#include <linux/mmu_notifier.h>
/*
- * hmm_pfn_flag_e - HMM flag enums
+ * On output:
+ * 0 - The page is faultable and a future call with
+ * HMM_PFN_REQ_FAULT could succeed.
+ * HMM_PFN_VALID - the pfn field points to a valid PFN. This PFN is at
+ * least readable. If dev_private_owner is !NULL then this could
+ * point at a DEVICE_PRIVATE page.
+ * HMM_PFN_WRITE - if the page memory can be written to (requires HMM_PFN_VALID)
+ * HMM_PFN_ERROR - accessing the pfn is impossible and the device should
+ * fail. ie poisoned memory, special pages, no vma, etc
*
- * Flags:
- * HMM_PFN_VALID: pfn is valid. It has, at least, read permission.
- * HMM_PFN_WRITE: CPU page table has write permission set
- *
- * The driver provides a flags array for mapping page protections to device
- * PTE bits. If the driver valid bit for an entry is bit 3,
- * i.e., (entry & (1 << 3)), then the driver must provide
- * an array in hmm_range.flags with hmm_range.flags[HMM_PFN_VALID] == 1 << 3.
- * Same logic apply to all flags. This is the same idea as vm_page_prot in vma
- * except that this is per device driver rather than per architecture.
+ * On input:
+ * 0 - Return the current state of the page, do not fault it.
+ * HMM_PFN_REQ_FAULT - The output must have HMM_PFN_VALID or hmm_range_fault()
+ * will fail
+ * HMM_PFN_REQ_WRITE - The output must have HMM_PFN_WRITE or hmm_range_fault()
+ * will fail. Must be combined with HMM_PFN_REQ_FAULT.
*/
-enum hmm_pfn_flag_e {
- HMM_PFN_VALID = 0,
- HMM_PFN_WRITE,
- HMM_PFN_FLAG_MAX
+enum hmm_pfn_flags {
+ /* Output flags */
+ HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1),
+ HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2),
+ HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3),
+
+ /* Input flags */
+ HMM_PFN_REQ_FAULT = HMM_PFN_VALID,
+ HMM_PFN_REQ_WRITE = HMM_PFN_WRITE,
+
+ HMM_PFN_FLAGS = HMM_PFN_VALID | HMM_PFN_WRITE | HMM_PFN_ERROR,
};
/*
- * hmm_pfn_value_e - HMM pfn special value
- *
- * Flags:
- * HMM_PFN_ERROR: corresponding CPU page table entry points to poisoned memory
- * HMM_PFN_NONE: corresponding CPU page table entry is pte_none()
+ * hmm_pfn_to_page() - return struct page pointed to by a device entry
*
- * Driver provides values for none entry, error entry, and special entry.
- * Driver can alias (i.e., use same value) error and special, but
- * it should not alias none with error or special.
- *
- * HMM pfn value returned by hmm_vma_get_pfns() or hmm_vma_fault() will be:
- * hmm_range.values[HMM_PFN_ERROR] if CPU page table entry is poisonous,
- * hmm_range.values[HMM_PFN_NONE] if there is no CPU page table entry,
+ * This must be called under the caller 'user_lock' after a successful
+ * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID
+ * already.
*/
-enum hmm_pfn_value_e {
- HMM_PFN_ERROR,
- HMM_PFN_NONE,
- HMM_PFN_VALUE_MAX
-};
+static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn)
+{
+ return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS);
+}
/*
* struct hmm_range - track invalidation lock on virtual address range
* @notifier_seq: result of mmu_interval_read_begin()
* @start: range virtual start address (inclusive)
* @end: range virtual end address (exclusive)
- * @pfns: array of pfns (big enough for the range)
- * @flags: pfn flags to match device driver page table
- * @values: pfn value for some special case (none, special, error, ...)
+ * @hmm_pfns: array of pfns (big enough for the range)
* @default_flags: default flags for the range (write, read, ... see hmm doc)
* @pfn_flags_mask: allows to mask pfn flags so that only default_flags matter
- * @pfn_shift: pfn shift value (should be <= PAGE_SHIFT)
* @dev_private_owner: owner of device private pages
*/
struct hmm_range {
unsigned long notifier_seq;
unsigned long start;
unsigned long end;
- uint64_t *pfns;
- const uint64_t *flags;
- const uint64_t *values;
- uint64_t default_flags;
- uint64_t pfn_flags_mask;
- uint8_t pfn_shift;
+ unsigned long *hmm_pfns;
+ unsigned long default_flags;
+ unsigned long pfn_flags_mask;
void *dev_private_owner;
};
-/*
- * hmm_device_entry_to_page() - return struct page pointed to by a device entry
- * @range: range use to decode device entry value
- * @entry: device entry value to get corresponding struct page from
- * Return: struct page pointer if entry is a valid, NULL otherwise
- *
- * If the device entry is valid (ie valid flag set) then return the struct page
- * matching the entry value. Otherwise return NULL.
- */
-static inline struct page *hmm_device_entry_to_page(const struct hmm_range *range,
- uint64_t entry)
-{
- if (entry == range->values[HMM_PFN_NONE])
- return NULL;
- if (entry == range->values[HMM_PFN_ERROR])
- return NULL;
- if (!(entry & range->flags[HMM_PFN_VALID]))
- return NULL;
- return pfn_to_page(entry >> range->pfn_shift);
-}
-
/*
* Please see Documentation/vm/hmm.rst for how to use the range API.
*/
projects / linux-2.6-microblaze.git / blobdiff