Re: [PATCH v3 03/10] kexec_file: factor out arch_kexec_kernel_*() from x86, powerpc

From: Dave Young
Date: Thu Sep 21 2017 - 03:35:36 EST

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Hi AKASHI,
On 09/15/17 at 07:59pm, AKASHI Takahiro wrote:
> arch_kexec_kernel_*() and arch_kimage_file_post_load_cleanup can now be
> duplicated among some architectures, so let's factor them out.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
> Cc: Dave Young <dyoung@xxxxxxxxxx>
> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
> Cc: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/kexec.h | 4 ++
> arch/powerpc/kernel/machine_kexec_file_64.c | 36 ++----------------
> arch/x86/kernel/machine_kexec_64.c | 59 +----------------------------
> include/linux/kexec.h | 26 ++++++++++---
> kernel/kexec_file.c | 52 +++++++++++++++++++------
> 5 files changed, 70 insertions(+), 107 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
> index 25668bc8cb2a..50810d24e38f 100644
> --- a/arch/powerpc/include/asm/kexec.h
> +++ b/arch/powerpc/include/asm/kexec.h
> @@ -94,6 +94,10 @@ static inline bool kdump_in_progress(void)
> #ifdef CONFIG_KEXEC_FILE
> extern struct kexec_file_ops kexec_elf64_ops;
>
> +#define arch_kexec_kernel_image_probe arch_kexec_kernel_image_probe
> +int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> + unsigned long buf_len);
> +
> #ifdef CONFIG_IMA_KEXEC
> #define ARCH_HAS_KIMAGE_ARCH
>
> diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
> index 992c0d258e5d..5b7c4a3fbb50 100644
> --- a/arch/powerpc/kernel/machine_kexec_file_64.c
> +++ b/arch/powerpc/kernel/machine_kexec_file_64.c
> @@ -31,8 +31,9 @@
>
> #define SLAVE_CODE_SIZE 256
>
> -static struct kexec_file_ops *kexec_file_loaders[] = {
> +struct kexec_file_ops *kexec_file_loaders[] = {
> &kexec_elf64_ops,
> + NULL
> };
>
> int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> @@ -45,38 +46,7 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> if (image->type == KEXEC_TYPE_CRASH)
> return -ENOTSUPP;
>
> - for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
> - fops = kexec_file_loaders[i];
> - if (!fops || !fops->probe)
> - continue;
> -
> - ret = fops->probe(buf, buf_len);
> - if (!ret) {
> - image->fops = fops;
> - return ret;
> - }
> - }
> -
> - return ret;
> -}
> -
> -void *arch_kexec_kernel_image_load(struct kimage *image)
> -{
> - if (!image->fops || !image->fops->load)
> - return ERR_PTR(-ENOEXEC);
> -
> - return image->fops->load(image, image->kernel_buf,
> - image->kernel_buf_len, image->initrd_buf,
> - image->initrd_buf_len, image->cmdline_buf,
> - image->cmdline_buf_len);
> -}
> -
> -int arch_kimage_file_post_load_cleanup(struct kimage *image)
> -{
> - if (!image->fops || !image->fops->cleanup)
> - return 0;
> -
> - return image->fops->cleanup(image->image_loader_data);
> + return kexec_kernel_image_probe(image, buf, buf_len);
> }
>
> /**
> diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> index cb0a30473c23..f4df8315d001 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -30,8 +30,9 @@
> #include <asm/set_memory.h>
>
> #ifdef CONFIG_KEXEC_FILE
> -static struct kexec_file_ops *kexec_file_loaders[] = {
> +struct kexec_file_ops *kexec_file_loaders[] = {
> &kexec_bzImage64_ops,
> + NULL
> };
> #endif
>
> @@ -361,62 +362,6 @@ void arch_crash_save_vmcoreinfo(void)
> /* arch-dependent functionality related to kexec file-based syscall */
>
> #ifdef CONFIG_KEXEC_FILE
> -int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> - unsigned long buf_len)
> -{
> - int i, ret = -ENOEXEC;
> - struct kexec_file_ops *fops;
> -
> - for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
> - fops = kexec_file_loaders[i];
> - if (!fops || !fops->probe)
> - continue;
> -
> - ret = fops->probe(buf, buf_len);
> - if (!ret) {
> - image->fops = fops;
> - return ret;
> - }
> - }
> -
> - return ret;
> -}
> -
> -void *arch_kexec_kernel_image_load(struct kimage *image)
> -{
> - vfree(image->arch.elf_headers);
> - image->arch.elf_headers = NULL;
> -
> - if (!image->fops || !image->fops->load)
> - return ERR_PTR(-ENOEXEC);
> -
> - return image->fops->load(image, image->kernel_buf,
> - image->kernel_buf_len, image->initrd_buf,
> - image->initrd_buf_len, image->cmdline_buf,
> - image->cmdline_buf_len);
> -}
> -
> -int arch_kimage_file_post_load_cleanup(struct kimage *image)
> -{
> - if (!image->fops || !image->fops->cleanup)
> - return 0;
> -
> - return image->fops->cleanup(image->image_loader_data);
> -}
> -
> -#ifdef CONFIG_KEXEC_VERIFY_SIG
> -int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
> - unsigned long kernel_len)
> -{
> - if (!image->fops || !image->fops->verify_sig) {
> - pr_debug("kernel loader does not support signature verification.");
> - return -EKEYREJECTED;
> - }
> -
> - return image->fops->verify_sig(kernel, kernel_len);
> -}
> -#endif
> -
> /*
> * Apply purgatory relocations.
> *
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index dd056fab9e35..4a2b24d94e04 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -134,6 +134,26 @@ struct kexec_file_ops {
> #endif
> };
>
> +int kexec_kernel_image_probe(struct kimage *image, void *buf,
> + unsigned long buf_len);
> +void *kexec_kernel_image_load(struct kimage *image);
> +int kexec_kernel_post_load_cleanup(struct kimage *image);
> +int kexec_kernel_verify_sig(struct kimage *image, void *buf,
> + unsigned long buf_len);
> +
> +#ifndef arch_kexec_kernel_image_probe
> +#define arch_kexec_kernel_image_probe kexec_kernel_image_probe
> +#endif
> +#ifndef arch_kexec_kernel_image_load
> +#define arch_kexec_kernel_image_load kexec_kernel_image_load
> +#endif
> +#ifndef arch_kimage_file_post_load_cleanup
> +#define arch_kimage_file_post_load_cleanup kexec_kernel_post_load_cleanup
> +#endif
> +#ifndef arch_kexec_kernel_verify_sig
> +#define arch_kexec_kernel_verify_sig kexec_kernel_verify_sig
> +#endif
> +
> /**
> * struct kexec_buf - parameters for finding a place for a buffer in memory
> * @image: kexec image in which memory to search.
> @@ -276,12 +296,6 @@ int crash_shrink_memory(unsigned long new_size);
> size_t crash_get_memory_size(void);
> void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
>
> -int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> - unsigned long buf_len);
> -void * __weak arch_kexec_kernel_image_load(struct kimage *image);
> -int __weak arch_kimage_file_post_load_cleanup(struct kimage *image);
> -int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
> - unsigned long buf_len);

