From 4368902bb90f0e208387f336c3fce0e6b2a110fc Mon Sep 17 00:00:00 2001 From: Gilad Ben-Yossef Date: Tue, 22 Jan 2013 16:48:45 +0530 Subject: [PATCH] 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 CC: Noam Camus Acked-by: Vineet Gupta Signed-off-by: Gilad Ben-Yossef Signed-off-by: Vineet Gupta --- arch/arc/Kconfig | 1 + arch/arc/include/asm/io.h | 2 ++ arch/arc/include/asm/page.h | 3 +++ arch/arc/mm/ioremap.c | 48 +++++++++++++++++++++++++++---------- 4 files changed, 42 insertions(+), 12 deletions(-) diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index cd4ad61c4c1..2dab40dd816 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -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 diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h index d20051bbbf0..473424d7528 100644 --- a/arch/arc/include/asm/io.h +++ b/arch/arc/include/asm/io.h @@ -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) diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h index dfe1f8a95f1..bdf54610455 100644 --- a/arch/arc/include/asm/page.h +++ b/arch/arc/include/asm/page.h @@ -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 diff --git a/arch/arc/mm/ioremap.c b/arch/arc/mm/ioremap.c index 52518b6d0f2..3e5c92c7993 100644 --- a/arch/arc/mm/ioremap.c +++ b/arch/arc/mm/ioremap.c @@ -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) { -- 2.41.0