Re: [PATCH v1 03/13] powerpc/mm/32s: rework mmu_mapin_ram()
From: Christophe Leroy
Date: Tue Dec 18 2018 - 04:19:02 EST
On 12/18/2018 03:05 AM, Jonathan Neuschäfer wrote:
On Mon, Dec 17, 2018 at 10:29:18AM +0100, Christophe Leroy wrote:
With patches 1-3:
[ 0.000000] setbat(0, c0000000, 00000000, 01000000, 311)
[ 0.000000] setbat(2, c1000000, 01000000, 00800000, 311)
[ 0.000000] setbat(4, d0000000, 10000000, 02000000, 791)
What we see is that BAT0 is not used in the origin. I have always wondered
the reason, maybe there is something odd behind and BAT0 shall no ne used.
Could you try and modify find_free_bat() so that it starts at b = 1 instead
of b = 0 ?
In this case, setbat is called with index 2, 3, and 4, but the Wii still
doesn't boot.
According to arch/powerpc/include/asm/book3s/32/hash.h,
- 0x591 = _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | _PAGE_PRESENT
- 0x311 = _PAGE_EXEC | _PAGE_ACCESSED | _PAGE_COHERENT | _PAGE_PRESENT
- 0x791 = _PAGE_RW | _PAGE_EXEC | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | _PAGE_PRESENT
Yes, patch 1 added _PAGE_EXEC which explains this 0x200.
Do you confirm it still works well with only patch 1 ?
Patch 1 alone boots to userspace.
Ok, thanks for testing.
The only difference I see then are the flags. Everything else is seems
identical.
I know you tried already, but would you mind trying once more with the
following change ?
diff --git b/arch/powerpc/mm/ppc_mmu_32.c a/arch/powerpc/mm/ppc_mmu_32.c
index 61c10ee00ba2..628fba266663 100644
--- b/arch/powerpc/mm/ppc_mmu_32.c
+++ a/arch/powerpc/mm/ppc_mmu_32.c
@@ -119,7 +119,7 @@ unsigned long __init mmu_mapin_ram(unsigned long
base, unsigned long top)
if (size < 128 << 10)
break;
- setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT);
+ setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_X);
base += size;
}
I think we may have some code trying to modify the kernel text without
using code patching functions.
Thanks,
Christophe
Jonathan