I thought we can keep using the __weak function in common code and drop
the arch functions, no need the #ifndef arch_kexec_kernel_image_probe
and the function renaming stuff. But I did not notice the powerpc
_probe function checks KEXEC_ON_CRASH, that should be checked earlier
and we can fail out early if not supported, but I have no idea
how to do it gracefully for now.

Also for x86 _load function it cleanups image->arch.elf_headers, it can
not be dropped simply.

Consider the above two issues, maybe you can keep the powerpc
version of _probe() and x86 version of _load(), and still copy the common code
to kexec_file.c weak functions. I can post patch to cleanup the x86
_load function in the future.

> int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
> Elf_Shdr *sechdrs, unsigned int relsec);
> int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 9f48f4412297..6203b54e04c5 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -26,30 +26,60 @@
> #include <linux/vmalloc.h>
> #include "kexec_internal.h"
>
> +__weak struct kexec_file_ops *kexec_file_loaders[] = {NULL};
> +
> static int kexec_calculate_store_digests(struct kimage *image);
>
> -/* Architectures can provide this probe function */
> -int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> - unsigned long buf_len)
> +int kexec_kernel_image_probe(struct kimage *image, void *buf,
> + unsigned long buf_len)
> {
> - return -ENOEXEC;
> + int i, ret = -ENOEXEC;
> + struct kexec_file_ops *fops;
> +
> + for (i = 0; ; i++) {
> + fops = kexec_file_loaders[i];
> + if (!fops || !fops->probe)
> + break;
> +
> + ret = fops->probe(buf, buf_len);
> + if (!ret) {
> + image->fops = fops;
> + return ret;
> + }
> + }
> +
> + return ret;
> }
>
> -void * __weak arch_kexec_kernel_image_load(struct kimage *image)
> +void *kexec_kernel_image_load(struct kimage *image)
> {
> - return ERR_PTR(-ENOEXEC);
> + if (!image->fops || !image->fops->load)
> + return ERR_PTR(-ENOEXEC);
> +
> + return image->fops->load(image, image->kernel_buf,
> + image->kernel_buf_len, image->initrd_buf,
> + image->initrd_buf_len, image->cmdline_buf,
> + image->cmdline_buf_len);
> }
>
> -int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
> +int kexec_kernel_post_load_cleanup(struct kimage *image)
> {
> - return -EINVAL;
> + if (!image->fops || !image->fops->cleanup)
> + return 0;
> +
> + return image->fops->cleanup(image->image_loader_data);
> }
>
> #ifdef CONFIG_KEXEC_VERIFY_SIG
> -int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
> - unsigned long buf_len)
> +int kexec_kernel_verify_sig(struct kimage *image, void *buf,
> + unsigned long buf_len)
> {
> - return -EKEYREJECTED;
> + if (!image->fops || !image->fops->verify_sig) {
> + pr_debug("kernel loader does not support signature verification.\n");
> + return -EKEYREJECTED;
> + }
> +
> + return image->fops->verify_sig(buf, buf_len);
> }
> #endif
>
> --
> 2.14.1
>
>
> _______________________________________________
> kexec mailing list
> kexec@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/kexec

Thanks
Dave

Next message: Hannes Reinecke: "Re: [PATCH v2 18/31] scsi/aic7xxx: Clean up timer usage"
Previous message: Martin Steigerwald: "Re: I/O hangs after resuming from suspend-to-ram"
Next in thread: AKASHI Takahiro: "Re: [PATCH v3 03/10] kexec_file: factor out arch_kexec_kernel_*() from x86, powerpc"
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