[mirror_ubuntu-bionic-kernel.git] / arch / arm / kernel / elf.c

// 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);

/*
 * Set READ_IMPLIES_EXEC if:
 *  - the binary requires an executable stack
 *  - we're running on a CPU which doesn't support NX.
 */
int arm_elf_read_implies_exec(int executable_stack)
{
	if (executable_stack != EXSTACK_DISABLE_X)
		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
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
ecea4ab6	2	#include <linux/export.h>
8ec53663 RK	3	#include <linux/sched.h>
	4	#include <linux/personality.h>
	5	#include <linux/binfmts.h>
	6	#include <linux/elf.h>
382e67ae	7	#include <linux/elf-fdpic.h>
9f97da78	8	#include <asm/system_info.h>
8ec53663 RK	9
	10	int elf_check_arch(const struct elf32_hdr *x)
	11	{
	12	unsigned int eflags;
	13
	14	/* Make sure it's an ARM executable */
	15	if (x->e_machine != EM_ARM)
	16	return 0;
	17
	18	/* Make sure the entry address is reasonable */
	19	if (x->e_entry & 1) {
	20	if (!(elf_hwcap & HWCAP_THUMB))
	21	return 0;
	22	} else if (x->e_entry & 3)
	23	return 0;
	24
	25	eflags = x->e_flags;
	26	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
d2ed5cb8 RK	27	unsigned int flt_fmt;
d2ed5cb8 RK	28
8ec53663 RK	29	/* APCS26 is only allowed if the CPU supports it */
	30	if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
	31	return 0;
	32
d2ed5cb8 RK	33	flt_fmt = eflags & (EF_ARM_VFP_FLOAT \| EF_ARM_SOFT_FLOAT);
d2ed5cb8 RK	34
8ec53663	35	/* VFP requires the supporting code */
d2ed5cb8	36	if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))
8ec53663 RK	37	return 0;
	38	}
	39	return 1;
	40	}
	41	EXPORT_SYMBOL(elf_check_arch);
	42
	43	void elf_set_personality(const struct elf32_hdr *x)
	44	{
	45	unsigned int eflags = x->e_flags;
5e143436 NP	46	unsigned int personality = current->personality & ~PER_MASK;
	47
	48	/*
	49	* We only support Linux ELF executables, so always set the
	50	* personality to LINUX.
	51	*/
	52	personality \|= PER_LINUX;
8ec53663 RK	53
	54	/*
	55	* APCS-26 is only valid for OABI executables
	56	*/
5e143436 NP	57	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN &&
	58	(eflags & EF_ARM_APCS_26))
	59	personality &= ~ADDR_LIMIT_32BIT;
	60	else
	61	personality \|= ADDR_LIMIT_32BIT;
8ec53663 RK	62
	63	set_personality(personality);
	64
	65	/*
	66	* Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
	67	* and CP1, we only enable access to the iWMMXt coprocessor if the
	68	* binary is EABI or softfloat (and thus, guaranteed not to use
	69	* FPA instructions.)
	70	*/
	71	if (elf_hwcap & HWCAP_IWMMXT &&
	72	eflags & (EF_ARM_EABI_MASK \| EF_ARM_SOFT_FLOAT)) {
	73	set_thread_flag(TIF_USING_IWMMXT);
	74	} else {
	75	clear_thread_flag(TIF_USING_IWMMXT);
	76	}
	77	}
	78	EXPORT_SYMBOL(elf_set_personality);
	79
	80	/*
	81	* Set READ_IMPLIES_EXEC if:
	82	* - the binary requires an executable stack
	83	* - we're running on a CPU which doesn't support NX.
	84	*/
e71fd631	85	int arm_elf_read_implies_exec(int executable_stack)
8ec53663	86	{
9da616fb	87	if (executable_stack != EXSTACK_DISABLE_X)
8ec53663	88	return 1;
9da616fb	89	if (cpu_architecture() < CPU_ARCH_ARMv6)
8ec53663 RK	90	return 1;
	91	return 0;
	92	}
	93	EXPORT_SYMBOL(arm_elf_read_implies_exec);
382e67ae NP	94
	95	#if defined(CONFIG_MMU) && defined(CONFIG_BINFMT_ELF_FDPIC)
	96
	97	void elf_fdpic_arch_lay_out_mm(struct elf_fdpic_params *exec_params,
	98	struct elf_fdpic_params *interp_params,
	99	unsigned long *start_stack,
	100	unsigned long *start_brk)
	101	{
	102	elf_set_personality(&exec_params->hdr);
	103
	104	exec_params->load_addr = 0x8000;
	105	interp_params->load_addr = ELF_ET_DYN_BASE;
	106	*start_stack = TASK_SIZE - SZ_16M;
	107
	108	if ((exec_params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_INDEPENDENT) {
	109	exec_params->flags &= ~ELF_FDPIC_FLAG_ARRANGEMENT;
	110	exec_params->flags \|= ELF_FDPIC_FLAG_CONSTDISP;
	111	}
	112	}
	113
	114	#endif