1 #include <linux/export.h> 2 #include <linux/sched.h> 3 #include <linux/personality.h> 4 #include <linux/binfmts.h> 5 #include <linux/elf.h> 6 #include <asm/system_info.h> 7 8 int elf_check_arch(const struct elf32_hdr *x) 9 { 10 unsigned int eflags; 11 12 /* Make sure it's an ARM executable */ 13 if (x->e_machine != EM_ARM) 14 return 0; 15 16 /* Make sure the entry address is reasonable */ 17 if (x->e_entry & 1) { 18 if (!(elf_hwcap & HWCAP_THUMB)) 19 return 0; 20 } else if (x->e_entry & 3) 21 return 0; 22 23 eflags = x->e_flags; 24 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) { 25 unsigned int flt_fmt; 26 27 /* APCS26 is only allowed if the CPU supports it */ 28 if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT)) 29 return 0; 30 31 flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT); 32 33 /* VFP requires the supporting code */ 34 if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP)) 35 return 0; 36 } 37 return 1; 38 } 39 EXPORT_SYMBOL(elf_check_arch); 40 41 void elf_set_personality(const struct elf32_hdr *x) 42 { 43 unsigned int eflags = x->e_flags; 44 unsigned int personality = current->personality & ~PER_MASK; 45 46 /* 47 * We only support Linux ELF executables, so always set the 48 * personality to LINUX. 49 */ 50 personality |= PER_LINUX; 51 52 /* 53 * APCS-26 is only valid for OABI executables 54 */ 55 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN && 56 (eflags & EF_ARM_APCS_26)) 57 personality &= ~ADDR_LIMIT_32BIT; 58 else 59 personality |= ADDR_LIMIT_32BIT; 60 61 set_personality(personality); 62 63 /* 64 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0 65 * and CP1, we only enable access to the iWMMXt coprocessor if the 66 * binary is EABI or softfloat (and thus, guaranteed not to use 67 * FPA instructions.) 68 */ 69 if (elf_hwcap & HWCAP_IWMMXT && 70 eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) { 71 set_thread_flag(TIF_USING_IWMMXT); 72 } else { 73 clear_thread_flag(TIF_USING_IWMMXT); 74 } 75 } 76 EXPORT_SYMBOL(elf_set_personality); 77 78 /* 79 * Set READ_IMPLIES_EXEC if: 80 * - the binary requires an executable stack 81 * - we're running on a CPU which doesn't support NX. 82 */ 83 int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack) 84 { 85 if (executable_stack != EXSTACK_DISABLE_X) 86 return 1; 87 if (cpu_architecture() < CPU_ARCH_ARMv6) 88 return 1; 89 return 0; 90 } 91 EXPORT_SYMBOL(arm_elf_read_implies_exec); 92