[PATCH v2 4/5] arm64: add support for uaccess logging

From: Peter Collingbourne <pcc@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,  Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	 Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	 Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	 Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	 Daniel Bristot de Oliveira <bristot@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	 Andy Lutomirski <luto@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	 Andrew Morton <akpm@linux-foundation.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	 Sami Tolvanen <samitolvanen@google.com>,
	YiFei Zhu <yifeifz2@illinois.edu>,
	 Colin Ian King <colin.king@canonical.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	 Andrey Konovalov <andreyknvl@gmail.com>,
	Peter Collingbourne <pcc@google.com>,
	 Gabriel Krisman Bertazi <krisman@collabora.com>,
	Chris Hyser <chris.hyser@oracle.com>,
	 Daniel Vetter <daniel.vetter@ffwll.ch>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Arnd Bergmann <arnd@arndb.de>, Dmitry Vyukov <dvyukov@google.com>,
	 Christian Brauner <christian.brauner@ubuntu.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	 Alexey Gladkov <legion@kernel.org>,
	Ran Xiaokai <ran.xiaokai@zte.com.cn>,
	 David Hildenbrand <david@redhat.com>,
	Xiaofeng Cao <caoxiaofeng@yulong.com>,
	 Cyrill Gorcunov <gorcunov@gmail.com>,
	Thomas Cedeno <thomascedeno@google.com>,
	 Marco Elver <elver@google.com>,
	Alexander Potapenko <glider@google.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	 Evgenii Stepanov <eugenis@google.com>
Subject: [PATCH v2 4/5] arm64: add support for uaccess logging
Date: Mon, 22 Nov 2021 21:16:57 -0800	[thread overview]
Message-ID: <20211123051658.3195589-5-pcc@google.com> (raw)
In-Reply-To: <20211123051658.3195589-1-pcc@google.com>

arm64 does not use CONFIG_GENERIC_ENTRY, so add the support for
uaccess logging directly to the architecture.

Link: https://linux-review.googlesource.com/id/I88de539fb9c4a9d27fa8cccbe201a6e4382faf89
Signed-off-by: Peter Collingbourne <pcc@google.com>
---
 arch/arm64/Kconfig          | 1 +
 arch/arm64/kernel/signal.c  | 5 +++++
 arch/arm64/kernel/syscall.c | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c4207cf9bb17..6023946abe4a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -161,6 +161,7 @@ config ARM64
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_ARCH_UACCESS_BUFFER
 	select HAVE_ARCH_VMAP_STACK
 	select HAVE_ARM_SMCCC
 	select HAVE_ASM_MODVERSIONS
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 8f6372b44b65..5bbd98e5c257 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -20,6 +20,7 @@
 #include <linux/tracehook.h>
 #include <linux/ratelimit.h>
 #include <linux/syscalls.h>
+#include <linux/uaccess-buffer.h>
 
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
@@ -919,6 +920,8 @@ static void do_signal(struct pt_regs *regs)
 
 void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
 {
+	bool uaccess_buffer_pending = uaccess_buffer_pre_exit_loop();
+
 	do {
 		if (thread_flags & _TIF_NEED_RESCHED) {
 			/* Unmask Debug and SError for the next task */
@@ -950,6 +953,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
 		local_daif_mask();
 		thread_flags = READ_ONCE(current_thread_info()->flags);
 	} while (thread_flags & _TIF_WORK_MASK);
+
+	uaccess_buffer_post_exit_loop(uaccess_buffer_pending);
 }
 
 unsigned long __ro_after_init signal_minsigstksz;
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 50a0f1a38e84..6de801c1af05 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -7,6 +7,7 @@
 #include <linux/ptrace.h>
 #include <linux/randomize_kstack.h>
 #include <linux/syscalls.h>
+#include <linux/uaccess-buffer.h>
 
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
@@ -139,7 +140,9 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 			goto trace_exit;
 	}
 
+	uaccess_buffer_syscall_entry();
 	invoke_syscall(regs, scno, sc_nr, syscall_table);
+	uaccess_buffer_syscall_exit();
 
 	/*
 	 * The tracing status may have changed under our feet, so we have to
-- 
2.34.0.rc2.393.gf8c9666880-goog


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