Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 3fec513..866a0fa 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -3,66 +3,14 @@
* Copyright 2013 Red Hat Inc.
*
* Authors: Jérôme Glisse <jglisse@redhat.com>
- */
-/*
- * Heterogeneous Memory Management (HMM)
*
- * See Documentation/vm/hmm.rst for reasons and overview of what HMM is and it
- * is for. Here we focus on the HMM API description, with some explanation of
- * the underlying implementation.
- *
- * Short description: HMM provides a set of helpers to share a virtual address
- * space between CPU and a device, so that the device can access any valid
- * address of the process (while still obeying memory protection). HMM also
- * provides helpers to migrate process memory to device memory, and back. Each
- * set of functionality (address space mirroring, and migration to and from
- * device memory) can be used independently of the other.
- *
- *
- * HMM address space mirroring API:
- *
- * Use HMM address space mirroring if you want to mirror a range of the CPU
- * page tables of a process into a device page table. Here, "mirror" means "keep
- * synchronized". Prerequisites: the device must provide the ability to write-
- * protect its page tables (at PAGE_SIZE granularity), and must be able to
- * recover from the resulting potential page faults.
- *
- * HMM guarantees that at any point in time, a given virtual address points to
- * either the same memory in both CPU and device page tables (that is: CPU and
- * device page tables each point to the same pages), or that one page table (CPU
- * or device) points to no entry, while the other still points to the old page
- * for the address. The latter case happens when the CPU page table update
- * happens first, and then the update is mirrored over to the device page table.
- * This does not cause any issue, because the CPU page table cannot start
- * pointing to a new page until the device page table is invalidated.
- *
- * HMM uses mmu_notifiers to monitor the CPU page tables, and forwards any
- * updates to each device driver that has registered a mirror. It also provides
- * some API calls to help with taking a snapshot of the CPU page table, and to
- * synchronize with any updates that might happen concurrently.
- *
- *
- * HMM migration to and from device memory:
- *
- * HMM provides a set of helpers to hotplug device memory as ZONE_DEVICE, with
- * a new MEMORY_DEVICE_PRIVATE type. This provides a struct page for each page
- * of the device memory, and allows the device driver to manage its memory
- * using those struct pages. Having struct pages for device memory makes
- * migration easier. Because that memory is not addressable by the CPU it must
- * never be pinned to the device; in other words, any CPU page fault can always
- * cause the device memory to be migrated (copied/moved) back to regular memory.
- *
- * A new migrate helper (migrate_vma()) has been added (see mm/migrate.c) that
- * allows use of a device DMA engine to perform the copy operation between
- * regular system memory and device memory.
+ * See Documentation/vm/hmm.rst for reasons and overview of what HMM is.
*/
#ifndef LINUX_HMM_H
#define LINUX_HMM_H
#include <linux/kconfig.h>
-#include <asm/pgtable.h>
-
-#ifdef CONFIG_HMM_MIRROR
+#include <linux/pgtable.h>
#include <linux/device.h>
#include <linux/migrate.h>
@@ -70,332 +18,96 @@
#include <linux/completion.h>
#include <linux/mmu_notifier.h>
-
/*
- * struct hmm - HMM per mm struct
+ * 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
*
- * @mm: mm struct this HMM struct is bound to
- * @lock: lock protecting ranges list
- * @ranges: list of range being snapshotted
- * @mirrors: list of mirrors for this mm
- * @mmu_notifier: mmu notifier to track updates to CPU page table
- * @mirrors_sem: read/write semaphore protecting the mirrors list
- * @wq: wait queue for user waiting on a range invalidation
- * @notifiers: count of active mmu notifiers
+ * 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.
*/
-struct hmm {
- struct mmu_notifier mmu_notifier;
- spinlock_t ranges_lock;
- struct list_head ranges;
- struct list_head mirrors;
- struct rw_semaphore mirrors_sem;
- wait_queue_head_t wq;
- long notifiers;
+enum hmm_pfn_flags {
+ /* Output fields and 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),
+ HMM_PFN_ORDER_SHIFT = (BITS_PER_LONG - 8),
+
+ /* Input flags */
+ HMM_PFN_REQ_FAULT = HMM_PFN_VALID,
+ HMM_PFN_REQ_WRITE = HMM_PFN_WRITE,
+
+ HMM_PFN_FLAGS = 0xFFUL << HMM_PFN_ORDER_SHIFT,
};
/*
- * hmm_pfn_flag_e - HMM flag enums
+ * hmm_pfn_to_page() - return struct page pointed to by a device entry
*
- * Flags:
- * HMM_PFN_VALID: pfn is valid. It has, at least, read permission.
- * HMM_PFN_WRITE: CPU page table has write permission set
- * HMM_PFN_DEVICE_PRIVATE: private device memory (ZONE_DEVICE)
- *
- * 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.
