The patch titled
Subject: kexec_file: add buffer hand-over support for the next kernel
has been added to the -mm tree. Its filename is
kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Subject: kexec_file: add buffer hand-over support for the next kernel
The buffer hand-over mechanism allows the currently running kernel to pass
data to kernel that will be kexec'd via a kexec segment. The second kernel
can check whether the previous kernel sent data and retrieve it.
This is the architecture-independent part of the feature.
Link: http://lkml.kernel.org/r/1472579105-26296-2-git-send-email-bauerman@xxxxxxxxxxxxxxxxxx
Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Stewart Smith <stewart@xxxxxxxxxxxxxxxxxx>
Cc: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Cc: Eric Richter <erichte@xxxxxxxxxxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kexec.h | 31 ++++++++++++++++++
kernel/kexec_file.c | 68 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 99 insertions(+)
diff -puN include/linux/kexec.h~kexec_file-add-buffer-hand-over-support-for-the-next-kernel include/linux/kexec.h
--- a/include/linux/kexec.h~kexec_file-add-buffer-hand-over-support-for-the-next-kernel
+++ a/include/linux/kexec.h
@@ -383,6 +383,37 @@ static inline void *boot_phys_to_virt(un
return phys_to_virt(boot_phys_to_phys(entry));
}
+#ifdef CONFIG_KEXEC_FILE
+bool __weak kexec_can_hand_over_buffer(void);
+int __weak arch_kexec_add_handover_buffer(struct kimage *image,
+ unsigned long load_addr,
+ unsigned long size);
+int kexec_add_handover_buffer(struct kexec_buf *kbuf);
+int __weak kexec_get_handover_buffer(void **addr, unsigned long *size);
+int __weak kexec_free_handover_buffer(void);
+#else
+struct kexec_buf;
+
+static inline bool kexec_can_hand_over_buffer(void)
+{
+ return false;
+}
+
+static inline int kexec_add_handover_buffer(struct kexec_buf *kbuf)
+{
+ return -ENOTSUPP;
+}
+
+static inline int kexec_get_handover_buffer(void **addr, unsigned long *size)
+{
+ return -ENOTSUPP;
+}
+
+static inline int kexec_free_handover_buffer(void)
+{
+ return -ENOTSUPP;
+}
+#endif /* CONFIG_KEXEC_FILE */
#else /* !CONFIG_KEXEC_CORE */
struct pt_regs;
struct task_struct;
diff -puN kernel/kexec_file.c~kexec_file-add-buffer-hand-over-support-for-the-next-kernel kernel/kexec_file.c
--- a/kernel/kexec_file.c~kexec_file-add-buffer-hand-over-support-for-the-next-kernel
+++ a/kernel/kexec_file.c
@@ -113,6 +113,74 @@ void kimage_file_post_load_cleanup(struc
image->image_loader_data = NULL;
}
+/**
+ * kexec_can_hand_over_buffer - can we pass data to the kexec'd kernel?
+ */
+bool __weak kexec_can_hand_over_buffer(void)
+{
+ return false;
+}
+
+/**
+ * arch_kexec_add_handover_buffer - do arch-specific steps to handover buffer
+ *
+ * Architectures should use this function to pass on the handover buffer
+ * information to the next kernel.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int __weak arch_kexec_add_handover_buffer(struct kimage *image,
+ unsigned long load_addr,
+ unsigned long size)
+{
+ return -ENOTSUPP;
+}
+
+/**
+ * kexec_add_handover_buffer - add buffer to be used by the next kernel
+ * @kbuf: Buffer contents and memory parameters.
+ *
+ * This function assumes that kexec_mutex is held.
+ * On successful return, @kbuf->mem will have the physical address of
+ * the buffer in the next kernel.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_add_handover_buffer(struct kexec_buf *kbuf)
+{
+ int ret;
+
+ if (!kexec_can_hand_over_buffer())
+ return -ENOTSUPP;
+
+ ret = kexec_add_buffer(kbuf);
+ if (ret)
+ return ret;
+
+ return arch_kexec_add_handover_buffer(kbuf->image, kbuf->mem,
+ kbuf->memsz);
+}
+
+/**
+ * kexec_get_handover_buffer - get the handover buffer from the previous kernel
+ * @addr: On successful return, set to point to the buffer contents.
+ * @size: On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int __weak kexec_get_handover_buffer(void **addr, unsigned long *size)
+{
+ return -ENOTSUPP;
+}
+
+/**
+ * kexec_free_handover_buffer - free memory used by the handover buffer
+ */
+int __weak kexec_free_handover_buffer(void)
+{
+ return -ENOTSUPP;
+}
+
/*
* In file mode list of segments is prepared by kernel. Copy relevant
* data from user space, do error checking, prepare segment list
_
Patches currently in -mm which might be from bauerman@xxxxxxxxxxxxxxxxxx are
kexec-fix-double-free-when-failing-to-relocate-the-purgatory.patch
kexec_file-allow-arch-specific-memory-walking-for-kexec_add_buffer.patch
kexec_file-change-kexec_add_buffer-to-take-kexec_buf-as-argument.patch
kexec_file-factor-out-kexec_locate_mem_hole-from-kexec_add_buffer.patch
powerpc-change-places-using-config_kexec-to-use-config_kexec_core-instead.patch
powerpc-factor-out-relocation-code-from-module_64c-to-elf_util_64c.patch
powerpc-generalize-elf64_apply_relocate_add.patch
powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load.patch
powerpc-add-functions-to-read-elf-files-of-any-endianness.patch
powerpc-implement-kexec_file_load.patch
powerpc-add-code-to-work-with-device-trees-in-kexec_file_load.patch
powerpc-add-support-for-loading-elf-kernels-with-kexec_file_load.patch
powerpc-add-purgatory-for-kexec_file_load-implementation.patch
powerpc-enable-config_kexec_file-in-powerpc-server-defconfigs.patch
kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
powerpc-kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
kexec_file-allow-skipping-checksum-calculation-for-some-segments.patch
kexec_file-add-mechanism-to-update-kexec-segments.patch
ima-demonstration-code-for-kexec-buffer-passing.patch
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