[PATCH v3 00/10] arm64: kexec: add kexec_file_load() support

[PATCH v3 00/10] arm64: kexec: add kexec_file_load() support

[AKASHI Takahiro]

This is the third round of implementing kexec_file_load() support
on arm64.[1]
Most of the code is based on kexec-tools (along with some kernel code
from x86, which also came from kexec-tools).


This patch series enables us to
  * load the kernel, Image, with kexec_file_load system call, and
  * optionally verify its signature at load time for trusted boot.

To load the kernel via kexec_file_load system call, a small change
is also needed to kexec-tools. See [2]. This enables '-s' option.

As we discussed a long time ago, users may not be allowed to specify
device-tree file of the 2nd kernel explicitly with kexec-tools, hence
re-using the blob of the first kernel.

Regarding a signing method, we conform with x86 (or rather Microsoft?)
style of signing since the binary can also be seen as in PE format
(assuming that CONFIG_EFI is enabled).

    Powerpc is also going to support extended-file-attribute-based
    verification[3] with vmlinux, but arm64 doesn't for now partly
    because we don't have TPM-based IMA at this moment.

Accordingly, we can use the existing command, sbsign, to sign the kernel.

    $ sbsign --key ${KEY} --cert ${CERT} Image

Please note that it is totally up to the system what key/certificate is
used for signing, but one of easy ways to *try* this feature is to turn on
CONFIG_MODULE_SIG so that we can reuse certs/signing_key.pem as a signing
key, KEY and CERT above, for kernel.
(This also enables CONFIG_CRYPTO_SHA1 by default.)


Some concerns(or future works):
* Even if the kernel is configured with CONFIG_RANDOMIZE_BASE, the 2nd
  kernel won't be placed at a randomized address. We will have to
  add some boot code similar to efi-stub to implement the feature.
* While big-endian kernel can support kernel signing, I'm not sure that
  Image can be recognized as in PE format because x86 standard only
  defines little-endian-based format.
* IMA(and extended file attribute)-based kexec
* vmlinux support

  [1] http://git.linaro.org/people/takahiro.akashi/linux-aarch64.git
	branch:arm64/kexec_file
  [2] http://git.linaro.org/people/takahiro.akashi/kexec-tools.git
	branch:arm64/kexec_file
  [3] http://lkml.iu.edu//hypermail/linux/kernel/1707.0/03669.html


Changes in v3 (Sep 15, 2017)
* fix kbuild test error
* factor out arch_kexec_kernel_*() & arch_kimage_file_post_load_cleanup()
* remove CONFIG_CRASH_CORE guard from kexec_file.c
* add vmapped kernel region to vmcore for gdb backtracing
  (see prepare_elf64_headers())
* merge asm/kexec_file.h into asm/kexec.h
* and some cleanups

Changes in v2 (Sep 8, 2017)
* move core-header-related functions from crash_core.c to kexec_file.c
* drop hash-check code from purgatory
* modify purgatory asm to remove arch_kexec_apply_relocations_add()
* drop older kernel support
* drop vmlinux support (at least, for this series)

Patch #1 to #5 are all preparatory patches on generic side.
Patch #6 is purgatory code.
Patch #7 to #9 are common for enabling kexec_file_load.
Patch #10 is for 'Image' support.

AKASHI Takahiro (10):
  include: pe.h: remove message[] from mz header definition
  resource: add walk_system_ram_res_rev()
  kexec_file: factor out arch_kexec_kernel_*() from x86, powerpc
  kexec_file: factor out crashdump elf header function from x86
  asm-generic: add kexec_file_load system call to unistd.h
  arm64: kexec_file: create purgatory
  arm64: kexec_file: load initrd, device-tree and purgatory segments
  arm64: kexec_file: set up for crash dump adding elf core header
  arm64: enable KEXEC_FILE config
  arm64: kexec_file: add Image format support

 arch/arm64/Kconfig                          |  29 +++
 arch/arm64/Makefile                         |   1 +
 arch/arm64/include/asm/kexec.h              |  93 +++++++
 arch/arm64/kernel/Makefile                  |   4 +-
 arch/arm64/kernel/kexec_image.c             | 105 ++++++++
 arch/arm64/kernel/machine_kexec_file.c      | 365 ++++++++++++++++++++++++++++
 arch/arm64/purgatory/Makefile               |  24 ++
 arch/arm64/purgatory/entry.S                |  55 +++++
 arch/powerpc/include/asm/kexec.h            |   4 +
 arch/powerpc/kernel/machine_kexec_file_64.c |  36 +--
 arch/x86/kernel/crash.c                     | 324 ------------------------
 arch/x86/kernel/machine_kexec_64.c          |  59 +----
 include/linux/ioport.h                      |   3 +
 include/linux/kexec.h                       |  43 +++-
 include/linux/pe.h                          |   2 +-
 include/uapi/asm-generic/unistd.h           |   4 +-
 kernel/kexec_file.c                         | 360 ++++++++++++++++++++++++++-
 kernel/kexec_internal.h                     |  20 ++
 kernel/resource.c                           |  59 +++++
 19 files changed, 1156 insertions(+), 434 deletions(-)
 create mode 100644 arch/arm64/kernel/kexec_image.c
 create mode 100644 arch/arm64/kernel/machine_kexec_file.c
 create mode 100644 arch/arm64/purgatory/Makefile
 create mode 100644 arch/arm64/purgatory/entry.S

-- 
2.14.1

[PATCH v3 01/10] include: pe.h: remove message[] from mz header definition

[AKASHI Takahiro]

message[] field won't be part of the definition of mz header.

This change is crucial for enabling kexec_file_load on arm64 because
arm64's "Image" binary, as in PE format, doesn't have any data for it and
accordingly the following check in pefile_parse_binary() will fail:

	chkaddr(cursor, mz->peaddr, sizeof(*pe));

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David S. Miller <davem@davemloft.net>
---
 include/linux/pe.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/pe.h b/include/linux/pe.h
index 143ce75be5f0..3482b18a48b5 100644
--- a/include/linux/pe.h
+++ b/include/linux/pe.h
@@ -166,7 +166,7 @@ struct mz_hdr {
 	uint16_t oem_info;	/* oem specific */
 	uint16_t reserved1[10];	/* reserved */
 	uint32_t peaddr;	/* address of pe header */
-	char     message[64];	/* message to print */
+	char     message[];	/* message to print */
 };
 
 struct mz_reloc {
-- 
2.14.1

[PATCH v3 02/10] resource: add walk_system_ram_res_rev()

[AKASHI Takahiro]

This function, being a variant of walk_system_ram_res() introduced in
commit 8c86e70acead ("resource: provide new functions to walk through
resources"), walks through a list of all the resources of System RAM
in reversed order, i.e., from higher to lower.

It will be used in kexec_file implementation on arm64.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/linux/ioport.h |  3 +++
 kernel/resource.c      | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 6230064d7f95..9a212266299f 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -271,6 +271,9 @@ extern int
 walk_system_ram_res(u64 start, u64 end, void *arg,
 		    int (*func)(u64, u64, void *));
 extern int
+walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+			int (*func)(u64, u64, void *));
+extern int
 walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
 		    void *arg, int (*func)(u64, u64, void *));
 
diff --git a/kernel/resource.c b/kernel/resource.c
index 9b5f04404152..572f2f91ce9c 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -23,6 +23,8 @@
 #include <linux/pfn.h>
 #include <linux/mm.h>
 #include <linux/resource_ext.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
 #include <asm/io.h>
 
 
@@ -469,6 +471,63 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
 	return ret;
 }
 
+int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
+				int (*func)(u64, u64, void *))
+{
+	struct resource res, *rams;
+	u64 orig_end;
+	int count, i;
+	int ret = -1;
+
+	count = 16; /* initial */
+
+	/* create a list */
+	rams = vmalloc(sizeof(struct resource) * count);
+	if (!rams)
+		return ret;
+
+	res.start = start;
+	res.end = end;
+	res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	orig_end = res.end;
+	i = 0;
+	while ((res.start < res.end) &&
+		(!find_next_iomem_res(&res, IORES_DESC_NONE, true))) {
+		if (i >= count) {
+			/* re-alloc */
+			struct resource *rams_new;
+			int count_new;
+
+			count_new = count + 16;
+			rams_new = vmalloc(sizeof(struct resource) * count_new);
+			if (!rams_new)
+				goto out;
+
+			memcpy(rams_new, rams, count);
+			vfree(rams);
+			rams = rams_new;
+			count = count_new;
+		}
+
+		rams[i].start = res.start;
+		rams[i++].end = res.end;
+
+		res.start = res.end + 1;
+		res.end = orig_end;
+	}
+
+	/* go reverse */
+	for (i--; i >= 0; i--) {
+		ret = (*func)(rams[i].start, rams[i].end, arg);
+		if (ret)
+			break;
+	}
+
+out:
+	vfree(rams);
+	return ret;
+}
+
 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 
 /*
-- 
2.14.1

