[PATCH v2 02/11] efi_selftest: add ACPI configuration table test

[Heinrich Schuchardt]

The new unit test checks if ACPI tables are available.

If yes, it checks if the RSDP correctly points to the RSDT or XSDT.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
v2:
	Correct commit message %s/RSDT/RSDP/.
	Check checksums.
	Add a 'skipped' message.
---
 lib/efi_selftest/Makefile            |   1 +
 lib/efi_selftest/efi_selftest_acpi.c | 138 +++++++++++++++++++++++++++
 2 files changed, 139 insertions(+)
 create mode 100644 lib/efi_selftest/efi_selftest_acpi.c

diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index 67102648703..c6cc2430bbf 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -17,6 +17,7 @@ CFLAGS_REMOVE_efi_selftest_miniapp_return.o := $(CFLAGS_NON_EFI)
 
 obj-y += \
 efi_selftest.o \
+efi_selftest_acpi.o \
 efi_selftest_bitblt.o \
 efi_selftest_config_table.o \
 efi_selftest_controllers.o \
diff --git a/lib/efi_selftest/efi_selftest_acpi.c b/lib/efi_selftest/efi_selftest_acpi.c
new file mode 100644
index 00000000000..94cf5c00484
--- /dev/null
+++ b/lib/efi_selftest/efi_selftest_acpi.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * efi_selftest_acpi
+ *
+ * Copyright 2026, Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
+ *
+ * Check ACPI configuration table availability and root table presence.
+ */
+
+#include <efi_selftest.h>
+#include <acpi/acpi_table.h>
+
+static const efi_guid_t acpi2_guid = EFI_ACPI_TABLE_GUID;
+static const efi_guid_t acpi1_guid = EFI_GUID_EFI_ACPI1;
+
+/**
+ * checksum_ok() - check if byte-sum of buffer is zero
+ *
+ * @buf:	buffer to check
+ * @len:	buffer length
+ * Return:	true if checksum is valid
+ */
+static bool checksum_ok(const void *buf, efi_uintn_t len)
+{
+	const u8 *pos = buf;
+	u8 sum = 0;
+
+	for (; len; --len, ++pos)
+		sum += *pos;
+
+	return !sum;
+}
+
+/**
+ * check_rsdp() - validate RSDP signature, checksum and root table pointer
+ *
+ * @rsdp:	RSDP to validate
+ * Return:	EFI_ST_SUCCESS or EFI_ST_FAILURE
+ */
+static int check_rsdp(struct acpi_rsdp *rsdp)
+{
+	struct acpi_table_header *table;
+	u32 rsdt_addr32;
+	u64 xsdt_addr64;
+	uintptr_t rsdt_addr;
+	uintptr_t xsdt_addr;
+	u32 rsdp_len;
+
+	if (memcmp(rsdp->signature, RSDP_SIG, sizeof(rsdp->signature))) {
+		efi_st_error("Wrong RSDP signature\n");
+		return EFI_ST_FAILURE;
+	}
+
+	if (!checksum_ok(rsdp, 20)) {
+		efi_st_error("Invalid RSDP checksum\n");
+		return EFI_ST_FAILURE;
+	}
+
+	if (rsdp->revision >= ACPI_RSDP_REV_ACPI_2_0) {
+		rsdp_len = rsdp->length;
+		if (rsdp_len < sizeof(*rsdp)) {
+			efi_st_error("Invalid ACPI 2.0 RSDP length\n");
+			return EFI_ST_FAILURE;
+		}
+		if (!checksum_ok(rsdp, rsdp_len)) {
+			efi_st_error("Invalid RSDP extended checksum\n");
+			return EFI_ST_FAILURE;
+		}
+	}
+
+	memcpy(&rsdt_addr32, &rsdp->rsdt_address, sizeof(rsdt_addr32));
+	rsdt_addr = rsdt_addr32;
+
+	xsdt_addr64 = 0;
+	if (rsdp->revision >= ACPI_RSDP_REV_ACPI_2_0)
+		memcpy(&xsdt_addr64, &rsdp->xsdt_address, sizeof(xsdt_addr64));
+	xsdt_addr = xsdt_addr64;
+
+	if (!rsdt_addr && !xsdt_addr) {
+		efi_st_error("Neither RSDT nor XSDT address is set\n");
+		return EFI_ST_FAILURE;
+	}
+
+	if (xsdt_addr) {
+		table = (struct acpi_table_header *)xsdt_addr;
+		if (!memcmp(table->signature, "XSDT", 4))
+			return EFI_ST_SUCCESS;
+		efi_st_error("XSDT address does not point to XSDT\n");
+	}
+
+	if (rsdt_addr) {
+		table = (struct acpi_table_header *)rsdt_addr;
+		if (!memcmp(table->signature, "RSDT", 4))
+			return EFI_ST_SUCCESS;
+		efi_st_error("RSDT address does not point to RSDT\n");
+	}
+
+	return EFI_ST_FAILURE;
+}
+
+/**
+ * efi_st_acpi_execute() - execute ACPI selftest
+ *
+ * Return: status code
+ */
+static int efi_st_acpi_execute(void)
+{
+	struct acpi_rsdp *rsdp2, *rsdp1;
+	int ret;
+
+	rsdp2 = efi_st_get_config_table(&acpi2_guid);
+	rsdp1 = efi_st_get_config_table(&acpi1_guid);
+
+	if (!rsdp2 && !rsdp1) {
+		efi_st_printf("No ACPI configuration table, test skipped\n");
+		return EFI_ST_SUCCESS;
+	}
+
+	if (rsdp2) {
+		ret = check_rsdp(rsdp2);
+		if (ret != EFI_ST_SUCCESS)
+			return ret;
+	}
+
+	if (rsdp1) {
+		ret = check_rsdp(rsdp1);
+		if (ret != EFI_ST_SUCCESS)
+			return ret;
+	}
+
+	return EFI_ST_SUCCESS;
+}
+
+EFI_UNIT_TEST(acpi) = {
+	.name = "acpi",
+	.phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
+	.execute = efi_st_acpi_execute,
+};
-- 
2.53.0