linux-kernel - [PATCH v6 13/17] kexec: add machine_kexec_post

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Date:   Fri,  4 Oct 2019 14:52:30 -0400
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, jmorris@...ei.org, sashal@...nel.org,
        ebiederm@...ssion.com, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, marc.zyngier@....com,
        james.morse@....com, vladimir.murzin@....com,
        matthias.bgg@...il.com, bhsharma@...hat.com, linux-mm@...ck.org,
        mark.rutland@....com
Subject: [PATCH v6 13/17] kexec: add machine_kexec_post_load()

It is the same as machine_kexec_prepare(), but is called after segments are
loaded. This way, can do processing work with already loaded relocation
segments. One such example is arm64: it has to have segments loaded in
order to create a page table, but it cannot do it during kexec time,
because at that time allocations won't be possible anymore.

Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
Acked-by: Dave Young <dyoung@...hat.com>
---
 kernel/kexec.c          | 4 ++++
 kernel/kexec_core.c     | 6 ++++++
 kernel/kexec_file.c     | 4 ++++
 kernel/kexec_internal.h | 2 ++
 4 files changed, 16 insertions(+)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index bc933c0db9bf..f977786fe498 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -159,6 +159,10 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
 
 	kimage_terminate(image);
 
+	ret = machine_kexec_post_load(image);
+	if (ret)
+		goto out;
+
 	/* Install the new kernel and uninstall the old */
 	image = xchg(dest_image, image);
 
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index f7ae04b8de6f..c19c0dad1ebe 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -589,6 +589,12 @@ static void kimage_free_extra_pages(struct kimage *image)
 	kimage_free_page_list(&image->unusable_pages);
 
 }
+
+int __weak machine_kexec_post_load(struct kimage *image)
+{
+	return 0;
+}
+
 void kimage_terminate(struct kimage *image)
 {
 	if (*image->entry != 0)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 79f252af7dee..5b7f802be177 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -441,6 +441,10 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 
 	kimage_terminate(image);
 
+	ret = machine_kexec_post_load(image);
+	if (ret)
+		goto out;
+
 	/*
 	 * Free up any temporary buffers allocated which are not needed
 	 * after image has been loaded
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 48aaf2ac0d0d..39d30ccf8d87 100644
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -13,6 +13,8 @@ void kimage_terminate(struct kimage *image);
 int kimage_is_destination_range(struct kimage *image,
 				unsigned long start, unsigned long end);
 
+int machine_kexec_post_load(struct kimage *image);
+
 extern struct mutex kexec_mutex;
 
 #ifdef CONFIG_KEXEC_FILE
-- 
2.23.0