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

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

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@linaro.org>
> >Cc: Dave Young <dyoung@redhat.com>
> >Cc: Vivek Goyal <vgoyal@redhat.com>
> >Cc: Baoquan He <bhe@redhat.com>
> >Cc: Michael Ellerman <mpe@ellerman.id.au>
> >Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
> >---
> >  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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