Re: [PATCH v4 03/10] kexec_file: factor out arch_kexec_kernel_*() from x86, powerpc

From: AKASHI Takahiro
Date: Fri Oct 06 2017 - 03:04:02 EST

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On Thu, Oct 05, 2017 at 11:21:38AM +0100, Julien Thierry wrote:
> Hi Takahiro,
>
> On 02/10/17 07:14, 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/kernel/kexec_elf_64.c | 2 +-
> > arch/powerpc/kernel/machine_kexec_file_64.c | 36 ++---------------
> > arch/x86/kernel/kexec-bzimage64.c | 2 +-
> > arch/x86/kernel/machine_kexec_64.c | 45 +--------------------
> > include/linux/kexec.h | 15 +++----
> > kernel/kexec_file.c | 63 ++++++++++++++++++++++++++---
> > 6 files changed, 73 insertions(+), 90 deletions(-)
> >
> >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 992c0d258e5d..e7ce78857f0b 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[] = {
> >+const struct kexec_file_ops * const 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/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 2b7590f5483a..c64c29c1fb0e 100644
> >--- a/include/linux/kexec.h
> >+++ b/include/linux/kexec.h
> >@@ -208,7 +208,7 @@ struct kimage {
> > unsigned long cmdline_buf_len;
> > /* File operations provided by image loader */
> >- struct kexec_file_ops *fops;
> >+ const struct kexec_file_ops *fops;
> > /* Image loader handling the kernel can store a pointer here */
> > void *image_loader_data;
> >@@ -276,12 +276,13 @@ 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);
> >+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);
> >+
> > 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..130965b28392 100644
> >--- a/kernel/kexec_file.c
> >+++ b/kernel/kexec_file.c
> >@@ -26,30 +26,83 @@
> > #include <linux/vmalloc.h>
> > #include "kexec_internal.h"
> >+const __weak struct kexec_file_ops * const kexec_file_loaders[] = {NULL};
> >+
> > static int kexec_calculate_store_digests(struct kimage *image);
> >+int _kexec_kernel_image_probe(struct kimage *image, void *buf,
> >+ unsigned long buf_len)
> >+{
> >+ int i, ret = -ENOEXEC;
> >+ const struct kexec_file_ops *fops;
> >+
> >+ for (i = 0; ; i++) {
> >+ fops = kexec_file_loaders[i];
> >+ if (!fops || !fops->probe)
> >+ break;
> >+
>
> Could we have something like:
>
> for (fops = &kexec_file_loaders[0]; fops && fops->probe; ++fops) {
> [...]
> }
>
> And get rid of i? I think it's nicer to have the condition clearly stated in
> the loop.

Okay

I will also fix kbuild errors for x86 & powerpc.

Thanks,
-Takahiro AKASHI

> Thanks,
>
> >+ ret = fops->probe(buf, buf_len);
> >+ if (!ret) {
> >+ image->fops = fops;
> >+ return ret;
> >+ }
> >+ }
> >+
> >+ return ret;
> >+}
> >+
> > /* Architectures can provide this probe function */
> > int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> > unsigned long buf_len)
> > {
> >- return -ENOEXEC;
> >+ return _kexec_kernel_image_probe(image, buf, buf_len);
> >+}
> >+
> >+void *_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);
> > }
> > void * __weak arch_kexec_kernel_image_load(struct kimage *image)
> > {
> >- return ERR_PTR(-ENOEXEC);
> >+ return _kexec_kernel_image_load(image);
> > }
> >-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);
> >+}
> >+
> >+int __weak arch_kexec_kernel_post_load_cleanup(struct kimage *image)
> >+{
> >+ return _kexec_kernel_post_load_cleanup(image);
> > }
> > #ifdef CONFIG_KEXEC_VERIFY_SIG
> >+int _kexec_kernel_verify_sig(struct kimage *image, void *buf,
> >+ unsigned long buf_len)
> >+{
> >+ 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);
> >+}
> >+
> > 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
> >
>
> --
> Julien Thierry

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