[Xen-devel] [PATCH 5/7] kexec: Get backup area start address and size directly from mem_range

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

Get backup area start address and size directly from mem_range.
Under Xen /proc/iomem contains invalid values.

Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
 kexec/arch/i386/crashdump-x86.c |   55 +++++++++++++-------------------------
 1 files changed, 19 insertions(+), 36 deletions(-)

diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index 77a1329..56ef59e 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -667,44 +667,28 @@ static int cmdline_add_memmap_acpi(char *cmdline, 
unsigned long start,
        return 0;
 }
 
-static void get_backup_area(unsigned long *start, unsigned long *end)
+static void get_backup_area(struct kexec_info *info,
+                               struct memory_range *range, int ranges)
 {
-       const char *iomem = proc_iomem();
-       char line[MAX_LINE];
-       FILE *fp;
+       int i;
 
-       fp = fopen(iomem, "r");
-       if (!fp) {
-               fprintf(stderr, "Cannot open %s: %s\n",
-                       iomem, strerror(errno));
-               return;
-       }
+       /* Look for first 640 KiB RAM region. */
+       for (i = 0; i < ranges; ++i) {
+               if (range[i].type != RANGE_RAM || range[i].end > 0xa0000)
+                       continue;
 
-       while(fgets(line, sizeof(line), fp) != 0) {
-               char *str;
-               int count, consumed;
-               unsigned long mstart, mend;
+               info->backup_src_start = range[i].start;
+               info->backup_src_size = range[i].end - range[i].start + 1;
 
-               count = sscanf(line, "%lx-%lx : %n",
-                       &mstart, &mend, &consumed);
-               if (count != 2)
-                       continue;
-               str = line + consumed;
-               dbgprintf("%016lx-%016lx : %s",
-                       mstart, mend, str);
-
-               /* Hopefully there is only one RAM region in the first 640K */
-               if (memcmp(str, "System RAM\n", 11) == 0 && mend <= 0xa0000 ) {
-                       dbgprintf("%s: %016lx-%016lx : %s", __func__, mstart, 
mend, str);
-                       *start = mstart;
-                       *end = mend;
-                       fclose(fp);
-                       return;
-               }
+               dbgprintf("%s: %016llx-%016llx : System RAM\n", __func__,
+                                               range[i].start, range[i].end);
+
+               return;
        }
-       *start = BACKUP_SRC_START;
-       *end = BACKUP_SRC_END;
-       fclose(fp);
+
+       /* First 640 KiB RAM region not found. Assume defaults. */
+       info->backup_src_start = BACKUP_SRC_START;
+       info->backup_src_size = BACKUP_SRC_END - BACKUP_SRC_START + 1;
 }
 
 /* Loads additional segments in case of a panic kernel is being loaded.
@@ -720,15 +704,12 @@ int load_crashdump_segments(struct kexec_info *info, 
char* mod_cmdline,
        struct memory_range *mem_range, *memmap_p;
        struct crash_elf_info elf_info;
        unsigned kexec_arch;
-       unsigned long tmp_backup_end = 0;
 
        memset(&elf_info, 0x0, sizeof(elf_info));
 
        /* Constant parts of the elf_info */
        memset(&elf_info, 0, sizeof(elf_info));
        elf_info.data             = ELFDATA2LSB;
-       get_backup_area(&info->backup_src_start, &tmp_backup_end);
-       info->backup_src_size = tmp_backup_end - info->backup_src_start + 1;
 
        /* Get the architecture of the running kernel */
        kexec_arch = info->kexec_flags & KEXEC_ARCH_MASK;
@@ -756,6 +737,8 @@ int load_crashdump_segments(struct kexec_info *info, char* 
mod_cmdline,
                                    elf_info.lowmem_limit) < 0)
                return -1;
 
+       get_backup_area(info, mem_range, nr_ranges);
+
        /*
         * if the core type has not been set on command line, set it here
         * automatically
-- 
1.5.6.5


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