Commit 18e780b4 authored by Kefeng Wang's avatar Kefeng Wang Committed by Will Deacon
Browse files

mm: ioremap: Add ioremap/iounmap_allowed() 



Add special hook for architecture to verify addr, size or prot
when ioremap() or iounmap(), which will make the generic ioremap
more useful.

  ioremap_allowed() return a bool,
    - true means continue to remap
    - false means skip remap and return directly
  iounmap_allowed() return a bool,
    - true means continue to vunmap
    - false code means skip vunmap and return directly

Meanwhile, only vunmap the address when it is in vmalloc area
as the generic ioremap only returns vmalloc addresses.

Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBaoquan He <bhe@redhat.com>
Link: https://lore.kernel.org/r/20220607125027.44946-5-wangkefeng.wang@huawei.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent a14fff1c

include/asm-generic/io.h

+26 −0
Original line number Diff line number Diff line
@@ -964,6 +964,32 @@ static inline void iounmap(volatile void __iomem *addr) 
#elif defined(CONFIG_GENERIC_IOREMAP)

#include <linux/pgtable.h>



/*

 * Arch code can implement the following two hooks when using GENERIC_IOREMAP

 * ioremap_allowed() return a bool,

 *   - true means continue to remap

 *   - false means skip remap and return directly

 * iounmap_allowed() return a bool,

 *   - true means continue to vunmap

 *   - false means skip vunmap and return directly

 */

#ifndef ioremap_allowed

#define ioremap_allowed ioremap_allowed

static inline bool ioremap_allowed(phys_addr_t phys_addr, size_t size,

				   unsigned long prot)

{

	return true;

}

#endif



#ifndef iounmap_allowed

#define iounmap_allowed iounmap_allowed

static inline bool iounmap_allowed(void *addr)

{

	return true;

}

#endif



void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,

			   unsigned long prot);

void iounmap(volatile void __iomem *addr);

mm/ioremap.c

+10 −1
Original line number Diff line number Diff line
@@ -28,6 +28,9 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, 
	phys_addr -= offset;

	size = PAGE_ALIGN(size + offset);



	if (!ioremap_allowed(phys_addr, size, prot))

		return NULL;



	area = get_vm_area_caller(size, VM_IOREMAP,

			__builtin_return_address(0));

	if (!area)
@@ -47,6 +50,12 @@ EXPORT_SYMBOL(ioremap_prot); 


void iounmap(volatile void __iomem *addr)

{

	vunmap((void *)((unsigned long)addr & PAGE_MASK));

	void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);



	if (!iounmap_allowed(vaddr))

		return;



	if (is_vmalloc_addr(vaddr))

		vunmap(vaddr);

}

EXPORT_SYMBOL(iounmap);