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 /* APCS26 is only allowed if the CPU supports it */ 25 if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT)) 26 return 0; 27 28 /* VFP requires the supporting code */ 29 if ((eflags & EF_ARM_VFP_FLOAT) && !(elf_hwcap & HWCAP_VFP)) 30 return 0; 31 } 32 return 1; 33 } 34 EXPORT_SYMBOL(elf_check_arch); 35 36 void elf_set_personality(const struct elf32_hdr *x) 37 { 38 unsigned int eflags = x->e_flags; 39 unsigned int personality = PER_LINUX_32BIT; 40 41 /* 42 * APCS-26 is only valid for OABI executables 43 */ 44 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) { 45 if (eflags & EF_ARM_APCS_26) 46 personality = PER_LINUX; 47 } 48 49 set_personality(personality); 50 51 /* 52 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0 53 * and CP1, we only enable access to the iWMMXt coprocessor if the 54 * binary is EABI or softfloat (and thus, guaranteed not to use 55 * FPA instructions.) 56 */ 57 if (elf_hwcap & HWCAP_IWMMXT && 58 eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) { 59 set_thread_flag(TIF_USING_IWMMXT); 60 } else { 61 clear_thread_flag(TIF_USING_IWMMXT); 62 } 63 } 64 EXPORT_SYMBOL(elf_set_personality); 65 66 /* 67 * Set READ_IMPLIES_EXEC if: 68 * - the binary requires an executable stack 69 * - we're running on a CPU which doesn't support NX. 70 */ 71 int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack) 72 { 73 if (executable_stack != EXSTACK_ENABLE_X) 74 return 1; 75 if (cpu_architecture() <= CPU_ARCH_ARMv6) 76 return 1; 77 return 0; 78 } 79 EXPORT_SYMBOL(arm_elf_read_implies_exec); 80