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