[PATCH v10 16/38] efi: Add an EFI table address match function

From: Tom Lendacky <thomas.lendacky@amd.com>
To: x86@kernel.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-efi@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-mm@kvack.org,
	kvm@vger.kernel.org, kasan-dev@googlegroups.com
Cc: "Radim Krčmář" <rkrcmar@redhat.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Matt Fleming" <matt@codeblueprint.co.uk>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Andy Lutomirski" <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Alexander Potapenko" <glider@google.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Dmitry Vyukov" <dvyukov@google.com>,
	"Rik van Riel" <riel@redhat.com>,
	"Larry Woodman" <lwoodman@redhat.com>,
	"Dave Young" <dyoung@redhat.com>,
	"Toshimitsu Kani" <toshi.kani@hpe.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Brijesh Singh" <brijesh.singh@amd.com>
Subject: [PATCH v10 16/38] efi: Add an EFI table address match function
Date: Mon, 17 Jul 2017 16:10:13 -0500	[thread overview]
Message-ID: <e1e06441d80f44776df391e0e4cb485b345b7518.1500319216.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1500319216.git.thomas.lendacky@amd.com>

Add a function that will determine if a supplied physical address matches
the address of an EFI table.

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 drivers/firmware/efi/efi.c | 33 +++++++++++++++++++++++++++++++++
 include/linux/efi.h        |  7 +++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 045d6d3..69d4d13 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -55,6 +55,25 @@ struct efi __read_mostly efi = {
 };
 EXPORT_SYMBOL(efi);
 
+static unsigned long *efi_tables[] = {
+	&efi.mps,
+	&efi.acpi,
+	&efi.acpi20,
+	&efi.smbios,
+	&efi.smbios3,
+	&efi.sal_systab,
+	&efi.boot_info,
+	&efi.hcdp,
+	&efi.uga,
+	&efi.uv_systab,
+	&efi.fw_vendor,
+	&efi.runtime,
+	&efi.config_table,
+	&efi.esrt,
+	&efi.properties_table,
+	&efi.mem_attr_table,
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
@@ -855,6 +874,20 @@ int efi_status_to_err(efi_status_t status)
 	return err;
 }
 
+bool efi_is_table_address(unsigned long phys_addr)
+{
+	unsigned int i;
+
+	if (phys_addr == EFI_INVALID_TABLE_ADDR)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(efi_tables); i++)
+		if (*(efi_tables[i]) == phys_addr)
+			return true;
+
+	return false;
+}
+
 #ifdef CONFIG_KEXEC
 static int update_efi_random_seed(struct notifier_block *nb,
 				  unsigned long code, void *unused)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8269bcb..8e24f09 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1091,6 +1091,8 @@ static inline bool efi_enabled(int feature)
 	return test_bit(feature, &efi.flags) != 0;
 }
 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+
+extern bool efi_is_table_address(unsigned long phys_addr);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1104,6 +1106,11 @@ static inline bool efi_enabled(int feature)
 {
 	return false;
 }
+
+static inline bool efi_is_table_address(unsigned long phys_addr)
+{
+	return false;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);
-- 
1.9.1

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