When kprobes is used, most of the entry-armv.S file is put into the .kprobes.text section rather than .text, but the kuser_cmpxchg64_fixup and kuser_cmpxchg32_fixup code is not, which can lead to a link error when extremely large kernels get built (typically for randconfig):
arch/arm/kernel/built-in.o: In function `__dabt_usr': :(.kprobes.text+0x47c): relocation truncated to fit: R_ARM_JUMP24 against `.text' arch/arm/kernel/built-in.o: In function `__irq_usr': :(.kprobes.text+0x4e4): relocation truncated to fit: R_ARM_JUMP24 against `.text' arch/arm/kernel/built-in.o: In function `__fiq_usr': :(.kprobes.text+0x740): relocation truncated to fit: R_ARM_JUMP24 against `.text' This moves the two remaining functions into the same section as the rest using a new macro suggested by Nicolas Pitre, which avoids the link error. The current behavior has existed for many years and has not caused problems in practice except for extreme randconfig builds, so the patch should not need to get backported. Signed-off-by: Arnd Bergmann <[email protected]> Fixes: b49c0f24cf67 ("[ARM] 4659/1: remove possibilities for spurious false negative with __kuser_cmpxchg") Fixes: 785d3cd286f0 ("ARM kprobes: prevent some functions involved with kprobes from being probed") Acked-by: Nicolas Pitre <[email protected]> --- arch/arm/kernel/entry-armv.S | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index e2550500486d..3bc1a196cb53 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -83,11 +83,12 @@ .endm #ifdef CONFIG_KPROBES - .section .kprobes.text,"ax",%progbits +#define KPROBE_TEXT .section .kprobes.text,"ax",%progbits #else - .text +#define KPROBE_TEXT .text #endif + KPROBE_TEXT /* * Invalid mode handlers */ @@ -895,7 +896,7 @@ __kuser_cmpxchg64: @ 0xffff0f60 rsbs r0, r3, #0 @ set return val and C flag ldmfd sp!, {r4, r5, r6, pc} - .text + KPROBE_TEXT kuser_cmpxchg64_fixup: @ Called from kuser_cmpxchg_fixup. @ r4 = address of interrupted insn (must be preserved). @@ -953,7 +954,7 @@ __kuser_cmpxchg: @ 0xffff0fc0 rsbs r0, r3, #0 @ set return val and C flag usr_ret lr - .text + KPROBE_TEXT kuser_cmpxchg32_fixup: @ Called from kuser_cmpxchg_check macro. @ r4 = address of interrupted insn (must be preserved). -- 2.7.0
