diff options
Diffstat (limited to 'arch/arm/cpu/armv8/cache.S')
| -rw-r--r-- | arch/arm/cpu/armv8/cache.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv8/cache.S b/arch/arm/cpu/armv8/cache.S index ab8c08917a..a9f4fec387 100644 --- a/arch/arm/cpu/armv8/cache.S +++ b/arch/arm/cpu/armv8/cache.S @@ -10,6 +10,7 @@ #include <asm-offsets.h> #include <config.h> #include <asm/macro.h> +#include <asm/system.h> #include <linux/linkage.h> /* @@ -160,3 +161,56 @@ ENTRY(__asm_flush_l3_cache) ret ENDPROC(__asm_flush_l3_cache) .weak __asm_flush_l3_cache + +/* + * void __asm_switch_ttbr(ulong new_ttbr) + * + * Safely switches to a new page table. + */ +ENTRY(__asm_switch_ttbr) + /* x2 = SCTLR (alive throghout the function) */ + switch_el x4, 3f, 2f, 1f +3: mrs x2, sctlr_el3 + b 0f +2: mrs x2, sctlr_el2 + b 0f +1: mrs x2, sctlr_el1 +0: + + /* Unset CR_M | CR_C | CR_I from SCTLR to disable all caches */ + movn x1, #(CR_M | CR_C | CR_I) + and x1, x2, x1 + switch_el x4, 3f, 2f, 1f +3: msr sctlr_el3, x1 + b 0f +2: msr sctlr_el2, x1 + b 0f +1: msr sctlr_el1, x1 +0: isb + + /* This call only clobbers x30 (lr) and x9 (unused) */ + mov x3, x30 + bl __asm_invalidate_tlb_all + + /* From here on we're running safely with caches disabled */ + + /* Set TTBR to our first argument */ + switch_el x4, 3f, 2f, 1f +3: msr ttbr0_el3, x0 + b 0f +2: msr ttbr0_el2, x0 + b 0f +1: msr ttbr0_el1, x0 +0: isb + + /* Restore original SCTLR and thus enable caches again */ + switch_el x4, 3f, 2f, 1f +3: msr sctlr_el3, x2 + b 0f +2: msr sctlr_el2, x2 + b 0f +1: msr sctlr_el1, x2 +0: isb + + ret x3 +ENDPROC(__asm_switch_ttbr) |
