Thread (10 messages) flat view 10 messages, 3 authors, 5d ago

Re: [PATCH 1/3] xz: add arch-specific tuning for alpha

From: Magnus Lindholm <linmag7@gmail.com>
Date: 2026-09-13 09:45:47
Also in: lkml

Hi Matt,

On Sat, Sep 12, 2026 at 9:55 PM Matt Turner [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Alpha has fixed-length, 4-byte-aligned instructions and no XZ BCJ
filter, so it wants the same LZMA2 settings as the other 4-byte-aligned
targets. Without an entry it hits the default case, which warns

  scripts/xz_wrap.sh: Arch-specific tuning is missing for 'alpha'

and conservatively assumes 2-byte alignment. Alpha gains HAVE_KERNEL_XZ
later in this series; the correct alignment also shrinks a UP1500
kernel's XZ image from 6469320 to 6448840 bytes.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
 scripts/xz_wrap.sh | 5 +++++
 1 file changed, 5 insertions(+)
diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh
index f19369687030..5af0d9045cbc 100755
--- a/scripts/xz_wrap.sh
+++ b/scripts/xz_wrap.sh
@@ -10,6 +10,7 @@
 # XZ-compressed kernel isn't currently supported on every listed arch.
 #
 #   Arch        Align   Notes
+#   alpha         4
 #   arm          2/4    ARM and ARM-Thumb2
 #   arm64         4
 #   csky          2
@@ -44,6 +45,10 @@ BCJ=
 # Set the BCJ filter if one is available.
 # It must match the #ifdef usage in lib/decompress_unxz.c.
 case $SRCARCH in
+       alpha)
+               ALIGN=4
+               ;;
+
        arm)
                if is_enabled CONFIG_THUMB2_KERNEL; then
                        ALIGN=2

--
2.54.0
I built the complete series with CONFIG_KERNEL_XZ=y  and successfully
boot-tested the resulting XZ self-extracting kernel on an UP2000+ through
SRM and aboot.

Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
Tested-by: Magnus Lindholm <linmag7@gmail.com>
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