Resolves: bz1097904
https://bugzilla.redhat.com/show_bug.cgi?id=1097904
This is back ported from upstream. It need be edited manually since
several irrelevant commits are not back ported.
commit 191a2fa0a8d2bbb64c98f9b1976fcb37ee5eae6b
Author: Michael Holzheu <holz...@linux.vnet.ibm.com>
Date: Thu Jul 18 12:18:27 2013 +0200
s390/kdump: Allow copy_oldmem_page() copy to virtual memory
The kdump mmap patch series (git commit 83086978c63afd7c73e1c) changed the
requirements for copy_oldmem_page(). Now this function is used for copying
to virtual memory.
So implement vmalloc support for the s390 version of copy_oldmem_page().
Signed-off-by: Michael Holzheu <holz...@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidef...@de.ibm.com>
Signed-off-by: Baoquan He <b...@redhat.com>
---
arch/s390/kernel/crash_dump.c | 49 ++++++++++++++++++++++++++++++++++++++++---
1 file changed, 46 insertions(+), 3 deletions(-)
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index b66edb9..0f70217 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -56,6 +56,47 @@ static int __init setup_elfcorehdr(char *arg)
early_param("elfcorehdr", setup_elfcorehdr);
/*
+ * Return physical address for virtual address
+ */
+static inline void *load_real_addr(void *addr)
+{
+ unsigned long real_addr;
+
+ asm volatile(
+ " lra %0,0(%1)\n"
+ " jz 0f\n"
+ " la %0,0\n"
+ "0:"
+ : "=a" (real_addr) : "a" (addr) : "cc");
+ return (void *)real_addr;
+}
+
+/*
+ * Copy up to one page to vmalloc or real memory
+ */
+static ssize_t copy_page_real(void *buf, void *src, size_t csize)
+{
+ size_t size;
+
+ if (is_vmalloc_addr(buf)) {
+ BUG_ON(csize >= PAGE_SIZE);
+ /* If buf is not page aligned, copy first part */
+ size = min(roundup(__pa(buf), PAGE_SIZE) - __pa(buf), csize);
+ if (size) {
+ if (memcpy_real(load_real_addr(buf), src, size))
+ return -EFAULT;
+ buf += size;
+ src += size;
+ }
+ /* Copy second part */
+ size = csize - size;
+ return (size) ? memcpy_real(load_real_addr(buf), src, size) : 0;
+ } else {
+ return memcpy_real(buf, src, csize);
+ }
+}
+
+/*
* Copy one page from "oldmem"
*
* For the kdump reserved memory this functions performs a swap operation:
@@ -66,6 +107,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
{
unsigned long src;
+ int rc;
if (!csize)
return 0;
@@ -77,10 +119,11 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
src < OLDMEM_BASE + OLDMEM_SIZE)
src -= OLDMEM_BASE;
if (userbuf)
- copy_to_user_real((void __user *) buf, (void *) src, csize);
+ rc = copy_to_user_real((void __force __user *) buf,
+ (void *) src, csize);
else
- memcpy_real(buf, (void *) src, csize);
- return csize;
+ rc = copy_page_real(buf, (void *) src, csize);
+ return (rc == 0) ? csize : rc;
}
/*
--
2.1.0
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