hangs at core_mmt_set_user_map when executing hello_world demo about optee_os

[MrVan]

When blx r3 which is the instruction which cause system hangs. Seems this is cache or mmu set issue. Still have no clear idea.

movw r3, #35e5

movt r3, #9c10

blx r3 --> system hangs

[jenswi-linaro]

Without LPAE ttbr0 is only supposed to cover low address (<= 32 MiB), perhaps TTBCR.N isn't 7.

[MrVan]

Hi Jens,

I have found the root cause. Actually TTBCR.N is 7. We should first clear the tbl_info.table before fill mmu entries. From my debug info, the first entry is leaved and not set. So when set ttbr0, it corrupts system and hangs. After the following piece of code, all is fine.

diff --git a/core/arch/arm/mm/core_mmu_v7.c b/core/arch/arm/mm/core_mmu_v7.c

index 0ea0da3..10ed12b 100644

--- a/core/arch/arm/mm/core_mmu_v7.c

+++ b/core/arch/arm/mm/core_mmu_v7.c

@@ -379,6 +379,13 @@ static paddr_t populate_user_map(struct tee_mmu_info *mmu)

tbl_info.shift = SECTION_SHIFT;

tbl_info.num_entries = TEE_MMU_UL1_NUM_ENTRIES;

+       /*


   \* Need to clear the table before use, because there maybe junk



   \* data at tlb_info.table, which may corrupt system when set ttbr0



   */



  memset(tbl_info.table, 0x00,



         sizeof(unsigned long) \* tbl_info.num_entries);



  region.pa = 0;
  region.va = va_range_base;
  region.attr = 0;

Fix in #342