s390/vmcore: use vmcore for zfcpdump

Modify the s390 copy_oldmem_page() and remap_oldmem_pfn_range() function
for zfcpdump to read from the HSA memory if memory below HSA_SIZE bytes is
requested.  Otherwise real memory is used.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Jan Willeke <willeke@de.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 110 insertions, 22 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index fb2723e8ba65..3ec272859e1e 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -526,6 +526,7 @@ config CRASH_DUMP
         bool "kernel crash dumps"
         depends on 64BIT && SMP
         select KEXEC
+        select ZFCPDUMP
         help
           Generate crash dump after being started by kexec.
           Crash dump kernels are loaded in the main kernel with kexec-tools
@@ -536,7 +537,7 @@ config CRASH_DUMP
 config ZFCPDUMP
         def_bool n
         prompt "zfcpdump support"
-        select SMP
+        depends on SMP
         help
           Select this option if you want to build an zfcpdump enabled kernel.
           Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h
index 06a136136047..7dc7f9c63b65 100644
--- a/arch/s390/include/asm/sclp.h
+++ b/arch/s390/include/asm/sclp.h
@@ -56,5 +56,6 @@ bool sclp_has_linemode(void);
 bool sclp_has_vt220(void);
 int sclp_pci_configure(u32 fid);
 int sclp_pci_deconfigure(u32 fid);
+int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode);
 
 #endif /* _ASM_S390_SCLP_H */
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 3e776158b330..c84f33d51f7b 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -16,6 +16,7 @@
 #include <asm/os_info.h>
 #include <asm/elf.h>
 #include <asm/ipl.h>
+#include <asm/sclp.h>
 
 #define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
@@ -69,22 +70,41 @@ static ssize_t copy_page_real(void *buf, void *src, size_t csize)
 static void *elfcorehdr_newmem;
 
 /*
- * Copy one page from "oldmem"
+ * Copy one page from zfcpdump "oldmem"
+ *
+ * For pages below ZFCPDUMP_HSA_SIZE memory from the HSA is copied. Otherwise
+ * real memory copy is used.
+ */
+static ssize_t copy_oldmem_page_zfcpdump(char *buf, size_t csize,
+                                         unsigned long src, int userbuf)
+{
+        int rc;
+
+        if (src < ZFCPDUMP_HSA_SIZE) {
+                rc = memcpy_hsa(buf, src, csize, userbuf);
+        } else {
+                if (userbuf)
+                        rc = copy_to_user_real((void __force __user *) buf,
+                                               (void *) src, csize);
+                else
+                        rc = memcpy_real(buf, (void *) src, csize);
+        }
+        return rc ? rc : csize;
+}
+
+/*
+ * Copy one page from kdump "oldmem"
  *
  * For the kdump reserved memory this functions performs a swap operation:
  *  - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
  *  - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
  */
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
-                         size_t csize, unsigned long offset, int userbuf)
+static ssize_t copy_oldmem_page_kdump(char *buf, size_t csize,
+                                      unsigned long src, int userbuf)
+
 {
-        unsigned long src;
         int rc;
 
-        if (!csize)
-                return 0;
-
-        src = (pfn << PAGE_SHIFT) + offset;
         if (src < OLDMEM_SIZE)
                 src += OLDMEM_BASE;
         else if (src > OLDMEM_BASE &&
@@ -95,17 +115,35 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
                                        (void *) src, csize);
         else
                 rc = copy_page_real(buf, (void *) src, csize);
-        return (rc == 0) ? csize : rc;
+        return (rc == 0) ? rc : csize;
 }
 
 /*
- * Remap "oldmem"
+ * Copy one page from "oldmem"
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
+                         unsigned long offset, int userbuf)
+{
+        unsigned long src;
+
+        if (!csize)
+                return 0;
+        src = (pfn << PAGE_SHIFT) + offset;
+        if (OLDMEM_BASE)
+                return copy_oldmem_page_kdump(buf, csize, src, userbuf);
+        else
+                return copy_oldmem_page_zfcpdump(buf, csize, src, userbuf);
+}
+
+/*
+ * Remap "oldmem" for kdump
  *
  * For the kdump reserved memory this functions performs a swap operation:
  * [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
  */
-int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
-                           unsigned long pfn, unsigned long size, pgprot_t prot)
+static int remap_oldmem_pfn_range_kdump(struct vm_area_struct *vma,
+                                        unsigned long from, unsigned long pfn,
+                                        unsigned long size, pgprot_t prot)
 {
         unsigned long size_old;
         int rc;
@@ -125,6 +163,43 @@ int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
 }
 
