From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: kexec@lists.infradead.org
Cc: linux-security-module@vger.kernel.org,
linux-ima-devel@lists.sourceforge.net,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Eric Biederman <ebiederm@xmission.com>,
Dave Young <dyoung@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Baoquan He <bhe@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Stewart Smith <stewart@linux.vnet.ibm.com>,
Samuel Mendoza-Jonas <sam@mendozajonas.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Eric Richter <erichte@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
Petko Manolov <petkan@mip-labs.com>,
David Laight <David.Laight@ACULAB.COM>,
Balbir Singh <bsingharora@gmail.com>,
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Subject: [PATCH v2 1/6] kexec_file: Add buffer hand-over support for the next kernel
Date: Sat, 13 Aug 2016 00:18:20 -0300 [thread overview]
Message-ID: <1471058305-30198-2-git-send-email-bauerman@linux.vnet.ibm.com> (raw)
In-Reply-To: <1471058305-30198-1-git-send-email-bauerman@linux.vnet.ibm.com>
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.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
---
include/linux/kexec.h | 29 ++++++++++++++++++++++
kernel/kexec_file.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index ceccc5856aab..4559a1a01b0a 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -388,6 +388,35 @@ static inline void *boot_phys_to_virt(unsigned long entry)
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
+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 --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 772cb491715e..c8418d62e2fc 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -135,6 +135,74 @@ int __weak arch_kexec_verify_buffer(enum kexec_file_type type, const void *buf,
return -EINVAL;
}
+/**
+ * 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
--
1.9.1
next prev parent reply other threads:[~2016-08-13 3:19 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-13 3:18 [PATCH v2 0/6] kexec_file: Add buffer hand-over for the next kernel Thiago Jung Bauermann
2016-08-13 3:18 ` Thiago Jung Bauermann [this message]
2016-08-13 3:18 ` [PATCH v2 2/6] powerpc: kexec_file: Add buffer hand-over support " Thiago Jung Bauermann
2016-08-22 3:21 ` Dave Young
2016-08-22 3:38 ` Thiago Jung Bauermann
2016-08-22 7:22 ` Dave Young
2016-08-22 22:21 ` Thiago Jung Bauermann
2016-08-13 3:18 ` [PATCH v2 3/6] kexec_file: Allow skipping checksum calculation for some segments Thiago Jung Bauermann
2016-08-18 9:03 ` Dave Young
2016-08-18 21:09 ` Thiago Jung Bauermann
2016-08-22 3:17 ` Dave Young
2016-08-22 3:25 ` Thiago Jung Bauermann
2016-08-22 3:36 ` Dave Young
2016-08-22 3:45 ` Thiago Jung Bauermann
2016-08-22 22:12 ` Thiago Jung Bauermann
2016-08-13 3:18 ` [PATCH v2 4/6] kexec_file: Add mechanism to update kexec segments Thiago Jung Bauermann
2016-08-15 22:27 ` Andrew Morton
2016-08-16 17:00 ` Thiago Jung Bauermann
2016-08-13 3:18 ` [PATCH v2 5/6] kexec: Share logic to copy segment page contents Thiago Jung Bauermann
2016-08-13 3:18 ` [PATCH v2 6/6] IMA: Demonstration code for kexec buffer passing Thiago Jung Bauermann
2016-08-17 2:52 ` [PATCH v2 0/6] kexec_file: Add buffer hand-over for the next kernel Dave Young
2016-08-17 4:58 ` Thiago Jung Bauermann
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