From c1ad12ee0efc07244be37f69311e6f7c4ac98e62 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 23 Oct 2023 13:01:54 +0200 Subject: kexec: fix KEXEC_FILE dependencies The cleanup for the CONFIG_KEXEC Kconfig logic accidentally changed the 'depends on CRYPTO=y' dependency to a plain 'depends on CRYPTO', which causes a link failure when all the crypto support is in a loadable module and kexec_file support is built-in: x86_64-linux-ld: vmlinux.o: in function `__x64_sys_kexec_file_load': (.text+0x32e30a): undefined reference to `crypto_alloc_shash' x86_64-linux-ld: (.text+0x32e58e): undefined reference to `crypto_shash_update' x86_64-linux-ld: (.text+0x32e6ee): undefined reference to `crypto_shash_final' Both s390 and x86 have this problem, while ppc64 and riscv have the correct dependency already. On riscv, the dependency is only used for the purgatory, not for the kexec_file code itself, which may be a bit surprising as it means that with CONFIG_CRYPTO=m, it is possible to enable KEXEC_FILE but then the purgatory code is silently left out. Move this into the common Kconfig.kexec file in a way that is correct everywhere, using the dependency on CRYPTO_SHA256=y only when the purgatory code is available. This requires reversing the dependency between ARCH_SUPPORTS_KEXEC_PURGATORY and KEXEC_FILE, but the effect remains the same, other than making riscv behave like the other ones. On s390, there is an additional dependency on CRYPTO_SHA256_S390, which should technically not be required but gives better performance. Remove this dependency here, noting that it was not present in the initial Kconfig code but was brought in without an explanation in commit 71406883fd357 ("s390/kexec_file: Add kexec_file_load system call"). [arnd@arndb.de: fix riscv build] Link: https://lkml.kernel.org/r/67ddd260-d424-4229-a815-e3fcfb864a77@app.fastmail.com Link: https://lkml.kernel.org/r/20231023110308.1202042-1-arnd@kernel.org Fixes: 6af5138083005 ("x86/kexec: refactor for kernel/Kconfig.kexec") Signed-off-by: Arnd Bergmann Reviewed-by: Eric DeVolder Tested-by: Eric DeVolder Cc: Albert Ou Cc: Alexander Gordeev Cc: Ard Biesheuvel Cc: Borislav Petkov Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Conor Dooley Cc: Dave Hansen Cc: David S. Miller Cc: Heiko Carstens Cc: Herbert Xu Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Sven Schnelle Cc: Thomas Gleixner Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- kernel/Kconfig.kexec | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec index 2fd510256604..92120e396008 100644 --- a/kernel/Kconfig.kexec +++ b/kernel/Kconfig.kexec @@ -36,6 +36,7 @@ config KEXEC config KEXEC_FILE bool "Enable kexec file based system call" depends on ARCH_SUPPORTS_KEXEC_FILE + depends on CRYPTO_SHA256=y || !ARCH_SUPPORTS_KEXEC_PURGATORY select KEXEC_CORE help This is new version of kexec system call. This system call is -- cgit From e63bde3d9417f8318d6dd0d0fafa35ebf307aabd Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 23 Oct 2023 13:01:55 +0200 Subject: kexec: select CRYPTO from KEXEC_FILE instead of depending on it All other users of crypto code use 'select' instead of 'depends on', so do the same thing with KEXEC_FILE for consistency. In practice this makes very little difference as kernels with kexec support are very likely to also include some other feature that already selects both crypto and crypto_sha256, but being consistent here helps for usability as well as to avoid potential circular dependencies. This reverts the dependency back to what it was originally before commit 74ca317c26a3f ("kexec: create a new config option CONFIG_KEXEC_FILE for new syscall"), which changed changed it with the comment "This should be safer as "select" is not recursive", but that appears to have been done in error, as "select" is indeed recursive, and there are no other dependencies that prevent CRYPTO_SHA256 from being selected here. Link: https://lkml.kernel.org/r/20231023110308.1202042-2-arnd@kernel.org Fixes: 74ca317c26a3f ("kexec: create a new config option CONFIG_KEXEC_FILE for new syscall") Signed-off-by: Arnd Bergmann Reviewed-by: Eric DeVolder Tested-by: Eric DeVolder Acked-by: Baoquan He Cc: Herbert Xu Cc: "David S. Miller" Cc: Albert Ou Cc: Alexander Gordeev Cc: Ard Biesheuvel Cc: Borislav Petkov Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Conor Dooley Cc: Dave Hansen Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Sven Schnelle Cc: Thomas Gleixner Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- kernel/Kconfig.kexec | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec index 92120e396008..946dffa048b7 100644 --- a/kernel/Kconfig.kexec +++ b/kernel/Kconfig.kexec @@ -36,7 +36,8 @@ config KEXEC config KEXEC_FILE bool "Enable kexec file based system call" depends on ARCH_SUPPORTS_KEXEC_FILE - depends on CRYPTO_SHA256=y || !ARCH_SUPPORTS_KEXEC_PURGATORY + select CRYPTO + select CRYPTO_SHA256 select KEXEC_CORE help This is new version of kexec system call. This system call is -- cgit