diff options
Diffstat (limited to 'lib/aarch64/misc_helpers.S')
| -rw-r--r-- | lib/aarch64/misc_helpers.S | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/lib/aarch64/misc_helpers.S b/lib/aarch64/misc_helpers.S index c33ade28..bccc936a 100644 --- a/lib/aarch64/misc_helpers.S +++ b/lib/aarch64/misc_helpers.S @@ -79,6 +79,9 @@ .globl zeromem16 .globl memcpy16 + .globl disable_mmu_el3 + .globl disable_mmu_icache_el3 + func get_afflvl_shift cmp x0, #3 @@ -332,3 +335,27 @@ m_loop1: subs x2, x2, #1 b.ne m_loop1 m_end: ret + +/* --------------------------------------------------------------------------- + * Disable the MMU at EL3 + * This is implemented in assembler to ensure that the data cache is cleaned + * and invalidated after the MMU is disabled without any intervening cacheable + * data accesses + * --------------------------------------------------------------------------- + */ + +func disable_mmu_el3 + mov x1, #(SCTLR_M_BIT | SCTLR_C_BIT) +do_disable_mmu: + mrs x0, sctlr_el3 + bic x0, x0, x1 + msr sctlr_el3, x0 + isb // ensure MMU is off + mov x0, #DCCISW // DCache clean and invalidate + b dcsw_op_all + + +func disable_mmu_icache_el3 + mov x1, #(SCTLR_M_BIT | SCTLR_C_BIT | SCTLR_I_BIT) + b do_disable_mmu + |