From c2467f2e89f9fca93c1348aa0ff26c8d41ba2755 Mon Sep 17 00:00:00 2001
From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Date: Mon, 18 Jan 2010 11:25:45 -0600
Subject: [PATCH] --- yaml --- r: 182275 b: refs/heads/master c:
 f125be1469303f7b9324447f251d74a0da24952f h: refs/heads/master i:   182273:
 dfbb430de2a1588b9125c614baf213fb0d307081   182271:
 f85754414df4c22b85b3b5c1259241c9a270428f v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/x86/oprofile/op_model_amd.c | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 91aa98440c67..be58bd3c2a72 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 64683da6643e8c6c93f1f99548399b08c029fd13
+refs/heads/master: f125be1469303f7b9324447f251d74a0da24952f
diff --git a/trunk/arch/x86/oprofile/op_model_amd.c b/trunk/arch/x86/oprofile/op_model_amd.c
index 6557683c190e..97c84ebe3f24 100644
--- a/trunk/arch/x86/oprofile/op_model_amd.c
+++ b/trunk/arch/x86/oprofile/op_model_amd.c
@@ -218,6 +218,29 @@ static void op_amd_setup_ctrs(struct op_x86_model_spec const *model,
 	}
 }
 
+/*
+ * 16-bit Linear Feedback Shift Register (LFSR)
+ *
+ *                       16   14   13    11
+ * Feedback polynomial = X  + X  + X  +  X  + 1
+ */
+static unsigned int lfsr_random(void)
+{
+	static unsigned int lfsr_value = 0xF00D;
+	unsigned int bit;
+
+	/* Compute next bit to shift in */
+	bit = ((lfsr_value >> 0) ^
+	       (lfsr_value >> 2) ^
+	       (lfsr_value >> 3) ^
+	       (lfsr_value >> 5)) & 0x0001;
+
+	/* Advance to next register value */
+	lfsr_value = (lfsr_value >> 1) | (bit << 15);
+
+	return lfsr_value;
+}
+
 static inline void
 op_amd_handle_ibs(struct pt_regs * const regs,
 		  struct op_msrs const * const msrs)