linux-kernel - [PATCH 4/5] xtensa: enable context tracking

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Date:   Mon, 18 Apr 2022 10:12:04 -0700
From:   Max Filippov <jcmvbkbc@...il.com>
To:     linux-xtensa@...ux-xtensa.org
Cc:     Chris Zankel <chris@...kel.net>, linux-kernel@...r.kernel.org,
        Max Filippov <jcmvbkbc@...il.com>
Subject: [PATCH 4/5] xtensa: enable context tracking

Put user exit context tracking call on the common kernel entry/exit path
(function calls are impossible at earlier kernel entry stages because
PS.EXCM is not cleared yet). Put user entry context tracking call on the
user exit path. Syscalls go through this common code too, so nothing
specific needs to be done for them.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
---
 .../features/time/context-tracking/arch-support.txt      | 2 +-
 arch/xtensa/Kconfig                                      | 1 +
 arch/xtensa/kernel/entry.S                               | 9 +++++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/features/time/context-tracking/arch-support.txt b/Documentation/features/time/context-tracking/arch-support.txt
index bb1c1801553e..72e7aadeda7e 100644
--- a/Documentation/features/time/context-tracking/arch-support.txt
+++ b/Documentation/features/time/context-tracking/arch-support.txt
@@ -27,5 +27,5 @@
     |       sparc: |  ok  |
     |          um: | TODO |
     |         x86: |  ok  |
-    |      xtensa: | TODO |
+    |      xtensa: |  ok  |
     -----------------------
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index e3ffd4564009..6134808a633d 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -31,6 +31,7 @@ config XTENSA
 	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_CONTEXT_TRACKING
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_EXIT_THREAD
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index d09f2c38ba84..f2c789a5a92a 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -456,6 +456,12 @@ KABI_W	or	a3, a3, a2
 	beqz		abi_tmp0, 1f
 	abi_call	trace_hardirqs_off
 1:
+#endif
+#ifdef CONFIG_CONTEXT_TRACKING
+	l32i		abi_tmp0, a1, PT_PS
+	bbci.l		abi_tmp0, PS_UM_BIT, 1f
+	abi_call	context_tracking_user_exit
+1:
 #endif
 
 	/* Go to second-level dispatcher. Set up parameters to pass to the
@@ -540,6 +546,9 @@ common_exception_return:
 	j		.Lrestore_state
 
 .Lexit_tif_loop_user:
+#ifdef CONFIG_CONTEXT_TRACKING
+	abi_call	context_tracking_user_enter
+#endif
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	_bbci.l		abi_saved0, TIF_DB_DISABLED, 1f
 	abi_call	restore_dbreak
-- 
2.30.2