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Subject[PATCH 5/8] arm64: Create cache sysfs directory without ACPI PPTT for hardware prefetch control
Date
This patch will create a cache sysfs directory without ACPI PPTT if
the CONFIG_HWPF_CONTROL is true.

Hardware prefetch control driver need cache sysfs directory and cache
level/type information. In ARM processor, these information can be
obtained from the register even without PPTT. Therefore, we set the
cpu_map_populated to true to create cache sysfs directory if the
machine doesn't have PPTT.

Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com>
---
arch/arm64/kernel/cacheinfo.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
index 587543c6c51c..039ec32d0b3d 100644
--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -43,6 +43,21 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
this_leaf->type = type;
}

+#if defined(CONFIG_HWPF_CONTROL)
+static bool acpi_has_pptt(void)
+{
+ struct acpi_table_header *table;
+ acpi_status status;
+
+ status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+ if (ACPI_FAILURE(status))
+ return false;
+
+ acpi_put_table(table);
+ return true;
+}
+#endif
+
int init_cache_level(unsigned int cpu)
{
unsigned int ctype, level, leaves, fw_level;
@@ -95,5 +110,19 @@ int populate_cache_leaves(unsigned int cpu)
ci_leaf_init(this_leaf++, type, level);
}
}
+
+#if defined(CONFIG_HWPF_CONTROL)
+ /*
+ * Hardware prefetch functions need cache sysfs directory and cache
+ * level/type information. In ARM processor, these information can be
+ * obtained from registers even without PPTT. Therefore, we set the
+ * cpu_map_populated to true to create cache sysfs directory, if the
+ * machine doesn't have PPTT.
+ **/
+ if (!acpi_disabled)
+ if (!acpi_has_pptt())
+ this_cpu_ci->cpu_map_populated = true;
+#endif
+
return 0;
}
--
2.27.0
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