[PATCH v15 09/43] arm64, dept: add support CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64

[Byungchul Park]

dept needs to notice every entrance from user to kernel mode to treat
every kernel context independently when tracking wait-event dependencies.
Roughly, system call and user oriented fault are the cases.

Make dept aware of the entrances of arm64 and add support
CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64.

Signed-off-by: Byungchul Park <byungc...@sk.com>
---
 arch/arm64/Kconfig          | 1 +
 arch/arm64/kernel/syscall.c | 7 +++++++
 arch/arm64/mm/fault.c       | 7 +++++++
 3 files changed, 15 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a182295e6f08..6c69598a6423 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -279,6 +279,7 @@ config ARM64
        select HAVE_SOFTIRQ_ON_OWN_STACK
        select USER_STACKTRACE_SUPPORT
        select VDSO_GETRANDOM
+       select ARCH_HAS_DEPT_SUPPORT
        help
          ARM 64-bit (AArch64) Linux support.
 
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index c442fcec6b9e..bbd306335179 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/dept.h>
 
 #include <asm/debug-monitors.h>
 #include <asm/exception.h>
@@ -96,6 +97,12 @@ static void el0_svc_common(struct pt_regs *regs, int scno, 
int sc_nr,
         * (Similarly for HVC and SMC elsewhere.)
         */
 
+       /*
+        * This is a system call from user mode.  Make dept work with a
+        * new kernel mode context.
+        */
+       dept_update_cxt();
+
        if (flags & _TIF_MTE_ASYNC_FAULT) {
                /*
                 * Process the asynchronous tag check fault before the actual
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index ec0a337891dd..0fcc3dc9c2a9 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -26,6 +26,7 @@
 #include <linux/pkeys.h>
 #include <linux/preempt.h>
 #include <linux/hugetlb.h>
+#include <linux/dept.h>
 
 #include <asm/acpi.h>
 #include <asm/bug.h>
@@ -616,6 +617,12 @@ static int __kprobes do_page_fault(unsigned long far, 
unsigned long esr,
        if (!(mm_flags & FAULT_FLAG_USER))
                goto lock_mmap;
 
+       /*
+        * This fault comes from user mode.  Make dept work with a new
+        * kernel mode context.
+        */
+       dept_update_cxt();
+
        vma = lock_vma_under_rcu(mm, addr);
        if (!vma)
                goto lock_mmap;
-- 
2.17.1