Thread (28 messages) flat view 28 messages, 3 authors, 2020-07-21

Re: [PATCH v4 09/10] powerpc/watchpoint: Return available watchpoints dynamically

From: Jordan Niethe <hidden>
Date: 2020-07-20 03:46:04
Also in: lkml

On Fri, Jul 17, 2020 at 2:11 PM Ravi Bangoria
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
 arch/powerpc/include/asm/cputable.h      | 4 +++-
 arch/powerpc/include/asm/hw_breakpoint.h | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 3445c86e1f6f..36a0851a7a9b 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -633,7 +633,9 @@ enum {
  * Maximum number of hw breakpoint supported on powerpc. Number of
  * breakpoints supported by actual hw might be less than this.
  */
-#define HBP_NUM_MAX    1
+#define HBP_NUM_MAX    2
+#define HBP_NUM_ONE    1
+#define HBP_NUM_TWO    2
I wonder if these defines are necessary - has it any advantage over
just using the literal?
quoted hunk ↗ jump to hunk
 #endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index cb424799da0d..d4eab1694bcd 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -5,10 +5,11 @@
  * Copyright 2010, IBM Corporation.
  * Author: K.Prasad <prasad@linux.vnet.ibm.com>
  */
-
Was removing this line deliberate?
quoted hunk ↗ jump to hunk
 #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 +47,7 @@ struct arch_hw_breakpoint {

 static inline int nr_wp_slots(void)
 {
-       return HBP_NUM_MAX;
+       return cpu_has_feature(CPU_FTR_DAWR1) ? HBP_NUM_TWO : HBP_NUM_ONE;
So it'd be something like:
+       return cpu_has_feature(CPU_FTR_DAWR1) ? HBP_NUM_MAX : 1;
But thinking that there might be more slots added in the future, it
may be better to make the number of slots a variable that is set
during the init and then have this function return that.
 }

 #ifdef CONFIG_HAVE_HW_BREAKPOINT
--
2.26.2
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