Re: [PATCH 5/5 V4] Help to dump the old memory encrypted into vmcore file
Hi Lianbo,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.18-rc2 next-20180628]
[cannot apply to tip/x86/core]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Lianbo-Jiang/Add-a-function-ioremap_encrypted-for-kdump-when-AMD-sme-enabled/20180628-173357
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=arm64
All errors (new ones prefixed by >>):
fs/proc/vmcore.c: In function 'elfcorehdr_read':
>> fs/proc/vmcore.c:180:9: error: implicit declaration of function 'memremap';
>> did you mean 'memset_p'? [-Werror=implicit-function-declaration]
kbuf = memremap(offset, count, MEMREMAP_WB);
^~~~
memset_p
fs/proc/vmcore.c:180:33: error: 'MEMREMAP_WB' undeclared (first use in this
function)
kbuf = memremap(offset, count, MEMREMAP_WB);
^~~
fs/proc/vmcore.c:180:33: note: each undeclared identifier is reported only
once for each function it appears in
fs/proc/vmcore.c:185:2: error: implicit declaration of function 'memunmap';
did you mean 'vm_munmap'? [-Werror=implicit-function-declaration]
memunmap(kbuf);
^~~~
vm_munmap
cc1: some warnings being treated as errors
vim +180 fs/proc/vmcore.c
158
159 /*
160 * Architectures may override this function to read from ELF header.
161 * The kexec-tools will allocated the memory and build the elf header
162 * in the first kernel, subsequently, we will copy the data in the
163 * memory to the reserved crash memory. In kdump mode, we will read the
164 * elf header from the reserved crash memory, from this point of view,
165 * which is not an old memory, the original function called may mislead
166 * and do unnecessary things.
167 * For SME, it copies the elf header from the memory encrypted(user
space)
168 * to the memory unencrypted(kernel space) when SME is activated in the
169 * first kernel, this operation just leads to decryption.
170 */
171 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
172 {
173 char *kbuf;
174 resource_size_t offset;
175
176 if (!count)
177 return 0;
178
179 offset = (resource_size_t)*ppos;
> 180 kbuf = memremap(offset, count, MEMREMAP_WB);
181 if (!kbuf)
182 return 0;
183
184 memcpy(buf, kbuf, count);
185 memunmap(kbuf);
186
187 return count;
188 }
189
---
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Re: [PATCH 5/5 V4] Help to dump the old memory encrypted into vmcore file
Hi Lianbo,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.18-rc2 next-20180628]
[cannot apply to tip/x86/core]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Lianbo-Jiang/Add-a-function-ioremap_encrypted-for-kdump-when-AMD-sme-enabled/20180628-173357
config: s390-allyesconfig (attached as .config)
compiler: s390x-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=s390
All errors (new ones prefixed by >>):
fs/proc/vmcore.c: In function 'elfcorehdr_read':
>> fs/proc/vmcore.c:180:9: error: implicit declaration of function 'memremap';
>> did you mean 'ioremap'? [-Werror=implicit-function-declaration]
kbuf = memremap(offset, count, MEMREMAP_WB);
^~~~
ioremap
>> fs/proc/vmcore.c:180:33: error: 'MEMREMAP_WB' undeclared (first use in this
>> function)
kbuf = memremap(offset, count, MEMREMAP_WB);
^~~
fs/proc/vmcore.c:180:33: note: each undeclared identifier is reported only
once for each function it appears in
>> fs/proc/vmcore.c:185:2: error: implicit declaration of function 'memunmap';
>> did you mean 'vm_munmap'? [-Werror=implicit-function-declaration]
memunmap(kbuf);
^~~~
vm_munmap
cc1: some warnings being treated as errors
vim +180 fs/proc/vmcore.c
158
159 /*
160 * Architectures may override this function to read from ELF header.
161 * The kexec-tools will allocated the memory and build the elf header
162 * in the first kernel, subsequently, we will copy the data in the
163 * memory to the reserved crash memory. In kdump mode, we will read the
164 * elf header from the reserved crash memory, from this point of view,
165 * which is not an old memory, the original function called may mislead
166 * and do unnecessary things.
167 * For SME, it copies the elf header from the memory encrypted(user
space)
168 * to the memory unencrypted(kernel space) when SME is activated in the
169 * first kernel, this operation just leads to decryption.
