[PATCH v3 0/4] Enable orphan-handling=warn for VDSO

[PATCH v3 0/4] Enable orphan-handling=warn for VDSO

[Joey Gouly]

Hi all,

This small series enables the orphan-handling linker flag for the VDSO.
This could catch subtle errors if features that use special sections are
introduced into the VDSO implementation.

Changes from v2 [1]:
  - Include vdso compat support

Thanks,
Joey

[1]: https://lore.kernel.org/linux-arm-kernel/20220407101304.539-1-joey.gouly@arm.com/

Joey Gouly (4):
  arm64: vdso: put ELF related sections in the linker script
  arm64: vdso: enable orphan handling for VDSO
  arm64: vdso32: put ELF related sections in the linker script
  arm64: vdso32: enable orphan handling for VDSO

 arch/arm64/kernel/vdso/Makefile     | 8 +++++++-
 arch/arm64/kernel/vdso/vdso.lds.S   | 4 ++++
 arch/arm64/kernel/vdso32/Makefile   | 1 +
 arch/arm64/kernel/vdso32/vdso.lds.S | 4 ++++
 4 files changed, 16 insertions(+), 1 deletion(-)

-- 
2.17.1


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[PATCH v3 1/4] arm64: vdso: put ELF related sections in the linker script

[Joey Gouly]

Use macros from vmlinux.lds.h to explicitly name sections that are included
in the VDSO output.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso/vdso.lds.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index a5e61e09ea92..8a8780c6d093 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -11,6 +11,7 @@
 #include <linux/const.h>
 #include <asm/page.h>
 #include <asm/vdso.h>
+#include <asm-generic/vmlinux.lds.h>
 
 OUTPUT_FORMAT("elf64-littleaarch64", "elf64-bigaarch64", "elf64-littleaarch64")
 OUTPUT_ARCH(aarch64)
@@ -54,6 +55,9 @@ SECTIONS
 	_end = .;
 	PROVIDE(end = .);
 
+	DWARF_DEBUG
+	ELF_DETAILS
+
 	/DISCARD/	: {
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
-- 
2.17.1


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[PATCH v3 2/4] arm64: vdso: enable orphan handling for VDSO

[Joey Gouly]

Like vmlinux, enable orphan-handling for the VDSO. This can catch
subtle errors that might arise from unexpected sections being included.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso/Makefile | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 172452f79e46..623d9ad2c717 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -24,7 +24,13 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
 # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
 # preparation in build-time C")).
 ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv	\
-	     -Bsymbolic --build-id=sha1 -n $(btildflags-y) -T
+	     -Bsymbolic --build-id=sha1 -n $(btildflags-y)
+
+ifdef CONFIG_LD_ORPHAN_WARN
+  ldflags-y += --orphan-handling=warn
+endif
+
+ldflags-y += -T
 
 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
-- 
2.17.1


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[PATCH v3 3/4] arm64: vdso32: put ELF related sections in the linker script

[Joey Gouly]

Use macros from vmlinux.lds.h to explicitly name sections that are included
in the compat VDSO32 output.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso32/vdso.lds.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kernel/vdso32/vdso.lds.S b/arch/arm64/kernel/vdso32/vdso.lds.S
index 3348ce5ea306..3bb955f08240 100644
--- a/arch/arm64/kernel/vdso32/vdso.lds.S
+++ b/arch/arm64/kernel/vdso32/vdso.lds.S
@@ -11,6 +11,7 @@
 #include <linux/const.h>
 #include <asm/page.h>
 #include <asm/vdso.h>
+#include <asm-generic/vmlinux.lds.h>
 
 OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
 OUTPUT_ARCH(arm)
@@ -42,6 +43,9 @@ SECTIONS
 	.got		: { *(.got) }
 	.rel.plt	: { *(.rel.plt) }
 
+	ELF_DETAILS
+	.ARM.attributes 0 : { *(.ARM.attributes) }
+
 	/DISCARD/	: {
 		*(.note.GNU-stack)
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
-- 
2.17.1


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[PATCH v3 4/4] arm64: vdso32: enable orphan handling for VDSO

[Joey Gouly]

Like vmlinux, enable orphan-handling for the compat VDSO32. This can catch
subtle errors that might arise from unexpected sections being included.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kernel/vdso32/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index ed181bedbffc..1bf0bfb99652 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -104,6 +104,7 @@ VDSO_AFLAGS += -D__ASSEMBLY__
 VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
 VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096
 VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1
+VDSO_LDFLAGS += --orphan-handling=warn
 
 
 # Borrow vdsomunge.c from the arm vDSO
-- 
2.17.1


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