On 2023-10-18 21:53, 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
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) { }
This looks terribly wrong. In all honesty, if the original patch creates problems and that people add this sort of stuff to paper over it, I'd rather your *revert* my patch altogether.
M.