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