[PATCH v1 06/11] x86/mm/pat: remove old pfnmap tracking interface

David Hildenbrand
2025-04-25T08:17:39Z

We can now get rid of the old interface along with get_pat_info() and
follow_phys().

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/x86/mm/pat/memtype.c | 147 --------------------------------------
include/linux/pgtable.h | 66 -----------------
2 files changed, 213 deletions(-)

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index c011d8dd8f441..668ebf0065157 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -933,119 +933,6 @@ static void free_pfn_range(u64 paddr, unsigned long size)
memtype_free(paddr, paddr + size);
}

-static int follow_phys(struct vm_area_struct *vma, unsigned long *prot,
- resource_size_t *phys)
-{
- struct follow_pfnmap_args args = { .vma = vma, .address = vma->vm_start };
-
- if (follow_pfnmap_start(&args))
- return -EINVAL;
-
- /* Never return PFNs of anon folios in COW mappings. */
- if (!args.special) {
- follow_pfnmap_end(&args);
- return -EINVAL;
- }
-
- *prot = pgprot_val(args.pgprot);
- *phys = (resource_size_t)args.pfn << PAGE_SHIFT;
- follow_pfnmap_end(&args);
- return 0;
-}
-
-static int get_pat_info(struct vm_area_struct *vma, resource_size_t *paddr,
- pgprot_t *pgprot)
-{
- unsigned long prot;
-
- VM_WARN_ON_ONCE(!(vma->vm_flags & VM_PAT));
-
- /*
- * We need the starting PFN and cachemode used for track_pfn_remap()
- * that covered the whole VMA. For most mappings, we can obtain that
- * information from the page tables. For COW mappings, we might now
- * suddenly have anon folios mapped and follow_phys() will fail.
- *
- * Fallback to using vma->vm_pgoff, see remap_pfn_range_notrack(), to
- * detect the PFN. If we need the cachemode as well, we're out of luck
- * for now and have to fail fork().
- */
- if (!follow_phys(vma, &prot, paddr)) {
- if (pgprot)
- *pgprot = __pgprot(prot);
- return 0;
- }
- if (is_cow_mapping(vma->vm_flags)) {
- if (pgprot)
- return -EINVAL;
- *paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
- return 0;
- }
- WARN_ON_ONCE(1);
- return -EINVAL;
-}
-
-int track_pfn_copy(struct vm_area_struct *dst_vma,
- struct vm_area_struct *src_vma, unsigned long *pfn)
-{
- const unsigned long vma_size = src_vma->vm_end - src_vma->vm_start;
- resource_size_t paddr;
- pgprot_t pgprot;
- int rc;
-
- if (!(src_vma->vm_flags & VM_PAT))
- return 0;
-
- /*
- * Duplicate the PAT information for the dst VMA based on the src
- * VMA.
- */
- if (get_pat_info(src_vma, &paddr, &pgprot))
- return -EINVAL;
- rc = reserve_pfn_range(paddr, vma_size, &pgprot, 1);
- if (rc)
- return rc;
-
- /* Reservation for the destination VMA succeeded. */
- vm_flags_set(dst_vma, VM_PAT);
- *pfn = PHYS_PFN(paddr);
- return 0;
-}
-
-void untrack_pfn_copy(struct vm_area_struct *dst_vma, unsigned long pfn)
-{
- untrack_pfn(dst_vma, pfn, dst_vma->vm_end - dst_vma->vm_start, true);
- /*
- * Reservation was freed, any copied page tables will get cleaned
- * up later, but without getting PAT involved again.
- */
-}
-
-/*
- * prot is passed in as a parameter for the new mapping. If the vma has
- * a linear pfn mapping for the entire range, or no vma is provided,
- * reserve the entire pfn + size range with single reserve_pfn_range
- * call.
- */
-int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
- unsigned long pfn, unsigned long addr, unsigned long size)
-{
- resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
-
- /* reserve the whole chunk starting from paddr */
- if (!vma || (addr == vma->vm_start
- && size == (vma->vm_end - vma->vm_start))) {
- int ret;
-
- ret = reserve_pfn_range(paddr, size, prot, 0);
- if (ret == 0 && vma)
- vm_flags_set(vma, VM_PAT);
- return ret;
- }
-
- return pfnmap_sanitize_pgprot(pfn, size, prot);
-}
-
int pfnmap_sanitize_pgprot(unsigned long pfn, unsigned long size, pgprot_t *prot)
{
resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
@@ -1082,40 +969,6 @@ void pfnmap_untrack(unsigned long pfn, unsigned long size)
free_pfn_range(paddr, size);
}

