linux-kernel - [PATCH v5 09/10] powerpc/watchpoint: Return available watchpoints dynamically

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Date:   Thu, 23 Jul 2020 14:38:12 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     mpe@...erman.id.au, mikey@...ling.org
Cc:     ravi.bangoria@...ux.ibm.com, paulus@...ba.org, npiggin@...il.com,
        christophe.leroy@....fr, naveen.n.rao@...ux.vnet.ibm.com,
        peterz@...radead.org, jolsa@...nel.org, oleg@...hat.com,
        fweisbec@...il.com, mingo@...nel.org, pedromfc@...ibm.com,
        miltonm@...ibm.com, jniethe5@...il.com, rogealve@...ibm.com,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v5 09/10] powerpc/watchpoint: Return available watchpoints dynamically

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@...ux.ibm.com>
---
 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 5583f2d08df7..fa1232c33ab9 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