[ARM] 5507/1: support R_ARM_MOVW_ABS_NC and MOVT_ABS relocation types

From: Bruce Ashfield <bruce.ashfield@windriver.com>

To fully support the armv7-a instruction set/optimizations, support
for the R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS relocation types is
required.

The MOVW and MOVT are both load-immediate instructions, MOVW loads 16
bits into the bottom half of a register, and MOVT loads 16 bits into the
top half of a register.

The relocation information for these instructions has a full 32 bit
value, plus an addend which is stored in the 16 immediate bits in the
instruction itself.  The immediate bits in the instruction are not
contiguous (the register # splits it into a 4 bit and 12 bit value),
so the addend has to be extracted accordingly and added to the value.
The value is then split and put into the instruction; a MOVW uses the
bottom 16 bits of the value, and a MOVT uses the top 16 bits.

Signed-off-by: David Borman <david.borman@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/elf.h

@@ -45,13 +45,15 @@ typedef struct user_fp elf_fpregset_t;
 #define EF_ARM_HASENTRY		0x00000002	/* All */
 #define EF_ARM_RELEXEC		0x00000001	/* All */
 
-#define R_ARM_NONE	0
-#define R_ARM_PC24	1
-#define R_ARM_ABS32	2
-#define R_ARM_CALL	28
-#define R_ARM_JUMP24	29
-#define R_ARM_V4BX	40
-#define R_ARM_PREL31	42
+#define R_ARM_NONE		0
+#define R_ARM_PC24		1
+#define R_ARM_ABS32		2
+#define R_ARM_CALL		28
+#define R_ARM_JUMP24		29
+#define R_ARM_V4BX		40
+#define R_ARM_PREL31		42
+#define R_ARM_MOVW_ABS_NC	43
+#define R_ARM_MOVT_ABS		44
 
 /*
  * These are used to set parameters in the core dumps.

arch/arm/kernel/module.c

@@ -169,6 +169,21 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 			*(u32 *)loc = offset & 0x7fffffff;
 			break;
 
+		case R_ARM_MOVW_ABS_NC:
+		case R_ARM_MOVT_ABS:
+			offset = *(u32 *)loc;
+			offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
+			offset = (offset ^ 0x8000) - 0x8000;
+
+			offset += sym->st_value;
+			if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
+				offset >>= 16;
+
+			*(u32 *)loc &= 0xfff0f000;
+			*(u32 *)loc |= ((offset & 0xf000) << 4) |
+					(offset & 0x0fff);
+			break;
+
 		default:
 			printk(KERN_ERR "%s: unknown relocation: %u\n",
 			       module->name, ELF32_R_TYPE(rel->r_info));