-/*
- * untrack_pfn is called while unmapping a pfnmap for a region.
- * untrack can be called for a specific region indicated by pfn and size or
- * can be for the entire vma (in which case pfn, size are zero).
- */
-void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
- unsigned long size, bool mm_wr_locked)
-{
- resource_size_t paddr;
-
- if (vma && !(vma->vm_flags & VM_PAT))
- return;
-
- /* free the chunk starting from pfn or the whole chunk */
- paddr = (resource_size_t)pfn << PAGE_SHIFT;
- if (!paddr && !size) {
- if (get_pat_info(vma, &paddr, NULL))
- return;
- size = vma->vm_end - vma->vm_start;
- }
- free_pfn_range(paddr, size);
- if (vma) {
- if (mm_wr_locked)
- vm_flags_clear(vma, VM_PAT);
- else
- __vm_flags_mod(vma, 0, VM_PAT);
- }
-}
-
-void untrack_pfn_clear(struct vm_area_struct *vma)
-{
- vm_flags_clear(vma, VM_PAT);
-}
-
pgprot_t pgprot_writecombine(pgprot_t prot)
{
pgprot_set_cachemode(&prot, _PAGE_CACHE_MODE_WC);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 898a3ab195578..0ffc6b9339182 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1489,17 +1489,6 @@ static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
* vmf_insert_pfn.
*/

-/*
- * track_pfn_remap is called when a _new_ pfn mapping is being established
- * by remap_pfn_range() for physical range indicated by pfn and size.
- */
-static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
- unsigned long pfn, unsigned long addr,
- unsigned long size)
-{
- return 0;
-}
-
static inline int pfnmap_sanitize_pgprot(unsigned long pfn, unsigned long size,
pgprot_t *prot)
{
@@ -1515,55 +1504,7 @@ static inline int pfnmap_track(unsigned long pfn, unsigned long size,
static inline void pfnmap_untrack(unsigned long pfn, unsigned long size)
{
}
-
-/*
- * track_pfn_copy is called when a VM_PFNMAP VMA is about to get the page
- * tables copied during copy_page_range(). Will store the pfn to be
- * passed to untrack_pfn_copy() only if there is something to be untracked.
- * Callers should initialize the pfn to 0.
- */
-static inline int track_pfn_copy(struct vm_area_struct *dst_vma,
- struct vm_area_struct *src_vma, unsigned long *pfn)
-{
- return 0;
-}
-
-/*
- * untrack_pfn_copy is called when a VM_PFNMAP VMA failed to copy during
- * copy_page_range(), but after track_pfn_copy() was already called. Can
- * be called even if track_pfn_copy() did not actually track anything:
- * handled internally.
- */
-static inline void untrack_pfn_copy(struct vm_area_struct *dst_vma,
- unsigned long pfn)
-{
-}
-
-/*
- * untrack_pfn is called while unmapping a pfnmap for a region.
- * untrack can be called for a specific region indicated by pfn and size or
- * can be for the entire vma (in which case pfn, size are zero).
- */
-static inline void untrack_pfn(struct vm_area_struct *vma,
- unsigned long pfn, unsigned long size,
- bool mm_wr_locked)
-{
-}
-
-/*
- * untrack_pfn_clear is called in the following cases on a VM_PFNMAP VMA:
- *
- * 1) During mremap() on the src VMA after the page tables were moved.
- * 2) During fork() on the dst VMA, immediately after duplicating the src VMA.
- */
-static inline void untrack_pfn_clear(struct vm_area_struct *vma)
-{
-}
#else
-extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
- unsigned long pfn, unsigned long addr,
- unsigned long size);
-
/**
* pfnmap_sanitize_pgprot - sanitize the pgprot for a pfn range
* @pfn: the start of the pfn range
@@ -1603,13 +1544,6 @@ int pfnmap_track(unsigned long pfn, unsigned long size, pgprot_t *prot);
* un-doing any reservation.
*/
void pfnmap_untrack(unsigned long pfn, unsigned long size);
-extern int track_pfn_copy(struct vm_area_struct *dst_vma,
- struct vm_area_struct *src_vma, unsigned long *pfn);
-extern void untrack_pfn_copy(struct vm_area_struct *dst_vma,
- unsigned long pfn);
-extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
- unsigned long size, bool mm_wr_locked);
-extern void untrack_pfn_clear(struct vm_area_struct *vma);
#endif

#ifdef CONFIG_MMU
--
2.49.0