kernel: Move to Linux v5.4.48-openpower1

This adds secure boot support backported from upstream and enables it
in the configuration.

Appearing in the backports is a patch to disable STRICT_KERNEL_RWX so
it drops out of the configuration.

Backported patches to support secureboot:

 powerpc/ima: Fix secure boot rules in ima arch policy
 powerpc/ima: Indicate kernel modules appended signatures are enforced
 powerpc/xmon: Allow listing and clearing breakpoints in read-only mode
 powerpc: Load firmware trusted keys/hashes into kernel keyring
 x86/efi: move common keyring handler functions to new file
 powerpc: expose secure variables to userspace via sysfs
 powerpc/powernv: Add OPAL API interface to access secure variable
 powerpc/ima: Update ima arch policy to check for blacklist
 ima: Check against blacklisted hashes for files with modsig
 certs: Add wrapper function to check blacklisted binary hash
 ima: Make process_buffer_measurement() generic
 powerpc/ima: Define trusted boot policy
 powerpc: Detect the trusted boot state of the system
 powerpc/ima: Add support to initialize ima policy rules
 powerpc: Detect the secure boot mode of the system

PowerPC related fixes:

 powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
 powerpc/64s: Don't let DT CPU features set FSCR_DSCR
 powerpc/kasan: Fix shadow pages allocation failure
 powerpc/kasan: Fix issues by lowering KASAN_SHADOW_END
 powerpc/fadump: Account for memory_limit while reserving memory
 powerpc/fadump: consider reserved ranges while reserving memory
 powerpc/fadump: use static allocation for reserved memory ranges
 powerpc/mm: Fix conditions to perform MMU specific management by blocks on PPC32.
 powerpc/spufs: fix copy_to_user while atomic
 sched/core: Fix illegal RCU from offline CPUs
 powerpc/ptdump: Properly handle non standard page size
 powerpc/xive: Clear the page tables for the ESB IO mapping
 bpf: Support llvm-objcopy for vmlinux BTF
 powerpc/xmon: Restrict when kernel is locked down
 powerpc/powernv: Avoid re-registration of imc debugfs directory
 powerpc/64s: Disable STRICT_KERNEL_RWX
 powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE
 powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32
 powerpc/kuap: PPC_KUAP_DEBUG should depend on PPC_KUAP
 powerpc/setup_64: Set cache-line-size based on cache-block-size
 Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled"

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/linux/skiroot_defconfig b/openpower/configs/linux/skiroot_defconfig
index d0cda0e..44309e1 100644
--- a/openpower/configs/linux/skiroot_defconfig
+++ b/openpower/configs/linux/skiroot_defconfig
@@ -3,6 +3,7 @@
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
 # CONFIG_CROSS_MEMORY_ATTACH is not set
+CONFIG_AUDIT=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
 # CONFIG_CPU_ISOLATION is not set
@@ -49,8 +50,8 @@
 CONFIG_CMDLINE="console=tty0 console=hvc0 ipr.fast_reboot=1 quiet"
 # CONFIG_SECCOMP is not set
 # CONFIG_PPC_MEM_KEYS is not set
+CONFIG_PPC_SECURE_BOOT=y
 CONFIG_JUMP_LABEL=y
-CONFIG_STRICT_KERNEL_RWX=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_SIG_FORCE=y
@@ -84,7 +85,6 @@
 # CONFIG_OCXL is not set
 CONFIG_BLK_DEV_SD=m
 CONFIG_BLK_DEV_SR=m
-CONFIG_BLK_DEV_SR_VENDOR=y
 CONFIG_CHR_DEV_SG=m
 CONFIG_SCSI_CONSTANTS=y
 CONFIG_SCSI_SCAN_ASYNC=y
@@ -209,7 +209,6 @@
 CONFIG_IPMI_POWERNV=y
 CONFIG_IPMI_WATCHDOG=y
 CONFIG_HW_RANDOM=y
-CONFIG_TCG_TPM=y
 CONFIG_TCG_TIS_I2C_NUVOTON=y
 # CONFIG_DEVPORT is not set
 CONFIG_I2C=y
@@ -282,9 +281,21 @@
 CONFIG_FORTIFY_SOURCE=y
 CONFIG_SECURITY_LOCKDOWN_LSM=y
 CONFIG_SECURITY_LOCKDOWN_LSM_EARLY=y
-# CONFIG_INTEGRITY is not set
+CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY=y
+CONFIG_INTEGRITY_SIGNATURE=y
+CONFIG_INTEGRITY_ASYMMETRIC_KEYS=y
+CONFIG_INTEGRITY_PLATFORM_KEYRING=y
+CONFIG_IMA=y
+CONFIG_IMA_KEXEC=y
+CONFIG_IMA_SIG_TEMPLATE=y
+CONFIG_IMA_DEFAULT_HASH_SHA256=y
+CONFIG_IMA_READ_POLICY=y
+CONFIG_IMA_APPRAISE=y
+CONFIG_IMA_ARCH_POLICY=y
+CONFIG_IMA_APPRAISE_MODSIG=y
 CONFIG_LSM="yama,loadpin,safesetid,integrity"
 # CONFIG_CRYPTO_HW is not set
+CONFIG_SYSTEM_BLACKLIST_KEYRING=y
 CONFIG_CRC16=y
 CONFIG_CRC_ITU_T=y
 CONFIG_LIBCRC32C=y