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

[AKASHI Takahiro]

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/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);
 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

[PATCH v3 04/10] kexec_file: factor out crashdump elf header function from x86

[AKASHI Takahiro]

prepare_elf_headers() can also be useful for other architectures,
including arm64. So let it factored 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>
---
 arch/x86/kernel/crash.c | 324 ------------------------------------------------
 include/linux/kexec.h   |  17 +++
 kernel/kexec_file.c     | 308 +++++++++++++++++++++++++++++++++++++++++++++
 kernel/kexec_internal.h |  20 +++
 4 files changed, 345 insertions(+), 324 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 44404e2307bb..3c6b880f6dbf 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -21,7 +21,6 @@
 #include <linux/elf.h>
 #include <linux/elfcore.h>
 #include <linux/export.h>
-#include <linux/slab.h>
 #include <linux/vmalloc.h>
 
 #include <asm/processor.h>
@@ -41,34 +40,6 @@
 /* Alignment required for elf header segment */
 #define ELF_CORE_HEADER_ALIGN   4096
 
-/* This primarily represents number of split ranges due to exclusion */
-#define CRASH_MAX_RANGES	16
-
-struct crash_mem_range {
-	u64 start, end;
-};
-
-struct crash_mem {
-	unsigned int nr_ranges;
-	struct crash_mem_range ranges[CRASH_MAX_RANGES];
-};
-
-/* Misc data about ram ranges needed to prepare elf headers */
-struct crash_elf_data {
-	struct kimage *image;
-	/*
-	 * Total number of ram ranges we have after various adjustments for
-	 * crash reserved region, etc.
-	 */
-	unsigned int max_nr_ranges;
-
-	/* Pointer to elf header */
-	void *ehdr;
-	/* Pointer to next phdr */
-	void *bufp;
-	struct crash_mem mem;
-};
-
 /* Used while preparing memory map entries for second kernel */
 struct crash_memmap_data {
 	struct boot_params *params;
@@ -209,301 +180,6 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 }
 
 #ifdef CONFIG_KEXEC_FILE
-static int get_nr_ram_ranges_callback(u64 start, u64 end, void *arg)
-{
-	unsigned int *nr_ranges = arg;
-
-	(*nr_ranges)++;
-	return 0;
-}
-
-
-/* Gather all the required information to prepare elf headers for ram regions */
-static void fill_up_crash_elf_data(struct crash_elf_data *ced,
-				   struct kimage *image)
-{
-	unsigned int nr_ranges = 0;
-
-	ced->image = image;
-
-	walk_system_ram_res(0, -1, &nr_ranges,
-				get_nr_ram_ranges_callback);
-
-	ced->max_nr_ranges = nr_ranges;
-
-	/* Exclusion of crash region could split memory ranges */
-	ced->max_nr_ranges++;
-
-	/* If crashk_low_res is not 0, another range split possible */
-	if (crashk_low_res.end)
-		ced->max_nr_ranges++;
-}
-
-static int exclude_mem_range(struct crash_mem *mem,
-		unsigned long long mstart, unsigned long long mend)
-{
-	int i, j;
-	unsigned long long start, end;
-	struct crash_mem_range temp_range = {0, 0};
-
-	for (i = 0; i < mem->nr_ranges; i++) {
-		start = mem->ranges[i].start;
-		end = mem->ranges[i].end;
-
-		if (mstart > end || mend < start)
-			continue;
-
-		/* Truncate any area outside of range */
-		if (mstart < start)
-			mstart = start;
-		if (mend > end)
-			mend = end;
-
-		/* Found completely overlapping range */
-		if (mstart == start && mend == end) {
-			mem->ranges[i].start = 0;
-			mem->ranges[i].end = 0;
-			if (i < mem->nr_ranges - 1) {
-				/* Shift rest of the ranges to left */
-				for (j = i; j < mem->nr_ranges - 1; j++) {
-					mem->ranges[j].start =
-						mem->ranges[j+1].start;
-					mem->ranges[j].end =
-							mem->ranges[j+1].end;
-				}
-			}
-			mem->nr_ranges--;
-			return 0;
-		}
-
-		if (mstart > start && mend < end) {
-			/* Split original range */
-			mem->ranges[i].end = mstart - 1;
-			temp_range.start = mend + 1;
-			temp_range.end = end;
-		} else if (mstart != start)
-			mem->ranges[i].end = mstart - 1;
-		else
-			mem->ranges[i].start = mend + 1;
-		break;
-	}
-
-	/* If a split happend, add the split to array */
-	if (!temp_range.end)
-		return 0;
-
-	/* Split happened */
-	if (i == CRASH_MAX_RANGES - 1) {
-		pr_err("Too many crash ranges after split\n");
-		return -ENOMEM;
-	}
-
-	/* Location where new range should go */
-	j = i + 1;
-	if (j < mem->nr_ranges) {
-		/* Move over all ranges one slot towards the end */
-		for (i = mem->nr_ranges - 1; i >= j; i--)
-			mem->ranges[i + 1] = mem->ranges[i];
-	}
-
-	mem->ranges[j].start = temp_range.start;
-	mem->ranges[j].end = temp_range.end;
-	mem->nr_ranges++;
-	return 0;
-}
-
-/*
- * Look for any unwanted ranges between mstart, mend and remove them. This
- * might lead to split and split ranges are put in ced->mem.ranges[] array
- */
-static int elf_header_exclude_ranges(struct crash_elf_data *ced,
-		unsigned long long mstart, unsigned long long mend)
-{
-	struct crash_mem *cmem = &ced->mem;
-	int ret = 0;
-
-	memset(cmem->ranges, 0, sizeof(cmem->ranges));
-
-	cmem->ranges[0].start = mstart;
-	cmem->ranges[0].end = mend;
-	cmem->nr_ranges = 1;
-
-	/* Exclude crashkernel region */
-	ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
-	if (ret)
-		return ret;
-
-	if (crashk_low_res.end) {
-		ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
-		if (ret)
-			return ret;
-	}
-
-	return ret;
-}
-
-static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
-{
-	struct crash_elf_data *ced = arg;
-	Elf64_Ehdr *ehdr;
-	Elf64_Phdr *phdr;
-	unsigned long mstart, mend;
-	struct kimage *image = ced->image;
-	struct crash_mem *cmem;
-	int ret, i;
-
-	ehdr = ced->ehdr;
-
-	/* Exclude unwanted mem ranges */
-	ret = elf_header_exclude_ranges(ced, start, end);
-	if (ret)
-		return ret;
-
-	/* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
-	cmem = &ced->mem;
-
-	for (i = 0; i < cmem->nr_ranges; i++) {
-		mstart = cmem->ranges[i].start;
-		mend = cmem->ranges[i].end;
-
-		phdr = ced->bufp;
-		ced->bufp += sizeof(Elf64_Phdr);
-
-		phdr->p_type = PT_LOAD;
-		phdr->p_flags = PF_R|PF_W|PF_X;
-		phdr->p_offset  = mstart;
-
-		/*
-		 * If a range matches backup region, adjust offset to backup
-		 * segment.
-		 */
-		if (mstart == image->arch.backup_src_start &&
-		    (mend - mstart + 1) == image->arch.backup_src_sz)
-			phdr->p_offset = image->arch.backup_load_addr;
-
-		phdr->p_paddr = mstart;
-		phdr->p_vaddr = (unsigned long long) __va(mstart);
-		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
-		phdr->p_align = 0;
-		ehdr->e_phnum++;
-		pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
-			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
-			ehdr->e_phnum, phdr->p_offset);
-	}
-
-	return ret;
-}
-
-static int prepare_elf64_headers(struct crash_elf_data *ced,
-		void **addr, unsigned long *sz)
-{
-	Elf64_Ehdr *ehdr;
-	Elf64_Phdr *phdr;
-	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
-	unsigned char *buf, *bufp;
-	unsigned int cpu;
-	unsigned long long notes_addr;
-	int ret;
-
-	/* extra phdr for vmcoreinfo elf note */
-	nr_phdr = nr_cpus + 1;
-	nr_phdr += ced->max_nr_ranges;
-
-	/*
-	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
-	 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
-	 * I think this is required by tools like gdb. So same physical
-	 * memory will be mapped in two elf headers. One will contain kernel
-	 * text virtual addresses and other will have __va(physical) addresses.
-	 */
-
-	nr_phdr++;
-	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
-	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
-
-	buf = vzalloc(elf_sz);
-	if (!buf)
-		return -ENOMEM;
-
-	bufp = buf;
-	ehdr = (Elf64_Ehdr *)bufp;
-	bufp += sizeof(Elf64_Ehdr);
-	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
-	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
-	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
-	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
-	ehdr->e_ident[EI_OSABI] = ELF_OSABI;
-	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
-	ehdr->e_type = ET_CORE;
-	ehdr->e_machine = ELF_ARCH;
-	ehdr->e_version = EV_CURRENT;
-	ehdr->e_phoff = sizeof(Elf64_Ehdr);
-	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
-	ehdr->e_phentsize = sizeof(Elf64_Phdr);
-
-	/* Prepare one phdr of type PT_NOTE for each present cpu */
-	for_each_present_cpu(cpu) {
-		phdr = (Elf64_Phdr *)bufp;
-		bufp += sizeof(Elf64_Phdr);
-		phdr->p_type = PT_NOTE;
-		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
-		phdr->p_offset = phdr->p_paddr = notes_addr;
-		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
-		(ehdr->e_phnum)++;
-	}
-
-	/* Prepare one PT_NOTE header for vmcoreinfo */
-	phdr = (Elf64_Phdr *)bufp;
-	bufp += sizeof(Elf64_Phdr);
-	phdr->p_type = PT_NOTE;
-	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
-	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
-	(ehdr->e_phnum)++;
-
-#ifdef CONFIG_X86_64
-	/* Prepare PT_LOAD type program header for kernel text region */
-	phdr = (Elf64_Phdr *)bufp;
-	bufp += sizeof(Elf64_Phdr);
-	phdr->p_type = PT_LOAD;
-	phdr->p_flags = PF_R|PF_W|PF_X;
-	phdr->p_vaddr = (Elf64_Addr)_text;
-	phdr->p_filesz = phdr->p_memsz = _end - _text;
-	phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
-	(ehdr->e_phnum)++;
-#endif
-
-	/* Prepare PT_LOAD headers for system ram chunks. */
-	ced->ehdr = ehdr;
-	ced->bufp = bufp;
-	ret = walk_system_ram_res(0, -1, ced,
-			prepare_elf64_ram_headers_callback);
-	if (ret < 0)
-		return ret;
-
-	*addr = buf;
-	*sz = elf_sz;
-	return 0;
-}
-
-/* Prepare elf headers. Return addr and size */
-static int prepare_elf_headers(struct kimage *image, void **addr,
-					unsigned long *sz)
-{
-	struct crash_elf_data *ced;
-	int ret;
-
-	ced = kzalloc(sizeof(*ced), GFP_KERNEL);
-	if (!ced)
-		return -ENOMEM;
-
-	fill_up_crash_elf_data(ced, image);
-
-	/* By default prepare 64bit headers */
-	ret =  prepare_elf64_headers(ced, addr, sz);
-	kfree(ced);
-	return ret;
-}
-
 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
 {
 	unsigned int nr_e820_entries;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 4a2b24d94e04..7547a3c1f94e 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -182,6 +182,23 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
 			       int (*func)(u64, u64, void *));
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
 int kexec_locate_mem_hole(struct kexec_buf *kbuf);
+extern int prepare_elf_headers(struct kimage *image, void **addr,
+				unsigned long *sz);
+
+/* This primarily represents number of split ranges due to exclusion */
+#define CRASH_MAX_RANGES        16
+
+struct crash_mem_range {
+	u64 start, end;
+};
+
+struct crash_mem {
+	unsigned int nr_ranges;
+	struct crash_mem_range ranges[CRASH_MAX_RANGES];
+};
+
+extern int exclude_mem_range(struct crash_mem *mem,
+		unsigned long long mstart, unsigned long long mend);
 #endif /* CONFIG_KEXEC_FILE */
 
