Thread (5 messages) 5 messages, 3 authors, 2007-06-23

Re: [patch 23/33] powerpc: Localize mmu_off

From: Milton Miller <hidden>
Date: 2007-06-18 14:08:45

On Sat Jun 16 08:06:19 EST 2007, Geoff Levand wrote:
This just removes the dependency __mmu_off has on the symbol
__after_prom_start.  I found the current code inconvenient when I
wanted to put some debugging code between the call to __mmu_off
and the branch to __after_prom_start.
You are entering this code with the mmu on?

My first thought was that is unexpected, but aparently Apple machines 
do that, so its supported for the master -- not the slaves.
quoted hunk ↗ jump to hunk
Signed-off-by: Geoff Levand <geoffrey.levand at am.sony.com>
---
 arch/powerpc/kernel/head_64.S |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -1695,9 +1695,11 @@ _GLOBAL(__start_initialization_multiplat
 2:

        /* Switch off MMU if not already */
-       LOAD_REG_IMMEDIATE(r4, .__after_prom_start - KERNELBASE)
+       LOAD_REG_IMMEDIATE(r4, __mmu_off_return - KERNELBASE)
        add     r4,r4,r30
        bl      .__mmu_off
+__mmu_off_return:
+
        b       .__after_prom_start

 _STATIC(__boot_from_prom)
-- 
That seems like a long label.

I could stand a 1: there (ie a local numeric label).

Hmm... how about always going directly there:

-       bl      .__mmu_off
-       b       .__after_prom_start
+       mtlr    r4
+       b       .__mmu_off


So that there is no space to add code that is skipped if the mmu was on?

milton
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