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/arch/arm/kernel/elf.c

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C | 83 lines | 53 code | 12 blank | 18 comment | 21 complexity | 595e381f6b4e0a15992b8d39d1f90d55 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
 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
 7int 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		unsigned int flt_fmt;
25
26		/* APCS26 is only allowed if the CPU supports it */
27		if ((eflags & EF_ARM_APCS_26) && !(elf_hwcap & HWCAP_26BIT))
28			return 0;
29
30		flt_fmt = eflags & (EF_ARM_VFP_FLOAT | EF_ARM_SOFT_FLOAT);
31
32		/* VFP requires the supporting code */
33		if (flt_fmt == EF_ARM_VFP_FLOAT && !(elf_hwcap & HWCAP_VFP))
34			return 0;
35	}
36	return 1;
37}
38EXPORT_SYMBOL(elf_check_arch);
39
40void elf_set_personality(const struct elf32_hdr *x)
41{
42	unsigned int eflags = x->e_flags;
43	unsigned int personality = PER_LINUX_32BIT;
44
45	/*
46	 * APCS-26 is only valid for OABI executables
47	 */
48	if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
49		if (eflags & EF_ARM_APCS_26)
50			personality = PER_LINUX;
51	}
52
53	set_personality(personality);
54
55	/*
56	 * Since the FPA coprocessor uses CP1 and CP2, and iWMMXt uses CP0
57	 * and CP1, we only enable access to the iWMMXt coprocessor if the
58	 * binary is EABI or softfloat (and thus, guaranteed not to use
59	 * FPA instructions.)
60	 */
61	if (elf_hwcap & HWCAP_IWMMXT &&
62	    eflags & (EF_ARM_EABI_MASK | EF_ARM_SOFT_FLOAT)) {
63		set_thread_flag(TIF_USING_IWMMXT);
64	} else {
65		clear_thread_flag(TIF_USING_IWMMXT);
66	}
67}
68EXPORT_SYMBOL(elf_set_personality);
69
70/*
71 * Set READ_IMPLIES_EXEC if:
72 *  - the binary requires an executable stack
73 *  - we're running on a CPU which doesn't support NX.
74 */
75int arm_elf_read_implies_exec(const struct elf32_hdr *x, int executable_stack)
76{
77	if (executable_stack != EXSTACK_DISABLE_X)
78		return 1;
79	if (cpu_architecture() < CPU_ARCH_ARMv6)
80		return 1;
81	return 0;
82}
83EXPORT_SYMBOL(arm_elf_read_implies_exec);