[PATCH v3 0/2] PRM handler direct call interface

[PATCH v3 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: 8400291e289ee6b2bf9779ff1c83a291501f017b

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/Kconfig    |  4 +++
 drivers/ras/amd/atl/Makefile   |  2 ++
 drivers/ras/amd/atl/internal.h | 10 ++++++
 drivers/ras/amd/atl/prm.c      | 57 ++++++++++++++++++++++++++++++++++
 drivers/ras/amd/atl/umc.c      |  5 +++
 include/linux/prmt.h           |  5 +++
 7 files changed, 107 insertions(+)
 create mode 100644 drivers/ras/amd/atl/prm.c

-- 
2.34.1

[PATCH v3 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>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
---
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 v3 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".

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

v3:
  - Add new AMD_ATL_PRM config instead of #if defined(CONFIG_APCI_PRMT)
    in prm.c
  - Shorten variable names
  - Update file header to include reference to the ACPI Porting Guide
---
 drivers/ras/amd/atl/Kconfig    |  4 +++
 drivers/ras/amd/atl/Makefile   |  2 ++
 drivers/ras/amd/atl/internal.h | 10 ++++++
 drivers/ras/amd/atl/prm.c      | 57 ++++++++++++++++++++++++++++++++++
 drivers/ras/amd/atl/umc.c      |  5 +++
 5 files changed, 78 insertions(+)
 create mode 100644 drivers/ras/amd/atl/prm.c

diff --git a/drivers/ras/amd/atl/Kconfig b/drivers/ras/amd/atl/Kconfig
index df49c23e7f62..551680073e43 100644
--- a/drivers/ras/amd/atl/Kconfig
+++ b/drivers/ras/amd/atl/Kconfig
@@ -19,3 +19,7 @@ config AMD_ATL
 
 	  Enable this option if using DRAM ECC on Zen-based systems
 	  and OS-based error handling.
+
+config AMD_ATL_PRM
+	depends on AMD_ATL && ACPI_PRMT
+	def_bool y
diff --git a/drivers/ras/amd/atl/Makefile b/drivers/ras/amd/atl/Makefile
index 4acd5f05bd9c..b56892c0c0d9 100644
--- a/drivers/ras/amd/atl/Makefile
+++ b/drivers/ras/amd/atl/Makefile
@@ -15,4 +15,6 @@ amd_atl-y		+= map.o
 amd_atl-y		+= system.o
 amd_atl-y		+= umc.o
 
+amd_atl-$(CONFIG_AMD_ATL_PRM) += prm.o
+
 obj-$(CONFIG_AMD_ATL)	+= amd_atl.o
diff --git a/drivers/ras/amd/atl/internal.h b/drivers/ras/amd/atl/internal.h
index 9de5d53d0568..143d04c779a8 100644
--- a/drivers/ras/amd/atl/internal.h
+++ b/drivers/ras/amd/atl/internal.h
@@ -282,6 +282,16 @@ unsigned long convert_umc_mca_addr_to_sys_addr(struct atl_err *err);
 u64 add_base_and_hole(struct addr_ctx *ctx, u64 addr);
 u64 remove_base_and_hole(struct addr_ctx *ctx, u64 addr);
 
+#ifdef CONFIG_AMD_ATL_PRM
+unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 umc_bank_inst_id, unsigned long addr);
+#else
+static inline unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 umc_bank_inst_id,
+						     unsigned long addr)
+{
+       return -ENODEV;
+}
+#endif
+
 /*
  * 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..0931a20d213b
--- /dev/null
+++ b/drivers/ras/amd/atl/prm.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Address Translation Library
+ *
+ * prm.c : Plumbing code for ACPI Platform Runtime Mechanism (PRM)
+ *
+ * Information on AMD PRM modules and handlers including the GUIDs and buffer
+ * structures used here are defined in the AMD ACPI Porting Guide in the
+ * chapter "Platform Runtime Mechanism Table (PRMT)"
+ *
+ * Copyright (c) 2024, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Author: John Allen <john.allen@amd.com>
+ */
+
+#include "internal.h"
+
+#include <linux/prmt.h>
+
+/*
+ * PRM parameter buffer - normalized to system physical address, as described
+ * in the "PRM Parameter Buffer" section of the AMD ACPI Porting Guide.
+ */
+struct norm_to_sys_param_buf {
+	u64 norm_addr;
+	u8 socket;
+	u64 bank_id;
+	void *out_buf;
+} __packed;
+
+static const guid_t norm_to_sys_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 bank_id, unsigned long addr)
+{
+	struct norm_to_sys_param_buf p_buf;
+	unsigned long ret_addr;
+	int ret;
+
+	p_buf.norm_addr = addr;
+	p_buf.socket    = socket_id;
+	p_buf.bank_id   = bank_id;
+	p_buf.out_buf   = &ret_addr;
+
+	ret = acpi_call_prm_handler(norm_to_sys_guid, &p_buf);
+	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;
+}
diff --git a/drivers/ras/amd/atl/umc.c b/drivers/ras/amd/atl/umc.c
index a1b4accf7b96..dc8aa12f63c8 100644
--- a/drivers/ras/amd/atl/umc.c
+++ b/drivers/ras/amd/atl/umc.c
@@ -401,9 +401,14 @@ 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

Re: [PATCH v3 0/2] PRM handler direct call interface

[Borislav Petkov]

On Tue, Jul 30, 2024 at 03:17:29PM +0000, John Allen wrote:
> 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: 8400291e289ee6b2bf9779ff1c83a291501f017b
> 
> 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/Kconfig    |  4 +++
>  drivers/ras/amd/atl/Makefile   |  2 ++
>  drivers/ras/amd/atl/internal.h | 10 ++++++
>  drivers/ras/amd/atl/prm.c      | 57 ++++++++++++++++++++++++++++++++++
>  drivers/ras/amd/atl/umc.c      |  5 +++
>  include/linux/prmt.h           |  5 +++
>  7 files changed, 107 insertions(+)
>  create mode 100644 drivers/ras/amd/atl/prm.c
> 
> -- 

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette