lkml.org 
[lkml]   [2018]   [Oct]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [tip:x86/mm] kdump, proc/vmcore: Enable kdumping encrypted memory with SME enabled
From
Date
在 2018年10月08日 16:00, Borislav Petkov 写道:
> On Mon, Oct 08, 2018 at 03:11:56PM +0800, lijiang wrote:
>> I used this ".config" to compile kernel in the attachment, and got a compile error.
>> Would you like to have a try?
>>
>> [root@hp-dl385g10-03 linux]# make ARCH=i386 -j32
>> ......
>> LD vmlinux.o
>> MODPOST vmlinux.o
>> fs/proc/vmcore.o:In function ‘read_from_oldmem’:
>> /home/linux/fs/proc/vmcore.c:127:undefined reference to ‘copy_oldmem_page_encrypted’
>> make: *** [vmlinux] error 1
>
> Thanks, that triggered here. Ok, I guess something like this, to avoid
> the ugly ifdeffery:
>
> ---
> diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c
> index 33ee47670b99..8696800f2eea 100644
> --- a/arch/x86/kernel/crash_dump_32.c
> +++ b/arch/x86/kernel/crash_dump_32.c
> @@ -80,6 +80,16 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> return csize;
> }
>
> +/*
> + * 32-bit parrot version to avoid build errors.
> + */
> +ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
> + unsigned long offset, int userbuf)
> +{
> + WARN_ON_ONCE(1);
> + return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
> +}
> +

It looks like a good way to avoid the 'ifdefined', and it's also good enough for i386.

But for other architectures, such as POWERPC/ARM..., we will also have to add the same
function for every architecture. Otherwise, i guess that they also have a same compile
error on other architectures.

Sometimes, it's hard to make a choice.

Regards,
Lianbo
> static int __init kdump_buf_page_init(void)
> {
> int ret = 0;
>
>
>

\
 
 \ /
  Last update: 2018-10-08 10:48    [W:0.088 / U:11.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site