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powerpc/watchpoint: Introduce function to get nr watchpoints dynamically

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So far we had only one watchpoint, so we have hardcoded HBP_NUM to 1.
But Power10 is introducing 2nd DAWR and thus kernel should be able to
dynamically find actual number of watchpoints supported by hw it's
running on. Introduce function for the same. Also convert HBP_NUM macro
to HBP_NUM_MAX, which will now represent maximum number of watchpoints
supported by Powerpc.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-4-ravi.bangoria@linux.ibm.com
This commit is contained in:
Ravi Bangoria 2020-05-14 16:47:28 +05:30 committed by Michael Ellerman
parent 4a4ec2289a
commit a6ba44e879
4 changed files with 12 additions and 3 deletions
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6
arch/powerpc/include/asm/cputable.h
View File

@ -614,7 +614,11 @@ enum {
};
#endif /* __powerpc64__ */
#define HBP_NUM 1
/*
* 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
#endif /* !__ASSEMBLY__ */

5
arch/powerpc/include/asm/hw_breakpoint.h
View File

@ -43,6 +43,11 @@ struct arch_hw_breakpoint {
#define DABR_MAX_LEN 8
#define DAWR_MAX_LEN 512
static inline int nr_wp_slots(void)
{
return HBP_NUM_MAX;
}
#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <linux/kdebug.h>
#include <asm/reg.h>

2
arch/powerpc/include/asm/processor.h
View File

@ -180,7 +180,7 @@ struct thread_struct {
int fpexc_mode; /* floating-point exception mode */
unsigned int align_ctl; /* alignment handling control */
#ifdef CONFIG_HAVE_HW_BREAKPOINT
struct perf_event *ptrace_bps[HBP_NUM];
struct perf_event *ptrace_bps[HBP_NUM_MAX];
/*
* Helps identify source of single-step exception and subsequent
* hw-breakpoint enablement

2
arch/powerpc/kernel/hw_breakpoint.c
View File

@ -39,7 +39,7 @@ static DEFINE_PER_CPU(struct perf_event *, bp_per_reg);
int hw_breakpoint_slots(int type)
{
if (type == TYPE_DATA)
return HBP_NUM;
return nr_wp_slots();
return 0; /* no instruction breakpoints available */
}