soc/intel: generate SSDT instead of using GNVS for SGX

GNVS should not be used for values that are static at runtime. Thus,
use SSDT for the SGX fields.

Change-Id: Icf9f035e0c2b8617eef82fb043293bcb913e3012
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58394
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

6 files changed, 41 insertions, 32 deletions

diff --git a/src/soc/intel/common/acpi/sgx.asl b/src/soc/intel/common/acpi/sgx.asl
index 9aea7a8b09..cfd7f7ed2a 100644
--- a/src/soc/intel/common/acpi/sgx.asl
+++ b/src/soc/intel/common/acpi/sgx.asl
@@ -6,6 +6,9 @@ Scope(\_SB)
 	// Secure Enclave memory
 	Device (EPC)
 	{
+		External (EPCS, IntObj)
+		External (EMNA, IntObj)
+		External (ELNG, IntObj)
 		Name (_HID, EISAID ("INT0E0C"))
 		Name (_STR, Unicode ("Enclave Page Cache 1.0"))
 		Name (_MLS, Package () {
diff --git a/src/soc/intel/common/block/acpi/acpi.c b/src/soc/intel/common/block/acpi/acpi.c
index 16017779d9..b827c58bc1 100644
--- a/src/soc/intel/common/block/acpi/acpi.c
+++ b/src/soc/intel/common/block/acpi/acpi.c
@@ -15,6 +15,7 @@
 #include <intelblocks/acpi_wake_source.h>
 #include <intelblocks/lpc_lib.h>
 #include <intelblocks/pmclib.h>
+#include <intelblocks/sgx.h>
 #include <intelblocks/uart.h>
 #include <soc/gpio.h>
 #include <soc/iomap.h>
@@ -427,4 +428,7 @@ void generate_cpu_entries(const struct device *device)
 
 	/* Add a method to notify processor nodes */
 	acpigen_write_processor_cnot(num_virt);
+
+	if (CONFIG(SOC_INTEL_COMMON_BLOCK_SGX_ENABLE))
+		sgx_fill_ssdt();
 }
diff --git a/src/soc/intel/common/block/acpi/acpi/globalnvs.asl b/src/soc/intel/common/block/acpi/acpi/globalnvs.asl
index 003a5ce3df..ab63a5c407 100644
--- a/src/soc/intel/common/block/acpi/acpi/globalnvs.asl
+++ b/src/soc/intel/common/block/acpi/acpi/globalnvs.asl
@@ -25,7 +25,4 @@ Field (GNVS, ByteAcc, NoLock, Preserve)
 	A4GB,	64,	// 0x30 - 0x37 Base of above 4GB MMIO Resource
 	A4GS,	64,	// 0x38 - 0x3f Length of above 4GB MMIO Resource
 	,	64, 	// 0x40 - 0x47 Hest log buffer (used in SMM, not ASL code)
-	EPCS,	8,	// 0x48 - SGX enabled status
-	EMNA,	64,	// 0x49 - 0x50 EPC base address
-	ELNG,	64,	// 0x51 - 0x58 EPC length
 }
diff --git a/src/soc/intel/common/block/include/intelblocks/nvs.h b/src/soc/intel/common/block/include/intelblocks/nvs.h
index 3ebb08b519..5adbdb8550 100644
--- a/src/soc/intel/common/block/include/intelblocks/nvs.h
+++ b/src/soc/intel/common/block/include/intelblocks/nvs.h
@@ -27,10 +27,6 @@ struct __packed global_nvs {
 	u64	a4gb; /* 0x30 - 0x37 Base of above 4GB MMIO Resource */
 	u64	a4gs; /* 0x38 - 0x3f Length of above 4GB MMIO Resource */
 	u64	hest_log_addr; /* 0x40 - 47 err log addr (used in SMM, not ASL code) */
-	/* SGX */
-	u8	epcs; /* 0x48 - SGX enabled status */
-	u64	emna; /* 0x49 - 0x50 EPC base address */
-	u64	elng; /* 0x51 - 0x58 EPC length */
 };
 
 #endif
diff --git a/src/soc/intel/common/block/include/intelblocks/sgx.h b/src/soc/intel/common/block/include/intelblocks/sgx.h
index 56e4a167b5..fc7282f011 100644
--- a/src/soc/intel/common/block/include/intelblocks/sgx.h
+++ b/src/soc/intel/common/block/include/intelblocks/sgx.h
@@ -17,7 +17,7 @@ void prmrr_core_configure(void);
  */
 void sgx_configure(void *unused);
 
-/* Fill GNVS data with SGX status, EPC base and length */
-void sgx_fill_gnvs(struct global_nvs *gnvs);
+/* Fill SSDT for SGX status, EPC base and length */
+void sgx_fill_ssdt(void);
 
 #endif	/* SOC_INTEL_COMMON_BLOCK_SGX_H */
diff --git a/src/soc/intel/common/block/sgx/sgx.c b/src/soc/intel/common/block/sgx/sgx.c
index e0dcd85861..d15fc0f049 100644
--- a/src/soc/intel/common/block/sgx/sgx.c
+++ b/src/soc/intel/common/block/sgx/sgx.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <acpi/acpigen.h>
 #include <console/console.h>
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>
@@ -10,7 +11,6 @@
 #include <intelblocks/sgx.h>
 #include <intelblocks/systemagent.h>
 #include <soc/cpu.h>
-#include <soc/nvs.h>
 #include <soc/pci_devs.h>
 
 static inline uint64_t sgx_resource(uint32_t low, uint32_t high)
@@ -235,31 +235,40 @@ void sgx_configure(void *unused)
 		activate_sgx();
 }
 
-void sgx_fill_gnvs(struct global_nvs *gnvs)
+void sgx_fill_ssdt(void)
 {
+	bool epcs = false;
 	struct cpuid_result cpuid_regs;
-
-	if (!is_sgx_supported()) {
-		printk(BIOS_DEBUG,
-			"SGX: not supported. skip gnvs fill\n");
-		return;
+	uint64_t emna = 0, elng = 0;
+
+	if (is_sgx_supported()) {
+		/*
+		 * Get EPC base and size.
+		 * Intel SDM: Table 36-6. CPUID Leaf 12H, Sub-Leaf Index 2 or
+		 * Higher for enumeration of SGX Resources. Same Table mentions
+		 * about return values of the CPUID
+		 */
+		cpuid_regs = cpuid_ext(SGX_RESOURCE_ENUM_CPUID_LEAF,
+					SGX_RESOURCE_ENUM_CPUID_SUBLEAF);
+
+		if (cpuid_regs.eax & SGX_RESOURCE_ENUM_BIT) {
+			/* EPC section enumerated */
+			epcs = true;
+			emna = sgx_resource(cpuid_regs.eax, cpuid_regs.ebx);
+			elng = sgx_resource(cpuid_regs.ecx, cpuid_regs.edx);
+		}
+
+		printk(BIOS_DEBUG, "SGX: EPC status = %d base = 0x%llx len = 0x%llx\n",
+				   epcs, emna, elng);
+	} else {
+		printk(BIOS_DEBUG, "SGX: not supported.\n");
 	}
 
-	/* Get EPC base and size.
-	 * Intel SDM: Table 36-6. CPUID Leaf 12H, Sub-Leaf Index 2 or
-	 * Higher for enumeration of SGX Resources. Same Table mentions
-	 * about return values of the CPUID */
-	cpuid_regs = cpuid_ext(SGX_RESOURCE_ENUM_CPUID_LEAF,
-				SGX_RESOURCE_ENUM_CPUID_SUBLEAF);
-
-	if (cpuid_regs.eax & SGX_RESOURCE_ENUM_BIT) {
-		/* EPC section enumerated */
-		gnvs->epcs = 1;
-		gnvs->emna = sgx_resource(cpuid_regs.eax, cpuid_regs.ebx);
-		gnvs->elng = sgx_resource(cpuid_regs.ecx, cpuid_regs.edx);
+	acpigen_write_scope("\\_SB.EPC");
+	{
+		acpigen_write_name_byte("EPCS", epcs);
+		acpigen_write_name_qword("EMNA", emna);
+		acpigen_write_name_qword("ELNG", elng);
 	}
-
-	printk(BIOS_DEBUG,
-		"SGX: gnvs EPC status = %d base = 0x%llx len = 0x%llx\n",
-			gnvs->epcs, gnvs->emna, gnvs->elng);
+	acpigen_pop_len();
 }