1 files changed, 166 insertions, 15 deletions

diff --git a/arch/arm/include/asm/opcodes.h b/arch/arm/include/asm/opcodes.h
index 19c48deda70f..74e211a6fb24 100644
--- a/arch/arm/include/asm/opcodes.h
+++ b/arch/arm/include/asm/opcodes.h
@@ -19,6 +19,33 @@ extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
 
 
 /*
+ * Assembler opcode byteswap helpers.
+ * These are only intended for use by this header: don't use them directly,
+ * because they will be suboptimal in most cases.
+ */
+#define ___asm_opcode_swab32(x) (       \
+          (((x) << 24) & 0xFF000000)    \
+        | (((x) <<  8) & 0x00FF0000)    \
+        | (((x) >>  8) & 0x0000FF00)    \
+        | (((x) >> 24) & 0x000000FF)    \
+)
+#define ___asm_opcode_swab16(x) (       \
+          (((x) << 8) & 0xFF00)         \
+        | (((x) >> 8) & 0x00FF)         \
+)
+#define ___asm_opcode_swahb32(x) (      \
+          (((x) << 8) & 0xFF00FF00)     \
+        | (((x) >> 8) & 0x00FF00FF)     \
+)
+#define ___asm_opcode_swahw32(x) (      \
+          (((x) << 16) & 0xFFFF0000)    \
+        | (((x) >> 16) & 0x0000FFFF)    \
+)
+#define ___asm_opcode_identity32(x) ((x) & 0xFFFFFFFF)
+#define ___asm_opcode_identity16(x) ((x) & 0xFFFF)
+
+
+/*
  * Opcode byteswap helpers
  *
  * These macros help with converting instructions between a canonical integer
@@ -41,39 +68,163 @@ extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr);
  * Note that values in the range 0x0000E800..0xE7FFFFFF intentionally do not
  * represent any valid Thumb-2 instruction.  For this range,
  * __opcode_is_thumb32() and __opcode_is_thumb16() will both be false.
+ *
+ * The ___asm variants are intended only for use by this header, in situations
+ * involving inline assembler.  For .S files, the normal __opcode_*() macros
+ * should do the right thing.
  */
+#ifdef __ASSEMBLY__
 
-#ifndef __ASSEMBLY__
+#define ___opcode_swab32(x) ___asm_opcode_swab32(x)
+#define ___opcode_swab16(x) ___asm_opcode_swab16(x)
+#define ___opcode_swahb32(x) ___asm_opcode_swahb32(x)
+#define ___opcode_swahw32(x) ___asm_opcode_swahw32(x)
+#define ___opcode_identity32(x) ___asm_opcode_identity32(x)
+#define ___opcode_identity16(x) ___asm_opcode_identity16(x)
+
+#else /* ! __ASSEMBLY__ */
 
 #include <linux/types.h>
 #include <linux/swab.h>
 
+#define ___opcode_swab32(x) swab32(x)
+#define ___opcode_swab16(x) swab16(x)
+#define ___opcode_swahb32(x) swahb32(x)
+#define ___opcode_swahw32(x) swahw32(x)
+#define ___opcode_identity32(x) ((u32)(x))
+#define ___opcode_identity16(x) ((u16)(x))
+
+#endif /* ! __ASSEMBLY__ */
+
+
 #ifdef CONFIG_CPU_ENDIAN_BE8
-#define __opcode_to_mem_arm(x) swab32(x)
-#define __opcode_to_mem_thumb16(x) swab16(x)
-#define __opcode_to_mem_thumb32(x) swahb32(x)
-#else
-#define __opcode_to_mem_arm(x) ((u32)(x))
-#define __opcode_to_mem_thumb16(x) ((u16)(x))
-#define __opcode_to_mem_thumb32(x) swahw32(x)
+
+#define __opcode_to_mem_arm(x) ___opcode_swab32(x)
+#define __opcode_to_mem_thumb16(x) ___opcode_swab16(x)
+#define __opcode_to_mem_thumb32(x) ___opcode_swahb32(x)
+#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_swab32(x)
+#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_swab16(x)
+#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahb32(x)
+
+#else /* ! CONFIG_CPU_ENDIAN_BE8 */
+
+#define __opcode_to_mem_arm(x) ___opcode_identity32(x)
+#define __opcode_to_mem_thumb16(x) ___opcode_identity16(x)
+#define ___asm_opcode_to_mem_arm(x) ___asm_opcode_identity32(x)
+#define ___asm_opcode_to_mem_thumb16(x) ___asm_opcode_identity16(x)
+#ifndef CONFIG_CPU_ENDIAN_BE32
+/*
+ * On BE32 systems, using 32-bit accesses to store Thumb instructions will not
+ * work in all cases, due to alignment constraints.  For now, a correct
+ * version is not provided for BE32.
+ */
+#define __opcode_to_mem_thumb32(x) ___opcode_swahw32(x)
+#define ___asm_opcode_to_mem_thumb32(x) ___asm_opcode_swahw32(x)
 #endif
 
+#endif /* ! CONFIG_CPU_ENDIAN_BE8 */
+
 #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x)
 #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x)
+#ifndef CONFIG_CPU_ENDIAN_BE32
 #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x)
+#endif
 
