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Subject[PATCH 27/29] crashdump-routines-for-copying-dump-pages
Date

kernel/crash.c has been renamed kernel/crash_dump.c to clarify it's purpose.

From: Hariprasad Nellitheertha <hari@in.ibm.com>

This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.

Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>

Signed-off-by: Eric Biederman <ebiederm@xmission.com>
---

arch/i386/mm/highmem.c | 18 ++++++++++++++++++
include/asm-i386/highmem.h | 1 +
include/linux/highmem.h | 1 +
kernel/crash_dump.c | 33 +++++++++++++++++++++++++++++++++
4 files changed, 53 insertions(+)

diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/arch/i386/mm/highmem.c linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/arch/i386/mm/highmem.c
--- linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/arch/i386/mm/highmem.c Fri Jan 14 04:32:22 2005
+++ linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/arch/i386/mm/highmem.c Tue Jan 18 23:16:41 2005
@@ -74,6 +74,24 @@
preempt_check_resched();
}

+/* This is the same as kmap_atomic() but can map memory that doesn't
+ * have a struct page associated with it.
+ */
+void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
+{
+ enum fixed_addresses idx;
+ unsigned long vaddr;
+
+ inc_preempt_count();
+
+ idx = type + KM_TYPE_NR*smp_processor_id();
+ vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+ set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
+ __flush_tlb_one(vaddr);
+
+ return (void*) vaddr;
+}
+
struct page *kmap_atomic_to_page(char *ptr)
{
unsigned long idx, vaddr = (unsigned long)ptr;
diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/include/asm-i386/highmem.h linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/include/asm-i386/highmem.h
--- linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/include/asm-i386/highmem.h Fri Jan 14 04:32:27 2005
+++ linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/include/asm-i386/highmem.h Tue Jan 18 23:16:41 2005
@@ -72,6 +72,7 @@
void kunmap(struct page *page);
char *kmap_atomic(struct page *page, enum km_type type);
void kunmap_atomic(char *kvaddr, enum km_type type);
+void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
struct page *kmap_atomic_to_page(char *ptr);

#define flush_cache_kmaps() do { } while (0)
diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/include/linux/highmem.h linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/include/linux/highmem.h
--- linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/include/linux/highmem.h Fri Jan 14 04:32:27 2005
+++ linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/include/linux/highmem.h Tue Jan 18 23:16:41 2005
@@ -28,6 +28,7 @@

#define kmap_atomic(page, idx) ((char *)page_address(page))
#define kunmap_atomic(addr, idx) do { char *p = addr; (void)p; } while (0)
+#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
#define kmap_atomic_to_page(ptr) virt_to_page(ptr)

#endif /* CONFIG_HIGHMEM */
diff -uNr linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/kernel/crash_dump.c linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/kernel/crash_dump.c
--- linux-2.6.11-rc1-mm1-nokexec-crashdump-memory-preserving-reboot-using-kexec/kernel/crash_dump.c Tue Jan 18 23:16:24 2005
+++ linux-2.6.11-rc1-mm1-nokexec-crashdump-routines-for-copying-dump-pages/kernel/crash_dump.c Tue Jan 18 23:16:41 2005
@@ -8,6 +8,39 @@
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/crash_dump.h>
+
#include <asm/io.h>
#include <asm/uaccess.h>

+/*
+ * 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, int userbuf)
+{
+ void *page, *vaddr;
+
+ if (!csize)
+ return 0;
+
+ page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+ vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
+ copy_page(page, vaddr);
+ kunmap_atomic(vaddr, KM_PTE0);
+
+ if (userbuf) {
+ if (copy_to_user(buf, page, csize)) {
+ kfree(page);
+ return -EFAULT;
+ }
+ } else
+ memcpy(buf, page, csize);
+ kfree(page);
+
+ return 0;
+}
-
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