linux-kernel - [PATCHv6 05/13] lib/decompress: Keep decompressor when CONFIG_KEEP

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Message-ID: <20260119032424.10781-6-piliu@redhat.com>
Date: Mon, 19 Jan 2026 11:24:16 +0800
From: Pingfan Liu <piliu@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Pingfan Liu <piliu@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	John Fastabend <john.fastabend@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	Jeremy Linton <jeremy.linton@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Ard Biesheuvel <ardb@...nel.org>,
	Simon Horman <horms@...nel.org>,
	Gerd Hoffmann <kraxel@...hat.com>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	Philipp Rudo <prudo@...hat.com>,
	Viktor Malik <vmalik@...hat.com>,
	Jan Hendrik Farr <kernel@...rr.cc>,
	Baoquan He <bhe@...hat.com>,
	Dave Young <dyoung@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	kexec@...ts.infradead.org,
	bpf@...r.kernel.org,
	systemd-devel@...ts.freedesktop.org
Subject: [PATCHv6 05/13] lib/decompress: Keep decompressor when CONFIG_KEEP_DECOMPRESSOR

The KEXE PE format parser needs the kernel built-in decompressor to
decompress the kernel image. So moving the decompressor out of __init
sections.

Signed-off-by: Pingfan Liu <piliu@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
To: linux-kernel@...r.kernel.org
---
 include/linux/decompress/mm.h | 8 ++++++++
 lib/Kconfig                   | 6 ++++++
 lib/decompress.c              | 6 +++---
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/include/linux/decompress/mm.h b/include/linux/decompress/mm.h
index ac862422df158..39df02bcbc661 100644
--- a/include/linux/decompress/mm.h
+++ b/include/linux/decompress/mm.h
@@ -81,6 +81,7 @@ MALLOC_VISIBLE void free(void *where)
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <generated/autoconf.h>
 
 /* Use defines rather than static inline in order to avoid spurious
  * warnings when not needed (indeed large_malloc / large_free are not
@@ -92,7 +93,14 @@ MALLOC_VISIBLE void free(void *where)
 #define large_malloc(a) vmalloc(a)
 #define large_free(a) vfree(a)
 
+#ifdef CONFIG_KEEP_DECOMPRESSOR
+#define INIT
+#define INITCONST
+#else
 #define INIT __init
+#define INITCONST __initconst
+#endif
+
 #define STATIC
 
 #include <linux/init.h>
diff --git a/lib/Kconfig b/lib/Kconfig
index 2923924bea78c..4424ae14dcf12 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -165,6 +165,12 @@ config RANDOM32_SELFTEST
 #
 # compression support is select'ed if needed
 #
+config KEEP_DECOMPRESSOR
+	bool "keeps the decompress routines after kernel initialization"
+	default n
+	help
+	  This option keeps the decompress routines after kernel initialization
+
 config 842_COMPRESS
 	select CRC32
 	tristate
diff --git a/lib/decompress.c b/lib/decompress.c
index 7785471586c62..29d4c749f1fc4 100644
--- a/lib/decompress.c
+++ b/lib/decompress.c
@@ -6,7 +6,7 @@
  */
 
 #include <linux/decompress/generic.h>
-
+#include <linux/decompress/mm.h>
 #include <linux/decompress/bunzip2.h>
 #include <linux/decompress/unlzma.h>
 #include <linux/decompress/unxz.h>
@@ -48,7 +48,7 @@ struct compress_format {
 	decompress_fn decompressor;
 };
 
-static const struct compress_format compressed_formats[] __initconst = {
+static const struct compress_format compressed_formats[] INITCONST = {
 	{ .magic = {0x1f, 0x8b}, .name = "gzip", .decompressor = gunzip },
 	{ .magic = {0x1f, 0x9e}, .name = "gzip", .decompressor = gunzip },
 	{ .magic = {0x42, 0x5a}, .name = "bzip2", .decompressor = bunzip2 },
@@ -60,7 +60,7 @@ static const struct compress_format compressed_formats[] __initconst = {
 	{ /* sentinel */ }
 };
 
-decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
+decompress_fn INIT decompress_method(const unsigned char *inbuf, long len,
 				const char **name)
 {
 	const struct compress_format *cf;
-- 
2.49.0