 /* Operations specific to Thumb opcodes */
 
 /* Instruction size checks: */
-#define __opcode_is_thumb32(x) ((u32)(x) >= 0xE8000000UL)
-#define __opcode_is_thumb16(x) ((u32)(x) < 0xE800UL)
+#define __opcode_is_thumb32(x) (                \
+           ((x) & 0xF8000000) == 0xE8000000     \
+        || ((x) & 0xF0000000) == 0xF0000000     \
+)
+#define __opcode_is_thumb16(x) (                                        \
+           ((x) & 0xFFFF0000) == 0                                      \
+        && !(((x) & 0xF800) == 0xE800 || ((x) & 0xF000) == 0xF000)      \
+)
 
 /* Operations to construct or split 32-bit Thumb instructions: */
-#define __opcode_thumb32_first(x) ((u16)((x) >> 16))
-#define __opcode_thumb32_second(x) ((u16)(x))
-#define __opcode_thumb32_compose(first, second) \
-        (((u32)(u16)(first) << 16) | (u32)(u16)(second))
+#define __opcode_thumb32_first(x) (___opcode_identity16((x) >> 16))
+#define __opcode_thumb32_second(x) (___opcode_identity16(x))
+#define __opcode_thumb32_compose(first, second) (                       \
+          (___opcode_identity32(___opcode_identity16(first)) << 16)     \
+        | ___opcode_identity32(___opcode_identity16(second))            \
+)
+#define ___asm_opcode_thumb32_first(x) (___asm_opcode_identity16((x) >> 16))
+#define ___asm_opcode_thumb32_second(x) (___asm_opcode_identity16(x))
+#define ___asm_opcode_thumb32_compose(first, second) (                      \
+          (___asm_opcode_identity32(___asm_opcode_identity16(first)) << 16) \
+        | ___asm_opcode_identity32(___asm_opcode_identity16(second))        \
+)
 
-#endif /* __ASSEMBLY__ */
+/*
+ * Opcode injection helpers
+ *
+ * In rare cases it is necessary to assemble an opcode which the
+ * assembler does not support directly, or which would normally be
+ * rejected because of the CFLAGS or AFLAGS used to build the affected
+ * file.
+ *
+ * Before using these macros, consider carefully whether it is feasible
+ * instead to change the build flags for your file, or whether it really
+ * makes sense to support old assembler versions when building that
+ * particular kernel feature.
+ *
+ * The macros defined here should only be used where there is no viable
+ * alternative.
+ *
+ *
+ * __inst_arm(x): emit the specified ARM opcode
+ * __inst_thumb16(x): emit the specified 16-bit Thumb opcode
+ * __inst_thumb32(x): emit the specified 32-bit Thumb opcode
+ *
+ * __inst_arm_thumb16(arm, thumb): emit either the specified arm or
+ *      16-bit Thumb opcode, depending on whether an ARM or Thumb-2
+ *      kernel is being built
+ *
+ * __inst_arm_thumb32(arm, thumb): emit either the specified arm or
+ *      32-bit Thumb opcode, depending on whether an ARM or Thumb-2
+ *      kernel is being built
+ *
+ *
+ * Note that using these macros directly is poor practice.  Instead, you
+ * should use them to define human-readable wrapper macros to encode the
+ * instructions that you care about.  In code which might run on ARMv7 or
+ * above, you can usually use the __inst_arm_thumb{16,32} macros to
+ * specify the ARM and Thumb alternatives at the same time.  This ensures
+ * that the correct opcode gets emitted depending on the instruction set
+ * used for the kernel build.
+ *
+ * Look at opcodes-virt.h for an example of how to use these macros.
+ */
+#include <linux/stringify.h>
+
+#define __inst_arm(x) ___inst_arm(___asm_opcode_to_mem_arm(x))
+#define __inst_thumb32(x) ___inst_thumb32(                              \
+        ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_first(x)),   \
+        ___asm_opcode_to_mem_thumb16(___asm_opcode_thumb32_second(x))   \
+)
+#define __inst_thumb16(x) ___inst_thumb16(___asm_opcode_to_mem_thumb16(x))
+
+#ifdef CONFIG_THUMB2_KERNEL
+#define __inst_arm_thumb16(arm_opcode, thumb_opcode) \
+        __inst_thumb16(thumb_opcode)
+#define __inst_arm_thumb32(arm_opcode, thumb_opcode) \
+        __inst_thumb32(thumb_opcode)
+#else
+#define __inst_arm_thumb16(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
+#define __inst_arm_thumb32(arm_opcode, thumb_opcode) __inst_arm(arm_opcode)
+#endif
+
+/* Helpers for the helpers.  Don't use these directly. */
+#ifdef __ASSEMBLY__
+#define ___inst_arm(x) .long x
+#define ___inst_thumb16(x) .short x
+#define ___inst_thumb32(first, second) .short first, second
+#else
+#define ___inst_arm(x) ".long " __stringify(x) "\n\t"
+#define ___inst_thumb16(x) ".short " __stringify(x) "\n\t"
+#define ___inst_thumb32(first, second) \
+        ".short " __stringify(first) ", " __stringify(second) "\n\t"
+#endif
 
 #endif /* __ASM_ARM_OPCODES_H */