linux-kernel - [PATCH v7 16/36] efi: Add an EFI table address match function

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Message-ID: <20170616185253.18967.55724.stgit@tlendack-t1.amdoffice.net>
Date:   Fri, 16 Jun 2017 13:52:53 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        kvm@...r.kernel.org, linux-doc@...r.kernel.org, x86@...nel.org,
        kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com, xen-devel@...ts.xen.org,
        linux-mm@...ck.org, iommu@...ts.linux-foundation.org
Cc:     Brijesh Singh <brijesh.singh@....com>,
        Toshimitsu Kani <toshi.kani@....com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Alexander Potapenko <glider@...gle.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Larry Woodman <lwoodman@...hat.com>,
        Jonathan Corbet <corbet@....net>,
        Joerg Roedel <joro@...tes.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Dave Young <dyoung@...hat.com>, Rik van Riel <riel@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Juergen Gross <jgross@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH v7 16/36] efi: Add an EFI table address match function

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

Reviewed-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@....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 b372aad..983675d 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)
 {
@@ -854,6 +873,20 @@ 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);