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Message-Id: <20240220021106.694-1-gaoshanliukou@163.com>
Date: Tue, 20 Feb 2024 10:11:06 +0800
From: "yang.zhang" <gaoshanliukou@....com>
To: ebiederm@...ssion.com
Cc: kexec@...ts.infradead.org,
linux-kernel@...r.kernel.org,
bhe@...hat.com,
akpm@...ux-foundation.org,
"yang.zhang" <yang.zhang@...intek.com>
Subject: [PATCH v2] kexec: copy only happens before uchunk goes to zero
From: "yang.zhang" <yang.zhang@...intek.com>
When load segments, all of the copying and the rest
only happens before uchunk goes to zero.
Signed-off-by: yang.zhang <yang.zhang@...intek.com>
---
v1 -> v2:
- Only copy before uchunk goes to zero
V1: https://lore.kernel.org/lkml/20240130101802.23850-1-gaoshanliukou@163.com/
---
kernel/kexec_core.c | 44 ++++++++++++++++++++++++--------------------
1 file changed, 24 insertions(+), 20 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index d08fc7b5db97..2fc3d0e3715a 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -800,22 +800,24 @@ static int kimage_load_normal_segment(struct kimage *image,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
- /* For file based kexec, source pages are in kernel memory */
- if (image->file_mode)
- memcpy(ptr, kbuf, uchunk);
- else
- result = copy_from_user(ptr, buf, uchunk);
+ if (uchunk) {
+ /* For file based kexec, source pages are in kernel memory */
+ if (image->file_mode)
+ memcpy(ptr, kbuf, uchunk);
+ else
+ result = copy_from_user(ptr, buf, uchunk);
+ ubytes -= uchunk;
+ if (image->file_mode)
+ kbuf += uchunk;
+ else
+ buf += uchunk;
+ }
kunmap_local(ptr);
if (result) {
result = -EFAULT;
goto out;
}
- ubytes -= uchunk;
maddr += mchunk;
- if (image->file_mode)
- kbuf += mchunk;
- else
- buf += mchunk;
mbytes -= mchunk;
cond_resched();
@@ -866,11 +868,18 @@ static int kimage_load_crash_segment(struct kimage *image,
memset(ptr + uchunk, 0, mchunk - uchunk);
}
- /* For file based kexec, source pages are in kernel memory */
- if (image->file_mode)
- memcpy(ptr, kbuf, uchunk);
- else
- result = copy_from_user(ptr, buf, uchunk);
+ if (uchunk) {
+ /* For file based kexec, source pages are in kernel memory */
+ if (image->file_mode)
+ memcpy(ptr, kbuf, uchunk);
+ else
+ result = copy_from_user(ptr, buf, uchunk);
+ ubytes -= uchunk;
+ if (image->file_mode)
+ kbuf += uchunk;
+ else
+ buf += uchunk;
+ }
kexec_flush_icache_page(page);
kunmap_local(ptr);
arch_kexec_pre_free_pages(page_address(page), 1);
@@ -878,12 +887,7 @@ static int kimage_load_crash_segment(struct kimage *image,
result = -EFAULT;
goto out;
}
- ubytes -= uchunk;
maddr += mchunk;
- if (image->file_mode)
- kbuf += mchunk;
- else
- buf += mchunk;
mbytes -= mchunk;
cond_resched();
--
2.25.1
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