From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Mon, 7 Jul 2014 18:38:17 +0000 (-0700)
Subject: sparc: add crash dump support
X-Git-Tag: v4.1.12-92~147^2~3^2~6
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=01b4d3df90ab75fff844e20c990dcc0b9f23d2a0;p=users%2Fjedix%2Flinux-maple.git

sparc: add crash dump support

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
---

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 7b1daebf6528c..9c56e0d822a93 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -290,6 +290,17 @@ config KEXEC
 	  support.  As of this writing the exact hardware interface is
 	  strongly in flux, so no good recommendation can be made.
 
+config CRASH_DUMP
+	bool "kernel crash dumps"
+	depends on KEXEC
+	---help---
+	  Generate crash dump after being started by kexec.
+	  This should be normally only set in special crash dump kernels
+	  which are loaded in the main kernel with kexec-tools into
+	  a specially reserved region and then later executed after
+	  a crash by kdump/kexec.
+	  For more details see Documentation/kdump/kdump.txt
+
 config US3_MC
 	tristate "UltraSPARC-III Memory Controller driver"
 	depends on SPARC64
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index acbd76897a17d..d096a33ee73d6 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -120,3 +120,4 @@ obj-$(CONFIG_SPARC64)	+= jump_label.o
 
 obj-$(CONFIG_SPARC64)	+= kexec_shim.o
 obj-$(CONFIG_KEXEC)	+= machine_kexec.o
+obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
diff --git a/arch/sparc/kernel/crash_dump.c b/arch/sparc/kernel/crash_dump.c
new file mode 100644
index 0000000000000..434ecd23bf410
--- /dev/null
+++ b/arch/sparc/kernel/crash_dump.c
@@ -0,0 +1,48 @@
+#include <linux/errno.h>
+#include <linux/crash_dump.h>
+#include <linux/io.h>
+#include <linux/bootmem.h>
+#include <asm/uaccess.h>
+
+/**
+ * copy_oldmem_page - copy one page from "oldmem"
+ * @pfn: page frame number to be copied
+ * @buf: target memory address for the copy; this can be in kernel address
+ *	space or user address space (see @userbuf)
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page (based on pfn) to begin the copy
+ * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+ *	otherwise @buf is in kernel address space, use memcpy().
+ *
+ * Copy a page from "oldmem". For this page, there is no pte mapped
+ * in the current kernel. We stitch up a pte, similar to kmap_atomic.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
+			 unsigned long offset, int userbuf)
+{
+	void  *vaddr;
+	int need_remap;
+
+	if (!csize)
+		return 0;
+
+	need_remap = (pfn < min_low_pfn) || (pfn > max_pfn);
+	if (need_remap)
+		vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+	else
+		vaddr = pfn_to_kaddr(pfn);
+
+	if (userbuf) {
+		if (copy_to_user(buf, (vaddr + offset), csize)) {
+			if (need_remap)
+				iounmap(vaddr);
+			return -EFAULT;
+		}
+	} else
+		memcpy(buf, (vaddr + offset), csize);
+
+	if (need_remap)
+		iounmap(vaddr);
+
+	return csize;
+}