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Date:   Tue, 29 Mar 2022 14:39:58 +0200
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Subject: [PATCH v2 29/48] kmsan: entry: handle register passing from
 uninstrumented code
From:   Alexander Potapenko <glider@google.com>
To:     glider@google.com
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Christoph Hellwig <hch@lst.de>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Eric Dumazet <edumazet@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Kees Cook <keescook@chromium.org>,
        Marco Elver <elver@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Pekka Enberg <penberg@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vegard Nossum <vegard.nossum@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>, linux-mm@kvack.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Replace instrumentation_begin()	with instrumentation_begin_with_regs()
to let KMSAN handle the non-instrumented code and unpoison pt_regs
passed from the instrumented part.

Signed-off-by: Alexander Potapenko <glider@google.com>
---
Link: https://linux-review.googlesource.com/id/I7f0a9809b66bd85faae43142971d0095771b7a42
---
 kernel/entry/common.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index bad713684c2e3..dcf91ab14512a 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -21,7 +21,7 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
 	CT_WARN_ON(ct_state() != CONTEXT_USER);
 	user_exit_irqoff();
 
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	trace_hardirqs_off_finish();
 	instrumentation_end();
 }
@@ -103,7 +103,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 
 	__enter_from_user_mode(regs);
 
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	local_irq_enable();
 	ret = __syscall_enter_from_user_work(regs, syscall);
 	instrumentation_end();
@@ -114,7 +114,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
 {
 	__enter_from_user_mode(regs);
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	local_irq_enable();
 	instrumentation_end();
 }
@@ -296,7 +296,7 @@ void syscall_exit_to_user_mode_work(struct pt_regs *regs)
 
 __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
 {
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	__syscall_exit_to_user_mode_work(regs);
 	instrumentation_end();
 	__exit_to_user_mode();
@@ -309,7 +309,7 @@ noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
 
 noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
 {
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	exit_to_user_mode_prepare(regs);
 	instrumentation_end();
 	__exit_to_user_mode();
@@ -357,7 +357,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
 		 */
 		lockdep_hardirqs_off(CALLER_ADDR0);
 		rcu_irq_enter();
-		instrumentation_begin();
+		instrumentation_begin_with_regs(regs);
 		trace_hardirqs_off_finish();
 		instrumentation_end();
 
@@ -372,7 +372,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
 	 * in having another one here.
 	 */
 	lockdep_hardirqs_off(CALLER_ADDR0);
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	rcu_irq_enter_check_tick();
 	trace_hardirqs_off_finish();
 	instrumentation_end();
@@ -409,7 +409,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
 		 * and RCU as the return to user mode path.
 		 */
 		if (state.exit_rcu) {
-			instrumentation_begin();
+			instrumentation_begin_with_regs(regs);
 			/* Tell the tracer that IRET will enable interrupts */
 			trace_hardirqs_on_prepare();
 			lockdep_hardirqs_on_prepare(CALLER_ADDR0);
@@ -419,7 +419,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
 			return;
 		}
 
-		instrumentation_begin();
+		instrumentation_begin_with_regs(regs);
 		if (IS_ENABLED(CONFIG_PREEMPTION)) {
 #ifdef CONFIG_PREEMPT_DYNAMIC
 			static_call(irqentry_exit_cond_resched)();
@@ -451,7 +451,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs)
 	lockdep_hardirq_enter();
 	rcu_nmi_enter();
 
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	trace_hardirqs_off_finish();
 	ftrace_nmi_enter();
 	instrumentation_end();
@@ -461,7 +461,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs)
 
 void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state)
 {
-	instrumentation_begin();
+	instrumentation_begin_with_regs(regs);
 	ftrace_nmi_exit();
 	if (irq_state.lockdep) {
 		trace_hardirqs_on_prepare();
-- 
2.35.1.1021.g381101b075-goog