On Fri, 20 Oct 2023, 7:18 pm Stefan Roese, sr@denx.de wrote:
Hi Chris,
On 10/18/23 22:53, Chris Packham wrote:
Since commit 6cdf6b7a340d ("arm64: Use FEAT_HAFDBS to track dirty pages when available") the default get_page_table_size() sets some flags for more efficient handling of dirty page table entries. This causes problems on the AC5/AC5X SoC (specifically a lockup when calling __asm_switch_ttbr() via mmu_set_region_dcache_behaviour()).
The reason for the lockup isn't at all clear but it can be avoided if we provide our own get_page_table_size() which stops gd->arch.has_hafdbs from being set to true effectively returning the AC5/AC5X to the older behaviour. This also opts for a simple fixed page table size rather than trying to duplicate the more complicated logic to optimise the table size.
Signed-off-by: Chris Packham judge.packham@gmail.com
I'm not 100% happy with this approach / workaround - still it fixes an issue on your board, so:
Reviewed-by: Stefan Roese sr@denx.de
Yeah I'm not super happy about this either. But this is about the best I could come up with.
Perhaps you (or someone else) can look into this in more depth to get to the root of this issue at a later time.
I did spend a reasonable amount of time tracking down where things were going wrong, even if I couldn't figure out why. The commit message basically reflects what I found.
Thanks, Stefan
arch/arm/mach-mvebu/alleycat5/cpu.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/arm/mach-mvebu/alleycat5/cpu.c
b/arch/arm/mach-mvebu/alleycat5/cpu.c
index 8204d9627515..7ba57ae75e76 100644 --- a/arch/arm/mach-mvebu/alleycat5/cpu.c +++ b/arch/arm/mach-mvebu/alleycat5/cpu.c @@ -63,6 +63,11 @@ static struct mm_region ac5_mem_map[] = {
struct mm_region *mem_map = ac5_mem_map;
+u64 get_page_table_size(void) +{
return 0x80000;+}
- void reset_cpu(void) { }
Viele Grüße, Stefan Roese
-- DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr@denx.de