On Fri, 20 Oct 2023, 7:18 pm Stefan Roese, <s...@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.pack...@gmail.com> > > I'm not 100% happy with this approach / workaround - still it fixes an > issue on your board, so: > > Reviewed-by: Stefan Roese <s...@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: s...@denx.de >