From: Masahiro Yamada Date: Fri, 18 Dec 2020 02:45:40 +0000 (+0900) Subject: arm64: do not descend to vdso directories twice X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a5b8ca97fbf8300a5e21c393df25ce6f521e7939;p=linux.git arm64: do not descend to vdso directories twice arm64 descends into each vdso directory twice; first in vdso_prepare, second during the ordinary build process. PPC mimicked it and uncovered a problem [1]. In the first descend, Kbuild directly visits the vdso directories, therefore it does not inherit subdir-ccflags-y from upper directories. This means the command line parameters may differ between the two. If it happens, the offset values in the generated headers might be different from real offsets of vdso.so in the kernel. This potential danger should be avoided. The vdso directories are built in the vdso_prepare stage, so the second descend is unneeded. [1]: https://lore.kernel.org/linux-kbuild/CAK7LNARAkJ3_-4gX0VA2UkapbOftuzfSTVMBbgbw=HD8n7N+7w@mail.gmail.com/T/#ma10dcb961fda13f36d42d58fa6cb2da988b7e73a Signed-off-by: Masahiro Yamada Link: https://lore.kernel.org/r/20201218024540.1102650-1-masahiroy@kernel.org Signed-off-by: Will Deacon --- diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 90309208bb28d..5b84aec31ed3b 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -188,10 +188,12 @@ ifeq ($(KBUILD_EXTMOD),) # this hack. prepare: vdso_prepare vdso_prepare: prepare0 - $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h - $(if $(CONFIG_COMPAT_VDSO),$(Q)$(MAKE) \ - $(build)=arch/arm64/kernel/vdso32 \ - include/generated/vdso32-offsets.h) + $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso \ + include/generated/vdso-offsets.h arch/arm64/kernel/vdso/vdso.so +ifdef CONFIG_COMPAT_VDSO + $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 \ + include/generated/vdso32-offsets.h arch/arm64/kernel/vdso32/vdso.so +endif endif define archhelp diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 86364ab6f13fd..42f6ad2c7eac3 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -59,9 +59,10 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o obj-$(CONFIG_ARM_SDE_INTERFACE) += sdei.o obj-$(CONFIG_ARM64_PTR_AUTH) += pointer_auth.o obj-$(CONFIG_ARM64_MTE) += mte.o +obj-y += vdso-wrap.o +obj-$(CONFIG_COMPAT_VDSO) += vdso32-wrap.o -obj-y += vdso/ probes/ -obj-$(CONFIG_COMPAT_VDSO) += vdso32/ +obj-y += probes/ head-y := head.o extra-y += $(head-y) vmlinux.lds diff --git a/arch/arm64/kernel/vdso-wrap.S b/arch/arm64/kernel/vdso-wrap.S new file mode 100644 index 0000000000000..c4b1990bf2be0 --- /dev/null +++ b/arch/arm64/kernel/vdso-wrap.S @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2012 ARM Limited + * + * Author: Will Deacon + */ + +#include +#include +#include +#include +#include + + .globl vdso_start, vdso_end + .section .rodata + .balign PAGE_SIZE +vdso_start: + .incbin "arch/arm64/kernel/vdso/vdso.so" + .balign PAGE_SIZE +vdso_end: + + .previous + +emit_aarch64_feature_1_and diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index cd9c3fa25902f..76c0255ecc919 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -44,7 +44,6 @@ endif # Disable gcov profiling for VDSO code GCOV_PROFILE := n -obj-y += vdso.o targets += vdso.lds CPPFLAGS_vdso.lds += -P -C -U$(ARCH) diff --git a/arch/arm64/kernel/vdso/vdso.S b/arch/arm64/kernel/vdso/vdso.S deleted file mode 100644 index c4b1990bf2be0..0000000000000 --- a/arch/arm64/kernel/vdso/vdso.S +++ /dev/null @@ -1,24 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright (C) 2012 ARM Limited - * - * Author: Will Deacon - */ - -#include -#include -#include -#include -#include - - .globl vdso_start, vdso_end - .section .rodata - .balign PAGE_SIZE -vdso_start: - .incbin "arch/arm64/kernel/vdso/vdso.so" - .balign PAGE_SIZE -vdso_end: - - .previous - -emit_aarch64_feature_1_and diff --git a/arch/arm64/kernel/vdso32-wrap.S b/arch/arm64/kernel/vdso32-wrap.S new file mode 100644 index 0000000000000..e72ac7bc4c04f --- /dev/null +++ b/arch/arm64/kernel/vdso32-wrap.S @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2012 ARM Limited + */ + +#include +#include +#include +#include + + .globl vdso32_start, vdso32_end + .section .rodata + .balign PAGE_SIZE +vdso32_start: + .incbin "arch/arm64/kernel/vdso32/vdso.so" + .balign PAGE_SIZE +vdso32_end: + + .previous diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index a1e0f91e6cea6..789ad420f16ba 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -155,7 +155,6 @@ c-obj-vdso-gettimeofday := $(addprefix $(obj)/, $(c-obj-vdso-gettimeofday)) asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso)) obj-vdso := $(c-obj-vdso) $(c-obj-vdso-gettimeofday) $(asm-obj-vdso) -obj-y += vdso.o targets += vdso.lds CPPFLAGS_vdso.lds += -P -C -U$(ARCH) diff --git a/arch/arm64/kernel/vdso32/vdso.S b/arch/arm64/kernel/vdso32/vdso.S deleted file mode 100644 index e72ac7bc4c04f..0000000000000 --- a/arch/arm64/kernel/vdso32/vdso.S +++ /dev/null @@ -1,19 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * Copyright (C) 2012 ARM Limited - */ - -#include -#include -#include -#include - - .globl vdso32_start, vdso32_end - .section .rodata - .balign PAGE_SIZE -vdso32_start: - .incbin "arch/arm64/kernel/vdso32/vdso.so" - .balign PAGE_SIZE -vdso32_end: - - .previous