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Message-Id: <1471058305-30198-6-git-send-email-bauerman@linux.vnet.ibm.com>
Date: Sat, 13 Aug 2016 00:18:24 -0300
From: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
To: kexec@...ts.infradead.org
Cc: linux-security-module@...r.kernel.org,
linux-ima-devel@...ts.sourceforge.net,
linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
x86@...nel.org, Eric Biederman <ebiederm@...ssion.com>,
Dave Young <dyoung@...hat.com>,
Vivek Goyal <vgoyal@...hat.com>, Baoquan He <bhe@...hat.com>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Stewart Smith <stewart@...ux.vnet.ibm.com>,
Samuel Mendoza-Jonas <sam@...dozajonas.com>,
Mimi Zohar <zohar@...ux.vnet.ibm.com>,
Eric Richter <erichte@...ux.vnet.ibm.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Petko Manolov <petkan@...-labs.com>,
David Laight <David.Laight@...LAB.COM>,
Balbir Singh <bsingharora@...il.com>,
Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Subject: [PATCH v2 5/6] kexec: Share logic to copy segment page contents.
Make kimage_load_normal_segment and kexec_update_segment share code
which they currently duplicate.
Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
---
kernel/kexec_core.c | 159 +++++++++++++++++++++++++++++++---------------------
1 file changed, 95 insertions(+), 64 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 806735201de6..68b5b245e457 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -721,6 +721,65 @@ static struct page *kimage_alloc_page(struct kimage *image,
return page;
}
+struct kimage_update_buffer_state {
+ /* Destination memory address currently being copied to. */
+ unsigned long maddr;
+
+ /* Bytes in buffer still left to copy. */
+ size_t ubytes;
+
+ /* Bytes in memory still left to copy. */
+ size_t mbytes;
+
+ /* If true, copy from kbuf. */
+ bool from_kernel;
+
+ /* Clear pages before copying? */
+ bool clear_pages;
+
+ /* Buffer position to continue copying from. */
+ const unsigned char *kbuf;
+ const unsigned char __user *buf;
+};
+
+static int kimage_update_page(struct page *page,
+ struct kimage_update_buffer_state *state)
+{
+ char *ptr;
+ int result = 0;
+ size_t uchunk, mchunk;
+
+ ptr = kmap(page);
+
+ /* Start with a clear page */
+ if (state->clear_pages)
+ clear_page(ptr);
+
+ ptr += state->maddr & ~PAGE_MASK;
+ mchunk = min_t(size_t, state->mbytes,
+ PAGE_SIZE - (state->maddr & ~PAGE_MASK));
+ uchunk = min(state->ubytes, mchunk);
+
+ if (state->from_kernel)
+ memcpy(ptr, state->kbuf, uchunk);
+ else
+ result = copy_from_user(ptr, state->buf, uchunk);
+
+ kunmap(page);
+ if (result)
+ return -EFAULT;
+
+ state->ubytes -= uchunk;
+ state->maddr += mchunk;
+ if (state->from_kernel)
+ state->kbuf += mchunk;
+ else
+ state->buf += mchunk;
+ state->mbytes -= mchunk;
+
+ return 0;
+}
+
/**
* kexec_update_segment - update the contents of a kimage segment
* @buffer: New contents of the segment.
@@ -739,6 +798,7 @@ int kexec_update_segment(const char *buffer, unsigned long bufsz,
unsigned long entry;
unsigned long *ptr = NULL;
void *dest = NULL;
+ struct kimage_update_buffer_state state;
if (kexec_image == NULL) {
pr_err("Can't update segment: no kexec image loaded.\n");
@@ -768,8 +828,15 @@ int kexec_update_segment(const char *buffer, unsigned long bufsz,
return -EINVAL;
}
- for (entry = kexec_image->head; !(entry & IND_DONE) && memsz;
- entry = *ptr++) {
+ state.maddr = load_addr;
+ state.ubytes = bufsz;
+ state.mbytes = memsz;
+ state.kbuf = buffer;
+ state.from_kernel = true;
+ state.clear_pages = false;
+
+ for (entry = kexec_image->head; !(entry & IND_DONE) &&
+ state.mbytes; entry = *ptr++) {
void *addr = (void *) (entry & PAGE_MASK);
switch (entry & IND_FLAGS) {
@@ -786,26 +853,13 @@ int kexec_update_segment(const char *buffer, unsigned long bufsz,
return -EINVAL;
}
- if (dest == (void *) load_addr) {
- struct page *page;
- char *ptr;
- size_t uchunk, mchunk;
-
- page = kmap_to_page(addr);
-
- ptr = kmap(page);
- ptr += load_addr & ~PAGE_MASK;
- mchunk = min_t(size_t, memsz,
- PAGE_SIZE - (load_addr & ~PAGE_MASK));
- uchunk = min(bufsz, mchunk);
- memcpy(ptr, buffer, uchunk);
-
- kunmap(page);
+ if (dest == (void *) state.maddr) {
+ int ret;
- bufsz -= uchunk;
- load_addr += mchunk;
- buffer += mchunk;
- memsz -= mchunk;
+ ret = kimage_update_page(kmap_to_page(addr),
+ &state);
+ if (ret)
+ return ret;
}
dest += PAGE_SIZE;
}
@@ -823,31 +877,30 @@ int kexec_update_segment(const char *buffer, unsigned long bufsz,
static int kimage_load_normal_segment(struct kimage *image,
struct kexec_segment *segment)
{
- unsigned long maddr;
- size_t ubytes, mbytes;
- int result;
- unsigned char __user *buf = NULL;
- unsigned char *kbuf = NULL;
-
- result = 0;
- if (image->file_mode)
- kbuf = segment->kbuf;
- else
- buf = segment->buf;
- ubytes = segment->bufsz;
- mbytes = segment->memsz;
- maddr = segment->mem;
+ int result = 0;
+ struct kimage_update_buffer_state state;
+
+ /* For file based kexec, source pages are in kernel memory */
+ if (image->file_mode) {
+ state.kbuf = segment->kbuf;
+ state.from_kernel = true;
+ } else {
+ state.buf = segment->buf;
+ state.from_kernel = false;
+ }
+ state.ubytes = segment->bufsz;
+ state.mbytes = segment->memsz;
+ state.maddr = segment->mem;
+ state.clear_pages = true;
- result = kimage_set_destination(image, maddr);
+ result = kimage_set_destination(image, state.maddr);
if (result < 0)
goto out;
- while (mbytes) {
+ while (state.mbytes) {
struct page *page;
- char *ptr;
- size_t uchunk, mchunk;
- page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
+ page = kimage_alloc_page(image, GFP_HIGHUSER, state.maddr);
if (!page) {
result = -ENOMEM;
goto out;
@@ -857,31 +910,9 @@ static int kimage_load_normal_segment(struct kimage *image,
if (result < 0)
goto out;
- ptr = kmap(page);
- /* Start with a clear page */
- clear_page(ptr);
- ptr += maddr & ~PAGE_MASK;
- mchunk = min_t(size_t, mbytes,
- 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);
- kunmap(page);
- if (result) {
- result = -EFAULT;
+ result = kimage_update_page(page, &state);
+ if (result)
goto out;
- }
- ubytes -= uchunk;
- maddr += mchunk;
- if (image->file_mode)
- kbuf += mchunk;
- else
- buf += mchunk;
- mbytes -= mchunk;
}
out:
return result;
--
1.9.1
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