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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 v4 14/17] arm/build: Warn on orphan section placement
Date: Sun, 28 Jun 2020 23:18:37 -0700
Message-ID: <20200629061840.4065483-15-keescook@chromium.org> (raw)
In-Reply-To: <20200629061840.4065483-1-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.

Specifically, this would have made a recently fixed bug very obvious:

ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'

Discard unneeded sections .iplt, .rel.iplt, .igot.plt, and .modinfo.

Add missing text stub sections .vfp11_veneer and .v4_bx.

Add debug sections explicitly.

Finally enable orphan section warning.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/include/asm/vmlinux.lds.h | 6 +++++-
 arch/arm/kernel/vmlinux-xip.lds.S  | 1 +
 arch/arm/kernel/vmlinux.lds.S      | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h
index c66b16cd8837..d44fae722e7a 100644
--- a/arch/arm/include/asm/vmlinux.lds.h
+++ b/arch/arm/include/asm/vmlinux.lds.h
@@ -39,6 +39,8 @@
 		__idmap_text_end = .;					\
 
 #define ARM_COMMON_DISCARD						\
+		*(.iplt) *(.rel.iplt) *(.igot.plt)                      \
+		*(.modinfo)                                             \
 		*(.discard)						\
 		*(.discard.*)
 
@@ -63,7 +65,9 @@
 #define ARM_STUBS_TEXT							\
 		*(.gnu.warning)						\
 		*(.glue_7)						\
-		*(.glue_7t)
+		*(.glue_7t)						\
+		*(.vfp11_veneer)                                        \
+		*(.v4_bx)
 
 #define ARM_TEXT							\
 		IDMAP_TEXT						\
diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
index 57fcbf55f913..11ffa79751da 100644
--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -150,6 +150,7 @@ SECTIONS
 	_end = .;
 
 	STABS_DEBUG
+	DWARF_DEBUG
 	ARM_DETAILS
 }
 
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 1d3d3b599635..dc672fe35de3 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -149,6 +149,7 @@ SECTIONS
 	_end = .;
 
 	STABS_DEBUG
+	DWARF_DEBUG
 	ARM_DETAILS
 }
 
-- 
2.25.1


  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29  6:18 [PATCH v4 00/17] " Kees Cook
2020-06-29  6:18 ` [PATCH v4 01/17] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook
2020-06-29  6:18 ` [PATCH v4 02/17] vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections Kees Cook
2020-06-29  6:18 ` [PATCH v4 03/17] vmlinux.lds.h: Split ELF_DETAILS from STABS_DEBUG Kees Cook
2020-06-29  6:18 ` [PATCH v4 04/17] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to ELF_DETAILS Kees Cook
2020-06-29  6:18 ` [PATCH v4 05/17] ctype: Work around Clang -mbranch-protection=none bug Kees Cook
2020-06-29  8:15   ` Ard Biesheuvel
2020-06-29 14:43     ` Kees Cook
2020-06-29 15:06     ` Kees Cook
2020-06-29 15:08       ` Ard Biesheuvel
2020-06-29 15:16         ` Kees Cook
2020-06-29 18:02       ` Nick Desaulniers
2020-06-29 18:37         ` Kees Cook
2020-06-29  6:18 ` [PATCH v4 06/17] efi/libstub: Disable -mbranch-protection Kees Cook
2020-06-29  6:18 ` [PATCH v4 07/17] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-06-29  6:18 ` [PATCH v4 08/17] arm64/mm: Remove needless section quotes Kees Cook
2020-06-29 19:53   ` Nick Desaulniers
2020-06-29 20:03     ` Joe Perches
2020-06-29 20:29       ` Nick Desaulniers
2020-06-29 20:04     ` Kees Cook
2020-06-29 20:54       ` Arvind Sankar
2020-06-29 21:06         ` Arvind Sankar
2020-06-29  6:18 ` [PATCH v4 09/17] arm64/build: Remove .eh_frame* sections due to unwind tables Kees Cook
2020-06-29  6:18 ` [PATCH v4 10/17] arm64/kernel: Remove needless Call Frame Information annotations Kees Cook
2020-06-29  6:18 ` [PATCH v4 11/17] arm64/build: Warn on orphan section placement Kees Cook
2020-06-29  6:18 ` [PATCH v4 12/17] arm/build: Refactor linker script headers Kees Cook
2020-06-29  6:18 ` [PATCH v4 13/17] arm/build: Explicitly keep .ARM.attributes sections Kees Cook
2020-06-29  6:18 ` Kees Cook [this message]
2020-06-29 15:54   ` [PATCH v4 14/17] arm/build: Warn on orphan section placement Arvind Sankar
2020-06-29 18:07     ` Russell King - ARM Linux admin
2020-06-29 18:15       ` Arvind Sankar
2020-06-29 19:03         ` Russell King - ARM Linux admin
2020-06-29 19:47   ` Nick Desaulniers
2020-06-29  6:18 ` [PATCH v4 15/17] arm/boot: " Kees Cook
2020-06-29  6:18 ` [PATCH v4 16/17] x86/build: " Kees Cook
2020-06-29  6:18 ` [PATCH v4 17/17] x86/boot: " Kees Cook

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