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From: Matt Turner <mattst88@gmail.com>
To: Lasse Collin <lasse.collin@tukaani.org>,
	 Richard Henderson <richard.henderson@linaro.org>,
	 Magnus Lindholm <linmag7@gmail.com>,
	Nick Terrell <terrelln@fb.com>,  David Sterba <dsterba@suse.com>
Cc: linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org,
	 Matt Turner <mattst88@gmail.com>
Subject: [PATCH 1/3] xz: add arch-specific tuning for alpha
Date: Sat, 12 Sep 2026 15:55:43 -0400	[thread overview]
Message-ID: <20260912-alpha-kernel-compression-v1-1-ce9d55330193@gmail.com> (raw)
In-Reply-To: <20260912-alpha-kernel-compression-v1-0-ce9d55330193@gmail.com>

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


  reply	other threads:[~2026-09-12 19:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-12 19:55 [PATCH 0/3] alpha: self-extracting compressed kernel images Matt Turner
2026-09-12 19:55 ` Matt Turner [this message]
2026-09-12 19:55 ` [PATCH 2/3] alpha: add self-extracting compressed kernel boot stub Matt Turner
2026-09-12 19:55 ` [PATCH 3/3] alpha: support the remaining kernel compression formats Matt Turner

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