Re: [PATCH 2/7] kexec_file,x86,powerpc: factor out kexec_file_ops functions

From: AKASHI Takahiro
Date: Fri Mar 02 2018 - 00:24:46 EST

On Fri, Mar 02, 2018 at 01:04:26PM +0800, Dave Young wrote:
> On 02/27/18 at 01:48pm, AKASHI Takahiro wrote:
> > As arch_kexec_kernel_image_{probe,load}(),
> > arch_kimage_file_post_load_cleanup() and arch_kexec_kernel_verify_sig()
> > are almost duplicated among architectures, they can be commonalized with
> > an architecture-defined kexec_file_ops array. 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 | 2 +-
> > arch/powerpc/kernel/kexec_elf_64.c | 2 +-
> > arch/powerpc/kernel/machine_kexec_file_64.c | 39 ++------------------
> > arch/x86/include/asm/kexec-bzimage64.h | 2 +-
> > arch/x86/kernel/kexec-bzimage64.c | 2 +-
> > arch/x86/kernel/machine_kexec_64.c | 45 ++---------------------
> > include/linux/kexec.h | 17 +++++----
> > kernel/kexec_file.c | 55 ++++++++++++++++++++++++++---
> > 8 files changed, 70 insertions(+), 94 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
> > index d8b1e8e7e035..4a585cba1787 100644
> > --- a/arch/powerpc/include/asm/kexec.h
> > +++ b/arch/powerpc/include/asm/kexec.h
> > @@ -95,7 +95,7 @@ static inline bool kdump_in_progress(void)
> > }
> >
> > #ifdef CONFIG_KEXEC_FILE
> > -extern struct kexec_file_ops kexec_elf64_ops;
> > +extern const struct kexec_file_ops kexec_elf64_ops;
> >
> > #ifdef CONFIG_IMA_KEXEC
> > #define ARCH_HAS_KIMAGE_ARCH
> > diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c
> > index 9a42309b091a..6c78c11c7faf 100644
> > --- a/arch/powerpc/kernel/kexec_elf_64.c
> > +++ b/arch/powerpc/kernel/kexec_elf_64.c
> > @@ -657,7 +657,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
> > return ret ? ERR_PTR(ret) : fdt;
> > }
> >
> > -struct kexec_file_ops kexec_elf64_ops = {
> > +const struct kexec_file_ops kexec_elf64_ops = {
> > .probe = elf64_probe,
> > .load = elf64_load,
> > };
> > diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
> > index e4395f937d63..a27ec647350c 100644
> > --- a/arch/powerpc/kernel/machine_kexec_file_64.c
> > +++ b/arch/powerpc/kernel/machine_kexec_file_64.c
> > @@ -31,52 +31,19 @@
> >
> > #define SLAVE_CODE_SIZE 256
> >
> > -static struct kexec_file_ops *kexec_file_loaders[] = {
> > +const struct kexec_file_ops * const kexec_file_loaders[] = {
> > &kexec_elf64_ops,
> > + NULL
> > };
> >
> > int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> > unsigned long buf_len)
> > {
> > - int i, ret = -ENOEXEC;
> > - struct kexec_file_ops *fops;
> > -
> > /* We don't support crash kernels yet. */
> > 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/include/asm/kexec-bzimage64.h b/arch/x86/include/asm/kexec-bzimage64.h
> > index 9f07cff43705..df89ee7d3e9e 100644
> > --- a/arch/x86/include/asm/kexec-bzimage64.h
> > +++ b/arch/x86/include/asm/kexec-bzimage64.h
> > @@ -2,6 +2,6 @@
> > #ifndef _ASM_KEXEC_BZIMAGE64_H
> > #define _ASM_KEXEC_BZIMAGE64_H
> >
> > -extern struct kexec_file_ops kexec_bzImage64_ops;
> > +extern const struct kexec_file_ops kexec_bzImage64_ops;
> >
> > #endif /* _ASM_KEXE_BZIMAGE64_H */
> > diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
> > index fb095ba0c02f..705654776c0c 100644
> > --- a/arch/x86/kernel/kexec-bzimage64.c
> > +++ b/arch/x86/kernel/kexec-bzimage64.c
> > @@ -538,7 +538,7 @@ static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
> > }
> > #endif
> >
> > -struct kexec_file_ops kexec_bzImage64_ops = {
> > +const struct kexec_file_ops kexec_bzImage64_ops = {
> > .probe = bzImage64_probe,
> > .load = bzImage64_load,
> > .cleanup = bzImage64_cleanup,
> > diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> > index 1f790cf9d38f..2cdd29d64181 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[] = {
> > +const struct kexec_file_ops * const kexec_file_loaders[] = {
> > &kexec_bzImage64_ops,
> > + NULL
> > };
> > #endif
> >
> > @@ -363,27 +364,6 @@ 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);
> > @@ -398,27 +378,6 @@ void *arch_kexec_kernel_image_load(struct kimage *image)
> > 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 f16f6ceb3875..2e095c3b4537 100644
> > --- a/include/linux/kexec.h
> > +++ b/include/linux/kexec.h
> > @@ -159,6 +159,15 @@ struct kexec_buf {
> > bool top_down;
> > };
> >
> > +extern const struct kexec_file_ops * const kexec_file_loaders[];
> > +
> > +int _kexec_kernel_image_probe(struct kimage *image, void *buf,
> > + unsigned long buf_len);
> > +void *_kexec_kernel_image_load(struct kimage *image);
> > +int _kimage_file_post_load_cleanup(struct kimage *image);
> > +int _kexec_kernel_verify_sig(struct kimage *image, void *buf,
> > + unsigned long buf_len);
>
> AKASHI, since the above 3 functions nobody else used, suppose it is for
> future use, they can be made static for now. Later if someone needs
> they can remove the static easily.

OK.
May I change those names, for example, to kexec_kernel_image_probe_default()
and so on? I don't like to export _XYZ as a global symbol.

-Takahiro AKASHI



> > +}
> > +
> > int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
> > unsigned long buf_len)
> > {
> > - return -EKEYREJECTED;
> > + return _kexec_kernel_verify_sig(image, buf, buf_len);
> > }
> > #endif
> >
> > --
> > 2.16.2
> >
>
> Thanks
> Dave