[PATCH v4 12/13] s390/kexec: refactor for kernel/Kconfig.kexec

Eric DeVolder
2023-07-05T15:24:41Z

NOTE: The original Kconfig has a KEXEC_SIG which depends on
MODULE_SIG_FORMAT. However, attempts to keep the MODULE_SIG_FORMAT
dependency (using the strategy outlined in this series, and other
techniques) results in 'error: recursive dependency detected'
on CRYPTO.

Per Alexander Gordeev <agordeev@linux.ibm.com>: "the MODULE_SIG_FORMAT
dependency was introduced with [git commit below] and in fact was not
necessary, since s390 did/does not use mod_check_sig() anyway.

commit c8424e776b09 ("MODSIGN: Export module signature definitions")

MODULE_SIG_FORMAT is needed to select SYSTEM_DATA_VERIFICATION. But
SYSTEM_DATA_VERIFICATION is also selected by FS_VERITY*, so dropping
MODULE_SIG_FORMAT does not hurt."

Therefore, the solution is to drop the MODULE_SIG_FORMAT dependency
from KEXEC_SIG. Still results in equivalent .config files for s390.

Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
arch/s390/Kconfig | 65 ++++++++++++++---------------------------------
1 file changed, 19 insertions(+), 46 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5b39918b7042..5d4fbbfdd1cd 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -244,6 +244,25 @@ config PGTABLE_LEVELS

source "kernel/livepatch/Kconfig"

+config ARCH_DEFAULT_KEXEC
+ def_bool y
+
+config ARCH_SUPPORTS_KEXEC
+ def_bool y
+
+config ARCH_SUPPORTS_KEXEC_FILE
+ def_bool CRYPTO && CRYPTO_SHA256 && CRYPTO_SHA256_S390
+
+config ARCH_HAS_KEXEC_PURGATORY
+ def_bool KEXEC_FILE
+
+config ARCH_SUPPORTS_CRASH_DUMP
+ def_bool y
+ help
+ Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
+ This option also enables s390 zfcpdump.
+ See also <file:Documentation/s390/zfcpdump.rst>
+
menu "Processor type and features"

config HAVE_MARCH_Z10_FEATURES
@@ -482,36 +501,6 @@ config SCHED_TOPOLOGY

source "kernel/Kconfig.hz"

-config KEXEC
- def_bool y
- select KEXEC_CORE
-
-config KEXEC_FILE
- bool "kexec file based system call"
- select KEXEC_CORE
- depends on CRYPTO
- depends on CRYPTO_SHA256
- depends on CRYPTO_SHA256_S390
- help
- Enable the kexec file based system call. In contrast to the normal
- kexec system call this system call takes file descriptors for the
- kernel and initramfs as arguments.
-
-config ARCH_HAS_KEXEC_PURGATORY
- def_bool y
- depends on KEXEC_FILE
-
-config KEXEC_SIG
- bool "Verify kernel signature during kexec_file_load() syscall"
- depends on KEXEC_FILE && MODULE_SIG_FORMAT
- help
- This option makes kernel signature verification mandatory for
- the kexec_file_load() syscall.
-
- In addition to that option, you need to enable signature
- verification for the corresponding kernel image type being
- loaded in order for this to work.
-
config KERNEL_NOBP
def_bool n
prompt "Enable modified branch prediction for the kernel by default"
@@ -733,22 +722,6 @@ config VFIO_AP

endmenu

-menu "Dump support"
-
-config CRASH_DUMP
- bool "kernel crash dumps"
- select KEXEC
- help
- Generate crash dump after being started by kexec.
- Crash dump kernels are loaded in the main kernel with kexec-tools
- into a specially reserved region and then later executed after
- a crash by kdump/kexec.
- Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
- This option also enables s390 zfcpdump.
- See also <file:Documentation/s390/zfcpdump.rst>
-
-endmenu
-
config CCW
def_bool y

--
2.31.1