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

[Peter Collingbourne <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