diff mbox series

[v9,26/43] x86/compressed/acpi: Move EFI config table lookup to helper

Message ID 20220128171804.569796-27-brijesh.singh@amd.com (mailing list archive)
State New, archived
Headers show
Series Add AMD Secure Nested Paging (SEV-SNP) Guest Support | expand

Commit Message

Brijesh Singh Jan. 28, 2022, 5:17 p.m. UTC 
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 | 25 ++++++------------
 arch/x86/boot/compressed/efi.c  | 45 +++++++++++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h |  9 +++++++
 3 files changed, 62 insertions(+), 17 deletions(-)

Comments

Borislav Petkov Feb. 3, 2022, 3:13 p.m. UTC | #1 
On Fri, Jan 28, 2022 at 11:17:47AM -0600, Brijesh Singh wrote:
> +int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
> +		       unsigned int *cfg_tbl_len)
> +{
> +	unsigned long sys_tbl_pa = 0;
> +	enum efi_type et;
> +	int ret;
> +
> +	if (!cfg_tbl_pa || !cfg_tbl_len)
> +		return -EINVAL;
> +
> +	sys_tbl_pa = efi_get_system_table(boot_params);
> +	if (!sys_tbl_pa)
> +		return -EINVAL;
> +
> +	/* Handle EFI bitness properly */
> +	et = efi_get_type(boot_params);
> +	if (et == EFI_TYPE_64) {
> +		efi_system_table_64_t *stbl =
> +			(efi_system_table_64_t *)sys_tbl_pa;
> +
> +		*cfg_tbl_pa = stbl->tables;
> +		*cfg_tbl_len = stbl->nr_tables;
> +	} else if (et == EFI_TYPE_32) {
> +		efi_system_table_32_t *stbl =
> +			(efi_system_table_32_t *)sys_tbl_pa;

You don't have to break those assignment lines - the 80 cols rule is not
a hard one. Readability is more important.
diff mbox series

Patch

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 58a3d3f3e305..9a824af69961 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -118,10 +118,13 @@  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_pa, config_tables;
+	unsigned long cfg_tbl_pa = 0;
+	unsigned int cfg_tbl_len;
+	unsigned long systab_pa;
 	unsigned int nr_tables;
 	enum efi_type et;
 	bool efi_64;
+	int ret;
 
 	et = efi_get_type(boot_params);
 	if (et == EFI_TYPE_64)
@@ -135,23 +138,11 @@  static acpi_physical_address efi_get_rsdp_addr(void)
 	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_pa;
-
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	} else {
-		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab_pa;
-
-		config_tables	= stbl->tables;
-		nr_tables	= stbl->nr_tables;
-	}
-
-	if (!config_tables)
-		error("EFI config tables not found.");
+	ret = efi_get_conf_table(boot_params, &cfg_tbl_pa, &cfg_tbl_len);
+	if (ret || !cfg_tbl_pa)
+		error("EFI config table not found.");
 
-	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
+	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len, efi_64);
 #else
 	return 0;
 #endif
diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c
index bf99768cd229..feb00c6b4919 100644
--- a/arch/x86/boot/compressed/efi.c
+++ b/arch/x86/boot/compressed/efi.c
@@ -77,3 +77,48 @@  unsigned long efi_get_system_table(struct boot_params *boot_params)
 
 	return sys_tbl_pa;
 }
+
+/**
+ * efi_get_conf_table - Given boot_params, locate EFI system table from it and
+ *                      return the physical address of EFI configuration table.
+ *
+ * @boot_params:        pointer to boot_params
+ * @cfg_tbl_pa:         location to store physical address of config table
+ * @cfg_tbl_len:        location to store number of config table entries
+ *
+ * Return: 0 on success. On error, return params are left unchanged.
+ */
+int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
+		       unsigned int *cfg_tbl_len)
+{
+	unsigned long sys_tbl_pa = 0;
+	enum efi_type et;
+	int ret;
+
+	if (!cfg_tbl_pa || !cfg_tbl_len)
+		return -EINVAL;
+
+	sys_tbl_pa = efi_get_system_table(boot_params);
+	if (!sys_tbl_pa)
+		return -EINVAL;
+
+	/* Handle EFI bitness properly */
+	et = efi_get_type(boot_params);
+	if (et == EFI_TYPE_64) {
+		efi_system_table_64_t *stbl =
+			(efi_system_table_64_t *)sys_tbl_pa;
+
+		*cfg_tbl_pa = stbl->tables;
+		*cfg_tbl_len = stbl->nr_tables;
+	} else if (et == EFI_TYPE_32) {
+		efi_system_table_32_t *stbl =
+			(efi_system_table_32_t *)sys_tbl_pa;
+
+		*cfg_tbl_pa = stbl->tables;
+		*cfg_tbl_len = stbl->nr_tables;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 24522be8c21d..162dbd7443eb 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -186,6 +186,8 @@  enum efi_type {
 /* 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);
+int efi_get_conf_table(struct boot_params *boot_params, unsigned long *cfg_tbl_pa,
+		       unsigned int *cfg_tbl_len);
 #else
 static inline enum efi_type efi_get_type(struct boot_params *boot_params)
 {
@@ -196,6 +198,13 @@  static inline unsigned long efi_get_system_table(struct boot_params *boot_params
 {
 	return 0;
 }
+
+static inline int efi_get_conf_table(struct boot_params *boot_params,
+				     unsigned long *cfg_tbl_pa,
+				     unsigned int *cfg_tbl_len)
+{
+	return -ENOENT;
+}
 #endif /* CONFIG_EFI */
 
 #endif /* BOOT_COMPRESSED_MISC_H */