[PATCH v2 0/2] PRM handler direct call interface

[PATCH v2 0/2] PRM handler direct call interface

[John Allen]

Platform Runtime Mechanism (PRM) introduces a means for the AML
interpreter and OS drivers to invoke runtime handlers from platform
firmware in order to remove the need for certain classes of SMIs.
Further details can be seen in the PRM specification[1].

Future AMD platforms will implement a PRM module in firmware that will
include handlers for performing various types of address translation.
The address translation PRM module is documented in chapter 22 of the
publicly available "AMD Family 1Ah Models 00h–0Fh and Models 10h–1Fh
ACPI v6.5 Porting Guide"[2].

While the kernel currently has support for calling PRM handlers from the
AML interpreter, it does not support calling PRM handlers directly from
OS drivers. This series implements the direct call interface and uses it
for translating normalized addresses to system physical addresses.

Thanks,
John

[1]:
https://uefi.org/sites/default/files/resources/Platform%20Runtime%20Mechanism%20-%20with%20legal%20notice.pdf
[2]:
https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/programmer-references/58088-0.75-pub.pdf

Tree: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Base commit: 4cece764965020c22cff7665b18a012006359095

John Allen (2):
  ACPI: PRM: Add PRM handler direct call support
  RAS/AMD/ATL: Translate normalized to system physical addresses using
    PRM

 drivers/acpi/prmt.c            | 24 +++++++++++++
 drivers/ras/amd/atl/Makefile   |  1 +
 drivers/ras/amd/atl/internal.h |  2 ++
 drivers/ras/amd/atl/prm.c      | 61 ++++++++++++++++++++++++++++++++++
 drivers/ras/amd/atl/umc.c      |  5 +++
 include/linux/prmt.h           |  5 +++
 6 files changed, 98 insertions(+)
 create mode 100644 drivers/ras/amd/atl/prm.c

-- 
2.34.1

[PATCH v2 1/2] ACPI: PRM: Add PRM handler direct call support

[John Allen]

Platform Runtime Mechanism (PRM) handlers can be invoked from either the
AML interpreter or directly by an OS driver. Implement the direct call
method.

Export the symbol as this will be used by modules such as the AMD
Address Translation Library and likely others in the future.

Signed-off-by: John Allen <john.allen@amd.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
v2:
  - Align statements setting fields in context buffer on '='
---
 drivers/acpi/prmt.c  | 24 ++++++++++++++++++++++++
 include/linux/prmt.h |  5 +++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index c78453c74ef5..1cfaa5957ac4 100644
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -214,6 +214,30 @@ static struct prm_handler_info *find_prm_handler(const guid_t *guid)
 #define UPDATE_LOCK_ALREADY_HELD 	4
 #define UPDATE_UNLOCK_WITHOUT_LOCK 	5
 
+int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
+{
+	struct prm_handler_info *handler = find_prm_handler(&handler_guid);
+	struct prm_module_info *module = find_prm_module(&handler_guid);
+	struct prm_context_buffer context;
+	efi_status_t status;
+
+	if (!module || !handler)
+		return -ENODEV;
+
+	memset(&context, 0, sizeof(context));
+	ACPI_COPY_NAMESEG(context.signature, "PRMC");
+	context.identifier         = handler->guid;
+	context.static_data_buffer = handler->static_data_buffer_addr;
+	context.mmio_ranges        = module->mmio_info;
+
+	status = efi_call_acpi_prm_handler(handler->handler_addr,
+					   (u64)param_buffer,
+					   &context);
+
+	return efi_status_to_err(status);
+}
+EXPORT_SYMBOL_GPL(acpi_call_prm_handler);
+
 /*
  * This is the PlatformRtMechanism opregion space handler.
  * @function: indicates the read/write. In fact as the PlatformRtMechanism
diff --git a/include/linux/prmt.h b/include/linux/prmt.h
index 24da8364b919..9c094294403f 100644
--- a/include/linux/prmt.h
+++ b/include/linux/prmt.h
@@ -2,6 +2,11 @@
 
 #ifdef CONFIG_ACPI_PRMT
 void init_prmt(void);
+int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer);
 #else
 static inline void init_prmt(void) { }
+static inline int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
+{
+	return -EOPNOTSUPP;
+}
 #endif
-- 
2.34.1

[PATCH v2 2/2] RAS/AMD/ATL: Translate normalized to system physical addresses using PRM

[John Allen]

Future AMD platforms will provide a UEFI PRM module that implements a
number of address translation PRM handlers. This will provide an
interface for the OS to call platform specific code without requiring
the use of SMM or other heavy firmware operations.

AMD Zen-based systems report memory error addresses through Machine
Check banks representing Unified Memory Controllers (UMCs) in the form
of UMC relative "normalized" addresses. A normalized address must be
converted to a system physical address to be usable by the OS.

Add support for the normalized to system physical address translation
PRM handler in the AMD Address Translation Library and prefer it over
native code if available. The GUID and parameter buffer structure are
specific to the normalized to system physical address handler provided
by the address translation PRM module included in future AMD systems.

