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Commit 214fad55 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
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arm64: relocation testing module 



This module tests the module loader's ELF relocation processing
routines. When loaded, it logs output like below.

    Relocation test:
    -------------------------------------------------------
    R_AARCH64_ABS64                 0xffff880000cccccc pass
    R_AARCH64_ABS32                 0x00000000f800cccc pass
    R_AARCH64_ABS16                 0x000000000000f8cc pass
    R_AARCH64_MOVW_SABS_Gn          0xffff880000cccccc pass
    R_AARCH64_MOVW_UABS_Gn          0xffff880000cccccc pass
    R_AARCH64_ADR_PREL_LO21         0xffffff9cf4d1a400 pass
    R_AARCH64_PREL64                0xffffff9cf4d1a400 pass
    R_AARCH64_PREL32                0xffffff9cf4d1a400 pass
    R_AARCH64_PREL16                0xffffff9cf4d1a400 pass

Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 46823dd1

arch/arm64/Kconfig.debug

+4 −0
Original line number Diff line number Diff line
@@ -92,6 +92,10 @@ config DEBUG_EFI 
	  the kernel that are only useful when using a debug build of the

	  UEFI firmware



config ARM64_RELOC_TEST

	depends on m

	tristate "Relocation testing module"



source "drivers/hwtracing/coresight/Kconfig"



endmenu

arch/arm64/kernel/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -50,6 +50,8 @@ arm64-obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o 
arm64-obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o

arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\

					   cpu-reset.o

arm64-obj-$(CONFIG_ARM64_RELOC_TEST)	+= arm64-reloc-test.o

arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o



obj-y					+= $(arm64-obj-y) vdso/ probes/

obj-m					+= $(arm64-obj-m)

arch/arm64/kernel/reloc_test_core.c

0 → 100644
+81 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */



#include <linux/module.h>



int sym64_rel;



#define SYM64_ABS_VAL		0xffff880000cccccc

#define SYM32_ABS_VAL		0xf800cccc

#define SYM16_ABS_VAL		0xf8cc



#define __SET_ABS(name, val)	asm(".globl " #name "; .set "#name ", " #val)

#define SET_ABS(name, val)	__SET_ABS(name, val)



SET_ABS(sym64_abs, SYM64_ABS_VAL);

SET_ABS(sym32_abs, SYM32_ABS_VAL);

SET_ABS(sym16_abs, SYM16_ABS_VAL);



asmlinkage u64 absolute_data64(void);

asmlinkage u64 absolute_data32(void);

asmlinkage u64 absolute_data16(void);

asmlinkage u64 signed_movw(void);

asmlinkage u64 unsigned_movw(void);

asmlinkage u64 relative_adrp(void);

asmlinkage u64 relative_adr(void);

asmlinkage u64 relative_data64(void);

asmlinkage u64 relative_data32(void);

asmlinkage u64 relative_data16(void);



static struct {

	char	name[32];

	u64	(*f)(void);

	u64	expect;

} const funcs[] = {

	{ "R_AARCH64_ABS64",		absolute_data64, UL(SYM64_ABS_VAL) },

	{ "R_AARCH64_ABS32",		absolute_data32, UL(SYM32_ABS_VAL) },

	{ "R_AARCH64_ABS16",		absolute_data16, UL(SYM16_ABS_VAL) },

	{ "R_AARCH64_MOVW_SABS_Gn",	signed_movw, UL(SYM64_ABS_VAL) },

	{ "R_AARCH64_MOVW_UABS_Gn",	unsigned_movw, UL(SYM64_ABS_VAL) },

#ifndef CONFIG_ARM64_ERRATUM_843419

	{ "R_AARCH64_ADR_PREL_PG_HI21",	relative_adrp, (u64)&sym64_rel },

#endif

	{ "R_AARCH64_ADR_PREL_LO21",	relative_adr, (u64)&sym64_rel },

	{ "R_AARCH64_PREL64",		relative_data64, (u64)&sym64_rel },

	{ "R_AARCH64_PREL32",		relative_data32, (u64)&sym64_rel },

	{ "R_AARCH64_PREL16",		relative_data16, (u64)&sym64_rel },

};



static int reloc_test_init(void)

{

	int i;



	pr_info("Relocation test:\n");

	pr_info("-------------------------------------------------------\n");



	for (i = 0; i < ARRAY_SIZE(funcs); i++) {

		u64 ret = funcs[i].f();



		pr_info("%-31s 0x%016llx %s\n", funcs[i].name, ret,

			ret == funcs[i].expect ? "pass" : "fail");

		if (ret != funcs[i].expect)

			pr_err("Relocation failed, expected 0x%016llx, not 0x%016llx\n",

			       funcs[i].expect, ret);

	}

	return 0;

}



static void reloc_test_exit(void)

{

}



module_init(reloc_test_init);

module_exit(reloc_test_exit);



MODULE_LICENSE("GPL v2");

arch/arm64/kernel/reloc_test_syms.S

0 → 100644
+83 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */



#include <linux/linkage.h>



ENTRY(absolute_data64)

	ldr	x0, 0f

	ret

0:	.quad	sym64_abs

ENDPROC(absolute_data64)



ENTRY(absolute_data32)

	ldr	w0, 0f

	ret

0:	.long	sym32_abs

ENDPROC(absolute_data32)



ENTRY(absolute_data16)

	adr	x0, 0f

	ldrh	w0, [x0]

	ret

0:	.short	sym16_abs, 0

ENDPROC(absolute_data16)



ENTRY(signed_movw)

	movz	x0, #:abs_g2_s:sym64_abs

	movk	x0, #:abs_g1_nc:sym64_abs

	movk	x0, #:abs_g0_nc:sym64_abs

	ret

ENDPROC(signed_movw)



ENTRY(unsigned_movw)

	movz	x0, #:abs_g3:sym64_abs

	movk	x0, #:abs_g2_nc:sym64_abs

	movk	x0, #:abs_g1_nc:sym64_abs

	movk	x0, #:abs_g0_nc:sym64_abs

	ret

ENDPROC(unsigned_movw)



#ifndef CONFIG_ARM64_ERRATUM_843419



ENTRY(relative_adrp)

	adrp	x0, sym64_rel

	add	x0, x0, #:lo12:sym64_rel

	ret

ENDPROC(relative_adrp)



#endif



ENTRY(relative_adr)

	adr	x0, sym64_rel

	ret

ENDPROC(relative_adr)



ENTRY(relative_data64)

	adr	x1, 0f

	ldr	x0, [x1]

	add	x0, x0, x1

	ret

0:	.quad	sym64_rel - .

ENDPROC(relative_data64)



ENTRY(relative_data32)

	adr	x1, 0f

	ldr	w0, [x1]

	add	x0, x0, x1

	ret

0:	.long	sym64_rel - .

ENDPROC(relative_data32)



ENTRY(relative_data16)

	adr	x1, 0f

	ldrsh	w0, [x1]

	add	x0, x0, x1

	ret

0:	.short	sym64_rel - ., 0

ENDPROC(relative_data16)