powerpc/ppc64/kdump: Better flag for running relocatable

[linux-2.6-omap-h63xx.git] / arch / powerpc / kernel / head_64.S

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 84856bee33a54a5bc58d7c99edf67286ddd281e0..b4bcf5a930fafd50a350d6e97bf8cf8cde833764 100644 (file)
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -106,6 +106,20 @@ __secondary_hold_acknowledge:
        .llong hvReleaseData-KERNELBASE
 #endif /* CONFIG_PPC_ISERIES */
 
+#ifdef CONFIG_CRASH_DUMP
+       /* This flag is set to 1 by a loader if the kernel should run
+        * at the loaded address instead of the linked address.  This
+        * is used by kexec-tools to keep the the kdump kernel in the
+        * crash_kernel region.  The loader is responsible for
+        * observing the alignment requirement.
+        */
+       /* Do not move this variable as kexec-tools knows about it. */
+       . = 0x5c
+       .globl  __run_at_load
+__run_at_load:
+       .long   0x72756e30      /* "run0" -- relocate to 0 by default */
+#endif
+
        . = 0x60
 /*
  * The following code is used to hold secondary processors
@@ -1384,7 +1398,13 @@ _STATIC(__after_prom_start)
        /* process relocations for the final address of the kernel */
        lis     r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
        sldi    r25,r25,32
-       mr      r3,r25
+#ifdef CONFIG_CRASH_DUMP
+       lwz     r7,__run_at_load-_stext(r26)
+       cmplwi  cr0,r7,1        /* kdump kernel ? - stay where we are */
+       bne     1f
+       add     r25,r25,r26
+#endif
+1:     mr      r3,r25
        bl      .relocate
 #endif
 
@@ -1398,11 +1418,26 @@ _STATIC(__after_prom_start)
        li      r3,0                    /* target addr */
        mr.     r4,r26                  /* In some cases the loader may  */
        beq     9f                      /* have already put us at zero */
-       lis     r5,(copy_to_here - _stext)@ha
-       addi    r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
        li      r6,0x100                /* Start offset, the first 0x100 */
                                        /* bytes were copied earlier.    */
 
+#ifdef CONFIG_CRASH_DUMP
+/*
+ * Check if the kernel has to be running as relocatable kernel based on the
+ * variable __run_at_load, if it is set the kernel is treated as relocatable
+ * kernel, otherwise it will be moved to PHYSICAL_START
+ */
+       lwz     r7,__run_at_load-_stext(r26)
+       cmplwi  cr0,r7,1
+       bne     3f
+
+       li      r5,__end_interrupts - _stext    /* just copy interrupts */
+       b       5f
+3:
+#endif
+       lis     r5,(copy_to_here - _stext)@ha
+       addi    r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
+
        bl      .copy_and_flush         /* copy the first n bytes        */
                                        /* this includes the code being  */
                                        /* executed here.                */
@@ -1411,15 +1446,15 @@ _STATIC(__after_prom_start)
        mtctr   r8
        bctr
 
+p_end: .llong  _end - _stext
+
 4:     /* Now copy the rest of the kernel up to _end */
        addis   r5,r26,(p_end - _stext)@ha
        ld      r5,(p_end - _stext)@l(r5)       /* get _end */
-       bl      .copy_and_flush         /* copy the rest */
+5:     bl      .copy_and_flush         /* copy the rest */
 
 9:     b       .start_here_multiplatform
 
-p_end: .llong  _end - _stext
-
 /*
  * Copy routine used to copy the kernel to start at physical address 0
  * and flush and invalidate the caches as needed.