ARM: P2V: extend to 16-bit translation offsets

MSM's memory is aligned to 2MB, which is more than we can do with our
existing method as we're limited to the upper 8 bits.  Extend this by
using two instructions to 16 bits, automatically selected when MSM is
enabled.

Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 21 insertions, 4 deletions

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 7197879e1cb..2398b3fc026 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -154,29 +154,42 @@
 #ifndef __virt_to_phys
 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 
+/*
+ * Constants used to force the right instruction encodings and shifts
+ * so that all we need to do is modify the 8-bit constant field.
+ */
+#define __PV_BITS_31_24 0x81000000
+#define __PV_BITS_23_16 0x00810000
+
 extern unsigned long __pv_phys_offset;
 #define PHYS_OFFSET __pv_phys_offset
 
-#define __pv_stub(from,to,instr)                        \
+#define __pv_stub(from,to,instr,type)                   \
         __asm__("@ __pv_stub\n"                         \
         "1:     " instr "       %0, %1, %2\n"           \
         "       .pushsection .pv_table,\"a\"\n"         \
         "       .long   1b\n"                           \
         "       .popsection\n"                          \
         : "=r" (to)                                     \
-        : "r" (from), "I" (0x81000000))
+        : "r" (from), "I" (type))
 
 static inline unsigned long __virt_to_phys(unsigned long x)
 {
         unsigned long t;
-        __pv_stub(x, t, "add");
+        __pv_stub(x, t, "add", __PV_BITS_31_24);
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
+        __pv_stub(t, t, "add", __PV_BITS_23_16);
+#endif
         return t;
 }
 
 static inline unsigned long __phys_to_virt(unsigned long x)
 {
         unsigned long t;
-        __pv_stub(x, t, "sub");
+        __pv_stub(x, t, "sub", __PV_BITS_31_24);
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
+        __pv_stub(t, t, "sub", __PV_BITS_23_16);
+#endif
         return t;
 }
 #else
diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index d072c21332e..a2b775b81cf 100644
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -31,7 +31,11 @@ struct mod_arch_specific {
 
 /* Add __virt_to_phys patching state as well */
 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
+#ifdef CONFIG_ARM_PATCH_PHYS_VIRT_16BIT
+#define MODULE_ARCH_VERMAGIC_P2V "p2v16 "
+#else
 #define MODULE_ARCH_VERMAGIC_P2V "p2v8 "
+#endif
 #else
 #define MODULE_ARCH_VERMAGIC_P2V ""
 #endif