diff options
| author | Pasha Tatashin <pasha.tatashin@soleen.com> | 2025-11-01 10:23:19 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-11-27 14:24:32 -0800 |
| commit | 36f8f7ef7fd2f238922e9d217e86c69838319d8c (patch) | |
| tree | c9f84f06a1baf749fafe79c80b9bca1625c4de97 | |
| parent | 70f9133096c833922c3b63461480248cefa7bb0f (diff) | |
| download | tip-36f8f7ef7fd2f238922e9d217e86c69838319d8c.tar.gz | |
kho: add interfaces to unpreserve folios, page ranges, and vmalloc
Allow users of KHO to cancel the previous preservation by adding the
necessary interfaces to unpreserve folio, pages, and vmallocs.
Link: https://lkml.kernel.org/r/20251101142325.1326536-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/kexec_handover.h | 18 | ||||
| -rw-r--r-- | kernel/kexec_handover.c | 104 |
2 files changed, 109 insertions, 13 deletions
diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h index 0d860d793b6673..80ece423261727 100644 --- a/include/linux/kexec_handover.h +++ b/include/linux/kexec_handover.h @@ -43,8 +43,11 @@ bool kho_is_enabled(void); bool is_kho_boot(void); int kho_preserve_folio(struct folio *folio); +int kho_unpreserve_folio(struct folio *folio); int kho_preserve_pages(struct page *page, unsigned int nr_pages); +int kho_unpreserve_pages(struct page *page, unsigned int nr_pages); int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation); +int kho_unpreserve_vmalloc(struct kho_vmalloc *preservation); struct folio *kho_restore_folio(phys_addr_t phys); struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages); void *kho_restore_vmalloc(const struct kho_vmalloc *preservation); @@ -72,17 +75,32 @@ static inline int kho_preserve_folio(struct folio *folio) return -EOPNOTSUPP; } +static inline int kho_unpreserve_folio(struct folio *folio) +{ + return -EOPNOTSUPP; +} + static inline int kho_preserve_pages(struct page *page, unsigned int nr_pages) { return -EOPNOTSUPP; } +static inline int kho_unpreserve_pages(struct page *page, unsigned int nr_pages) +{ + return -EOPNOTSUPP; +} + static inline int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation) { return -EOPNOTSUPP; } +static inline int kho_unpreserve_vmalloc(struct kho_vmalloc *preservation) +{ + return -EOPNOTSUPP; +} + static inline struct folio *kho_restore_folio(phys_addr_t phys) { return NULL; diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 3dd917bfedcc40..4e033f96637d0d 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -157,26 +157,33 @@ static void *xa_load_or_alloc(struct xarray *xa, unsigned long index) return no_free_ptr(elm); } -static void __kho_unpreserve(struct kho_mem_track *track, unsigned long pfn, - unsigned long end_pfn) +static void __kho_unpreserve_order(struct kho_mem_track *track, unsigned long pfn, + unsigned int order) { struct kho_mem_phys_bits *bits; struct kho_mem_phys *physxa; + const unsigned long pfn_high = pfn >> order; - while (pfn < end_pfn) { - const unsigned int order = - min(count_trailing_zeros(pfn), ilog2(end_pfn - pfn)); - const unsigned long pfn_high = pfn >> order; + physxa = xa_load(&track->orders, order); + if (WARN_ON_ONCE(!physxa)) + return; - physxa = xa_load(&track->orders, order); - if (WARN_ON_ONCE(!physxa)) - return; + bits = xa_load(&physxa->phys_bits, pfn_high / PRESERVE_BITS); + if (WARN_ON_ONCE(!bits)) + return; - bits = xa_load(&physxa->phys_bits, pfn_high / PRESERVE_BITS); - if (WARN_ON_ONCE(!bits)) - return; + clear_bit(pfn_high % PRESERVE_BITS, bits->preserve); +} + +static void __kho_unpreserve(struct kho_mem_track *track, unsigned long pfn, + unsigned long end_pfn) +{ + unsigned int order; + + while (pfn < end_pfn) { + order = min(count_trailing_zeros(pfn), ilog2(end_pfn - pfn)); - clear_bit(pfn_high % PRESERVE_BITS, bits->preserve); + __kho_unpreserve_order(track, pfn, order); pfn += 1 << order; } @@ -746,6 +753,30 @@ int kho_preserve_folio(struct folio *folio) EXPORT_SYMBOL_GPL(kho_preserve_folio); /** + * kho_unpreserve_folio - unpreserve a folio. + * @folio: folio to unpreserve. + * + * Instructs KHO to unpreserve a folio that was preserved by + * kho_preserve_folio() before. The provided @folio (pfn and order) + * must exactly match a previously preserved folio. + * + * Return: 0 on success, error code on failure + */ +int kho_unpreserve_folio(struct folio *folio) +{ + const unsigned long pfn = folio_pfn(folio); + const unsigned int order = folio_order(folio); + struct kho_mem_track *track = &kho_out.track; + + if (kho_out.finalized) + return -EBUSY; + + __kho_unpreserve_order(track, pfn, order); + return 0; +} +EXPORT_SYMBOL_GPL(kho_unpreserve_folio); + +/** * kho_preserve_pages - preserve contiguous pages across kexec * @page: first page in the list. * @nr_pages: number of pages. @@ -789,6 +820,33 @@ int kho_preserve_pages(struct page *page, unsigned int nr_pages) } EXPORT_SYMBOL_GPL(kho_preserve_pages); +/** + * kho_unpreserve_pages - unpreserve contiguous pages. + * @page: first page in the list. + * @nr_pages: number of pages. + * + * Instructs KHO to unpreserve @nr_pages contiguous pages starting from @page. + * This must be called with the same @page and @nr_pages as the corresponding + * kho_preserve_pages() call. Unpreserving arbitrary sub-ranges of larger + * preserved blocks is not supported. + * + * Return: 0 on success, error code on failure + */ +int kho_unpreserve_pages(struct page *page, unsigned int nr_pages) +{ + struct kho_mem_track *track = &kho_out.track; + const unsigned long start_pfn = page_to_pfn(page); + const unsigned long end_pfn = start_pfn + nr_pages; + + if (kho_out.finalized) + return -EBUSY; + + __kho_unpreserve(track, start_pfn, end_pfn); + + return 0; +} +EXPORT_SYMBOL_GPL(kho_unpreserve_pages); + struct kho_vmalloc_hdr { DECLARE_KHOSER_PTR(next, struct kho_vmalloc_chunk *); }; @@ -951,6 +1009,26 @@ err_free: EXPORT_SYMBOL_GPL(kho_preserve_vmalloc); /** + * kho_unpreserve_vmalloc - unpreserve memory allocated with vmalloc() + * @preservation: preservation metadata returned by kho_preserve_vmalloc() + * + * Instructs KHO to unpreserve the area in vmalloc address space that was + * previously preserved with kho_preserve_vmalloc(). + * + * Return: 0 on success, error code on failure + */ +int kho_unpreserve_vmalloc(struct kho_vmalloc *preservation) +{ + if (kho_out.finalized) + return -EBUSY; + + kho_vmalloc_free_chunks(preservation); + + return 0; +} +EXPORT_SYMBOL_GPL(kho_unpreserve_vmalloc); + +/** * kho_restore_vmalloc - recreates and populates an area in vmalloc address * space from the preserved memory. * @preservation: preservation metadata. |