linux/arch/arm/kernel/elf.c
Rabin Vincent a7b2296277 ARM: 5883/1: Revert "disable NX support for OABI-supporting kernels"
This reverts commit 14f0aa3593.

That commit was needed earlier because system call restarting for
OABI (compat) required an executable stack and thus had problems
with NX.  Since ab72b00734 ("ARM: Fix signal restart issues
with NX and OABI compat") has reworked the code to not require an
executable stack anymore, we can re-enable NX support for kernels
with OABI (compat) support.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-01-18 14:12:11 +00:00

83 lines
2 KiB
C

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/elf.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 = PER_LINUX_32BIT;
/*
* APCS-26 is only valid for OABI executables
*/
if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
if (eflags & EF_ARM_APCS_26)
personality = PER_LINUX;
}
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(const struct elf32_hdr *x, 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);