diff mbox series

kdump, proc/vmcore: fix building without CONFIG_ARCH_HAS_MEM_ENCRYPT

Message ID 20181010143306.2051406-1-arnd@arndb.de (mailing list archive)
State New, archived
Headers show
Series kdump, proc/vmcore: fix building without CONFIG_ARCH_HAS_MEM_ENCRYPT | expand

Commit Message

Arnd Bergmann Oct. 10, 2018, 2:32 p.m. UTC
We get a link failure when calling copy_oldmem_page_encrypted()
when the compiler fails to do constant-propagation of the
sme_active() result into read_from_oldmem:

fs/proc/vmcore.o: In function `read_from_oldmem.part.0':
vmcore.c:(.text+0xb7): undefined reference to `copy_oldmem_page_encrypted'

Adding an IS_ENABLED() check means the compiler will always
know when it cannot be enabled.

Fixes: 992b649a3f01 ("kdump, proc/vmcore: Enable kdumping encrypted memory with SME enabled")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
There may be a better way of doing this, not sure what kinds
of assumptions we want to make here.
---
 fs/proc/vmcore.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Borislav Petkov Oct. 10, 2018, 2:40 p.m. UTC | #1
On Wed, Oct 10, 2018 at 04:32:45PM +0200, Arnd Bergmann wrote:
> We get a link failure when calling copy_oldmem_page_encrypted()
> when the compiler fails to do constant-propagation of the
> sme_active() result into read_from_oldmem:
> 
> fs/proc/vmcore.o: In function `read_from_oldmem.part.0':
> vmcore.c:(.text+0xb7): undefined reference to `copy_oldmem_page_encrypted'
> 
> Adding an IS_ENABLED() check means the compiler will always
> know when it cannot be enabled.
> 
> Fixes: 992b649a3f01 ("kdump, proc/vmcore: Enable kdumping encrypted memory with SME enabled")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> There may be a better way of doing this, not sure what kinds
> of assumptions we want to make here.
> ---
>  fs/proc/vmcore.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index d469ce9d8c0c..92e1e520a52d 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -123,7 +123,9 @@ static ssize_t read_from_oldmem(char *buf, size_t count,
>  		if (pfn_is_ram(pfn) == 0)
>  			memset(buf, 0, nr_bytes);
>  		else {
> -			if (encrypted)
> +			if (IS_ENABLED(CONFIG_X86_64) &&
> +			    IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) &&
> +			    encrypted)
>  				tmp = copy_oldmem_page_encrypted(pfn, buf,
>  								 nr_bytes,
>  								 offset,
> -- 

Doesn't that fix it?

https://git.kernel.org/tip/cf089611f4c446285046fcd426d90c18f37d2905
Arnd Bergmann Oct. 10, 2018, 2:45 p.m. UTC | #2
On 10/10/18, Borislav Petkov <bp@suse.de> wrote:
> On Wed, Oct 10, 2018 at 04:32:45PM +0200, Arnd Bergmann wrote:
>> We get a link failure when calling copy_oldmem_page_encrypted()
>> when the compiler fails to do constant-propagation of the
>> sme_active() result into read_from_oldmem:
>>
>> fs/proc/vmcore.o: In function `read_from_oldmem.part.0':
>> vmcore.c:(.text+0xb7): undefined reference to
>> `copy_oldmem_page_encrypted'
>>
>> Adding an IS_ENABLED() check means the compiler will always
>> know when it cannot be enabled.
>>
>> Fixes: 992b649a3f01 ("kdump, proc/vmcore: Enable kdumping encrypted memory
>> with SME enabled")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> ---
>> There may be a better way of doing this, not sure what kinds
>> of assumptions we want to make here.
>> ---
>>  fs/proc/vmcore.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
>> index d469ce9d8c0c..92e1e520a52d 100644
>> --- a/fs/proc/vmcore.c
>> +++ b/fs/proc/vmcore.c
>> @@ -123,7 +123,9 @@ static ssize_t read_from_oldmem(char *buf, size_t
>> count,
>>  		if (pfn_is_ram(pfn) == 0)
>>  			memset(buf, 0, nr_bytes);
>>  		else {
>> -			if (encrypted)
>> +			if (IS_ENABLED(CONFIG_X86_64) &&
>> +			    IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) &&
>> +			    encrypted)
>>  				tmp = copy_oldmem_page_encrypted(pfn, buf,
>>  								 nr_bytes,
>>  								 offset,
>> --
>
> Doesn't that fix it?
>
> https://git.kernel.org/tip/cf089611f4c446285046fcd426d90c18f37d2905

Sorry, my mistake. I noticed this patch was still in my queue and not marked
as 'submitted'. I forgot we had already discussed it.

      Arnd
diff mbox series

Patch

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index d469ce9d8c0c..92e1e520a52d 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -123,7 +123,9 @@  static ssize_t read_from_oldmem(char *buf, size_t count,
 		if (pfn_is_ram(pfn) == 0)
 			memset(buf, 0, nr_bytes);
 		else {
-			if (encrypted)
+			if (IS_ENABLED(CONFIG_X86_64) &&
+			    IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) &&
+			    encrypted)
 				tmp = copy_oldmem_page_encrypted(pfn, buf,
 								 nr_bytes,
 								 offset,