dev/null
+++ b/lib/earlycpio.c
@@ -0,0 +1,145 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2012 Intel Corporation; author H. Peter Anvin
+ *
+ *   This file is part of the Linux kernel, and is made available
+ *   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 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * earlycpio.c
+ *
+ * Find a specific cpio member; must precede any compressed content.
+ * This is used to locate data items in the initramfs used by the
+ * kernel itself during early boot (before the main initramfs is
+ * decompressed.)  It is the responsibility of the initramfs creator
+ * to ensure that these items are uncompressed at the head of the
+ * blob.  Depending on the boot loader or package tool that may be a
+ * separate file or part of the same file.
+ */
+
+#include <linux/earlycpio.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+enum cpio_fields {
+        C_MAGIC,
+        C_INO,
+        C_MODE,
+        C_UID,
+        C_GID,
+        C_NLINK,
+        C_MTIME,
+        C_FILESIZE,
+        C_MAJ,
+        C_MIN,
+        C_RMAJ,
+        C_RMIN,
+        C_NAMESIZE,
+        C_CHKSUM,
+        C_NFIELDS
+};
+
+/**
+ * cpio_data find_cpio_data - Search for files in an uncompressed cpio
+ * @path:   The directory to search for, including a slash at the end
+ * @data:   Pointer to the the cpio archive or a header inside
+ * @len:    Remaining length of the cpio based on data pointer
+ * @offset: When a matching file is found, this is the offset to the
+ *          beginning of the cpio. It can be used to iterate through
+ *          the cpio to find all files inside of a directory path
+ *
+ * @return: struct cpio_data containing the address, length and
+ *          filename (with the directory path cut off) of the found file.
+ *          If you search for a filename and not for files in a directory,
+ *          pass the absolute path of the filename in the cpio and make sure
+ *          the match returned an empty filename string.
+ */
+
+struct cpio_data __cpuinit find_cpio_data(const char *path, void *data,
+                                          size_t len,  long *offset)
+{
+        const size_t cpio_header_len = 8*C_NFIELDS - 2;
+        struct cpio_data cd = { NULL, 0, "" };
+        const char *p, *dptr, *nptr;
+        unsigned int ch[C_NFIELDS], *chp, v;
+        unsigned char c, x;
+        size_t mypathsize = strlen(path);
+        int i, j;
+
+        p = data;
+
+        while (len > cpio_header_len) {
+                if (!*p) {
+                        /* All cpio headers need to be 4-byte aligned */
+                        p += 4;
+                        len -= 4;
+                        continue;
+                }
+
+                j = 6;          /* The magic field is only 6 characters */
+                chp = ch;
+                for (i = C_NFIELDS; i; i--) {
+                        v = 0;
+                        while (j--) {
+                                v <<= 4;
+                                c = *p++;
+
+                                x = c - '0';
+                                if (x < 10) {
+                                        v += x;
+                                        continue;
+                                }
+
+                                x = (c | 0x20) - 'a';
+                                if (x < 6) {
+                                        v += x + 10;
+                                        continue;
+                                }
+
+                                goto quit; /* Invalid hexadecimal */
+                        }
+                        *chp++ = v;
+                        j = 8;  /* All other fields are 8 characters */
+                }
+
+                if ((ch[C_MAGIC] - 0x070701) > 1)
+                        goto quit; /* Invalid magic */
+
+                len -= cpio_header_len;
+
+                dptr = PTR_ALIGN(p + ch[C_NAMESIZE], 4);
+                nptr = PTR_ALIGN(dptr + ch[C_FILESIZE], 4);
+
+                if (nptr > p + len || dptr < p || nptr < dptr)
+                        goto quit; /* Buffer overrun */
+
+                if ((ch[C_MODE] & 0170000) == 0100000 &&
+                    ch[C_NAMESIZE] >= mypathsize &&
+                    !memcmp(p, path, mypathsize)) {
+                        *offset = (long)nptr - (long)data;
+                        if (ch[C_NAMESIZE] - mypathsize >= MAX_CPIO_FILE_NAME) {
+                                pr_warn(
+                                "File %s exceeding MAX_CPIO_FILE_NAME [%d]\n",
+                                p, MAX_CPIO_FILE_NAME);
+                        }
+                        strlcpy(cd.name, p + mypathsize, MAX_CPIO_FILE_NAME);
+
+                        cd.data = (void *)dptr;
+                        cd.size = ch[C_FILESIZE];
+                        return cd; /* Found it! */
+                }
+                len -= (nptr - p);
+                p = nptr;
+        }
+
+quit:
+        return cd;
+}