From 188a81409ff7de1c5aae947a96356ddd8ff4aaa3 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <cl@linux.com>
Date: Mon, 7 Apr 2014 15:39:44 -0700
Subject: percpu: add preemption checks to __this_cpu ops

We define a check function in order to avoid trouble with the include
files.  Then the higher level __this_cpu macros are modified to invoke
the preemption check.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 4e4d2afc..e7a0b95 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -173,6 +173,12 @@ extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
 
 extern void __bad_size_call_parameter(void);
 
+#ifdef CONFIG_DEBUG_PREEMPT
+extern void __this_cpu_preempt_check(const char *op);
+#else
+static inline void __this_cpu_preempt_check(const char *op) { }
+#endif
+
 #define __pcpu_size_call_return(stem, variable)				\
 ({	typeof(variable) pscr_ret__;					\
 	__verify_pcpu_ptr(&(variable));					\
@@ -725,18 +731,24 @@ do {									\
 
 /*
  * Generic percpu operations for context that are safe from preemption/interrupts.
- * Checks will be added here soon.
  */
 #ifndef __this_cpu_read
-# define __this_cpu_read(pcp)	__pcpu_size_call_return(raw_cpu_read_, (pcp))
+# define __this_cpu_read(pcp) \
+	(__this_cpu_preempt_check("read"),__pcpu_size_call_return(raw_cpu_read_, (pcp)))
 #endif
 
 #ifndef __this_cpu_write
-# define __this_cpu_write(pcp, val)	__pcpu_size_call(raw_cpu_write_, (pcp), (val))
+# define __this_cpu_write(pcp, val)					\
+do { __this_cpu_preempt_check("write");					\
+     __pcpu_size_call(raw_cpu_write_, (pcp), (val));			\
+} while (0)
 #endif
 
 #ifndef __this_cpu_add
-# define __this_cpu_add(pcp, val)	__pcpu_size_call(raw_cpu_add_, (pcp), (val))
+# define __this_cpu_add(pcp, val)					 \
+do { __this_cpu_preempt_check("add");					\
+	__pcpu_size_call(raw_cpu_add_, (pcp), (val));			\
+} while (0)
 #endif
 
 #ifndef __this_cpu_sub
@@ -752,16 +764,23 @@ do {									\
 #endif
 
 #ifndef __this_cpu_and
-# define __this_cpu_and(pcp, val)	__pcpu_size_call(raw_cpu_and_, (pcp), (val))
+# define __this_cpu_and(pcp, val)					\
+do { __this_cpu_preempt_check("and");					\
+	__pcpu_size_call(raw_cpu_and_, (pcp), (val));			\
+} while (0)
+
 #endif
 
 #ifndef __this_cpu_or
-# define __this_cpu_or(pcp, val)	__pcpu_size_call(raw_cpu_or_, (pcp), (val))
+# define __this_cpu_or(pcp, val)					\
+do { __this_cpu_preempt_check("or");					\
+	__pcpu_size_call(raw_cpu_or_, (pcp), (val));			\
+} while (0)
 #endif
 
 #ifndef __this_cpu_add_return
 # define __this_cpu_add_return(pcp, val)	\
-	__pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
+	(__this_cpu_preempt_check("add_return"),__pcpu_size_call_return2(raw_cpu_add_return_, pcp, val))
 #endif
 
 #define __this_cpu_sub_return(pcp, val)	__this_cpu_add_return(pcp, -(typeof(pcp))(val))
@@ -770,17 +789,17 @@ do {									\
 
 #ifndef __this_cpu_xchg
 # define __this_cpu_xchg(pcp, nval)	\
-	__pcpu_size_call_return2(raw_cpu_xchg_, (pcp), nval)
+	(__this_cpu_preempt_check("xchg"),__pcpu_size_call_return2(raw_cpu_xchg_, (pcp), nval))
 #endif
 
 #ifndef __this_cpu_cmpxchg
 # define __this_cpu_cmpxchg(pcp, oval, nval)	\
-	__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)
+	(__this_cpu_preempt_check("cmpxchg"),__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval))
 #endif
 
 #ifndef __this_cpu_cmpxchg_double
 # define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\
-	__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
+	(__this_cpu_preempt_check("cmpxchg_double"),__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2)))
 #endif
 
 #endif /* __LINUX_PERCPU_H */
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 04abe53..1afec32 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -7,7 +7,8 @@
 #include <linux/kallsyms.h>
 #include <linux/sched.h>
 
-notrace unsigned int debug_smp_processor_id(void)
+notrace static unsigned int check_preemption_disabled(const char *what1,
+							const char *what2)
 {
 	int this_cpu = raw_smp_processor_id();
 
@@ -38,9 +39,9 @@ notrace unsigned int debug_smp_processor_id(void)
 	if (!printk_ratelimit())
 		goto out_enable;
 
-	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
-			"code: %s/%d\n",
-			preempt_count() - 1, current->comm, current->pid);
+	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
+		what1, what2, preempt_count() - 1, current->comm, current->pid);
+
 	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
 	dump_stack();
 
@@ -50,5 +51,14 @@ out:
 	return this_cpu;
 }
 
+notrace unsigned int debug_smp_processor_id(void)
+{
+	return check_preemption_disabled("smp_processor_id", "");
+}
 EXPORT_SYMBOL(debug_smp_processor_id);
 
+notrace void __this_cpu_preempt_check(const char *op)
+{
+	check_preemption_disabled("__this_cpu_", op);
+}
+EXPORT_SYMBOL(__this_cpu_preempt_check);
-- 
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