 struct kimage {
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 6203b54e04c5..6a0e31e175af 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -22,6 +22,11 @@
 #include <linux/ima.h>
 #include <crypto/hash.h>
 #include <crypto/sha.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/slab.h>
 #include <linux/syscalls.h>
 #include <linux/vmalloc.h>
 #include "kexec_internal.h"
@@ -1051,3 +1056,306 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
 
 	return 0;
 }
+
+static int get_nr_ram_ranges_callback(u64 start, u64 end, void *arg)
+{
+	unsigned int *nr_ranges = arg;
+
+	(*nr_ranges)++;
+	return 0;
+}
+
+
+/* Gather all the required information to prepare elf headers for ram regions */
+static void fill_up_crash_elf_data(struct crash_elf_data *ced,
+				   struct kimage *image)
+{
+	unsigned int nr_ranges = 0;
+
+	ced->image = image;
+
+	walk_system_ram_res(0, -1, &nr_ranges,
+				get_nr_ram_ranges_callback);
+
+	ced->max_nr_ranges = nr_ranges;
+
+	/* Exclusion of crash region could split memory ranges */
+	ced->max_nr_ranges++;
+
+#ifdef CONFIG_X86_64
+	/* If crashk_low_res is not 0, another range split possible */
+	if (crashk_low_res.end)
+		ced->max_nr_ranges++;
+#endif
+}
+
+int exclude_mem_range(struct crash_mem *mem,
+		unsigned long long mstart, unsigned long long mend)
+{
+	int i, j;
+	unsigned long long start, end;
+	struct crash_mem_range temp_range = {0, 0};
+
+	for (i = 0; i < mem->nr_ranges; i++) {
+		start = mem->ranges[i].start;
+		end = mem->ranges[i].end;
+
+		if (mstart > end || mend < start)
+			continue;
+
+		/* Truncate any area outside of range */
+		if (mstart < start)
+			mstart = start;
+		if (mend > end)
+			mend = end;
+
+		/* Found completely overlapping range */
+		if (mstart == start && mend == end) {
+			mem->ranges[i].start = 0;
+			mem->ranges[i].end = 0;
+			if (i < mem->nr_ranges - 1) {
+				/* Shift rest of the ranges to left */
+				for (j = i; j < mem->nr_ranges - 1; j++) {
+					mem->ranges[j].start =
+						mem->ranges[j+1].start;
+					mem->ranges[j].end =
+							mem->ranges[j+1].end;
+				}
+			}
+			mem->nr_ranges--;
+			return 0;
+		}
+
+		if (mstart > start && mend < end) {
+			/* Split original range */
+			mem->ranges[i].end = mstart - 1;
+			temp_range.start = mend + 1;
+			temp_range.end = end;
+		} else if (mstart != start)
+			mem->ranges[i].end = mstart - 1;
+		else
+			mem->ranges[i].start = mend + 1;
+		break;
+	}
+
+	/* If a split happened, add the split to array */
+	if (!temp_range.end)
+		return 0;
+
+	/* Split happened */
+	if (i == CRASH_MAX_RANGES - 1) {
+		pr_err("Too many crash ranges after split\n");
+		return -ENOMEM;
+	}
+
+	/* Location where new range should go */
+	j = i + 1;
+	if (j < mem->nr_ranges) {
+		/* Move over all ranges one slot towards the end */
+		for (i = mem->nr_ranges - 1; i >= j; i--)
+			mem->ranges[i + 1] = mem->ranges[i];
+	}
+
+	mem->ranges[j].start = temp_range.start;
+	mem->ranges[j].end = temp_range.end;
+	mem->nr_ranges++;
+	return 0;
+}
+
+/*
+ * Look for any unwanted ranges between mstart, mend and remove them. This
+ * might lead to split and split ranges are put in ced->mem.ranges[] array
+ */
+static int elf_header_exclude_ranges(struct crash_elf_data *ced,
+		unsigned long long mstart, unsigned long long mend)
+{
+	struct crash_mem *cmem = &ced->mem;
+	int ret = 0;
+
+	memset(cmem->ranges, 0, sizeof(cmem->ranges));
+
+	cmem->ranges[0].start = mstart;
+	cmem->ranges[0].end = mend;
+	cmem->nr_ranges = 1;
+
+	/* Exclude crashkernel region */
+	ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_X86_64
+	if (crashk_low_res.end) {
+		ret = exclude_mem_range(cmem, crashk_low_res.start,
+							crashk_low_res.end);
+		if (ret)
+			return ret;
+	}
+#endif
+
+	return ret;
+}
+
+static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
+{
+	struct crash_elf_data *ced = arg;
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	unsigned long mstart, mend;
+#ifdef CONFIG_X86_64
+	struct kimage *image = ced->image;
+#endif
+	struct crash_mem *cmem;
+	int ret, i;
+
+	ehdr = ced->ehdr;
+
+	/* Exclude unwanted mem ranges */
+	ret = elf_header_exclude_ranges(ced, start, end);
+	if (ret)
+		return ret;
+
+	/* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
+	cmem = &ced->mem;
+
+	for (i = 0; i < cmem->nr_ranges; i++) {
+		mstart = cmem->ranges[i].start;
+		mend = cmem->ranges[i].end;
+
+		phdr = ced->bufp;
+		ced->bufp += sizeof(Elf64_Phdr);
+
+		phdr->p_type = PT_LOAD;
+		phdr->p_flags = PF_R|PF_W|PF_X;
+		phdr->p_offset  = mstart;
+
+#ifdef CONFIG_X86_64
+		/*
+		 * If a range matches backup region, adjust offset to backup
+		 * segment.
+		 */
+		if (mstart == image->arch.backup_src_start &&
+		    (mend - mstart + 1) == image->arch.backup_src_sz)
+			phdr->p_offset = image->arch.backup_load_addr;
+#endif
+
+		phdr->p_paddr = mstart;
+		phdr->p_vaddr = (unsigned long long) __va(mstart);
+		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
+		phdr->p_align = 0;
+		ehdr->e_phnum++;
+		pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+			ehdr->e_phnum, phdr->p_offset);
+	}
+
+	return ret;
+}
+
+static int prepare_elf64_headers(struct crash_elf_data *ced,
+		void **addr, unsigned long *sz)
+{
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
+	unsigned char *buf, *bufp;
+	unsigned int cpu;
+	unsigned long long notes_addr;
+	int ret;
+
+	/* extra phdr for vmcoreinfo elf note */
+	nr_phdr = nr_cpus + 1;
+	nr_phdr += ced->max_nr_ranges;
+
+	/*
+	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
