From b28f07005cef03d5eea43a8a7954154b391871fe Mon Sep 17 00:00:00 2001
From: Atish Patra <atish.patra@wdc.com>
Date: Mon, 8 Nov 2021 10:53:05 -0800
Subject: lib: sbi: Enable PMU extension for platforms without mcountinhibit
Some platforms such as hifive unmatched doesn't implement mcountinhibit
csr. However, it has hardware events that can be monitored using 2
hpmcounter it has (i.e. mhpmcounter3 & mhpmcounter4).
Currently, PMU extension disabled if mcountinhibit is absent. That's not
really necessary as long as the supervisor OS keeps track of the delta
value of the counters. Without mcountinhibit, the delta value won't be
entirely accurate because the counters are freely running. However, that
should be fine to produce an approximate counter value which can help
performance analysis. Perf sampling won't work though as sscof extension
is not present in hifive unmatched.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
lib/utils/fdt/fdt_pmu.c | 4 ++++
1 file changed, 4 insertions(+)
(limited to 'lib/utils')
diff --git a/lib/utils/fdt/fdt_pmu.c b/lib/utils/fdt/fdt_pmu.c
index 9ebf1c2..09c83c8 100644
--- a/lib/utils/fdt/fdt_pmu.c
+++ b/lib/utils/fdt/fdt_pmu.c
@@ -9,6 +9,7 @@
*/
#include <libfdt.h>
+#include <sbi/sbi_hart.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_pmu.h>
#include <sbi_utils/fdt/fdt_helper.h>
@@ -40,6 +41,7 @@ uint64_t fdt_pmu_get_select_value(uint32_t event_idx)
int fdt_pmu_fixup(void *fdt)
{
int pmu_offset;
+ struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
if (!fdt)
return SBI_EINVAL;
@@ -51,6 +53,8 @@ int fdt_pmu_fixup(void *fdt)
fdt_delprop(fdt, pmu_offset, "pmu,event-to-mhpmcounters");
fdt_delprop(fdt, pmu_offset, "pmu,event-to-mhpmevent");
fdt_delprop(fdt, pmu_offset, "pmu,raw-event-to-mhpmcounters");
+ if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_SSCOFPMF))
+ fdt_delprop(fdt, pmu_offset, "interrupts-extended");
return 0;
}
--
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