swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 6fbc7275c7a9ba97877050335f290341a1fd8dbf authored by Linus Torvalds on 30 June 2019, 03:25:36 UTC
Linux 5.2-rc7
Linux 5.2-rc7
Tip revision: 6fbc727
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