[PATCH v9 25/43] x86/compressed/acpi: Move EFI system table lookup to helper

From: Brijesh Singh <brijesh.singh@amd.com>
To: <x86@kernel.org>, <linux-kernel@vger.kernel.org>,
	<kvm@vger.kernel.org>, <linux-efi@vger.kernel.org>,
	<platform-driver-x86@vger.kernel.org>,
	<linux-coco@lists.linux.dev>, <linux-mm@kvack.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	Jim Mattson <jmattson@google.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	Dov Murik <dovmurik@linux.ibm.com>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Borislav Petkov <bp@alien8.de>,
	Michael Roth <michael.roth@amd.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	Andi Kleen <ak@linux.intel.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	<brijesh.ksingh@gmail.com>, <tony.luck@intel.com>,
	<marcorr@google.com>,
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v9 25/43] x86/compressed/acpi: Move EFI system table lookup to helper
Date: Fri, 28 Jan 2022 11:17:46 -0600	[thread overview]
Message-ID: <20220128171804.569796-26-brijesh.singh@amd.com> (raw)
In-Reply-To: <20220128171804.569796-1-brijesh.singh@amd.com>

From: Michael Roth <michael.roth@amd.com>

Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related
code into a set of helpers that can be re-used for that purpose.

Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/acpi.c | 21 +++++++--------------
 arch/x86/boot/compressed/efi.c  | 29 +++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h |  6 ++++++
 3 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index db6c561920f0..58a3d3f3e305 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -105,7 +105,7 @@ static acpi_physical_address kexec_get_rsdp_addr(void)
 	}
 
 	/* Get systab from boot params. */
-	systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
+	systab = (efi_system_table_64_t *)efi_get_system_table(boot_params);
 	if (!systab)
 		error("EFI system table not found in kexec boot_params.");
 
@@ -118,9 +118,8 @@ static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
 static acpi_physical_address efi_get_rsdp_addr(void)
 {
 #ifdef CONFIG_EFI
-	unsigned long systab, config_tables;
+	unsigned long systab_pa, config_tables;
 	unsigned int nr_tables;
-	struct efi_info *ei;
 	enum efi_type et;
 	bool efi_64;
 
@@ -132,24 +131,18 @@ static acpi_physical_address efi_get_rsdp_addr(void)
 	else
 		return 0;
 
-	/* Get systab from boot params. */
-	ei = &boot_params->efi_info;
-#ifdef CONFIG_X86_64
-	systab = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
-#else
-	systab = ei->efi_systab;
-#endif
-	if (!systab)
-		error("EFI system table not found.");
+	systab_pa = efi_get_system_table(boot_params);
+	if (!systab_pa)
+		error("EFI support advertised, but unable to locate system table.");
 
 	/* Handle EFI bitness properly */
 	if (efi_64) {
-		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab;
+		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab_pa;
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
 	} else {
-		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;
+		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab_pa;
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
index daa73efdc7a5..bf99768cd229 100644
--- a/arch/x86/boot/compressed/efi.c
+++ b/arch/x86/boot/compressed/efi.c
@@ -48,3 +48,32 @@ enum efi_type efi_get_type(struct boot_params *boot_params)
 
 	return et;
 }
+
+/*
+ * efi_get_system_table - Given boot_params, retrieve the physical address of
+ *                        EFI system table.
+ *
+ * @boot_params:        pointer to boot_params
+ *
+ * Return: EFI system table address on success. On error, return 0.
+ */
+unsigned long efi_get_system_table(struct boot_params *boot_params)
+{
+	unsigned long sys_tbl_pa;
+	struct efi_info *ei;
+	enum efi_type et;
+
+	/* Get systab from boot params. */
+	ei = &boot_params->efi_info;
+#ifdef CONFIG_X86_64
+	sys_tbl_pa = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
+#else
+	sys_tbl_pa = ei->efi_systab;
+#endif
+	if (!sys_tbl_pa) {
+		debug_putstr("EFI system table not found.");
+		return 0;
+	}
+
+	return sys_tbl_pa;
+}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index a26244c0fe01..24522be8c21d 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -185,11 +185,17 @@ enum efi_type {
 #ifdef CONFIG_EFI
 /* helpers for early EFI config table access */
 enum efi_type efi_get_type(struct boot_params *boot_params);
+unsigned long efi_get_system_table(struct boot_params *boot_params);
 #else
 static inline enum efi_type efi_get_type(struct boot_params *boot_params)
 {
 	return EFI_TYPE_NONE;
 }
+
+static inline unsigned long efi_get_system_table(struct boot_params *boot_params)
+{
+	return 0;
+}
 #endif /* CONFIG_EFI */
 
 #endif /* BOOT_COMPRESSED_MISC_H */
-- 
2.25.1

