Merge patch series "zfs: Fix zfs support on aarch64"

mwleeds@mailtundra.com <mwleeds@mailtundra.com> says:

This patch series is needed to get U-Boot to boot from a ZFS filesystem
on an aarch64 computer. Some of the patches are not architecture specific
and would be needed to boot ZFS on other platforms as well. The ZFS
support in U-Boot hasn't been substantively touched in several years and
to me it seems like it must have been broken for a long time on all
platforms, but I have only tested on aarch64.

Since there doesn't seem to be a mantainer for this area who I can cc,
I'm hoping these patches get seen and pulled in by a general U-Boot
maintainer.

[trini: Per Igor's comment and Phaedrus agreement, dropped his Tested-by
 on the patches themselves]

1 files changed, 26 insertions, 4 deletions

diff --git a/fs/zfs/zfs.c b/fs/zfs/zfs.c
index 1fec96cd5ce..bfc11fa6676 100644
--- a/fs/zfs/zfs.c
+++ b/fs/zfs/zfs.c
@@ -655,7 +655,7 @@ dmu_read(dnode_end_t *dn, uint64_t blkid, void **buf,
 											dn->endian)
 				<< SPA_MINBLOCKSHIFT;
 			*buf = malloc(size);
-			if (*buf) {
+			if (!*buf) {
 				err = ZFS_ERR_OUT_OF_MEMORY;
 				break;
 			}
@@ -1559,6 +1559,10 @@ nvlist_find_value(char *nvlist, char *name, int valtype, char **val,
 	return 0;
 }
 
+int is_word_aligned_ptr(void *ptr) {
+	return ((uintptr_t)ptr & (sizeof(void *) - 1)) == 0;
+}
+
 int
 zfs_nvlist_lookup_uint64(char *nvlist, char *name, uint64_t *out)
 {
@@ -1574,6 +1578,20 @@ zfs_nvlist_lookup_uint64(char *nvlist, char *name, uint64_t *out)
 		return ZFS_ERR_BAD_FS;
 	}
 
+	/* On arm64, calling be64_to_cpu() on a value stored at a memory address
+	 * that's not 8-byte aligned causes the CPU to reset. Avoid that by copying the
+	 * value somewhere else if needed.
+	 */
+	if (!is_word_aligned_ptr((void *)nvpair)) {
+		uint64_t *alignedptr = malloc(sizeof(uint64_t));
+		if (!alignedptr)
+			return 0;
+		memcpy(alignedptr, nvpair, sizeof(uint64_t));
+		*out = be64_to_cpu(*alignedptr);
+		free(alignedptr);
+		return 1;
+	}
+
 	*out = be64_to_cpu(*(uint64_t *) nvpair);
 	return 1;
 }
@@ -1617,6 +1635,11 @@ zfs_nvlist_lookup_nvlist(char *nvlist, char *name)
 							  &size, 0);
 	if (!found)
 		return 0;
+
+	/* Allocate 12 bytes in addition to the nvlist size: One uint32 before the
+	 * nvlist to hold the encoding method, and two zero uint32's after the
+	 * nvlist as the NULL terminator.
+	 */
 	ret = calloc(1, size + 3 * sizeof(uint32_t));
 	if (!ret)
 		return 0;
@@ -2112,7 +2135,7 @@ zfs_read(zfs_file_t file, char *buf, uint64_t len)
 		 * Find requested blkid and the offset within that block.
 		 */
 		uint64_t blkid = file->offset + red;
-		blkid = do_div(blkid, blksz);
+		uint64_t blkoff = do_div(blkid, blksz);
 		free(data->file_buf);
 		data->file_buf = 0;
 
@@ -2127,8 +2150,7 @@ zfs_read(zfs_file_t file, char *buf, uint64_t len)
 
 		movesize = min(length, data->file_end - (int)file->offset - red);
 
-		memmove(buf, data->file_buf + file->offset + red
-				- data->file_start, movesize);
+		memmove(buf, data->file_buf + blkoff, movesize);
 		buf += movesize;
 		length -= movesize;
 		red += movesize;