Commit 4368902b authored by Gilad Ben-Yossef's avatar Gilad Ben-Yossef Committed by Vineet Gupta
Browse files

ARC: Add support for ioremap_prot API 



Implement ioremap_prot() to allow mapping IO memory with variable
protection
via TLB.

Implementing this allows the /dev/mem driver to use its generic access()
VMA callback, which in turn allows ptrace to examine data in memory
mapped regions mapped via /dev/mem, such as Arc DCCM.

The end result is that it is possible to examine values of variables
placed into DCCM in user space programs via GDB.

CC: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
CC: Noam Camus <noamc@ezchip.com>
Acked-by: default avatarVineet Gupta <vgupta@synopsys.com>
Signed-off-by: default avatarGilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 8c2f4a8d

arch/arc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ config ARC 
	select HAVE_ARCH_KGDB

	select HAVE_ARCH_TRACEHOOK

	select HAVE_GENERIC_HARDIRQS

	select HAVE_IOREMAP_PROT

	select HAVE_IRQ_WORK

	select HAVE_KPROBES

	select HAVE_KRETPROBES

arch/arc/include/asm/io.h

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#define PCI_IOBASE ((void __iomem *)0)



extern void __iomem *ioremap(unsigned long physaddr, unsigned long size);

extern void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,

				  unsigned long flags);

extern void iounmap(const void __iomem *addr);



#define ioremap_nocache(phy, sz)	ioremap(phy, sz)

arch/arc/include/asm/page.h

+3 −0
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ typedef unsigned long pgtable_t; 
#define __pgd(x)        ((pgd_t) { (x) })

#define __pgprot(x)     ((pgprot_t) { (x) })



#define pte_pgprot(x) __pgprot(pte_val(x))



#else /* !STRICT_MM_TYPECHECKS */



typedef unsigned long pte_t;
@@ -60,6 +62,7 @@ typedef unsigned long pgtable_t; 
#define pgprot_val(x)	(x)

#define __pte(x)	(x)

#define __pgprot(x)	(x)

#define pte_pgprot(x)	(x)



#endif

arch/arc/mm/ioremap.c

+36 −12
Original line number Diff line number Diff line
@@ -16,25 +16,49 @@ 


void __iomem *ioremap(unsigned long paddr, unsigned long size)

{

	unsigned long vaddr;

	struct vm_struct *area;

	unsigned long off, end;

	const pgprot_t prot = PAGE_KERNEL_NO_CACHE;

	unsigned long end;



	/* Don't allow wraparound or zero size */

	end = paddr + size - 1;

	if (!size || (end < paddr))

		return NULL;



	/* If the region is h/w uncached, nothing special needed */

	/* If the region is h/w uncached, avoid MMU mappings */

	if (paddr >= ARC_UNCACHED_ADDR_SPACE)

		return (void __iomem *)paddr;



	return ioremap_prot(paddr, size, PAGE_KERNEL_NO_CACHE);

}

EXPORT_SYMBOL(ioremap);



/*

 * ioremap with access flags

 * Cache semantics wise it is same as ioremap - "forced" uncached.

 * However unline vanilla ioremap which bypasses ARC MMU for addresses in

 * ARC hardware uncached region, this one still goes thru the MMU as caller

 * might need finer access control (R/W/X)

 */

void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size,

			   unsigned long flags)

{

	void __iomem *vaddr;

	struct vm_struct *area;

	unsigned long off, end;

	pgprot_t prot = __pgprot(flags);



	/* Don't allow wraparound, zero size */

	end = paddr + size - 1;

	if ((!size) || (end < paddr))

		return NULL;



	/* An early platform driver might end up here */

	if (!slab_is_available())

		return NULL;



	/* Mappings have to be page-aligned, page-sized */

	/* force uncached */

	prot = pgprot_noncached(prot);



	/* Mappings have to be page-aligned */

	off = paddr & ~PAGE_MASK;

	paddr &= PAGE_MASK;

	size = PAGE_ALIGN(end + 1) - paddr;
@@ -45,17 +69,17 @@ void __iomem *ioremap(unsigned long paddr, unsigned long size) 
	area = get_vm_area(size, VM_IOREMAP);

	if (!area)

		return NULL;



	area->phys_addr = paddr;

	vaddr = (unsigned long)area->addr;

	if (ioremap_page_range(vaddr, vaddr + size, paddr, prot)) {

		vfree(area->addr);

	vaddr = (void __iomem *)area->addr;

	if (ioremap_page_range((unsigned long)vaddr,

			       (unsigned long)vaddr + size, paddr, prot)) {

		vunmap((void __force *)vaddr);

		return NULL;

	}



	return (void __iomem *)(off + (char __iomem *)vaddr);

}

EXPORT_SYMBOL(ioremap);

EXPORT_SYMBOL(ioremap_prot);





void iounmap(const void __iomem *addr)

{

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