// SPDX-License-Identifier: GPL-2.0#include <linux/export.h>#include <linux/sched.h>#include <linux/personality.h>#include <linux/binfmts.h>#include <linux/elf.h>#include <linux/elf-fdpic.h>#include <asm/system_info.h> int elf_check_arch(const struct elf32_hdr *x){	unsigned int eflags; 	/* Make sure it's an ARM executable */	if (x->e_machine != EM_ARM)		return 0; 	/* Make sure the entry address is reasonable */	if (x->e_entry & 1) {		if (!(elf_hwcap & HWCAP_THUMB))			return 0;	} else if (x->e_entry & 3)		return 0; 	eflags = x->e_flags;	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {		unsigned int flt_fmt; 		/* APCS26 is only allowed if the CPU supports it */		if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))			return 0; 		flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT); 		/* VFP requires the supporting code */		if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))			return 0;	}	return 1;}EXPORT_SYMBOL(elf_check_arch); void elf_set_personality(const struct elf32_hdr *x){	unsigned int eflags = x->e_flags;	unsigned int personality = current->personality & ~PER_MASK; 	/*	 * We only support Linux ELF executables, so always set the	 * personality to LINUX.	 */	personality |= PER_LINUX; 	/*	 * APCS-26 is only valid for OABI executables	 */	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN &&	    (eflags & EF_ARM_APCS_26))		personality &= ~ADDR_LIMIT_32BIT;	else		personality |= ADDR_LIMIT_32BIT; 	set_personality(personality); 	/*	 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0	 * and CP1, we only enable access to the iWMMXt coprocessor if the	 * binary is EABI or softfloat (and thus, guaranteed not to use	 * FPA instructions.)	 */	if (elf_hwcap & HWCAP_IWMMXT &&	    eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) {		set_thread_flag(TIF_USING_IWMMXT);	} else {		clear_thread_flag(TIF_USING_IWMMXT);	}}EXPORT_SYMBOL(elf_set_personality); /* * An executable for which elf_read_implies_exec() returns TRUE will * have the READ_IMPLIES_EXEC personality flag set automatically. * * The decision process for determining the results are: * *                 CPU: | lacks NX*  | has NX     | * ELF:                 |            |            | * ---------------------|------------|------------| * missing PT_GNU_STACK | exec-all   | exec-all   | * PT_GNU_STACK == RWX  | exec-all   | exec-stack | * PT_GNU_STACK == RW   | exec-all   | exec-none  | * *  exec-all  : all PROT_READ user mappings are executable, except when *              backed by files on a noexec-filesystem. *  exec-none : only PROT_EXEC user mappings are executable. *  exec-stack: only the stack and PROT_EXEC user mappings are executable. * *  *this column has no architectural effect: NX markings are ignored by *   hardware, but may have behavioral effects when "wants X" collides with *   "cannot be X" constraints in memory permission flags, as in *   https://lkml.kernel.org/r/20190418055759.GA3155@mellanox.com * */int arm_elf_read_implies_exec(int executable_stack){	if (executable_stack == EXSTACK_DEFAULT)		return 1;	if (cpu_architecture() < CPU_ARCH_ARMv6)		return 1;	return 0;}EXPORT_SYMBOL(arm_elf_read_implies_exec); #if defined(CONFIG_MMU) && defined(CONFIG_BINFMT_ELF_FDPIC) void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,			       struct elf_fdpic_params *interp_params,			       unsigned long *start_stack,			       unsigned long *start_brk){	elf_set_personality(&exec_params->hdr); 	exec_params->load_addr = 0x8000;	interp_params->load_addr = ELF_ET_DYN_BASE;	*start_stack = TASK_SIZE - SZ_16M; 	if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_INDEPENDENT) {		exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;		exec_params->flags |= ELF_FDPIC_FLAG_CONSTDISP;	}} #endif