+ * 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_flag_e {
- HMM_PFN_VALID = 0,
- HMM_PFN_WRITE,
- HMM_PFN_DEVICE_PRIVATE,
- HMM_PFN_FLAG_MAX
-};
+static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn)
+{
+ return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS);
+}
/*
- * hmm_pfn_value_e - HMM pfn special value
+ * hmm_pfn_to_map_order() - return the CPU mapping size order
*
- * 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_SPECIAL: corresponding CPU page table entry is special; i.e., the
- * result of vmf_insert_pfn() or vm_insert_page(). Therefore, it should not
- * be mirrored by a device, because the entry will never have HMM_PFN_VALID
- * set and the pfn value is undefined.
+ * This is optionally useful to optimize processing of the pfn result
+ * array. It indicates that the page starts at the order aligned VA and is
+ * 1<<order bytes long. Every pfn within an high order page will have the
+ * same pfn flags, both access protections and the map_order. The caller must
+ * be careful with edge cases as the start and end VA of the given page may
+ * extend past the range used with hmm_range_fault().
*
- * 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,
- * hmm_range.values[HMM_PFN_SPECIAL] if CPU page table entry is a special one
+ * 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_SPECIAL,
- HMM_PFN_VALUE_MAX
-};
+static inline unsigned int hmm_pfn_to_map_order(unsigned long hmm_pfn)
+{
+ return (hmm_pfn >> HMM_PFN_ORDER_SHIFT) & 0x1F;
+}
/*
* struct hmm_range - track invalidation lock on virtual address range
*
- * @hmm: the core HMM structure this range is active against
- * @vma: the vm area struct for the range
- * @list: all range lock are on a list
+ * @notifier: a mmu_interval_notifier that includes the start/end
+ * @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_shifts: pfn shift value (should be <= PAGE_SHIFT)
- * @valid: pfns array did not change since it has been fill by an HMM function
+ * @dev_private_owner: owner of device private pages
*/
struct hmm_range {
- struct hmm *hmm;
- struct list_head list;
+ struct mmu_interval_notifier *notifier;
+ 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;
- bool valid;
+ unsigned long *hmm_pfns;
+ unsigned long default_flags;
+ unsigned long pfn_flags_mask;
+ void *dev_private_owner;
};
/*
- * hmm_range_wait_until_valid() - wait for range to be valid
- * @range: range affected by invalidation to wait on
- * @timeout: time out for wait in ms (ie abort wait after that period of time)
- * Return: true if the range is valid, false otherwise.
- */
-static inline bool hmm_range_wait_until_valid(struct hmm_range *range,
- unsigned long timeout)
-{
- return wait_event_timeout(range->hmm->wq, range->valid,
- msecs_to_jiffies(timeout)) != 0;
-}
-
-/*
- * hmm_range_valid() - test if a range is valid or not
- * @range: range
- * Return: true if the range is valid, false otherwise.
- */
-static inline bool hmm_range_valid(struct hmm_range *range)
-{
- return range->valid;
-}
-
-/*
- * 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->values[HMM_PFN_SPECIAL])
- return NULL;
- if (!(entry & range->flags[HMM_PFN_VALID]))
- return NULL;
- return pfn_to_page(entry >> range->pfn_shift);
-}
-
-/*
- * hmm_device_entry_to_pfn() - return pfn value store in a device entry
- * @range: range use to decode device entry value
- * @entry: device entry to extract pfn from
- * Return: pfn value if device entry is valid, -1UL otherwise
- */
-static inline unsigned long
-hmm_device_entry_to_pfn(const struct hmm_range *range, uint64_t pfn)
-{
- if (pfn == range->values[HMM_PFN_NONE])
- return -1UL;
- if (pfn == range->values[HMM_PFN_ERROR])
- return -1UL;
- if (pfn == range->values[HMM_PFN_SPECIAL])
- return -1UL;
- if (!(pfn & range->flags[HMM_PFN_VALID]))
- return -1UL;
- return (pfn >> range->pfn_shift);
-}
-
-/*
- * hmm_device_entry_from_page() - create a valid device entry for a page
- * @range: range use to encode HMM pfn value
- * @page: page for which to create the device entry
- * Return: valid device entry for the page
- */
-static inline uint64_t hmm_device_entry_from_page(const struct hmm_range *range,
- struct page *page)
-{
- return (page_to_pfn(page) << range->pfn_shift) |
- range->flags[HMM_PFN_VALID];
-}
-
-/*
- * hmm_device_entry_from_pfn() - create a valid device entry value from pfn
- * @range: range use to encode HMM pfn value
- * @pfn: pfn value for which to create the device entry
- * Return: valid device entry for the pfn
- */
-static inline uint64_t hmm_device_entry_from_pfn(const struct hmm_range *range,
- unsigned long pfn)
-{
- return (pfn << range->pfn_shift) |
- range->flags[HMM_PFN_VALID];
-}
-
-/*
- * Mirroring: how to synchronize device page table with CPU page table.
