proc: move /proc/vmcore creation to fs/proc/vmcore.c

[linux-2.6-omap-h63xx.git] / include / linux / crash_dump.h

diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index 6cd39a927e1fc80d2c92248e8c71895caf06aa91..2dac064d8359046c178f0d98bd9ea915ca369eaa 100644 (file)
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -8,11 +8,12 @@
 #include <linux/proc_fs.h>
 
 #define ELFCORE_ADDR_MAX       (-1ULL)
+#define ELFCORE_ADDR_ERR       (-2ULL)
+
 extern unsigned long long elfcorehdr_addr;
+
 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
                                                unsigned long, int);
-extern const struct file_operations proc_vmcore_operations;
-extern struct proc_dir_entry *proc_vmcore;
 
 /* Architecture code defines this if there are other possible ELF
  * machine types, e.g. on bi-arch capable hardware. */
@@ -22,10 +23,43 @@ extern struct proc_dir_entry *proc_vmcore;
 
 #define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
 
+/*
+ * is_kdump_kernel() checks whether this kernel is booting after a panic of
+ * previous kernel or not. This is determined by checking if previous kernel
+ * has passed the elf core header address on command line.
+ *
+ * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
+ * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
+ * previous kernel.
+ */
+
 static inline int is_kdump_kernel(void)
 {
        return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
 }
+
+/* is_vmcore_usable() checks if the kernel is booting after a panic and
+ * the vmcore region is usable.
+ *
+ * This makes use of the fact that due to alignment -2ULL is not
+ * a valid pointer, much in the vain of IS_ERR(), except
+ * dealing directly with an unsigned long long rather than a pointer.
+ */
+
+static inline int is_vmcore_usable(void)
+{
+       return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
+}
+
+/* vmcore_unusable() marks the vmcore as unusable,
+ * without disturbing the logic of is_kdump_kernel()
+ */
+
+static inline void vmcore_unusable(void)
+{
+       if (is_kdump_kernel())
+               elfcorehdr_addr = ELFCORE_ADDR_ERR;
+}
 #else /* !CONFIG_CRASH_DUMP */
 static inline int is_kdump_kernel(void) { return 0; }
 #endif /* CONFIG_CRASH_DUMP */