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authorChristoph Hellwig <hch@lst.de>2020-10-17 16:15:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-18 09:27:10 -0700
commit3e9a9e256b1e1e6e8f19faf76fa9c37578ae35ee (patch)
tree241415091329c60aab89e0cca627c762567e6931 /mm
parentb944afc9d64ddf1b6a152c23ff86bf26e1fd430c (diff)
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mm: add a vmap_pfn function
Add a proper helper to remap PFNs into kernel virtual space so that drivers don't have to abuse alloc_vm_area and open coded PTE manipulation for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Juergen Gross <jgross@suse.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Link: https://lkml.kernel.org/r/20201002122204.1534411-4-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig3
-rw-r--r--mm/vmalloc.c45
2 files changed, 48 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index c7f30f8b282b..d42423f884a7 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -816,6 +816,9 @@ config DEVICE_PRIVATE
memory; i.e., memory that is only accessible from the device (or
group of devices). You likely also want to select HMM_MIRROR.
+config VMAP_PFN
+ bool
+
config FRAME_VECTOR
bool
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 63b19a571be7..c6bf73a64db8 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2413,6 +2413,51 @@ void *vmap(struct page **pages, unsigned int count,
}
EXPORT_SYMBOL(vmap);
+#ifdef CONFIG_VMAP_PFN
+struct vmap_pfn_data {
+ unsigned long *pfns;
+ pgprot_t prot;
+ unsigned int idx;
+};
+
+static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
+{
+ struct vmap_pfn_data *data = private;
+
+ if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
+ return -EINVAL;
+ *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+ return 0;
+}
+
+/**
+ * vmap_pfn - map an array of PFNs into virtually contiguous space
+ * @pfns: array of PFNs
+ * @count: number of pages to map
+ * @prot: page protection for the mapping
+ *
+ * Maps @count PFNs from @pfns into contiguous kernel virtual space and returns
+ * the start address of the mapping.
+ */
+void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot)
+{
+ struct vmap_pfn_data data = { .pfns = pfns, .prot = pgprot_nx(prot) };
+ struct vm_struct *area;
+
+ area = get_vm_area_caller(count * PAGE_SIZE, VM_IOREMAP,
+ __builtin_return_address(0));
+ if (!area)
+ return NULL;
+ if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
+ count * PAGE_SIZE, vmap_pfn_apply, &data)) {
+ free_vm_area(area);
+ return NULL;
+ }
+ return area->addr;
+}
+EXPORT_SYMBOL_GPL(vmap_pfn);
+#endif /* CONFIG_VMAP_PFN */
+
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
pgprot_t prot, int node)
{