[PATCH] arm64: relocation testing module
Ard Biesheuvel
ard.biesheuvel at linaro.org
Thu Mar 23 11:18:41 PDT 2017
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
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
arch/arm64/Kconfig.debug | 4 ++
arch/arm64/kernel/Makefile | 2 +
arch/arm64/kernel/reloc_test_core.c | 79 +++++++++++++++++++++++++++++++++++
arch/arm64/kernel/reloc_test_syms.S | 83 +++++++++++++++++++++++++++++++++++++
4 files changed, 168 insertions(+)
create mode 100644 arch/arm64/kernel/reloc_test_core.c
create mode 100644 arch/arm64/kernel/reloc_test_syms.S
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index b661fe742615..5b0c07cbe766 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -62,6 +62,10 @@ config DEBUG_ALIGN_RODATA
If in doubt, say N.
+config ARM64_RELOC_TEST
+ depends on m
+ tristate "Relocation testing module"
+
source "drivers/hwtracing/coresight/Kconfig"
endmenu
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 7d66bbaafc0c..38d67a5db973 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -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)
diff --git a/arch/arm64/kernel/reloc_test_core.c b/arch/arm64/kernel/reloc_test_core.c
new file mode 100644
index 000000000000..22d84fdb6d98
--- /dev/null
+++ b/arch/arm64/kernel/reloc_test_core.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2016 Linaro Ltd; <ard.biesheuvel at 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);
diff --git a/arch/arm64/kernel/reloc_test_syms.S b/arch/arm64/kernel/reloc_test_syms.S
new file mode 100644
index 000000000000..b01732802e7d
--- /dev/null
+++ b/arch/arm64/kernel/reloc_test_syms.S
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2016 Linaro Ltd; <ard.biesheuvel at 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)
--
2.9.3
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