From 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Fri, 25 Mar 2016 03:53:42 -0300
Subject: Linux-libre 4.5-gnu

---
 include/linux/kernel.h | 64 ++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 46 insertions(+), 18 deletions(-)

(limited to 'include/linux/kernel.h')

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 350dfb08a..f31638c6e 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -202,26 +202,26 @@ extern int _cond_resched(void);
 
 /**
  * abs - return absolute value of an argument
- * @x: the value.  If it is unsigned type, it is converted to signed type first
- *   (s64, long or int depending on its size).
+ * @x: the value.  If it is unsigned type, it is converted to signed type first.
+ *     char is treated as if it was signed (regardless of whether it really is)
+ *     but the macro's return type is preserved as char.
  *
- * Return: an absolute value of x.  If x is 64-bit, macro's return type is s64,
- *   otherwise it is signed long.
+ * Return: an absolute value of x.
  */
-#define abs(x) __builtin_choose_expr(sizeof(x) == sizeof(s64), ({	\
-		s64 __x = (x);						\
-		(__x < 0) ? -__x : __x;					\
-	}), ({								\
-		long ret;						\
-		if (sizeof(x) == sizeof(long)) {			\
-			long __x = (x);					\
-			ret = (__x < 0) ? -__x : __x;			\
-		} else {						\
-			int __x = (x);					\
-			ret = (__x < 0) ? -__x : __x;			\
-		}							\
-		ret;							\
-	}))
+#define abs(x)	__abs_choose_expr(x, long long,				\
+		__abs_choose_expr(x, long,				\
+		__abs_choose_expr(x, int,				\
+		__abs_choose_expr(x, short,				\
+		__abs_choose_expr(x, char,				\
+		__builtin_choose_expr(					\
+			__builtin_types_compatible_p(typeof(x), char),	\
+			(char)({ signed char __x = (x); __x<0?-__x:__x; }), \
+			((void)0)))))))
+
+#define __abs_choose_expr(x, type, other) __builtin_choose_expr(	\
+	__builtin_types_compatible_p(typeof(x),   signed type) ||	\
+	__builtin_types_compatible_p(typeof(x), unsigned type),		\
+	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
 
 /**
  * reciprocal_scale - "scale" a value into range [0, ep_ro)
@@ -255,6 +255,7 @@ extern long (*panic_blink)(int state);
 __printf(1, 2)
 void panic(const char *fmt, ...)
 	__noreturn __cold;
+void nmi_panic_self_stop(struct pt_regs *);
 extern void oops_enter(void);
 extern void oops_exit(void);
 void print_oops_end_marker(void);
@@ -445,6 +446,33 @@ extern int sysctl_panic_on_stackoverflow;
 
 extern bool crash_kexec_post_notifiers;
 
+/*
+ * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
+ * holds a CPU number which is executing panic() currently. A value of
+ * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
+ */
+extern atomic_t panic_cpu;
+#define PANIC_CPU_INVALID	-1
+
+/*
+ * A variant of panic() called from NMI context. We return if we've already
+ * panicked on this CPU. If another CPU already panicked, loop in
+ * nmi_panic_self_stop() which can provide architecture dependent code such
+ * as saving register state for crash dump.
+ */
+#define nmi_panic(regs, fmt, ...)					\
+do {									\
+	int old_cpu, cpu;						\
+									\
+	cpu = raw_smp_processor_id();					\
+	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);	\
+									\
+	if (old_cpu == PANIC_CPU_INVALID)				\
+		panic(fmt, ##__VA_ARGS__);				\
+	else if (old_cpu != cpu)					\
+		nmi_panic_self_stop(regs);				\
+} while (0)
+
 /*
  * Only to be used by arch init code. If the user over-wrote the default
  * CONFIG_PANIC_TIMEOUT, honor it.
-- 
cgit v1.2.3-54-g00ecf