MIPS: Enable IOREMAP_PROT config option for MIPS cpus

Allows the users of ptrace to access memory mapped by the ptraced process
using the same cache coherency attributes as the original process.
For example while using gdb with ioremap_prot() incorporated, both gdb and
the process being traced will have same cache coherency attributes.

Signed-off-by: Hassan Naveed <hnaveed@wavecomp.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20955/
Cc: <linux-mips@linux-mips.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 266257d56fb6..b5322f7386bf 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -218,6 +218,18 @@ static inline void __iomem * __ioremap_mode(phys_addr_t offset, unsigned long si
 }
 
 /*
+ * ioremap_prot     -   map bus memory into CPU space
+ * @offset:    bus address of the memory
+ * @size:      size of the resource to map
+
+ * ioremap_prot gives the caller control over cache coherency attributes (CCA)
+ */
+static inline void __iomem *ioremap_prot(phys_addr_t offset,
+		unsigned long size, unsigned long prot_val) {
+	return __ioremap_mode(offset, size, prot_val & _CACHE_MASK);
+}
+
+/*
  * ioremap     -   map bus memory into CPU space
  * @offset:    bus address of the memory
  * @size:      size of the resource to map