powerpc/powernv: Add OPAL API interface to access secure variable

The X.509 certificates trusted by the platform and required to secure
boot the OS kernel are wrapped in secure variables, which are
controlled by OPAL.

This patch adds firmware/kernel interface to read and write OPAL
secure variables based on the unique key.

This support can be enabled using CONFIG_OPAL_SECVAR.

Signed-off-by: Claudio Carvalho <[email protected]>
Signed-off-by: Nayna Jain <[email protected]>
Signed-off-by: Eric Richter <[email protected]>
[mpe: Make secvar_ops __ro_after_init, only build opal-secvar.c if PPC_SECURE_BOOT=y]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index a0cf8fba4d12..9986ac34b8e2 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -298,6 +298,13 @@ int opal_sensor_group_clear(u32 group_hndl, int token);
 int opal_sensor_group_enable(u32 group_hndl, int token, bool enable);
 int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
 
+int opal_secvar_get(const char *key, uint64_t key_len, u8 *data,
+		    uint64_t *data_size);
+int opal_secvar_get_next(const char *key, uint64_t *key_len,
+			 uint64_t key_buf_size);
+int opal_secvar_enqueue_update(const char *key, uint64_t key_len, u8 *data,
+			       uint64_t data_size);
+
 s64 opal_mpipl_update(enum opal_mpipl_ops op, u64 src, u64 dest, u64 size);
 s64 opal_mpipl_register_tag(enum opal_mpipl_tags tag, u64 addr);
 s64 opal_mpipl_query_tag(enum opal_mpipl_tags tag, u64 *addr);