Re: [PATCH 1/2] kexec: fix KEXEC_FILE dependencies

Eric DeVolder
2023-11-30T20:54:30Z

On 11/30/23 10:56, Andrew Morton wrote:
> On Thu, 2 Nov 2023 16:03:18 +0800 Baoquan He <bhe@redhat.com> wrote:
>
>>>> CONFIG_KEXEC_FILE, but still get purgatory code built in which is
>>>> totally useless.
>>>>
>>>> Not sure if I think too much over this.
>>> I see your point here, and I would suggest changing the
>>> CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY symbol to just indicate
>>> the availability of the purgatory code for the arch, rather
>>> than actually controlling the code itself. I already mentioned
>>> this for s390, but riscv would need the same thing on top.
>>>
>>> I think the change below should address your concern.
>> Since no new comment, do you mind spinning v2 to wrap all these up?
> This patchset remains in mm-hotfixes-unstable from the previous -rc
> cycle. Eric, do you have any comments? Arnd, do you plan on a v2? If
> not, should I merge v1? If so, should I now add cc:stable?

My apologies, I lost this. I've looked at these changes, and I am in
favor of these changes.

Furthermore, I ran the following thru the Kconfig regression script, and
did not find anything!

I believe the following patch represents the current discussion threads
around Kconfig and KEXEC/CRASH.

Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>

Tested-by: Eric DeVolder <eric_devolder@yahoo.com>

Thanks!

eric

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 6f105ee4f3cf..1f11a62809f2 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -608,10 +608,10 @@ config ARCH_SUPPORTS_KEXEC
def_bool PPC_BOOK3S || PPC_E500 || (44x && !SMP)

config ARCH_SUPPORTS_KEXEC_FILE
-    def_bool PPC64 && CRYPTO=y && CRYPTO_SHA256=y
+    def_bool PPC64

config ARCH_SUPPORTS_KEXEC_PURGATORY
-    def_bool KEXEC_FILE
+    def_bool y

config ARCH_SELECTS_KEXEC_FILE
def_bool y
diff --git a/arch/riscv/Kbuild b/arch/riscv/Kbuild
index d25ad1c19f88..ab181d187c23 100644
--- a/arch/riscv/Kbuild
+++ b/arch/riscv/Kbuild
@@ -5,7 +5,7 @@ obj-$(CONFIG_BUILTIN_DTB) += boot/dts/
obj-y += errata/
obj-$(CONFIG_KVM) += kvm/

-obj-$(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) += purgatory/
+obj-$(CONFIG_KEXEC_FILE) += purgatory/

# for cleaning
subdir- += boot
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 95a2a06acc6a..98857d76e458 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -702,9 +702,7 @@ config ARCH_SELECTS_KEXEC_FILE
select KEXEC_ELF

config ARCH_SUPPORTS_KEXEC_PURGATORY
-    def_bool KEXEC_FILE
-    depends on CRYPTO=y
-    depends on CRYPTO_SHA256=y
+    def_bool y

config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
index e60fbd8660c4..3ac341d296db 100644
--- a/arch/riscv/kernel/elf_kexec.c
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -266,7 +266,7 @@ static void *elf_kexec_load(struct kimage *image,
char *kernel_buf,
cmdline = modified_cmdline;
}

-#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
+#ifdef CONFIG_KEXEC_FILE
/* Add purgatory to the image */
kbuf.top_down = true;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
@@ -280,7 +280,7 @@ static void *elf_kexec_load(struct kimage *image,
char *kernel_buf,
sizeof(kernel_start), 0);
if (ret)
pr_err("Error update purgatory ret=%d\n", ret);
-#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */
+#endif /* CONFIG_KEXEC_FILE */

/* Add the initrd to the image */
if (initrd != NULL) {
diff --git a/arch/s390/Kbuild b/arch/s390/Kbuild
index a5d3503b353c..f2ce80b65551 100644
--- a/arch/s390/Kbuild
+++ b/arch/s390/Kbuild
@@ -7,7 +7,7 @@ obj-$(CONFIG_S390_HYPFS)    += hypfs/
obj-$(CONFIG_APPLDATA_BASE)    += appldata/
obj-y                += net/
obj-$(CONFIG_PCI)        += pci/
-obj-$(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY) += purgatory/
+obj-$(CONFIG_KEXEC_FILE) += purgatory/

# for cleaning
subdir- += boot tools
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 3bec98d20283..d5d8f99d1f25 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -254,13 +254,13 @@ config ARCH_SUPPORTS_KEXEC
def_bool y

config ARCH_SUPPORTS_KEXEC_FILE
-    def_bool CRYPTO && CRYPTO_SHA256 && CRYPTO_SHA256_S390
+    def_bool y

config ARCH_SUPPORTS_KEXEC_SIG
def_bool MODULE_SIG_FORMAT

config ARCH_SUPPORTS_KEXEC_PURGATORY
-    def_bool KEXEC_FILE
+    def_bool y

config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3762f41bb092..1566748f16c4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2072,7 +2072,7 @@ config ARCH_SUPPORTS_KEXEC
def_bool y

config ARCH_SUPPORTS_KEXEC_FILE
-    def_bool X86_64 && CRYPTO && CRYPTO_SHA256
+    def_bool X86_64

config ARCH_SELECTS_KEXEC_FILE
def_bool y
@@ -2080,7 +2080,7 @@ config ARCH_SELECTS_KEXEC_FILE
select HAVE_IMA_KEXEC if IMA

config ARCH_SUPPORTS_KEXEC_PURGATORY
-    def_bool KEXEC_FILE
+    def_bool y

config ARCH_SUPPORTS_KEXEC_SIG
def_bool y
diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 7aff28ded2f4..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
@@ -94,10 +95,8 @@ config KEXEC_JUMP
config CRASH_DUMP
bool "kernel crash dumps"
depends on ARCH_SUPPORTS_CRASH_DUMP
-    depends on ARCH_SUPPORTS_KEXEC
select CRASH_CORE
select KEXEC_CORE
-    select KEXEC
help
Generate crash dump after being started by kexec.
This should be normally only set in special crash dump kernels