From 10cd706d180b62a61aace5b440247c8785026ac1 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Thu, 11 Oct 2007 22:11:12 +0200
Subject: [PATCH] lockdep: x86_64: connect the sysexit hook

Run the lockdep_sys_exit hook after all other C code on the syscall
return path.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/entry_64.S    | 23 +++++++++++------------
 arch/x86/lib/thunk_64.S       |  4 ++++
 include/asm-x86/irqflags_64.h | 14 ++++++++++++++
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 1d232e5f56..f1cacd4897 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -244,6 +244,7 @@ ret_from_sys_call:
 	movl $_TIF_ALLWORK_MASK,%edi
 	/* edi:	flagmask */
 sysret_check:		
+	LOCKDEP_SYS_EXIT
 	GET_THREAD_INFO(%rcx)
 	cli
 	TRACE_IRQS_OFF
@@ -333,6 +334,7 @@ int_ret_from_sys_call:
 	movl $_TIF_ALLWORK_MASK,%edi
 	/* edi:	mask to check */
 int_with_check:
+	LOCKDEP_SYS_EXIT_IRQ
 	GET_THREAD_INFO(%rcx)
 	movl threadinfo_flags(%rcx),%edx
 	andl %edi,%edx
@@ -544,11 +546,13 @@ exit_intr:
 retint_with_reschedule:
 	movl $_TIF_WORK_MASK,%edi
 retint_check:
+	LOCKDEP_SYS_EXIT_IRQ
 	movl threadinfo_flags(%rcx),%edx
 	andl %edi,%edx
 	CFI_REMEMBER_STATE
 	jnz  retint_careful
-retint_swapgs:	 	
+
+retint_swapgs:		/* return to user-space */
 	/*
 	 * The iretq could re-enable interrupts:
 	 */
@@ -557,7 +561,7 @@ retint_swapgs:
 	swapgs 
 	jmp restore_args
 
-retint_restore_args:				
+retint_restore_args:	/* return to kernel space */
 	cli
 	/*
 	 * The iretq could re-enable interrupts:
@@ -866,26 +870,21 @@ error_sti:
 	movq ORIG_RAX(%rsp),%rsi	/* get error code */ 
 	movq $-1,ORIG_RAX(%rsp)
 	call *%rax
-	/* ebx:	no swapgs flag (1: don't need swapgs, 0: need it) */	 
-error_exit:		
-	movl %ebx,%eax		
+	/* ebx:	no swapgs flag (1: don't need swapgs, 0: need it) */
+error_exit:
+	movl %ebx,%eax
 	RESTORE_REST
 	cli
 	TRACE_IRQS_OFF
 	GET_THREAD_INFO(%rcx)	
 	testl %eax,%eax
 	jne  retint_kernel
+	LOCKDEP_SYS_EXIT_IRQ
 	movl  threadinfo_flags(%rcx),%edx
 	movl  $_TIF_WORK_MASK,%edi
 	andl  %edi,%edx
 	jnz  retint_careful
-	/*
-	 * The iret might restore flags:
-	 */
-	TRACE_IRQS_IRETQ
-	swapgs 
-	RESTORE_ARGS 0,8,0						
-	jmp iret_label
+	jmp retint_swapgs
 	CFI_ENDPROC
 
 error_kernelspace:
diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S
index 55e586d352..6ea73f3de5 100644
--- a/arch/x86/lib/thunk_64.S
+++ b/arch/x86/lib/thunk_64.S
@@ -50,6 +50,10 @@
 	thunk trace_hardirqs_on_thunk,trace_hardirqs_on
 	thunk trace_hardirqs_off_thunk,trace_hardirqs_off
 #endif
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	thunk lockdep_sys_exit_thunk,lockdep_sys_exit
+#endif
 	
 	/* SAVE_ARGS below is used only for the .cfi directives it contains. */
 	CFI_STARTPROC
diff --git a/include/asm-x86/irqflags_64.h b/include/asm-x86/irqflags_64.h
index 86e70fe236..5341ea1f81 100644
--- a/include/asm-x86/irqflags_64.h
+++ b/include/asm-x86/irqflags_64.h
@@ -137,6 +137,20 @@ static inline void halt(void)
 #  define TRACE_IRQS_ON
 #  define TRACE_IRQS_OFF
 # endif
+# ifdef CONFIG_DEBUG_LOCK_ALLOC
+#  define LOCKDEP_SYS_EXIT	call lockdep_sys_exit_thunk
+#  define LOCKDEP_SYS_EXIT_IRQ	\
+	TRACE_IRQS_ON; \
+	sti; \
+	SAVE_REST; \
+	LOCKDEP_SYS_EXIT; \
+	RESTORE_REST; \
+	cli; \
+	TRACE_IRQS_OFF;
+# else
+#  define LOCKDEP_SYS_EXIT
+#  define LOCKDEP_SYS_EXIT_IRQ
+# endif
 #endif
 
 #endif
-- 
2.39.5