+	 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
+	 * I think this is required by tools like gdb. So same physical
+	 * memory will be mapped in two elf headers. One will contain kernel
+	 * text virtual addresses and other will have __va(physical) addresses.
+	 */
+
+	nr_phdr++;
+	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
+	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
+
+	buf = vzalloc(elf_sz);
+	if (!buf)
+		return -ENOMEM;
+
+	bufp = buf;
+	ehdr = (Elf64_Ehdr *)bufp;
+	bufp += sizeof(Elf64_Ehdr);
+	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+	ehdr->e_ident[EI_OSABI] = ELF_OSABI;
+	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+	ehdr->e_type = ET_CORE;
+	ehdr->e_machine = ELF_ARCH;
+	ehdr->e_version = EV_CURRENT;
+	ehdr->e_phoff = sizeof(Elf64_Ehdr);
+	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+	ehdr->e_phentsize = sizeof(Elf64_Phdr);
+
+	/* Prepare one phdr of type PT_NOTE for each present cpu */
+	for_each_present_cpu(cpu) {
+		phdr = (Elf64_Phdr *)bufp;
+		bufp += sizeof(Elf64_Phdr);
+		phdr->p_type = PT_NOTE;
+		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+		phdr->p_offset = phdr->p_paddr = notes_addr;
+		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
+		(ehdr->e_phnum)++;
+	}
+
+	/* Prepare one PT_NOTE header for vmcoreinfo */
+	phdr = (Elf64_Phdr *)bufp;
+	bufp += sizeof(Elf64_Phdr);
+	phdr->p_type = PT_NOTE;
+	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
+	(ehdr->e_phnum)++;
+
+#ifdef CONFIG_X86_64
+	/* Prepare PT_LOAD type program header for kernel text region */
+	phdr = (Elf64_Phdr *)bufp;
+	bufp += sizeof(Elf64_Phdr);
+	phdr->p_type = PT_LOAD;
+	phdr->p_flags = PF_R|PF_W|PF_X;
+	phdr->p_vaddr = (Elf64_Addr)_text;
+	phdr->p_filesz = phdr->p_memsz = _end - _text;
+	phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
+	(ehdr->e_phnum)++;
+#endif
+
+	/* Prepare PT_LOAD headers for system ram chunks. */
+	ced->ehdr = ehdr;
+	ced->bufp = bufp;
+	ret = walk_system_ram_res(0, -1, ced,
+			prepare_elf64_ram_headers_callback);
+	if (ret < 0)
+		return ret;
+
+	*addr = buf;
+	*sz = elf_sz;
+	return 0;
+}
+
+/* Prepare elf headers. Return addr and size */
+int prepare_elf_headers(struct kimage *image, void **addr, unsigned long *sz)
+{
+	struct crash_elf_data *ced;
+	int ret;
+
+	ced = kzalloc(sizeof(*ced), GFP_KERNEL);
+	if (!ced)
+		return -ENOMEM;
+
+	fill_up_crash_elf_data(ced, image);
+
+	/* By default prepare 64bit headers */
+	ret =  prepare_elf64_headers(ced, addr, sz);
+	kfree(ced);
+	return ret;
+}
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 50dfcb039a41..3c7a034f1fe1 100644
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -16,6 +16,26 @@ extern struct mutex kexec_mutex;
 
 #ifdef CONFIG_KEXEC_FILE
 #include <linux/purgatory.h>
+
+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN   4096
+
+/* Misc data about ram ranges needed to prepare elf headers */
+struct crash_elf_data {
+	struct kimage *image;
+	/*
+	 * Total number of ram ranges we have after various adjustments for
+	 * crash reserved region, etc.
+	 */
+	unsigned int max_nr_ranges;
+
+	/* Pointer to elf header */
+	void *ehdr;
+	/* Pointer to next phdr */
+	void *bufp;
+	struct crash_mem mem;
+};
+
 void kimage_file_post_load_cleanup(struct kimage *image);
 extern char kexec_purgatory[];
 extern size_t kexec_purgatory_size;
-- 
2.14.1

[PATCH v3 05/10] asm-generic: add kexec_file_load system call to unistd.h

[AKASHI Takahiro]

The initial user of this system call number is arm64.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 include/uapi/asm-generic/unistd.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 061185a5eb51..086697fe3917 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -731,9 +731,11 @@ __SYSCALL(__NR_pkey_alloc,    sys_pkey_alloc)
 __SYSCALL(__NR_pkey_free,     sys_pkey_free)
 #define __NR_statx 291
 __SYSCALL(__NR_statx,     sys_statx)
+#define __NR_kexec_file_load 292
+__SYSCALL(__NR_kexec_file_load,     sys_kexec_file_load)
 
 #undef __NR_syscalls
-#define __NR_syscalls 292
+#define __NR_syscalls 293
 
 /*
  * All syscalls below here should go away really,
-- 
2.14.1

[PATCH v3 06/10] arm64: kexec_file: create purgatory

[AKASHI Takahiro]

This is a basic purgatory, or a kind of glue code between the two kernels,
for arm64.

Since purgatory is assumed to be relocatable (not executable) object by
kexec generic code, arch_kexec_apply_relocations_add() is required in
general. Arm64's purgatory, however, is a simple asm and all the references
can be resolved as local, no re-linking is needed here.

Please note that even if we don't support digest check at purgatory we
need purgatory_sha_regions and purgatory_sha256_digest as they are
referenced by generic kexec code.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/Makefile           |  1 +
 arch/arm64/purgatory/Makefile | 24 +++++++++++++++++++
 arch/arm64/purgatory/entry.S  | 55 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 80 insertions(+)
 create mode 100644 arch/arm64/purgatory/Makefile
 create mode 100644 arch/arm64/purgatory/entry.S

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 9b41f1e3b1a0..429f60728c0a 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -105,6 +105,7 @@ core-$(CONFIG_XEN) += arch/arm64/xen/
 core-$(CONFIG_CRYPTO) += arch/arm64/crypto/
 libs-y		:= arch/arm64/lib/ $(libs-y)
 core-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
+core-$(CONFIG_KEXEC_FILE) += arch/arm64/purgatory/
 
