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Commit ae51e609 authored by Paul Gortmaker's avatar Paul Gortmaker Committed by Russell King
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[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: default avatarDavid Borman <david.borman@windriver.com>
Signed-off-by: default avatarBruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a029b706

arch/arm/include/asm/elf.h

+9 −7
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ typedef struct user_fp elf_fpregset_t; 
#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

+15 −0
Original line number Diff line number Diff line
@@ -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));