From: Kees Cook <keescook@chromium.org> To: Will Deacon <will@kernel.org> Cc: Kees Cook <keescook@chromium.org>, Catalin Marinas <catalin.marinas@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ard Biesheuvel <ardb@kernel.org>, Peter Collingbourne <pcc@google.com>, James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Russell King <linux@armlinux.org.uk>, Masahiro Yamada <masahiroy@kernel.org>, Arvind Sankar <nivedita@alum.mit.edu>, Nick Desaulniers <ndesaulniers@google.com>, Nathan Chancellor <natechancellor@gmail.com>, Arnd Bergmann <arnd@arndb.de>, x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 4/9] x86/build: Warn on orphan section placement Date: Tue, 23 Jun 2020 18:49:35 -0700 [thread overview] Message-ID: <20200624014940.1204448-5-keescook@chromium.org> (raw) In-Reply-To: <20200624014940.1204448-1-keescook@chromium.org> We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly named in the linker script. Discards the unused rela, plt, and got sections that are not needed in the final vmlinux, stop emitting kprobe sections without kprobes, and enable orphan section warnings. Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/x86/Makefile | 4 ++++ arch/x86/include/asm/asm.h | 6 +++++- arch/x86/kernel/vmlinux.lds.S | 6 ++++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 00e378de8bc0..f8a5b2333729 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -51,6 +51,10 @@ ifdef CONFIG_X86_NEED_RELOCS LDFLAGS_vmlinux := --emit-relocs --discard-none endif +# We never want expected sections to be placed heuristically by the +# linker. All sections should be explicitly named in the linker script. +LDFLAGS_vmlinux += --orphan-handling=warn + # # Prevent GCC from generating any FP code by mistake. # diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 0f63585edf5f..92feec0f0a12 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -138,11 +138,15 @@ # define _ASM_EXTABLE_FAULT(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) -# define _ASM_NOKPROBE(entry) \ +# ifdef CONFIG_KPROBES +# define _ASM_NOKPROBE(entry) \ .pushsection "_kprobe_blacklist","aw" ; \ _ASM_ALIGN ; \ _ASM_PTR (entry); \ .popsection +# else +# define _ASM_NOKPROBE(entry) +# endif #else # define _EXPAND_EXTABLE_HANDLE(x) #x diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3bfc8dd8a43d..bb085ceeaaad 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -412,6 +412,12 @@ SECTIONS DWARF_DEBUG DISCARDS + /DISCARD/ : { + *(.rela.*) *(.rela_*) + *(.rel.*) *(.rel_*) + *(.got) *(.got.*) + *(.igot.*) *(.iplt) + } } -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org> To: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com>, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>, Catalin Marinas <catalin.marinas@arm.com>, Masahiro Yamada <masahiroy@kernel.org>, x86@kernel.org, Nick Desaulniers <ndesaulniers@google.com>, Russell King <linux@armlinux.org.uk>, linux-kernel@vger.kernel.org, Nathan Chancellor <natechancellor@gmail.com>, clang-built-linux@googlegroups.com, Arvind Sankar <nivedita@alum.mit.edu>, Ingo Molnar <mingo@redhat.com>, James Morse <james.morse@arm.com>, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@suse.de>, Peter Collingbourne <pcc@google.com>, Ard Biesheuvel <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 4/9] x86/build: Warn on orphan section placement Date: Tue, 23 Jun 2020 18:49:35 -0700 [thread overview] Message-ID: <20200624014940.1204448-5-keescook@chromium.org> (raw) In-Reply-To: <20200624014940.1204448-1-keescook@chromium.org> We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly named in the linker script. Discards the unused rela, plt, and got sections that are not needed in the final vmlinux, stop emitting kprobe sections without kprobes, and enable orphan section warnings. Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/x86/Makefile | 4 ++++ arch/x86/include/asm/asm.h | 6 +++++- arch/x86/kernel/vmlinux.lds.S | 6 ++++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 00e378de8bc0..f8a5b2333729 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -51,6 +51,10 @@ ifdef CONFIG_X86_NEED_RELOCS LDFLAGS_vmlinux := --emit-relocs --discard-none endif +# We never want expected sections to be placed heuristically by the +# linker. All sections should be explicitly named in the linker script. +LDFLAGS_vmlinux += --orphan-handling=warn + # # Prevent GCC from generating any FP code by mistake. # diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 0f63585edf5f..92feec0f0a12 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -138,11 +138,15 @@ # define _ASM_EXTABLE_FAULT(from, to) \ _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) -# define _ASM_NOKPROBE(entry) \ +# ifdef CONFIG_KPROBES +# define _ASM_NOKPROBE(entry) \ .pushsection "_kprobe_blacklist","aw" ; \ _ASM_ALIGN ; \ _ASM_PTR (entry); \ .popsection +# else +# define _ASM_NOKPROBE(entry) +# endif #else # define _EXPAND_EXTABLE_HANDLE(x) #x diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3bfc8dd8a43d..bb085ceeaaad 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -412,6 +412,12 @@ SECTIONS DWARF_DEBUG DISCARDS + /DISCARD/ : { + *(.rela.*) *(.rela_*) + *(.rel.*) *(.rel_*) + *(.got) *(.got.*) + *(.igot.*) *(.iplt) + } } -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-06-24 1:50 UTC|newest] Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-24 1:49 [PATCH v3 0/9] Warn on orphan section placement Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 1/9] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 2/9] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to STABS_DEBUG Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 15:39 ` Arvind Sankar 2020-06-24 15:39 ` Arvind Sankar 2020-06-24 15:39 ` Arvind Sankar 2020-06-24 16:16 ` Fangrui Song 2020-06-24 16:16 ` Fangrui Song 2020-06-24 17:11 ` Arvind Sankar 2020-06-24 17:11 ` Arvind Sankar 2020-06-24 17:11 ` Arvind Sankar 2020-06-24 17:26 ` Fangrui Song 2020-06-24 17:26 ` Fangrui Song 2020-06-24 17:35 ` Arvind Sankar 2020-06-24 17:35 ` Arvind Sankar 2020-06-24 17:35 ` Arvind Sankar 2020-06-24 1:49 ` [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 3:31 ` Fangrui Song 2020-06-24 3:31 ` Fangrui Song 2020-06-24 4:44 ` Kees Cook 2020-06-24 4:44 ` Kees Cook 2020-06-24 10:43 ` Will Deacon 2020-06-24 10:43 ` Will Deacon 2020-06-24 10:46 ` Ard Biesheuvel 2020-06-24 10:46 ` Ard Biesheuvel 2020-06-24 10:46 ` Ard Biesheuvel 2020-06-24 11:26 ` Will Deacon 2020-06-24 11:26 ` Will Deacon 2020-06-24 11:26 ` Will Deacon 2020-06-24 13:48 ` Dave Martin 2020-06-24 13:48 ` Dave Martin 2020-06-24 13:48 ` Dave Martin 2020-06-24 15:26 ` Will Deacon 2020-06-24 15:26 ` Will Deacon 2020-06-24 15:26 ` Will Deacon 2020-06-24 16:26 ` Dave Martin 2020-06-24 16:26 ` Dave Martin 2020-06-24 16:26 ` Dave Martin 2020-06-24 15:21 ` Kees Cook 2020-06-24 15:21 ` Kees Cook 2020-06-24 15:21 ` Kees Cook 2020-06-24 15:31 ` Ard Biesheuvel 2020-06-24 15:31 ` Ard Biesheuvel 2020-06-24 15:31 ` Ard Biesheuvel 2020-06-24 15:45 ` Kees Cook 2020-06-24 15:45 ` Kees Cook 2020-06-24 15:45 ` Kees Cook 2020-06-24 15:48 ` Ard Biesheuvel 2020-06-24 15:48 ` Ard Biesheuvel 2020-06-24 15:48 ` Ard Biesheuvel 2020-06-24 16:29 ` Dave Martin 2020-06-24 16:29 ` Dave Martin 2020-06-24 16:29 ` Dave Martin 2020-06-24 16:40 ` Ard Biesheuvel 2020-06-24 16:40 ` Ard Biesheuvel 2020-06-24 16:40 ` Ard Biesheuvel 2020-06-24 17:16 ` Dave Martin 2020-06-24 17:16 ` Dave Martin 2020-06-24 17:16 ` Dave Martin 2020-06-24 18:23 ` Ard Biesheuvel 2020-06-24 18:23 ` Ard Biesheuvel 2020-06-24 18:23 ` Ard Biesheuvel 2020-06-24 18:57 ` Ard Biesheuvel 2020-06-24 18:57 ` Ard Biesheuvel 2020-06-24 18:57 ` Ard Biesheuvel 2020-06-24 1:49 ` Kees Cook [this message] 2020-06-24 1:49 ` [PATCH v3 4/9] x86/build: Warn on orphan section placement Kees Cook 2020-06-24 18:36 ` kernel test robot 2020-06-27 15:44 ` Kees Cook 2020-06-27 15:44 ` Kees Cook 2020-06-29 14:54 ` Marco Elver 2020-06-29 14:54 ` Marco Elver 2020-06-29 15:26 ` Kees Cook 2020-06-29 15:26 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 5/9] x86/boot: " Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 6/9] arm/build: " Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 7/9] arm/boot: " Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 8/9] arm64/build: Use common DISCARDS in linker script Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 1:49 ` [PATCH v3 9/9] arm64/build: Warn on orphan section placement Kees Cook 2020-06-24 1:49 ` Kees Cook 2020-06-24 7:57 ` Will Deacon 2020-06-24 7:57 ` Will Deacon 2020-06-24 15:36 ` Kees Cook 2020-06-24 15:36 ` Kees Cook
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