[PATCHv2 35/59] acpi/hmat: Determine existence of an ACPI HMAT

Kirill A. Shutemov
2019-07-31T15:23:52Z

From: Alison Schofield <alison.schofield@intel.com>

Platforms that need to confirm the presence of an HMAT table
can use this function that simply reports the HMATs existence.

This is added in support of the Multi-Key Total Memory Encryption
(MKTME), a feature on future Intel platforms. These platforms will
need to confirm an HMAT is present at init time.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
drivers/acpi/hmat/hmat.c | 13 +++++++++++++
include/linux/acpi.h | 4 ++++
2 files changed, 17 insertions(+)

diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
index 96b7d39a97c6..38e3341f569f 100644
--- a/drivers/acpi/hmat/hmat.c
+++ b/drivers/acpi/hmat/hmat.c
@@ -664,3 +664,16 @@ static __init int hmat_init(void)
return 0;
}
subsys_initcall(hmat_init);
+
+bool acpi_hmat_present(void)
+{
+ struct acpi_table_header *tbl;
+ acpi_status status;
+
+ status = acpi_get_table(ACPI_SIG_HMAT, 0, &tbl);
+ if (ACPI_FAILURE(status))
+ return false;
+
+ acpi_put_table(tbl);
+ return true;
+}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index fc1e7d4648bf..d27f4d17dfb3 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1335,4 +1335,8 @@ acpi_platform_notify(struct device *dev, enum kobject_action action)
}
#endif

+#ifdef CONFIG_X86_INTEL_MKTME
+extern bool acpi_hmat_present(void);
+#endif /* CONFIG_X86_INTEL_MKTME */
+
#endif /*_LINUX_ACPI_H*/
--
2.21.0