Commit 3e9a9e25 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew 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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b944afc9

include/linux/vmalloc.h

+1 −0
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ extern void vfree_atomic(const void *addr); 


extern void *vmap(struct page **pages, unsigned int count,

			unsigned long flags, pgprot_t prot);

void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot);

extern void vunmap(const void *addr);



extern int remap_vmalloc_range_partial(struct vm_area_struct *vma,

mm/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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

mm/vmalloc.c

+45 −0
Original line number Diff line number Diff line
@@ -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)

{

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