Re: [PATCH] powerpc/mm: Invalidate partition table cache on host proc tbl base update

On Wed, 2017-08-09 at 20:30 +1000, Michael Ellerman wrote:

Suraj Jitindar Singh [off-list ref] writes:

quoted

The host process table base is stored in the partition table by
calling
the function native_register_process_table(). Currently this just
sets
the entry in memory and is missing a proceeding cache invalidation
instruction. Any update to the partition table should be followed
by a
cache invalidation instruction specifying invalidation of the
caching of
any partition table entries (RIC = 2, PRS = 0).

We already have a function to update the partition table with the
required cache invalidation instructions -
mmu_partition_table_set_entry().
Update the native_register_process_table() function to call
mmu_partition_table_set_entry(), this ensures all appropriate
invalidation will be performed.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 arch/powerpc/mm/pgtable-radix.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/pgtable-radix.c

b/arch/powerpc/mm/pgtable-radix.c
index 671a45d..1d5178f 100644

--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c

@@ -33,7 +33,8 @@ static int native_register_process_table(unsigned

long base, unsigned long pg_sz
 {
 	unsigned long patb1 = base | table_size | PATB_GR;
 
-	partition_tb->patb1 = cpu_to_be64(patb1);
+	mmu_partition_table_set_entry(0, be64_to_cpu(partition_tb-

quoted

patb0),

+				      patb1);

This is really a bit gross.

Can we agree on whether partition_tb is an array or not?

Well it is an array, it's just we only ever want the first element in
this function. That being said we might as well access it as an array
to make that clear.

Looks good :)