1 #include <linux/module.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 = PER_LINUX_32BIT; 44 45 /* 46 * APCS-26 is only valid for OABI executables 47 */ 48 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) { 49 if (eflags & EF_ARM_APCS_26) 50 personality = PER_LINUX; 51 } 52 53 set_personality(personality); 54 55 /* 56 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0 57 * and CP1, we only enable access to the iWMMXt coprocessor if the 58 * binary is EABI or softfloat (and thus, guaranteed not to use 59 * FPA instructions.) 60 */ 61 if (elf_hwcap & HWCAP_IWMMXT && 62 eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) { 63 set_thread_flag(TIF_USING_IWMMXT); 64 } else { 65 clear_thread_flag(TIF_USING_IWMMXT); 66 } 67 } 68 EXPORT_SYMBOL(elf_set_personality); 69 70 /* 71 * Set READ_IMPLIES_EXEC if: 72 * - the binary requires an executable stack 73 * - we're running on a CPU which doesn't support NX. 74 */ 75 int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack) 76 { 77 if (executable_stack != EXSTACK_DISABLE_X) 78 return 1; 79 if (cpu_architecture() < CPU_ARCH_ARMv6) 80 return 1; 81 #if !defined(CONFIG_AEABI) || defined(CONFIG_OABI_COMPAT) 82 /* 83 * If we have support for OABI programs, we can never allow NX 84 * support - our signal syscall restart mechanism relies upon 85 * being able to execute code placed on the user stack. 86 */ 87 return 1; 88 #else 89 return 0; 90 #endif 91 } 92 EXPORT_SYMBOL(arm_elf_read_implies_exec); 93