Commit bd0dbb73 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman

powerpc/mm/books3s: Add new pte bit to mark pte temporarily invalid.

When splitting a huge pmd pte, we need to mark the pmd entry invalid. We
can do that by clearing _PAGE_PRESENT bit. But then that will be taken as a
swap pte. In order to differentiate between the two use a software pte bit
when invalidating.

For regular pte, due to bd5050e3 ("powerpc/mm/radix: Change pte relax
sequence to handle nest MMU hang") we need to mark the pte entry invalid when
relaxing access permission. Instead of marking pte_none which can result in
different page table walk routines possibly skipping this pte entry, invalidate
it but still keep it marked present.
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 810e9f86
...@@ -44,6 +44,16 @@ ...@@ -44,6 +44,16 @@
#define _PAGE_PTE 0x4000000000000000UL /* distinguishes PTEs from pointers */ #define _PAGE_PTE 0x4000000000000000UL /* distinguishes PTEs from pointers */
#define _PAGE_PRESENT 0x8000000000000000UL /* pte contains a translation */ #define _PAGE_PRESENT 0x8000000000000000UL /* pte contains a translation */
/*
* We need to mark a pmd pte invalid while splitting. We can do that by clearing
* the _PAGE_PRESENT bit. But then that will be taken as a swap pte. In order to
* differentiate between two use a SW field when invalidating.
*
* We do that temporary invalidate for regular pte entry in ptep_set_access_flags
*
* This is used only when _PAGE_PRESENT is cleared.
*/
#define _PAGE_INVALID _RPAGE_SW0
/* /*
* Top and bottom bits of RPN which can be used by hash * Top and bottom bits of RPN which can be used by hash
...@@ -568,7 +578,13 @@ static inline pte_t pte_clear_savedwrite(pte_t pte) ...@@ -568,7 +578,13 @@ static inline pte_t pte_clear_savedwrite(pte_t pte)
static inline int pte_present(pte_t pte) static inline int pte_present(pte_t pte)
{ {
return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT)); /*
* A pte is considerent present if _PAGE_PRESENT is set.
* We also need to consider the pte present which is marked
* invalid during ptep_set_access_flags. Hence we look for _PAGE_INVALID
* if we find _PAGE_PRESENT cleared.
*/
return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID));
} }
#ifdef CONFIG_PPC_MEM_KEYS #ifdef CONFIG_PPC_MEM_KEYS
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment