From deb2bd9bcc8428d4b65b6ba640ba8b57c1b20b17 Mon Sep 17 00:00:00 2001
From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Date: Thu, 23 Jul 2020 14:38:12 +0530
Subject: [PATCH] powerpc/watchpoint: Return available watchpoints dynamically

References: jsc#SLE-12936
Patch-mainline: v5.9-rc1
Git-commit: deb2bd9bcc8428d4b65b6ba640ba8b57c1b20b17

So far Book3S Powerpc supported only one watchpoint. Power10 is
introducing 2nd DAWR. Enable 2nd DAWR support for Power10.
Availability of 2nd DAWR will depend on CPU_FTR_DAWR1.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200723090813.303838-10-ravi.bangoria@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/cputable.h      | 5 +++--
 arch/powerpc/include/asm/hw_breakpoint.h | 4 +++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index d36db35e3aac..fdddb822d564 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -629,9 +629,10 @@ enum {
 
 /*
  * Maximum number of hw breakpoint supported on powerpc. Number of
- * breakpoints supported by actual hw might be less than this.
+ * breakpoints supported by actual hw might be less than this, which
+ * is decided at run time in nr_wp_slots().
  */
-#define HBP_NUM_MAX	1
+#define HBP_NUM_MAX	2
 
 #endif /* !__ASSEMBLY__ */
 
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index cb424799da0d..c89250b6ac34 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -9,6 +9,8 @@
 #ifndef _PPC_BOOK3S_64_HW_BREAKPOINT_H
 #define _PPC_BOOK3S_64_HW_BREAKPOINT_H
 
+#include <asm/cpu_has_feature.h>
+
 #ifdef	__KERNEL__
 struct arch_hw_breakpoint {
 	unsigned long	address;
@@ -46,7 +48,7 @@ struct arch_hw_breakpoint {
 
 static inline int nr_wp_slots(void)
 {
-	return HBP_NUM_MAX;
+	return cpu_has_feature(CPU_FTR_DAWR1) ? 2 : 1;
 }
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
-- 
2.26.2