From: Vasily Gorbik <gor@linux.ibm.com>
Date: Mon, 20 Nov 2017 11:15:10 +0000 (+0100)
Subject: s390/kasan: reipl and kexec support
X-Git-Tag: v5.4-rc1~2425^2~29
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ac1256f82619724357242eb514f162c40d5b64d8;p=platform%2Fkernel%2Flinux-rpi.git

s390/kasan: reipl and kexec support

Some functions from both arch/s390/kernel/ipl.c and
arch/s390/kernel/machine_kexec.c are called without DAT enabled
(or with and without DAT enabled code paths). There is no easy way
to partially disable kasan for those files without a substantial
rework. Disable kasan for both files for now.

To avoid disabling kasan for arch/s390/kernel/diag.c DAT flag is
enabled in diag308 call. pcpu_delegate which disables DAT is marked
with __no_sanitize_address to disable instrumentation for that one
function.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 55956c9..34768e6 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -242,7 +242,7 @@ static inline unsigned long current_stack_pointer(void)
 	return sp;
 }
 
-static inline unsigned short stap(void)
+static __no_sanitize_address_or_inline unsigned short stap(void)
 {
 	unsigned short cpu_address;
 
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 1f9c98f..386b1abb 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -24,6 +24,8 @@ UBSAN_SANITIZE_early.o		:= n
 UBSAN_SANITIZE_early_nobss.o	:= n
 
 KASAN_SANITIZE_early_nobss.o	:= n
+KASAN_SANITIZE_ipl.o		:= n
+KASAN_SANITIZE_machine_kexec.o	:= n
 
 #
 # Passing null pointers is ok for smp code, since we access the lowcore here.
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index f1d69f7..18a5d63 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -156,6 +156,8 @@ static inline int __diag308(unsigned long subcode, void *addr)
 
 int diag308(unsigned long subcode, void *addr)
 {
+	if (IS_ENABLED(CONFIG_KASAN))
+		__arch_local_irq_stosm(0x04); /* enable DAT */
 	diag_stat_inc(DIAG_STAT_X308);
 	return __diag308(subcode, addr);
 }
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index c98059f..1b3188f 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -313,8 +313,9 @@ static void __pcpu_delegate(void (*func)(void*), void *data)
 	func(data);	/* should not return */
 }
 
-static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
-			  void *data, unsigned long stack)
+static void __no_sanitize_address pcpu_delegate(struct pcpu *pcpu,
+						void (*func)(void *),
+						void *data, unsigned long stack)
 {
 	struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 	unsigned long source_cpu = stap();