v4.19.13 snapshot.
diff --git a/arch/powerpc/boot/decompress.c b/arch/powerpc/boot/decompress.c
new file mode 100644
index 0000000..3aff442
--- /dev/null
+++ b/arch/powerpc/boot/decompress.c
@@ -0,0 +1,148 @@
+/*
+ * Wrapper around the kernel's pre-boot decompression library.
+ *
+ * Copyright (C) IBM Corporation 2016.
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include "elf.h"
+#include "page.h"
+#include "string.h"
+#include "stdio.h"
+#include "ops.h"
+#include "reg.h"
+#include "types.h"
+
+/*
+ * The decompressor_*.c files play #ifdef games so they can be used in both
+ * pre-boot and regular kernel code. We need these definitions to make the
+ * includes work.
+ */
+
+#define STATIC static
+#define INIT
+#define __always_inline inline
+
+/*
+ * The build process will copy the required zlib source files and headers
+ * out of lib/ and "fix" the includes so they do not pull in other kernel
+ * headers.
+ */
+
+#ifdef CONFIG_KERNEL_GZIP
+# include "decompress_inflate.c"
+#endif
+
+#ifdef CONFIG_KERNEL_XZ
+# include "xz_config.h"
+# include "../../../lib/decompress_unxz.c"
+#endif
+
+/* globals for tracking the state of the decompression */
+static unsigned long decompressed_bytes;
+static unsigned long limit;
+static unsigned long skip;
+static char *output_buffer;
+
+/*
+ * flush() is called by __decompress() when the decompressor's scratch buffer is
+ * full.
+ */
+static long flush(void *v, unsigned long buffer_size)
+{
+ unsigned long end = decompressed_bytes + buffer_size;
+ unsigned long size = buffer_size;
+ unsigned long offset = 0;
+ char *in = v;
+ char *out;
+
+ /*
+ * if we hit our decompression limit, we need to fake an error to abort
+ * the in-progress decompression.
+ */
+ if (decompressed_bytes >= limit)
+ return -1;
+
+ /* skip this entire block */
+ if (end <= skip) {
+ decompressed_bytes += buffer_size;
+ return buffer_size;
+ }
+
+ /* skip some data at the start, but keep the rest of the block */
+ if (decompressed_bytes < skip && end > skip) {
+ offset = skip - decompressed_bytes;
+
+ in += offset;
+ size -= offset;
+ decompressed_bytes += offset;
+ }
+
+ out = &output_buffer[decompressed_bytes - skip];
+ size = min(decompressed_bytes + size, limit) - decompressed_bytes;
+
+ memcpy(out, in, size);
+ decompressed_bytes += size;
+
+ return buffer_size;
+}
+
+static void print_err(char *s)
+{
+ /* suppress the "error" when we terminate the decompressor */
+ if (decompressed_bytes >= limit)
+ return;
+
+ printf("Decompression error: '%s'\n\r", s);
+}
+
+/**
+ * partial_decompress - decompresses part or all of a compressed buffer
+ * @inbuf: input buffer
+ * @input_size: length of the input buffer
+ * @outbuf: input buffer
+ * @output_size: length of the input buffer
+ * @skip number of output bytes to ignore
+ *
+ * This function takes compressed data from inbuf, decompresses and write it to
+ * outbuf. Once output_size bytes are written to the output buffer, or the
+ * stream is exhausted the function will return the number of bytes that were
+ * decompressed. Otherwise it will return whatever error code the decompressor
+ * reported (NB: This is specific to each decompressor type).
+ *
+ * The skip functionality is mainly there so the program and discover
+ * the size of the compressed image so that it can ask firmware (if present)
+ * for an appropriately sized buffer.
+ */
+long partial_decompress(void *inbuf, unsigned long input_size,
+ void *outbuf, unsigned long output_size, unsigned long _skip)
+{
+ int ret;
+
+ /*
+ * The skipped bytes needs to be included in the size of data we want
+ * to decompress.
+ */
+ output_size += _skip;
+
+ decompressed_bytes = 0;
+ output_buffer = outbuf;
+ limit = output_size;
+ skip = _skip;
+
+ ret = __decompress(inbuf, input_size, NULL, flush, outbuf,
+ output_size, NULL, print_err);
+
+ /*
+ * If decompression was aborted due to an actual error rather than
+ * a fake error that we used to abort, then we should report it.
+ */
+ if (decompressed_bytes < limit)
+ return ret;
+
+ return decompressed_bytes - skip;
+}