Commit 382e67ae authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

ARM: enable elf_fdpic on systems with an MMU 



Provide the necessary changes to be able to execute ELF-FDPIC binaries
on ARM systems with an MMU.

The default for CONFIG_BINFMT_ELF_FDPIC is also set to n if the regular
ELF loader is already configured so not to force FDPIC support on
everyone. Given that CONFIG_BINFMT_ELF depends on CONFIG_MMU, this means
CONFIG_BINFMT_ELF_FDPIC will still default to y when !MMU.

Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Acked-by: default avatarMickael GUENE <mickael.guene@st.com>
Tested-by: default avatarVincent Abriou <vincent.abriou@st.com>
Tested-by: default avatarAndras Szemzo <szemzo.andras@gmail.com>
parent 50b2b2e6

arch/arm/include/asm/mmu.h

+4 −0
Original line number Diff line number Diff line
@@ -14,6 +14,10 @@ typedef struct { 
#ifdef CONFIG_VDSO

	unsigned long	vdso;

#endif

#ifdef CONFIG_BINFMT_ELF_FDPIC

	unsigned long	exec_fdpic_loadmap;

	unsigned long	interp_fdpic_loadmap;

#endif

} mm_context_t;



#ifdef CONFIG_CPU_HAS_ASID

arch/arm/kernel/elf.c

+22 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#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)
@@ -89,3 +90,24 @@ int arm_elf_read_implies_exec(int executable_stack) 
	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

fs/Kconfig.binfmt

+2 −2
Original line number Diff line number Diff line
@@ -34,8 +34,8 @@ config ARCH_BINFMT_ELF_STATE 


config BINFMT_ELF_FDPIC

	bool "Kernel support for FDPIC ELF binaries"

	default y

	depends on ((ARM && !MMU) || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)

	default y if !BINFMT_ELF

	depends on (ARM || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)

	select ELFCORE

	help

	  ELF FDPIC binaries are based on ELF, but allow the individual load

fs/binfmt_elf_fdpic.c

+5 −0
Original line number Diff line number Diff line
@@ -377,6 +377,11 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) 
				 executable_stack);

	if (retval < 0)

		goto error;

#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES

	retval = arch_setup_additional_pages(bprm, !!interpreter_name);

	if (retval < 0)

		goto error;

#endif

#endif



	/* load the executable and interpreter into memory */

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