ARM: 9013/2: Disable KASan instrumentation for some code

Disable instrumentation for arch/arm/boot/compressed/*
since that code is executed before the kernel has even
set up its mappings and definately out of scope for
KASan.

Disable instrumentation of arch/arm/vdso/* because that code
is not linked with the kernel image, so the KASan management
code would fail to link.

Disable instrumentation of arch/arm/mm/physaddr.c. See commit
ec6d06efb0ba ("arm64: Add support for CONFIG_DEBUG_VIRTUAL")
for more details.

Disable kasan check in the function unwind_pop_register because
it does not matter that kasan checks failed when unwind_pop_register()
reads the stack memory of a task.

Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org> # QEMU/KVM/mach-virt/LPAE/8G
Tested-by: Florian Fainelli <f.fainelli@gmail.com> # Brahma SoCs
Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de> # i.MX6Q
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Abbott Liu <liuwenliang@huawei.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 47f001c..a815b1a 100644 (file)
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -24,6 +24,7 @@ OBJS          += hyp-stub.o
 endif
 
 GCOV_PROFILE           := n
+KASAN_SANITIZE         := n
 
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT                := n

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index d2bd0df..f35eb58 100644 (file)
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -236,7 +236,11 @@ static int unwind_pop_register(struct unwind_ctrl_block *ctrl,
                if (*vsp >= (unsigned long *)ctrl->sp_high)
                        return -URC_FAILURE;
 
-       ctrl->vrs[reg] = *(*vsp)++;
+       /* Use READ_ONCE_NOCHECK here to avoid this memory access
+        * from being tracked by KASAN.
+        */
+       ctrl->vrs[reg] = READ_ONCE_NOCHECK(*(*vsp));
+       (*vsp)++;
        return URC_OK;
 }
 

diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
index 7cb1699..99699c3 100644 (file)
--- a/arch/arm/mm/Makefile
+++ b/arch/arm/mm/Makefile
@@ -7,6 +7,7 @@ obj-y                           := extable.o fault.o init.o iomap.o
 obj-y                          += dma-mapping$(MMUEXT).o
 obj-$(CONFIG_MMU)              += fault-armv.o flush.o idmap.o ioremap.o \
                                   mmap.o pgd.o mmu.o pageattr.o
+KASAN_SANITIZE_mmu.o           := n
 
 ifneq ($(CONFIG_MMU),y)
 obj-y                          += nommu.o
@@ -16,6 +17,7 @@ endif
 obj-$(CONFIG_ARM_PTDUMP_CORE)  += dump.o
 obj-$(CONFIG_ARM_PTDUMP_DEBUGFS)       += ptdump_debugfs.o
 obj-$(CONFIG_MODULES)          += proc-syms.o
+KASAN_SANITIZE_physaddr.o      := n
 obj-$(CONFIG_DEBUG_VIRTUAL)    += physaddr.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)   += alignment.o

diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index 150ce6e..b558bee 100644 (file)
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -42,6 +42,8 @@ GCOV_PROFILE := n
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT := n
 
+KASAN_SANITIZE := n
+
 # Force dependency
 $(obj)/vdso.o : $(obj)/vdso.so