 # Default target when executing plain make
 boot		:= arch/arm64/boot
diff --git a/arch/arm64/purgatory/Makefile b/arch/arm64/purgatory/Makefile
new file mode 100644
index 000000000000..c2127a2cbd51
--- /dev/null
+++ b/arch/arm64/purgatory/Makefile
@@ -0,0 +1,24 @@
+OBJECT_FILES_NON_STANDARD := y
+
+purgatory-y := entry.o
+
+targets += $(purgatory-y)
+PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
+
+LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined \
+					-nostdlib -z nodefaultlib
+targets += purgatory.ro
+
+$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
+		$(call if_changed,ld)
+
+targets += kexec_purgatory.c
+
+CMD_BIN2C = $(objtree)/scripts/basic/bin2c
+quiet_cmd_bin2c = BIN2C $@
+	cmd_bin2c = $(CMD_BIN2C) kexec_purgatory < $< > $@
+
+$(obj)/kexec_purgatory.c: $(obj)/purgatory.ro FORCE
+	$(call if_changed,bin2c)
+
+obj-${CONFIG_KEXEC_FILE}	+= kexec_purgatory.o
diff --git a/arch/arm64/purgatory/entry.S b/arch/arm64/purgatory/entry.S
new file mode 100644
index 000000000000..fe6e968076db
--- /dev/null
+++ b/arch/arm64/purgatory/entry.S
@@ -0,0 +1,55 @@
+/*
+ * kexec core purgatory
+ */
+#include <linux/linkage.h>
+#include <uapi/linux/kexec.h>
+
+#define SHA256_DIGEST_SIZE	32 /* defined in crypto/sha.h */
+
+.text
+
+ENTRY(purgatory_start)
+	/* Start new image. */
+	ldr	x17, __kernel_entry
+	ldr	x0, __dtb_addr
+	mov	x1, xzr
+	mov	x2, xzr
+	mov	x3, xzr
+	br	x17
+END(purgatory_start)
+
+/*
+ * data section:
+ * kernel_entry and dtb_addr are global but also labelled as local,
+ * "__xxx:", to avoid unwanted re-linking.
+ *
+ * purgatory_sha_regions and purgatory_sha256_digest are referenced
+ * by kexec generic code and so must exist, but not actually used
+ * here because hash check is not that useful in purgatory.
+ */
+.align 3
+
+.globl kernel_entry
+kernel_entry:
+__kernel_entry:
+	.quad	0
+END(kernel_entry)
+
+.globl dtb_addr
+dtb_addr:
+__dtb_addr:
+	.quad	0
+END(dtb_addr)
+
+.globl purgatory_sha_regions
+purgatory_sha_regions:
+	.rept	KEXEC_SEGMENT_MAX
+	.quad	0
+	.quad	0
+	.endr
+END(purgatory_sha_regions)
+
+.globl purgatory_sha256_digest
+purgatory_sha256_digest:
+        .skip   SHA256_DIGEST_SIZE
+END(purgatory_sha256_digest)
-- 
2.14.1

[PATCH v3 07/10] arm64: kexec_file: load initrd, device-tree and purgatory segments

[AKASHI Takahiro]

load_other_segments() sets up and adds all the memory segments necessary
other than kernel, including initrd, device-tree blob and purgatory.
Most of the code was borrowed from kexec-tools' counterpart.

arch_kimage_kernel_post_load_cleanup() is meant to free arm64-specific data
allocated for loading kernel.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/include/asm/kexec.h         |  22 ++++
 arch/arm64/kernel/Makefile             |   3 +-
 arch/arm64/kernel/machine_kexec_file.c | 213 +++++++++++++++++++++++++++++++++
 3 files changed, 237 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/kernel/machine_kexec_file.c

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index e17f0529a882..2fadd3cbf3af 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -93,6 +93,28 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#ifdef CONFIG_KEXEC_FILE
+#define ARCH_HAS_KIMAGE_ARCH
+
+struct kimage_arch {
+	void *dtb_buf;
+};
+
+struct kimage;
+
+#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
+extern int arch_kimage_file_post_load_cleanup(struct kimage *image);
+
+extern int setup_dtb(struct kimage *image,
+		unsigned long initrd_load_addr, unsigned long initrd_len,
+		char *cmdline, unsigned long cmdline_len,
+		char **dtb_buf, size_t *dtb_buf_len);
+extern int load_other_segments(struct kimage *image,
+		unsigned long kernel_load_addr,
+		char *initrd, unsigned long initrd_len,
+		char *cmdline, unsigned long cmdline_len);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index f2b4e816b6de..5df003d6157c 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -48,8 +48,9 @@ arm64-obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL)	+= acpi_parking_protocol.o
 arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o
 arm64-obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
 arm64-obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o
-arm64-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o	\
+arm64-obj-$(CONFIG_KEXEC_CORE)		+= machine_kexec.o relocate_kernel.o	\
 					   cpu-reset.o
+arm64-obj-$(CONFIG_KEXEC_FILE)		+= machine_kexec_file.o
 arm64-obj-$(CONFIG_ARM64_RELOC_TEST)	+= arm64-reloc-test.o
 arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
 arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
new file mode 100644
index 000000000000..09be2674c2ab
--- /dev/null
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -0,0 +1,213 @@
+/*
+ * kexec_file for arm64
+ *
+ * Copyright (C) 2017 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ *
+ * Most code is derived from arm64 port of kexec-tools
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "kexec_file: " fmt
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/libfdt.h>
+#include <linux/memblock.h>
+#include <linux/of_fdt.h>
+
+static int __dt_root_addr_cells;
+static int __dt_root_size_cells;
+
+struct kexec_file_ops *kexec_file_loaders[] = {
+	NULL
+};
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+	vfree(image->arch.dtb_buf);
+	image->arch.dtb_buf = NULL;
+
+	return kexec_kernel_post_load_cleanup(image);
+}
+
+int arch_kexec_walk_mem(struct kexec_buf *kbuf, int (*func)(u64, u64, void *))
+{
+	if (kbuf->image->type == KEXEC_TYPE_CRASH)
+		return walk_iomem_res_desc(crashk_res.desc,
+					IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+					crashk_res.start, crashk_res.end,
+					kbuf, func);
+	else if (kbuf->top_down)
+		return walk_system_ram_res_rev(0, ULONG_MAX, kbuf, func);
+	else
+		return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
+}
+
+int setup_dtb(struct kimage *image,
+		unsigned long initrd_load_addr, unsigned long initrd_len,
+		char *cmdline, unsigned long cmdline_len,
+		char **dtb_buf, size_t *dtb_buf_len)
+{
+	char *buf = NULL;
+	size_t buf_size;
+	int nodeoffset;
+	u64 value;
+	int range_len;
+	int ret;
+
+	/* duplicate dt blob */
+	buf_size = fdt_totalsize(initial_boot_params);
+	range_len = (__dt_root_addr_cells + __dt_root_size_cells) * sizeof(u32);
+
+	if (initrd_load_addr)
+		buf_size += fdt_prop_len("initrd-start", sizeof(u64))
+				+ fdt_prop_len("initrd-end", sizeof(u64));
+
+	if (cmdline)
+		buf_size += fdt_prop_len("bootargs", cmdline_len + 1);
+
+	buf = vmalloc(buf_size);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	ret = fdt_open_into(initial_boot_params, buf, buf_size);
+	if (ret)
+		goto out_err;
+
+	nodeoffset = fdt_path_offset(buf, "/chosen");
+	if (nodeoffset < 0)
+		goto out_err;
+
+	/* add bootargs */
+	if (cmdline) {
+		ret = fdt_setprop(buf, nodeoffset, "bootargs",
+						cmdline, cmdline_len + 1);
+		if (ret)
+			goto out_err;
+	}
+
+	/* add initrd-* */
+	if (initrd_load_addr) {
+		value = cpu_to_fdt64(initrd_load_addr);
+		ret = fdt_setprop(buf, nodeoffset, "initrd-start",
+				&value, sizeof(value));
+		if (ret)
+			goto out_err;
+
+		value = cpu_to_fdt64(initrd_load_addr + initrd_len);
+		ret = fdt_setprop(buf, nodeoffset, "initrd-end",
+				&value, sizeof(value));
+		if (ret)
+			goto out_err;
+	}
+
+	/* trim a buffer */
+	fdt_pack(buf);
+	*dtb_buf = buf;
+	*dtb_buf_len = fdt_totalsize(buf);
+
+	return 0;
+
+out_err:
+	vfree(buf);
+	return ret;
+}
+
+int load_other_segments(struct kimage *image, unsigned long kernel_load_addr,
+			char *initrd, unsigned long initrd_len,
+			char *cmdline, unsigned long cmdline_len)
+{
+	struct kexec_buf kbuf;
+	unsigned long initrd_load_addr = 0;
+	unsigned long purgatory_load_addr, dtb_load_addr;
+	char *dtb = NULL;
+	unsigned long dtb_len;
+	int ret = 0;
+
+	kbuf.image = image;
+	/* not allocate anything below the kernel */
+	kbuf.buf_min = kernel_load_addr;
+
+	/* Load initrd */
+	if (initrd) {
+		kbuf.buffer = initrd;
+		kbuf.bufsz = initrd_len;
+		kbuf.memsz = initrd_len;
+		kbuf.buf_align = PAGE_SIZE;
+		/* within 1GB-aligned window of up to 32GB in size */
+		kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
+						+ (unsigned long)SZ_1G * 31;
+		kbuf.top_down = 0;
+
+		ret = kexec_add_buffer(&kbuf);
+		if (ret)
+			goto out_err;
+		initrd_load_addr = kbuf.mem;
+
+		pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+				initrd_load_addr, initrd_len, initrd_len);
+	}
+
+	/* Load dtb blob */
+	ret = setup_dtb(image, initrd_load_addr, initrd_len,
+				cmdline, cmdline_len, &dtb, &dtb_len);
+	if (ret) {
+		pr_err("Preparing for new dtb failed\n");
+		goto out_err;
+	}
+
+	kbuf.buffer = dtb;
+	kbuf.bufsz = dtb_len;
+	kbuf.memsz = dtb_len;
+	/* not across 2MB boundary */
+	kbuf.buf_align = SZ_2M;
+	kbuf.buf_max = ULONG_MAX;
+	kbuf.top_down = 1;
+
+	ret = kexec_add_buffer(&kbuf);
+	if (ret)
+		goto out_err;
+	dtb_load_addr = kbuf.mem;
+	image->arch.dtb_buf = dtb;
+
+	pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+			dtb_load_addr, dtb_len, dtb_len);
+
+	/* Load purgatory  */
+	ret = kexec_load_purgatory(image, kernel_load_addr, ULONG_MAX, 1,
+				   &purgatory_load_addr);
+	if (ret) {
+		pr_err("Loading purgatory failed\n");
+		goto out_err;
+	}
+
+	ret = kexec_purgatory_get_set_symbol(image, "kernel_entry",
+				&kernel_load_addr, sizeof(kernel_load_addr), 0);
+	if (ret) {
+		pr_err("Setting symbol (kernel_entry) failed.\n");
+		goto out_err;
+	}
+
+	ret = kexec_purgatory_get_set_symbol(image, "dtb_addr",
+				&dtb_load_addr, sizeof(dtb_load_addr), 0);
+	if (ret) {
+		pr_err("Setting symbol (dtb_addr) failed.\n");
+		goto out_err;
+	}
+
+	pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
+
+	return 0;
+
+out_err:
+	vfree(dtb);
+	image->arch.dtb_buf = NULL;
+	return ret;
+}
-- 
2.14.1

