[PATCH] mips: Enable KCSAN

[PATCH] mips: Enable KCSAN

[Nemanja Rakovic]

This patch enables KCSAN for the 64-bit version. Updated rules
for the incompatible compilation units (vdso, boot/compressed).

Signed-off-by: Nemanja Rakovic <nemanja.rakovic@syrmia.com>
---
 arch/mips/Kconfig                  | 1 +
 arch/mips/boot/compressed/Makefile | 1 +
 arch/mips/vdso/Makefile            | 3 +++
 3 files changed, 5 insertions(+)

Changes were tested on qemu (qemu-system-mips64el) with the
64r6el_defconfig configuration and KCSAN enabled.

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 058446f01487..651d4fe355da 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -101,6 +101,7 @@ config MIPS
 	select TRACE_IRQFLAGS_SUPPORT
 	select VIRT_TO_BUS
 	select ARCH_HAS_ELFCORE_COMPAT
+	select HAVE_ARCH_KCSAN if 64BIT
 
 config MIPS_FIXUP_BIGPHYS_ADDR
 	bool
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index 5a15d51e8884..a35f78212ea9 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -38,6 +38,7 @@ KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
 KCOV_INSTRUMENT		:= n
 GCOV_PROFILE := n
 UBSAN_SANITIZE := n
+KASAN_SANITIZE			:= n
 
 # decompressor objects (linked with vmlinuz)
 vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o $(obj)/bswapsi.o
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index d65f55f67e19..f72658b3a53f 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -1,6 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
 # Objects to go into the VDSO.
 
+# Sanitizer runtimes are unavailable and cannot be linked here.
+ KCSAN_SANITIZE			:= n
+
 # Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
 # the inclusion of generic Makefile.
 ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT
-- 
2.17.1

Re: [PATCH] mips: Enable KCSAN

[Thomas Bogendoerfer]

On Mon, Jan 31, 2022 at 11:17:09AM +0100, Nemanja Rakovic wrote:
> This patch enables KCSAN for the 64-bit version. Updated rules
> for the incompatible compilation units (vdso, boot/compressed).
> 
> Signed-off-by: Nemanja Rakovic <nemanja.rakovic@syrmia.com>
> ---
>  arch/mips/Kconfig                  | 1 +
>  arch/mips/boot/compressed/Makefile | 1 +
>  arch/mips/vdso/Makefile            | 3 +++
>  3 files changed, 5 insertions(+)

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

Re: [PATCH] mips: Enable KCSAN

[Marco Elver]

On Mon, Jan 31, 2022 at 11:17AM +0100, Nemanja Rakovic wrote:
> This patch enables KCSAN for the 64-bit version. Updated rules
> for the incompatible compilation units (vdso, boot/compressed).
> 
> Signed-off-by: Nemanja Rakovic <nemanja.rakovic@syrmia.com>
[...]
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index 5a15d51e8884..a35f78212ea9 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -38,6 +38,7 @@ KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
>  KCOV_INSTRUMENT		:= n
>  GCOV_PROFILE := n
>  UBSAN_SANITIZE := n
> +KASAN_SANITIZE			:= n
>  

Should this have said KCSAN_SANITIZE? You probably want one for
KASAN_SANITIZE as well, but probably not in this patch, given mips
doesn't support KASAN yet (AFAIK).

Thanks,
-- Marco