- *
- * A device driver that is participating in HMM mirroring must always
- * synchronize with CPU page table updates. For this, device drivers can either
- * directly use mmu_notifier APIs or they can use the hmm_mirror API. Device
- * drivers can decide to register one mirror per device per process, or just
- * one mirror per process for a group of devices. The pattern is:
- *
- * int device_bind_address_space(..., struct mm_struct *mm, ...)
- * {
- * struct device_address_space *das;
- *
- * // Device driver specific initialization, and allocation of das
- * // which contains an hmm_mirror struct as one of its fields.
- * ...
- *
- * ret = hmm_mirror_register(&das->mirror, mm, &device_mirror_ops);
- * if (ret) {
- * // Cleanup on error
- * return ret;
- * }
- *
- * // Other device driver specific initialization
- * ...
- * }
- *
- * Once an hmm_mirror is registered for an address space, the device driver
- * will get callbacks through sync_cpu_device_pagetables() operation (see
- * hmm_mirror_ops struct).
- *
- * Device driver must not free the struct containing the hmm_mirror struct
- * before calling hmm_mirror_unregister(). The expected usage is to do that when
- * the device driver is unbinding from an address space.
- *
- *
- * void device_unbind_address_space(struct device_address_space *das)
- * {
- * // Device driver specific cleanup
- * ...
- *
- * hmm_mirror_unregister(&das->mirror);
- *
- * // Other device driver specific cleanup, and now das can be freed
- * ...
- * }
- */
-
-struct hmm_mirror;
-
-/*
- * struct hmm_mirror_ops - HMM mirror device operations callback
- *
- * @update: callback to update range on a device
- */
-struct hmm_mirror_ops {
- /* release() - release hmm_mirror
- *
- * @mirror: pointer to struct hmm_mirror
- *
- * This is called when the mm_struct is being released. The callback
- * must ensure that all access to any pages obtained from this mirror
- * is halted before the callback returns. All future access should
- * fault.
- */
- void (*release)(struct hmm_mirror *mirror);
-
- /* sync_cpu_device_pagetables() - synchronize page tables
- *
- * @mirror: pointer to struct hmm_mirror
- * @update: update information (see struct mmu_notifier_range)
- * Return: -EAGAIN if mmu_notifier_range_blockable(update) is false
- * and callback needs to block, 0 otherwise.
- *
- * This callback ultimately originates from mmu_notifiers when the CPU
- * page table is updated. The device driver must update its page table
- * in response to this callback. The update argument tells what action
- * to perform.
- *
- * The device driver must not return from this callback until the device
- * page tables are completely updated (TLBs flushed, etc); this is a
- * synchronous call.
- */
- int (*sync_cpu_device_pagetables)(
- struct hmm_mirror *mirror,
- const struct mmu_notifier_range *update);
-};
-
-/*
- * struct hmm_mirror - mirror struct for a device driver
- *
- * @hmm: pointer to struct hmm (which is unique per mm_struct)
- * @ops: device driver callback for HMM mirror operations
- * @list: for list of mirrors of a given mm
- *
- * Each address space (mm_struct) being mirrored by a device must register one
- * instance of an hmm_mirror struct with HMM. HMM will track the list of all
- * mirrors for each mm_struct.
- */
-struct hmm_mirror {
- struct hmm *hmm;
- const struct hmm_mirror_ops *ops;
- struct list_head list;
-};
-
-int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm);
-void hmm_mirror_unregister(struct hmm_mirror *mirror);
-
-/*
* Please see Documentation/vm/hmm.rst for how to use the range API.
*/
-int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror);
-void hmm_range_unregister(struct hmm_range *range);
-
-/*
- * Retry fault if non-blocking, drop mmap_sem and return -EAGAIN in that case.
- */
-#define HMM_FAULT_ALLOW_RETRY (1 << 0)
-
-/* Don't fault in missing PTEs, just snapshot the current state. */
-#define HMM_FAULT_SNAPSHOT (1 << 1)
-
-long hmm_range_fault(struct hmm_range *range, unsigned int flags);
-
-long hmm_range_dma_map(struct hmm_range *range,
- struct device *device,
- dma_addr_t *daddrs,
- unsigned int flags);
-long hmm_range_dma_unmap(struct hmm_range *range,
- struct device *device,
- dma_addr_t *daddrs,
- bool dirty);
+int hmm_range_fault(struct hmm_range *range);
/*
* HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range
@@ -406,6 +118,4 @@
*/
#define HMM_RANGE_DEFAULT_TIMEOUT 1000
-#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
-
#endif /* LINUX_HMM_H */