[PATCH v3 08/10] arm64: kexec_file: set up for crash dump adding elf core header

[AKASHI Takahiro]

load_crashdump_segments() creates and loads a memory segment of elf core
header for crash dump.

"linux,usable-memory-range" and "linux,elfcorehdr" will add to the 2nd
kernel's device-tree blob. The logic of this cod is also from kexec-tools.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/include/asm/kexec.h         |   5 ++
 arch/arm64/kernel/machine_kexec_file.c | 149 +++++++++++++++++++++++++++++++++
 kernel/kexec_file.c                    |   2 +-
 3 files changed, 155 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 2fadd3cbf3af..edb702e64a8a 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -98,6 +98,10 @@ static inline void crash_post_resume(void) {}
 
 struct kimage_arch {
 	void *dtb_buf;
+	/* Core ELF header buffer */
+	void *elf_headers;
+	unsigned long elf_headers_sz;
+	unsigned long elf_load_addr;
 };
 
 struct kimage;
@@ -113,6 +117,7 @@ extern int load_other_segments(struct kimage *image,
 		unsigned long kernel_load_addr,
 		char *initrd, unsigned long initrd_len,
 		char *cmdline, unsigned long cmdline_len);
+extern int load_crashdump_segments(struct kimage *image);
 #endif
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 09be2674c2ab..e4671610fb12 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -32,6 +32,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
 	vfree(image->arch.dtb_buf);
 	image->arch.dtb_buf = NULL;
 
+	vfree(image->arch.elf_headers);
+	image->arch.elf_headers = NULL;
+	image->arch.elf_headers_sz = 0;
+
 	return kexec_kernel_post_load_cleanup(image);
 }
 
@@ -48,6 +52,77 @@ int arch_kexec_walk_mem(struct kexec_buf *kbuf, int (*func)(u64, u64, void *))
 		return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
 }
 
+static int __init arch_kexec_file_init(void)
+{
+	/* Those values are used later on loading the kernel */
+	__dt_root_addr_cells = dt_root_addr_cells;
+	__dt_root_size_cells = dt_root_size_cells;
+
+	return 0;
+}
+late_initcall(arch_kexec_file_init);
+
+#define FDT_ALIGN(x, a)	(((x) + (a) - 1) & ~((a) - 1))
+#define FDT_TAGALIGN(x)	(FDT_ALIGN((x), FDT_TAGSIZE))
+
+static int fdt_prop_len(const char *prop_name, int len)
+{
+	return (strlen(prop_name) + 1) +
+		sizeof(struct fdt_property) +
+		FDT_TAGALIGN(len);
+}
+
+static bool cells_size_fitted(unsigned long base, unsigned long size)
+{
+	/* if *_cells >= 2, cells can hold 64-bit values anyway */
+	if ((__dt_root_addr_cells == 1) && (base >= (1ULL << 32)))
+		return false;
+
+	if ((__dt_root_size_cells == 1) && (size >= (1ULL << 32)))
+		return false;
+
+	return true;
+}
+
+static void fill_property(void *buf, u64 val64, int cells)
+{
+	u32 val32;
+	int i;
+
+	if (cells == 1) {
+		val32 = cpu_to_fdt32((u32)val64);
+		memcpy(buf, &val32, sizeof(val32));
+	} else {
+		for (i = 0; i < (cells * sizeof(u32) - sizeof(u64)); i++)
+			*(char *)buf++ = 0;
+
+		val64 = cpu_to_fdt64(val64);
+		memcpy(buf, &val64, sizeof(val64));
+	}
+}
+
+static int fdt_setprop_range(void *fdt, int nodeoffset, const char *name,
+				unsigned long addr, unsigned long size)
+{
+	u64 range[2];
+	void *prop;
+	size_t buf_size;
+	int result;
+
+	prop = range;
+	buf_size = (__dt_root_addr_cells + __dt_root_size_cells) * sizeof(u32);
+
+	fill_property(prop, addr, __dt_root_addr_cells);
+	prop += __dt_root_addr_cells * sizeof(u32);
+
+	fill_property(prop, size, __dt_root_size_cells);
+	prop += __dt_root_size_cells * sizeof(u32);
+
+	result = fdt_setprop(fdt, nodeoffset, name, range, buf_size);
+
+	return result;
+}
+
 int setup_dtb(struct kimage *image,
 		unsigned long initrd_load_addr, unsigned long initrd_len,
 		char *cmdline, unsigned long cmdline_len,
@@ -60,10 +135,26 @@ int setup_dtb(struct kimage *image,
 	int range_len;
 	int ret;
 
+	/* check ranges against root's #address-cells and #size-cells */
+	if (image->type == KEXEC_TYPE_CRASH &&
+		(!cells_size_fitted(image->arch.elf_load_addr,
+				image->arch.elf_headers_sz) ||
+		 !cells_size_fitted(crashk_res.start,
+				crashk_res.end - crashk_res.start + 1))) {
+		pr_err("Crash memory region doesn't fit into DT's root cell sizes.\n");
+		ret = -EINVAL;
+		goto out_err;
+	}
+
 	/* duplicate dt blob */
 	buf_size = fdt_totalsize(initial_boot_params);
 	range_len = (__dt_root_addr_cells + __dt_root_size_cells) * sizeof(u32);
 
+	if (image->type == KEXEC_TYPE_CRASH)
+		buf_size += fdt_prop_len("linux,elfcorehdr", range_len)
+				+ fdt_prop_len("linux,usable-memory-range",
+								range_len);
+
 	if (initrd_load_addr)
 		buf_size += fdt_prop_len("initrd-start", sizeof(u64))
 				+ fdt_prop_len("initrd-end", sizeof(u64));
@@ -85,6 +176,23 @@ int setup_dtb(struct kimage *image,
 	if (nodeoffset < 0)
 		goto out_err;
 
