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ARC: Add support for ioremap_prot API

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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: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Gilad Ben-Yossef 2013-01-22 16:48:45 +05:30 committed by Vineet Gupta
parent 8c2f4a8dd0
commit 4368902bb9
4 changed files with 42 additions and 12 deletions
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1
arch/arc/Kconfig
View File

@ -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

2
arch/arc/include/asm/io.h
View File

@ -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)

3
arch/arc/include/asm/page.h
View File

@ -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

48
arch/arc/mm/ioremap.c
View File

@ -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)
{