[PATCH v11 25/45] x86/compressed/acpi: Move EFI system table lookup to helper

Brijesh Singh
2022-02-24T17:00:07Z

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 bad0ce3e2ef6..72a81ba1f87b 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 *bp)

return et;
}
+
+/**
+ * efi_get_system_table - Given a pointer to boot_params, retrieve the physical address
+ * of the EFI system table.
+ *
+ * @bp: pointer to boot_params
+ *
+ * Return: EFI system table address on success. On error, return 0.
+ */
+unsigned long efi_get_system_table(struct boot_params *bp)
+{
+ unsigned long sys_tbl_pa;
+ struct efi_info *ei;
+ enum efi_type et;
+
+ /* Get systab from boot params. */
+ ei = &bp->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 fede1afa39e9..b2acd3ac6525 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 *bp);
+unsigned long efi_get_system_table(struct boot_params *bp);
#else
static inline enum efi_type efi_get_type(struct boot_params *bp)
{
return EFI_TYPE_NONE;
}
+
+static inline unsigned long efi_get_system_table(struct boot_params *bp)
+{
+ return 0;
+}
#endif /* CONFIG_EFI */

#endif /* BOOT_COMPRESSED_MISC_H */
--
2.25.1