+	if (image->type == KEXEC_TYPE_CRASH) {
+		/* add linux,elfcorehdr */
+		ret = fdt_setprop_range(buf, nodeoffset, "linux,elfcorehdr",
+				image->arch.elf_load_addr,
+				image->arch.elf_headers_sz);
+		if (ret)
+			goto out_err;
+
+		/* add linux,usable-memory-range */
+		ret = fdt_setprop_range(buf, nodeoffset,
+				"linux,usable-memory-range",
+				crashk_res.start,
+				crashk_res.end - crashk_res.start + 1);
+		if (ret)
+			goto out_err;
+	}
+
 	/* add bootargs */
 	if (cmdline) {
 		ret = fdt_setprop(buf, nodeoffset, "bootargs",
@@ -211,3 +319,44 @@ int load_other_segments(struct kimage *image, unsigned long kernel_load_addr,
 	image->arch.dtb_buf = NULL;
 	return ret;
 }
+
+int load_crashdump_segments(struct kimage *image)
+{
+	void *elf_addr;
+	unsigned long elf_sz;
+	struct kexec_buf kbuf;
+	int ret;
+
+	if (image->type != KEXEC_TYPE_CRASH)
+		return 0;
+
+	/* Prepare elf headers and add a segment */
+	ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
+	if (ret) {
+		pr_err("Preparing elf core header failed\n");
+		return ret;
+	}
+
+	kbuf.image = image;
+	kbuf.buffer = elf_addr;
+	kbuf.bufsz = elf_sz;
+	kbuf.memsz = elf_sz;
+	kbuf.buf_align = PAGE_SIZE;
+	kbuf.buf_min = crashk_res.start;
+	kbuf.buf_max = crashk_res.end + 1;
+	kbuf.top_down = 1;
+
+	ret = kexec_add_buffer(&kbuf);
+	if (ret) {
+		vfree(elf_addr);
+		return ret;
+	}
+	image->arch.elf_headers = elf_addr;
+	image->arch.elf_headers_sz = elf_sz;
+	image->arch.elf_load_addr = kbuf.mem;
+
+	pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+			 image->arch.elf_load_addr, elf_sz, elf_sz);
+
+	return ret;
+}
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 6a0e31e175af..6b206883f429 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -1317,7 +1317,7 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
 	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
 	(ehdr->e_phnum)++;
 
-#ifdef CONFIG_X86_64
+#if defined(CONFIG_X86_64) || defined(CONFIG_ARM64)
 	/* Prepare PT_LOAD type program header for kernel text region */
 	phdr = (Elf64_Phdr *)bufp;
 	bufp += sizeof(Elf64_Phdr);
-- 
2.14.1

[PATCH v3 09/10] arm64: enable KEXEC_FILE config

[AKASHI Takahiro]

Modify arm64/Kconfig and Makefile to enable kexec_file_load support.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/Kconfig | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index dfd908630631..fa7299f08cc6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -756,6 +756,28 @@ config KEXEC
 	  but it is independent of the system firmware.   And like a reboot
 	  you can start any kernel with it, not just Linux.
 
+config KEXEC_FILE
+	bool "kexec file based system call"
+	select KEXEC_CORE
+	select BUILD_BIN2C
+	---help---
+	  This is new version of kexec system call. This system call is
+	  file based and takes file descriptors as system call argument
+	  for kernel and initramfs as opposed to list of segments as
+	  accepted by previous system call.
+
+	  In addition to this option, you need to enable a specific type
+	  of image support.
+
+config KEXEC_VERIFY_SIG
+	bool "Verify kernel signature during kexec_file_load() syscall"
+	depends on KEXEC_FILE
+	select SYSTEM_DATA_VERIFICATION
+	---help---
+	  Select this option to verify a signature with loaded kernel
+	  image. If configured, any attempt of loading a image without
+	  valid signature will fail.
+
 config CRASH_DUMP
 	bool "Build kdump crash kernel"
 	help
-- 
2.14.1

[PATCH v3 10/10] arm64: kexec_file: add Image format support

[AKASHI Takahiro]

The "Image" binary will be loaded at the offset of TEXT_OFFSET from
the start of system memory. TEXT_OFFSET is determined from the header
of the image.

Regarding kernel signature verification, it will be done through
verify_pefile_signature() as arm64's "Image" binary can be seen as
in PE format. This approach is consistent with x86 implementation.

we can sign an image with sbsign command.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/Kconfig                     |   7 +++
 arch/arm64/include/asm/kexec.h         |  66 +++++++++++++++++++++
 arch/arm64/kernel/Makefile             |   1 +
 arch/arm64/kernel/kexec_image.c        | 105 +++++++++++++++++++++++++++++++++
 arch/arm64/kernel/machine_kexec_file.c |   3 +
 5 files changed, 182 insertions(+)
 create mode 100644 arch/arm64/kernel/kexec_image.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fa7299f08cc6..b7f1a760434a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -769,10 +769,17 @@ config KEXEC_FILE
 	  In addition to this option, you need to enable a specific type
 	  of image support.
 
+config KEXEC_FILE_IMAGE_FMT
+	bool "Enable Image support"
+	depends on KEXEC_FILE
+	---help---
+	  Select this option to enable 'Image' kernel loading.
+
 config KEXEC_VERIFY_SIG
 	bool "Verify kernel signature during kexec_file_load() syscall"
 	depends on KEXEC_FILE
 	select SYSTEM_DATA_VERIFICATION
+	select SIGNED_PE_FILE_VERIFICATION if KEXEC_FILE_IMAGE_FMT
 	---help---
 	  Select this option to verify a signature with loaded kernel
 	  image. If configured, any attempt of loading a image without
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index edb702e64a8a..7ec529e11a8b 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -104,6 +104,72 @@ struct kimage_arch {
 	unsigned long elf_load_addr;
 };
 
+/**
+ * struct arm64_image_header - arm64 kernel image header
+ *
+ * @pe_sig: Optional PE format 'MZ' signature
+ * @branch_code: Instruction to branch to stext
+ * @text_offset: Image load offset, little endian
+ * @image_size: Effective image size, little endian
+ * @flags:
+ *	Bit 0: Kernel endianness. 0=little endian, 1=big endian
+ * @reserved: Reserved
+ * @magic: Magic number, "ARM\x64"
+ * @pe_header: Optional offset to a PE format header
+ **/
+
+struct arm64_image_header {
+	u8 pe_sig[2];
+	u8 pad[2];
+	u32 branch_code;
+	u64 text_offset;
+	u64 image_size;
+	u64 flags;
+	u64 reserved[3];
+	u8 magic[4];
+	u32 pe_header;
+};
+
+static const u8 arm64_image_magic[4] = {'A', 'R', 'M', 0x64U};
+static const u8 arm64_image_pe_sig[2] = {'M', 'Z'};
+
+/**
+ * arm64_header_check_magic - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if header is OK.
+ */
+
+static inline int arm64_header_check_magic(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	if (!h->text_offset)
+		return 0;
+
+	return (h->magic[0] == arm64_image_magic[0]
+		&& h->magic[1] == arm64_image_magic[1]
+		&& h->magic[2] == arm64_image_magic[2]
+		&& h->magic[3] == arm64_image_magic[3]);
+}
+
+/**
+ * arm64_header_check_pe_sig - Helper to check the arm64 image header.
+ *
+ * Returns non-zero if 'MZ' signature is found.
+ */
+
+static inline int arm64_header_check_pe_sig(const struct arm64_image_header *h)
+{
+	if (!h)
+		return 0;
+
+	return (h->pe_sig[0] == arm64_image_pe_sig[0]
+		&& h->pe_sig[1] == arm64_image_pe_sig[1]);
+}
+
+extern struct kexec_file_ops kexec_image_ops;
+
 struct kimage;
 
