1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/export.h> 3 #include <linux/sched.h> 4 #include <linux/personality.h> 5 #include <linux/binfmts.h> 6 #include <linux/elf.h> 7 #include <asm/system_info.h> 8 9 int elf_check_arch(const struct elf32_hdr *x) 10 { 11 unsigned int eflags; 12 13 /* Make sure it's an ARM executable */ 14 if (x->e_machine != EM_ARM) 15 return 0; 16 17 /* Make sure the entry address is reasonable */ 18 if (x->e_entry & 1) { 19 if (!(elf_hwcap & HWCAP_THUMB)) 20 return 0; 21 } else if (x->e_entry & 3) 22 return 0; 23 24 eflags = x->e_flags; 25 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) { 26 unsigned int flt_fmt; 27 28 /* APCS26 is only allowed if the CPU supports it */ 29 if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT)) 30 return 0; 31 32 flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT); 33 34 /* VFP requires the supporting code */ 35 if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP)) 36 return 0; 37 } 38 return 1; 39 } 40 EXPORT_SYMBOL(elf_check_arch); 41 42 void elf_set_personality(const struct elf32_hdr *x) 43 { 44 unsigned int eflags = x->e_flags; 45 unsigned int personality = current->personality & ~PER_MASK; 46 47 /* 48 * We only support Linux ELF executables, so always set the 49 * personality to LINUX. 50 */ 51 personality |= PER_LINUX; 52 53 /* 54 * APCS-26 is only valid for OABI executables 55 */ 56 if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN && 57 (eflags & EF_ARM_APCS_26)) 58 personality &= ~ADDR_LIMIT_32BIT; 59 else 60 personality |= ADDR_LIMIT_32BIT; 61 62 set_personality(personality); 63 64 /* 65 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0 66 * and CP1, we only enable access to the iWMMXt coprocessor if the 67 * binary is EABI or softfloat (and thus, guaranteed not to use 68 * FPA instructions.) 69 */ 70 if (elf_hwcap & HWCAP_IWMMXT && 71 eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) { 72 set_thread_flag(TIF_USING_IWMMXT); 73 } else { 74 clear_thread_flag(TIF_USING_IWMMXT); 75 } 76 } 77 EXPORT_SYMBOL(elf_set_personality); 78 79 /* 80 * Set READ_IMPLIES_EXEC if: 81 * - the binary requires an executable stack 82 * - we're running on a CPU which doesn't support NX. 83 */ 84 int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack) 85 { 86 if (executable_stack != EXSTACK_DISABLE_X) 87 return 1; 88 if (cpu_architecture() < CPU_ARCH_ARMv6) 89 return 1; 90 return 0; 91 } 92 EXPORT_SYMBOL(arm_elf_read_implies_exec); 93