powerpc/boot: don't clobber r6 and r7 in epapr boot

We use r6 and r7 for epapr boot, but the current pre-C init will clobber
both of these.

This change does a simple replacement, of r6 -> r12 and r7 -> r13, so
that we hit platform init with these registers intact.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S
index e0040621d00c54033d7061beedd8ea57abdf0f97..12866ccb5694d3bce05fa7ab8030a57585eb2914 100644 (file)
--- a/arch/powerpc/boot/crt0.S
+++ b/arch/powerpc/boot/crt0.S
@@ -155,29 +155,29 @@ p_base:   mflr    r10             /* r10 now points to runtime addr of p_base */
        ld      r9,(p_rela-p_base)(r10)
        add     r9,r9,r10
 
-       li      r7,0
+       li      r13,0
        li      r8,0
-9:     ld      r6,0(r11)       /* get tag */
-       cmpdi   r6,0
+9:     ld      r12,0(r11)       /* get tag */
+       cmpdi   r12,0
        beq     12f              /* end of list */
-       cmpdi   r6,RELA
+       cmpdi   r12,RELA
        bne     10f
-       ld      r7,8(r11)       /* get RELA pointer in r7 */
+       ld      r13,8(r11)       /* get RELA pointer in r13 */
        b       11f
-10:    addis   r6,r6,(-RELACOUNT)@ha
-       cmpdi   r6,RELACOUNT@l
+10:    addis   r12,r12,(-RELACOUNT)@ha
+       cmpdi   r12,RELACOUNT@l
        bne     11f
        ld      r8,8(r11)       /* get RELACOUNT value in r8 */
 11:    addi    r11,r11,16
        b       9b
 12:
-       cmpdi   r7,0            /* check we have both RELA and RELACOUNT */
+       cmpdi   r13,0            /* check we have both RELA and RELACOUNT */
        cmpdi   cr1,r8,0
        beq     3f
        beq     cr1,3f
 
        /* Calcuate the runtime offset. */
-       subf    r7,r7,r9
+       subf    r13,r13,r9
 
        /* Run through the list of relocations and process the
         * R_PPC64_RELATIVE ones. */
@@ -185,10 +185,10 @@ p_base:   mflr    r10             /* r10 now points to runtime addr of p_base */
 13:    ld      r0,8(r9)        /* ELF64_R_TYPE(reloc->r_info) */
        cmpdi   r0,22           /* R_PPC64_RELATIVE */
        bne     3f
-       ld      r6,0(r9)        /* reloc->r_offset */
+       ld      r12,0(r9)        /* reloc->r_offset */
        ld      r0,16(r9)       /* reloc->r_addend */
-       add     r0,r0,r7
-       stdx    r0,r7,r6
+       add     r0,r0,r13
+       stdx    r0,r13,r12
        addi    r9,r9,24
        bdnz    13b