 #define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 5df003d6157c..a1161bab6810 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -51,6 +51,7 @@ arm64-obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o
 arm64-obj-$(CONFIG_KEXEC_CORE)		+= machine_kexec.o relocate_kernel.o	\
 					   cpu-reset.o
 arm64-obj-$(CONFIG_KEXEC_FILE)		+= machine_kexec_file.o
+arm64-obj-$(CONFIG_KEXEC_FILE_IMAGE_FMT)	+= kexec_image.o
 arm64-obj-$(CONFIG_ARM64_RELOC_TEST)	+= arm64-reloc-test.o
 arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o
 arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
new file mode 100644
index 000000000000..b19538af2f3d
--- /dev/null
+++ b/arch/arm64/kernel/kexec_image.c
@@ -0,0 +1,105 @@
+/*
+ * Kexec image loader
+
+ * Copyright (C) 2017 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt)	"kexec_file(Image): " fmt
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/verification.h>
+#include <asm/byteorder.h>
+#include <asm/memory.h>
+
+static int image_probe(const char *kernel_buf, unsigned long kernel_len)
+{
+	const struct arm64_image_header *h;
+
+	h = (const struct arm64_image_header *)(kernel_buf);
+
+	if ((kernel_len < sizeof(*h)) || !arm64_header_check_magic(h))
+		return -EINVAL;
+
+	pr_debug("PE format: %s\n",
+			(arm64_header_check_pe_sig(h) ? "yes" : "no"));
+
+	return 0;
+}
+
+static void *image_load(struct kimage *image, char *kernel,
+			    unsigned long kernel_len, char *initrd,
+			    unsigned long initrd_len, char *cmdline,
+			    unsigned long cmdline_len)
+{
+	struct kexec_buf kbuf;
+	struct arm64_image_header *h = (struct arm64_image_header *)kernel;
+	unsigned long text_offset, kernel_load_addr;
+	int ret;
+
+	/* Create elf core header segment */
+	ret = load_crashdump_segments(image);
+	if (ret)
+		goto out;
+
+	/* Load the kernel */
+	kbuf.image = image;
+	if (image->type == KEXEC_TYPE_CRASH) {
+		kbuf.buf_min = crashk_res.start;
+		kbuf.buf_max = crashk_res.end + 1;
+	} else {
+		kbuf.buf_min = 0;
+		kbuf.buf_max = ULONG_MAX;
+	}
+	kbuf.top_down = 0;
+
+	kbuf.buffer = kernel;
+	kbuf.bufsz = kernel_len;
+	kbuf.memsz = le64_to_cpu(h->image_size);
+	text_offset = le64_to_cpu(h->text_offset);
+	kbuf.buf_align = SZ_2M;
+
+	/* Adjust kernel segment with TEXT_OFFSET */
+	kbuf.memsz += text_offset;
+
+	ret = kexec_add_buffer(&kbuf);
+	if (ret)
+		goto out;
+
+	image->segment[image->nr_segments - 1].mem += text_offset;
+	image->segment[image->nr_segments - 1].memsz -= text_offset;
+	kernel_load_addr = kbuf.mem + text_offset;
+
+	pr_debug("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+		 kernel_load_addr, kbuf.bufsz, kbuf.memsz);
+
+	/* Load additional data */
+	ret = load_other_segments(image, kernel_load_addr,
+			    initrd, initrd_len, cmdline, cmdline_len);
+
+out:
+	return ERR_PTR(ret);
+}
+
+#ifdef CONFIG_KEXEC_VERIFY_SIG
+static int image_verify_sig(const char *kernel, unsigned long kernel_len)
+{
+	return verify_pefile_signature(kernel, kernel_len, NULL,
+				       VERIFYING_KEXEC_PE_SIGNATURE);
+}
+#endif
+
+struct kexec_file_ops kexec_image_ops = {
+	.probe = image_probe,
+	.load = image_load,
+#ifdef CONFIG_KEXEC_VERIFY_SIG
+	.verify_sig = image_verify_sig,
+#endif
+};
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index e4671610fb12..fbf1cb4b58df 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -24,6 +24,9 @@ static int __dt_root_addr_cells;
 static int __dt_root_size_cells;
 
 struct kexec_file_ops *kexec_file_loaders[] = {
+#ifdef CONFIG_KEXEC_FILE_IMAGE_FMT
+	&kexec_image_ops,
+#endif
 	NULL
 };
 
-- 
2.14.1

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

[Dave Young]

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@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/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@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

Thanks
Dave

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

[AKASHI Takahiro]

Hi Dave,

On Thu, Sep 21, 2017 at 03:35:16PM +0800, Dave Young wrote:
> 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@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/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.

Yeah, arm64 post_load_cleanup function also has some extra stuff.
See my patch #7/8.

> 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.

It was exactly what I made before submitting v3, but I changed
my mind a bit. My intension is to prevent the code being duplicated
even though it has only a few lines of code.

I agree that '#ifndef arch_kexec_kernel_image_probe' in kexec.h would be
quite ugly, but similar usages can be spotted in the kernel source.

That said if you don't like it at all, I defer to you.

Thanks,
-Takahiro AKASHI

> 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@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
> 
> Thanks
> Dave

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

[Dave Young]

HI AKASHI,
On 09/22/17 at 04:58pm, AKASHI Takahiro wrote:
> Hi Dave,
> 
[snip]

> > >  /*
> > >   * 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.
> 
> Yeah, arm64 post_load_cleanup function also has some extra stuff.
> See my patch #7/8.

But the x86 cleanup was dropped silently, can you add it in x86
post_load_cleanup as well?

> 
> > 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.
> 
> It was exactly what I made before submitting v3, but I changed
> my mind a bit. My intension is to prevent the code being duplicated
> even though it has only a few lines of code.
> 
> I agree that '#ifndef arch_kexec_kernel_image_probe' in kexec.h would be
> quite ugly, but similar usages can be spotted in the kernel source.
> 
> That said if you don't like it at all, I defer to you.

I understand your concern, maybe still use a weak function for 
arch_kexec_kernel_image_*, and they call the kexec_kernel_image_* in
kexec_file.c common code.

Like in general code:

int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
                                         unsigned long buf_len)
{
	return kexec_kernel_image_probe(image, buf, buf_len);
}

In architechture code it can add other code and call
kexec_kernel_image_*

It looks a bit better than the #ifdef way. 

[snip]

> 
> Thanks,
> -Takahiro AKASHI
> 

Thanks
Dave

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

[Dave Young]

On 09/25/17 at 04:03pm, Dave Young wrote:
> HI AKASHI,
> On 09/22/17 at 04:58pm, AKASHI Takahiro wrote:
> > Hi Dave,
> > 
> [snip]
> 
> > > >  /*
> > > >   * 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.
> > 
> > Yeah, arm64 post_load_cleanup function also has some extra stuff.
> > See my patch #7/8.
> 
> But the x86 cleanup was dropped silently, can you add it in x86
> post_load_cleanup as well?
> 
> > 
> > > 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.
> > 
> > It was exactly what I made before submitting v3, but I changed
> > my mind a bit. My intension is to prevent the code being duplicated
> > even though it has only a few lines of code.
> > 
> > I agree that '#ifndef arch_kexec_kernel_image_probe' in kexec.h would be
> > quite ugly, but similar usages can be spotted in the kernel source.
> > 
> > That said if you don't like it at all, I defer to you.
> 
> I understand your concern, maybe still use a weak function for 
> arch_kexec_kernel_image_*, and they call the kexec_kernel_image_* in
> kexec_file.c common code.
> 
> Like in general code:
> 
> int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
>                                          unsigned long buf_len)
> {
> 	return kexec_kernel_image_probe(image, buf, buf_len);

in this way, we maybe move kexec_kernel_image_probe to
_kexec_kernel_image_probe, add a underscore prefix to mean that is used
internally.

> }
> 
> In architechture code it can add other code and call
> kexec_kernel_image_*
> 
> It looks a bit better than the #ifdef way. 
> 
> [snip]
> 
> > 
> > Thanks,
> > -Takahiro AKASHI
> > 
> 
> Thanks
> Dave
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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

[David Howells]

AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:

> > > -static struct kexec_file_ops *kexec_file_loaders[] = {
> > > +struct kexec_file_ops *kexec_file_loaders[] = {
> > >  	&kexec_elf64_ops,
> > > +	NULL
> > >  };

const?

David

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

[AKASHI Takahiro]

On Mon, Sep 25, 2017 at 04:03:13PM +0800, Dave Young wrote:
> HI AKASHI,
> On 09/22/17 at 04:58pm, AKASHI Takahiro wrote:
> > Hi Dave,
> > 
> [snip]
> 
> > > >  /*
> > > >   * 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.
> > 
> > Yeah, arm64 post_load_cleanup function also has some extra stuff.
> > See my patch #7/8.
> 
> But the x86 cleanup was dropped silently, can you add it in x86
> post_load_cleanup as well?

Sure, I will do.

> > 
> > > 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.
> > 
> > It was exactly what I made before submitting v3, but I changed
> > my mind a bit. My intension is to prevent the code being duplicated
> > even though it has only a few lines of code.
> > 
> > I agree that '#ifndef arch_kexec_kernel_image_probe' in kexec.h would be
> > quite ugly, but similar usages can be spotted in the kernel source.
> > 
> > That said if you don't like it at all, I defer to you.
> 
> I understand your concern, maybe still use a weak function for 
> arch_kexec_kernel_image_*, and they call the kexec_kernel_image_* in
> kexec_file.c common code.
> 
> Like in general code:
> 
> int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
>                                          unsigned long buf_len)
> {
> 	return kexec_kernel_image_probe(image, buf, buf_len);

as you suggested,
        "return _kexec_kernel_image_probe(...);

would be fine.

-Takahiro AKASHI


> }
> 
> In architechture code it can add other code and call
> kexec_kernel_image_*
> 
> It looks a bit better than the #ifdef way. 
> 
> [snip]
> 
> > 
> > Thanks,
> > -Takahiro AKASHI
> > 
> 
> Thanks
> Dave

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

[AKASHI Takahiro]

On Mon, Sep 25, 2017 at 04:36:43PM +0100, David Howells wrote:
> AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:
> 
> > > > -static struct kexec_file_ops *kexec_file_loaders[] = {
> > > > +struct kexec_file_ops *kexec_file_loaders[] = {
> > > >  	&kexec_elf64_ops,
> > > > +	NULL
> > > >  };
> 
> const?

Yes, it makes sense.

-Takahiro AKASHI

> 
> David