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Commit 8dd47741 authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
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ARM: 6189/1: Add support for the MOVW/MOVT relocations in Thumb-2 



The patch adds handling case for the R_ARM_THM_MOVW_ABS_NC and
R_ARM_THM_MOVT_ABS relocations in arch/arm/kernel/module.c. Such
relocations may appear in Thumb-2 compiled kernel modules.

Reported-by: default avatarKyungmin Park <kmpark@infradead.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 3cfc2c42

arch/arm/include/asm/elf.h

+2 −0
Original line number Diff line number Diff line
@@ -59,6 +59,8 @@ typedef struct user_fp elf_fpregset_t; 


#define R_ARM_THM_CALL		10

#define R_ARM_THM_JUMP24	30

#define R_ARM_THM_MOVW_ABS_NC	47

#define R_ARM_THM_MOVT_ABS	48



/*

 * These are used to set parameters in the core dumps.

arch/arm/kernel/module.c

+32 −0
Original line number Diff line number Diff line
@@ -237,6 +237,38 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 
			lower = *(u16 *)(loc + 2);

			break;



		case R_ARM_THM_MOVW_ABS_NC:

		case R_ARM_THM_MOVT_ABS:

			upper = *(u16 *)loc;

			lower = *(u16 *)(loc + 2);



			/*

			 * MOVT/MOVW instructions encoding in Thumb-2:

			 *

			 * i	= upper[10]

			 * imm4	= upper[3:0]

			 * imm3	= lower[14:12]

			 * imm8	= lower[7:0]

			 *

			 * imm16 = imm4:i:imm3:imm8

			 */

			offset = ((upper & 0x000f) << 12) |

				((upper & 0x0400) << 1) |

				((lower & 0x7000) >> 4) | (lower & 0x00ff);

			offset = (offset ^ 0x8000) - 0x8000;

			offset += sym->st_value;



			if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)

				offset >>= 16;



			*(u16 *)loc = (u16)((upper & 0xfbf0) |

					    ((offset & 0xf000) >> 12) |

					    ((offset & 0x0800) >> 1));

			*(u16 *)(loc + 2) = (u16)((lower & 0x8f00) |

						  ((offset & 0x0700) << 4) |

						  (offset & 0x00ff));

			break;



		default:

			printk(KERN_ERR "%s: unknown relocation: %u\n",

			       module->name, ELF32_R_TYPE(rel->r_info));