From 0a9ad8273ff4643dd50ff6b3ec991ab270e87a89 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 13 Jan 2023 18:10:13 +0100 Subject: nios2/mm: refactor swap PTE layout nios2 disables swap for a good reason: it doesn't even provide sufficient type bits as required by core MM. However, swap entries are nowadays also used for other purposes (migration entries, PTE markers, HWPoison, ...), and accidential use could be problematic. Let's properly use 5 bits for the swap type and document the layout. Bits 26--31 should get ignored by hardware completely, so they can be used. Link: https://lkml.kernel.org/r/20230113171026.582290-14-david@redhat.com Signed-off-by: David Hildenbrand Cc: Dinh Nguyen Signed-off-by: Andrew Morton --- arch/nios2/include/asm/pgtable.h | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'arch/nios2/include/asm/pgtable.h') diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h index ab793bc517f5..d1e5c9eb4643 100644 --- a/arch/nios2/include/asm/pgtable.h +++ b/arch/nios2/include/asm/pgtable.h @@ -232,19 +232,21 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) __FILE__, __LINE__, pgd_val(e)) /* - * Encode and decode a swap entry (must be !pte_none(pte) && !pte_present(pte): + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). * - * 31 30 29 28 27 26 25 24 23 22 21 20 19 18 ... 1 0 - * 0 0 0 0 type. 0 0 0 0 0 0 offset......... + * Format of swap PTEs: * - * This gives us up to 2**2 = 4 swap files and 2**20 * 4K = 4G per swap file. + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * 0 < type -> 0 0 0 0 0 0 <-------------- offset ---------------> * - * Note that the offset field is always non-zero, thus !pte_none(pte) is always - * true. + * Note that the offset field is always non-zero if the swap type is 0, thus + * !pte_none() is always true. */ -#define __swp_type(swp) (((swp).val >> 26) & 0x3) +#define __swp_type(swp) (((swp).val >> 26) & 0x1f) #define __swp_offset(swp) ((swp).val & 0xfffff) -#define __swp_entry(type, off) ((swp_entry_t) { (((type) & 0x3) << 26) \ +#define __swp_entry(type, off) ((swp_entry_t) { (((type) & 0x1f) << 26) \ | ((off) & 0xfffff) }) #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) -- cgit v1.2.3 From 4d1d955f7c0cdbb7562d19049f859c74276fdfeb Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 13 Jan 2023 18:10:14 +0100 Subject: nios2/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using the yet-unused bit 31. Link: https://lkml.kernel.org/r/20230113171026.582290-15-david@redhat.com Signed-off-by: David Hildenbrand Cc: Thomas Bogendoerfer Signed-off-by: Andrew Morton --- arch/nios2/include/asm/pgtable.h | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) (limited to 'arch/nios2/include/asm/pgtable.h') diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h index d1e5c9eb4643..05999da01731 100644 --- a/arch/nios2/include/asm/pgtable.h +++ b/arch/nios2/include/asm/pgtable.h @@ -239,7 +239,9 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) * * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 - * 0 < type -> 0 0 0 0 0 0 <-------------- offset ---------------> + * E < type -> 0 0 0 0 0 0 <-------------- offset ---------------> + * + * E is the exclusive marker that is not stored in swap entries. * * Note that the offset field is always non-zero if the swap type is 0, thus * !pte_none() is always true. @@ -251,6 +253,24 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + pte_val(pte) |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} + extern void __init paging_init(void); extern void __init mmu_init(void); -- cgit v1.2.3 From 950fe885a89770619e315f9b46301eebf0aab7b3 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 13 Jan 2023 18:10:26 +0100 Subject: mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE __HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that support swp PTEs, so let's drop it. Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton --- arch/nios2/include/asm/pgtable.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/nios2/include/asm/pgtable.h') diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h index 05999da01731..0f5c2564e9f5 100644 --- a/arch/nios2/include/asm/pgtable.h +++ b/arch/nios2/include/asm/pgtable.h @@ -253,7 +253,6 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) -#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE static inline int pte_swp_exclusive(pte_t pte) { return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; -- cgit v1.2.3