On Fri, Mar 10, 2023 at 01:22:04PM +0100, Nico Boehr wrote:
> Diag 308 subcodes expect a physical address as their parameter.
>
> This currently is not a bug, but in the future physical and virtual
> addresses might differ.
>
> Fix the confusion by doing a virtual-to-physical conversion in the
> exported diag308() and leave the assembly wrapper __diag308() alone.
>
> Note that several callers pass NULL as addr, this is fine since
> virt_to_phys(0) == 0.
>
> Suggested-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
> Signed-off-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
> ---
> arch/s390/kernel/ipl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
> index 5f0f5c86963a..5611ba8f68b9 100644
> --- a/arch/s390/kernel/ipl.c
> +++ b/arch/s390/kernel/ipl.c
> @@ -176,7 +176,7 @@ static bool reipl_fcp_clear;
> static bool reipl_ccw_clear;
> static bool reipl_eckd_clear;
>
> -static inline int __diag308(unsigned long subcode, void *addr)
> +static inline int __diag308(unsigned long subcode, u64 addr)
> {
> union register_pair r1;
>
> @@ -195,7 +195,7 @@ static inline int __diag308(unsigned long subcode, void *addr)
> int diag308(unsigned long subcode, void *addr)
> {
> diag_stat_inc(DIAG_STAT_X308);
> - return __diag308(subcode, addr);
> + return __diag308(subcode, virt_to_phys(addr));
> }
> EXPORT_SYMBOL_GPL(diag308);
Please note diag308() is called with NULL a lot.
I think a proper fix would be like this:
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 0f91cd401eef..43de939b7af1 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -176,11 +176,11 @@ static bool reipl_fcp_clear;
static bool reipl_ccw_clear;
static bool reipl_eckd_clear;
-static inline int __diag308(unsigned long subcode, void *addr)
+static inline int __diag308(unsigned long subcode, unsigned long addr)
{
union register_pair r1;
- r1.even = (unsigned long) addr;
+ r1.even = addr;
r1.odd = 0;
asm volatile(
" diag %[r1],%[subcode],0x308\n"
@@ -195,7 +195,7 @@ static inline int __diag308(unsigned long subcode, void *addr)
int diag308(unsigned long subcode, void *addr)
{
diag_stat_inc(DIAG_STAT_X308);
- return __diag308(subcode, addr);
+ return __diag308(subcode, addr ? virt_to_phys(addr) : 0);
}
EXPORT_SYMBOL_GPL(diag308);
