of: kexec: Mark ima_{free,stable}_kexec_buffer() as __init

This commit has no direct upstream equivalent.

After commit d48016d74836 ("mm,ima,kexec,of: use memblock_free_late from
ima_free_kexec_buffer") in 5.15, there is a modpost warning for certain
configurations:

  WARNING: modpost: vmlinux.o(.text+0xb14064): Section mismatch in reference from the function ima_free_kexec_buffer() to the function .init.text:__memblock_free_late()
  The function ima_free_kexec_buffer() references
  the function __init __memblock_free_late().
  This is often because ima_free_kexec_buffer lacks a __init
  annotation or the annotation of __memblock_free_late is wrong.

In mainline, there is no issue because ima_free_kexec_buffer() is marked
as __init, which was done as part of commit b69a2afd5afc ("x86/kexec:
Carry forward IMA measurement log on kexec") in 6.0, which is not
suitable for stable.

Mark ima_free_kexec_buffer() and its single caller
ima_load_kexec_buffer() as __init in 5.15, as ima_load_kexec_buffer() is
only called from ima_init(), which is __init, clearing up the warning.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/of/kexec.c

@@ -165,7 +165,7 @@ int ima_get_kexec_buffer(void **addr, size_t *size)
 /**
  * ima_free_kexec_buffer - free memory used by the IMA buffer
  */
-int ima_free_kexec_buffer(void)
+int __init ima_free_kexec_buffer(void)
 {
 	int ret;
 	unsigned long addr;

include/linux/of.h

@@ -574,7 +574,7 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 				   unsigned long initrd_len,
 				   const char *cmdline, size_t extra_fdt_size);
 int ima_get_kexec_buffer(void **addr, size_t *size);
-int ima_free_kexec_buffer(void);
+int __init ima_free_kexec_buffer(void);
 #else /* CONFIG_OF */
 
 static inline void of_core_init(void)

security/integrity/ima/ima.h

@@ -122,7 +122,7 @@ struct ima_kexec_hdr {
 extern const int read_idmap[];
 
 #ifdef CONFIG_HAVE_IMA_KEXEC
-void ima_load_kexec_buffer(void);
+void __init ima_load_kexec_buffer(void);
 #else
 static inline void ima_load_kexec_buffer(void) {}
 #endif /* CONFIG_HAVE_IMA_KEXEC */

security/integrity/ima/ima_kexec.c

@@ -137,7 +137,7 @@ void ima_add_kexec_buffer(struct kimage *image)
 /*
  * Restore the measurement list from the previous kernel.
  */
-void ima_load_kexec_buffer(void)
+void __init ima_load_kexec_buffer(void)
 {
 	void *kexec_buffer = NULL;
 	size_t kexec_buffer_size = 0;