170 */
171 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
172 {
173 char *kbuf;
174 resource_size_t offset;
175
176 if (!count)
177 return 0;
178
179 offset = (resource_size_t)*ppos;
> 180 kbuf = memremap(offset, count, MEMREMAP_WB);
181 if (!kbuf)
182 return 0;
183
184 memcpy(buf, kbuf, count);
> 185 memunmap(kbuf);
186
187 return count;
188 }
189
---
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[PATCH 5/5 V4] Help to dump the old memory encrypted into vmcore file
In kdump mode, we need to dump the old memory into vmcore file,
if SME is enabled in the first kernel, we must remap the old
memory in encrypted manner, which will be automatically decrypted
when we read from DRAM. It helps to parse the vmcore for some tools.
Signed-off-by: Lianbo Jiang
---
Some changes:
1. add a new file and modify Makefile.
2. revert some code about previously using sev_active().
3. modify elfcorehdr_read().
arch/x86/kernel/Makefile | 1 +
arch/x86/kernel/crash_dump_encrypt.c | 53
fs/proc/vmcore.c | 45 +-
include/linux/crash_dump.h | 12
4 files changed, 104 insertions(+), 7 deletions(-)
create mode 100644 arch/x86/kernel/crash_dump_encrypt.c
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 02d6f5c..afb5bad 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -96,6 +96,7 @@ obj-$(CONFIG_KEXEC_CORE) += machine_kexec_$(BITS).o
obj-$(CONFIG_KEXEC_CORE) += relocate_kernel_$(BITS).o crash.o
obj-$(CONFIG_KEXEC_FILE) += kexec-bzimage64.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
+obj-$(CONFIG_AMD_MEM_ENCRYPT) += crash_dump_encrypt.o
obj-y += kprobes/
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
diff --git a/arch/x86/kernel/crash_dump_encrypt.c
b/arch/x86/kernel/crash_dump_encrypt.c
new file mode 100644
index 000..e1b1a57
--- /dev/null
+++ b/arch/x86/kernel/crash_dump_encrypt.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Memory preserving reboot related code.
+ *
+ * Created by: Lianbo Jiang (liji...@redhat.com)
+ * Copyright (C) RedHat Corporation, 2018. All rights reserved
+ */
+
+#include
+#include
+#include
+#include
+
+/**
+ * copy_oldmem_page_encrypted - copy one page from "oldmem encrypted"
+ * @pfn: page frame number to be copied
+ * @buf: target memory address for the copy; this can be in kernel address
+ * space or user address space (see @userbuf)
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page (based on pfn) to begin the copy
+ * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+ * otherwise @buf is in kernel address space, use memcpy().
+ *
+ * Copy a page from "oldmem encrypted". For this page, there is no pte
+ * mapped in the current kernel. We stitch up a pte, similar to
+ * kmap_atomic.
+ */
+
+ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
+ size_t csize, unsigned long offset, int userbuf)
+{
+ void *vaddr;
+
+ if (!csize)
+ return 0;
+
+ vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT,
+ PAGE_SIZE);
+ if (!vaddr)
+ return -ENOMEM;
+
+ if (userbuf) {
+ if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
+ iounmap((void __iomem *)vaddr);
+ return -EFAULT;
+ }
+ } else
+ memcpy(buf, vaddr + offset, csize);
+
+ set_iounmap_nonlazy();
+ iounmap((void __iomem *)vaddr);
+ return csize;
+}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index cfb6674..5fef489 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -26,6 +26,8 @@
#include
#include
#include "internal.h"
+#include
+#include
/* List representing chunks of contiguous memory areas and their offsets in
* vmcore file.
@@ -98,7 +100,8 @@ static int pfn_is_ram(unsigned long pfn)
/* Reads a page from the oldmem device from given offset. */
static ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf)
+ u64 *ppos, int userbuf,
+ bool encrypted)
{
unsigned long pfn, offset;
size_t nr_bytes;
@@ -120,8 +123,11 @@ static ssize_t read_from_oldmem(char *buf, size_t count,
if (pfn_is_ram(pfn) == 0)
memset(buf, 0, nr_bytes);
else {
- tmp = copy_oldmem_page(pfn, buf, nr_bytes,
- offset, userbuf);
+ tmp = encrypted ? copy_oldmem_page_encrypted(pfn,
+ buf, nr_bytes, offset, userbuf)
+ : copy_oldmem_page(pfn, buf, nr_bytes,
+ offset, userbuf);
+
if (tmp < 0)
return tmp;
}
@@ -151,11 +157,34 @@ void __weak elfcorehdr_free(unsigned long long addr)
{}
/*
- * Architectures may override this function to read from ELF header
+ * Architectures may override this function to read from ELF header.
+ * The kexec-tools will
