Commit ae51e609 authored May 07, 2009 by Paul Gortmaker Committed by Russell King May 07, 2009

[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>

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));

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