The address translation PRM module is documented in chapter 22 of the
publicly available "AMD Family 1Ah Models 00h–0Fh and Models 10h–1Fh
ACPI v6.5 Porting Guide":
https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/programmer-references/58088-0.75-pub.pdf

Signed-off-by: John Allen <john.allen@amd.com>
---
v2:
  - Make norm_to_sys_prm_handler_guid static.
  - Change pr_info statements to more appropriate pr_debug and
    pr_info_once statements.
---
 drivers/ras/amd/atl/Makefile   |  1 +
 drivers/ras/amd/atl/internal.h |  2 ++
 drivers/ras/amd/atl/prm.c      | 61 ++++++++++++++++++++++++++++++++++
 drivers/ras/amd/atl/umc.c      |  5 +++
 4 files changed, 69 insertions(+)
 create mode 100644 drivers/ras/amd/atl/prm.c

diff --git a/drivers/ras/amd/atl/Makefile b/drivers/ras/amd/atl/Makefile
index 4acd5f05bd9c..8f1afa793e3b 100644
--- a/drivers/ras/amd/atl/Makefile
+++ b/drivers/ras/amd/atl/Makefile
@@ -14,5 +14,6 @@ amd_atl-y		+= denormalize.o
 amd_atl-y		+= map.o
 amd_atl-y		+= system.o
 amd_atl-y		+= umc.o
+amd_atl-y		+= prm.o
 
 obj-$(CONFIG_AMD_ATL)	+= amd_atl.o
diff --git a/drivers/ras/amd/atl/internal.h b/drivers/ras/amd/atl/internal.h
index 5de69e0bb0f9..f739dcada126 100644
--- a/drivers/ras/amd/atl/internal.h
+++ b/drivers/ras/amd/atl/internal.h
@@ -234,6 +234,8 @@ int dehash_address(struct addr_ctx *ctx);
 unsigned long norm_to_sys_addr(u8 socket_id, u8 die_id, u8 coh_st_inst_id, unsigned long addr);
 unsigned long convert_umc_mca_addr_to_sys_addr(struct atl_err *err);
 
+unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 umc_bank_inst_id, unsigned long addr);
+
 /*
  * Make a gap in @data that is @num_bits long starting at @bit_num.
  * e.g. data		= 11111111'b
diff --git a/drivers/ras/amd/atl/prm.c b/drivers/ras/amd/atl/prm.c
new file mode 100644
index 000000000000..8e96a6370ae3
--- /dev/null
+++ b/drivers/ras/amd/atl/prm.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Address Translation Library
+ *
+ * prm.c : Plumbing code to UEFI Platform Runtime Mechanism (PRM)
+ *
+ * Copyright (c) 2024, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Author: John Allen <john.allen@amd.com>
+ */
+
+#include "internal.h"
+
+#if defined(CONFIG_ACPI_PRMT)
+
+#include <linux/prmt.h>
+
+struct prm_umc_param_buffer_norm {
+	u64 norm_addr;
+	u8 socket;
+	u64 umc_bank_inst_id;
+	void *output_buffer;
+} __packed;
+
+static const guid_t norm_to_sys_prm_handler_guid = GUID_INIT(0xE7180659, 0xA65D,
+							     0x451D, 0x92, 0xCD,
+							     0x2B, 0x56, 0xF1, 0x2B,
+							     0xEB, 0xA6);
+
+unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 umc_bank_inst_id, unsigned long addr)
+{
+	struct prm_umc_param_buffer_norm param_buffer;
+	unsigned long ret_addr;
+	int ret;
+
+	param_buffer.norm_addr        = addr;
+	param_buffer.socket           = socket_id;
+	param_buffer.umc_bank_inst_id = umc_bank_inst_id;
+	param_buffer.output_buffer    = &ret_addr;
+
+	ret = acpi_call_prm_handler(norm_to_sys_prm_handler_guid, &param_buffer);
+	if (!ret)
+		return ret_addr;
+
+	if (ret == -ENODEV)
+		pr_debug("PRM module/handler not available\n");
+	else
+		pr_notice_once("PRM address translation failed\n");
+
+	return ret;
+}
+
+#else /* ACPI_PRMT */
+
+unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 umc_bank_inst_id, unsigned long addr)
+{
+	return -ENODEV;
+}
+
+#endif
diff --git a/drivers/ras/amd/atl/umc.c b/drivers/ras/amd/atl/umc.c
index 08c6dbd44c62..3c018870633c 100644
--- a/drivers/ras/amd/atl/umc.c
+++ b/drivers/ras/amd/atl/umc.c
@@ -333,9 +333,14 @@ unsigned long convert_umc_mca_addr_to_sys_addr(struct atl_err *err)
 	u8 coh_st_inst_id = get_coh_st_inst_id(err);
 	unsigned long addr = get_addr(err->addr);
 	u8 die_id = get_die_id(err);
+	unsigned long ret_addr;
 
 	pr_debug("socket_id=0x%x die_id=0x%x coh_st_inst_id=0x%x addr=0x%016lx",
 		 socket_id, die_id, coh_st_inst_id, addr);
 
+	ret_addr = prm_umc_norm_to_sys_addr(socket_id, err->ipid, addr);
+	if (!IS_ERR_VALUE(ret_addr))
+		return ret_addr;
+
 	return norm_to_sys_addr(socket_id, die_id, coh_st_inst_id, addr);
 }
-- 
2.34.1