 /*
+ * Remap "oldmem" for zfcpdump
+ *
+ * We only map available memory above ZFCPDUMP_HSA_SIZE. Memory below
+ * ZFCPDUMP_HSA_SIZE is read on demand using the copy_oldmem_page() function.
+ */
+static int remap_oldmem_pfn_range_zfcpdump(struct vm_area_struct *vma,
+                                           unsigned long from,
+                                           unsigned long pfn,
+                                           unsigned long size, pgprot_t prot)
+{
+        unsigned long size_hsa;
+
+        if (pfn < ZFCPDUMP_HSA_SIZE >> PAGE_SHIFT) {
+                size_hsa = min(size, ZFCPDUMP_HSA_SIZE - (pfn << PAGE_SHIFT));
+                if (size == size_hsa)
+                        return 0;
+                size -= size_hsa;
+                from += size_hsa;
+                pfn += size_hsa >> PAGE_SHIFT;
+        }
+        return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
+/*
+ * Remap "oldmem" for kdump or zfcpdump
+ */
+int remap_oldmem_pfn_range(struct vm_area_struct *vma, unsigned long from,
+                           unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+        if (OLDMEM_BASE)
+                return remap_oldmem_pfn_range_kdump(vma, from, pfn, size, prot);
+        else
+                return remap_oldmem_pfn_range_zfcpdump(vma, from, pfn, size,
+                                                       prot);
+}
+
+/*
  * Copy memory from old kernel
  */
 int copy_from_oldmem(void *dest, void *src, size_t count)
@@ -132,11 +207,21 @@ int copy_from_oldmem(void *dest, void *src, size_t count)
         unsigned long copied = 0;
         int rc;
 
-        if ((unsigned long) src < OLDMEM_SIZE) {
-                copied = min(count, OLDMEM_SIZE - (unsigned long) src);
-                rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
-                if (rc)
-                        return rc;
+        if (OLDMEM_BASE) {
+                if ((unsigned long) src < OLDMEM_SIZE) {
+                        copied = min(count, OLDMEM_SIZE - (unsigned long) src);
+                        rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
+                        if (rc)
+                                return rc;
+                }
+        } else {
+                if ((unsigned long) src < ZFCPDUMP_HSA_SIZE) {
+                        copied = min(count,
+                                     ZFCPDUMP_HSA_SIZE - (unsigned long) src);
+                        rc = memcpy_hsa(dest, (unsigned long) src, copied, 0);
+                        if (rc)
+                                return rc;
+                }
         }
         return memcpy_real(dest + copied, src + copied, count - copied);
 }
@@ -466,7 +551,8 @@ int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
         u32 alloc_size;
         u64 hdr_off;
 
-        if (!OLDMEM_BASE)
+        /* If we are not in kdump or zfcpdump mode return */
+        if (!OLDMEM_BASE && ipl_info.type != IPL_TYPE_FCP_DUMP)
                 return 0;
         /* If elfcorehdr= has been passed via cmdline, we use that one */
         if (elfcorehdr_addr != ELFCORE_ADDR_MAX)
diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 9e5e14686e75..794820a123d0 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -30,8 +30,8 @@
 
 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
 
-#define TO_USER         0
-#define TO_KERNEL       1
+#define TO_USER         1
+#define TO_KERNEL       0
 #define CHUNK_INFO_SIZE 34 /* 2 16-byte char, each followed by blank */
 
 enum arch_id {
@@ -73,7 +73,7 @@ static struct ipl_parameter_block *ipl_block;
  * @count: Size of buffer, which should be copied
  * @mode:  Either TO_KERNEL or TO_USER
  */
-static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
+int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
 {
         int offs, blk_num;
         static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));