diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/aarch64/cache_helpers.S | 6 | ||||
| -rw-r--r-- | lib/xlat_tables_v2/ro_xlat_tables.mk | 37 | ||||
| -rw-r--r-- | lib/xlat_tables_v2/xlat_tables.mk | 6 | ||||
| -rw-r--r-- | lib/xlat_tables_v2/xlat_tables_context.c | 78 |
4 files changed, 122 insertions, 5 deletions
diff --git a/lib/aarch64/cache_helpers.S b/lib/aarch64/cache_helpers.S index 9ef8ca79b..de9c8e4f0 100644 --- a/lib/aarch64/cache_helpers.S +++ b/lib/aarch64/cache_helpers.S @@ -1,5 +1,5 @@ /* - * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ @@ -30,7 +30,7 @@ loop_\op: dc \op, x0 add x0, x0, x2 cmp x0, x1 - b.lo loop_\op + b.lo loop_\op dsb sy exit_loop_\op: ret @@ -140,7 +140,7 @@ loop3_\_op: level_done: add x10, x10, #2 // increment cache number cmp x3, x10 - b.hi loop1 + b.hi loop1 msr csselr_el1, xzr // select cache level 0 in csselr dsb sy // barrier to complete final cache operation isb diff --git a/lib/xlat_tables_v2/ro_xlat_tables.mk b/lib/xlat_tables_v2/ro_xlat_tables.mk new file mode 100644 index 000000000..7991e1afd --- /dev/null +++ b/lib/xlat_tables_v2/ro_xlat_tables.mk @@ -0,0 +1,37 @@ +# +# Copyright (c) 2020, ARM Limited. All rights reserved. +# +# SPDX-License-Identifier: BSD-3-Clause +# + +ifeq (${USE_DEBUGFS}, 1) + $(error "Debugfs requires functionality from the dynamic translation \ + library and is incompatible with ALLOW_RO_XLAT_TABLES.") +endif + +ifeq (${ARCH},aarch32) + ifeq (${RESET_TO_SP_MIN},1) + $(error "RESET_TO_SP_MIN requires functionality from the dynamic \ + translation library and is incompatible with \ + ALLOW_RO_XLAT_TABLES.") + endif +else # if AArch64 + ifeq (${PLAT},tegra) + $(error "Tegra requires functionality from the dynamic translation \ + library and is incompatible with ALLOW_RO_XLAT_TABLES.") + endif + ifeq (${RESET_TO_BL31},1) + $(error "RESET_TO_BL31 requires functionality from the dynamic \ + translation library and is incompatible with \ + ALLOW_RO_XLAT_TABLES.") + endif + ifeq (${SPD},trusty) + $(error "Trusty requires functionality from the dynamic translation \ + library and is incompatible with ALLOW_RO_XLAT_TABLES.") + endif + ifeq (${SPM_MM},1) + $(error "SPM_MM requires functionality to change memory region \ + attributes, which is not possible once the translation tables \ + have been made read-only.") + endif +endif diff --git a/lib/xlat_tables_v2/xlat_tables.mk b/lib/xlat_tables_v2/xlat_tables.mk index c946315bf..bcc3e68d8 100644 --- a/lib/xlat_tables_v2/xlat_tables.mk +++ b/lib/xlat_tables_v2/xlat_tables.mk @@ -1,5 +1,5 @@ # -# Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved. +# Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved. # # SPDX-License-Identifier: BSD-3-Clause # @@ -13,3 +13,7 @@ XLAT_TABLES_LIB_SRCS := $(addprefix lib/xlat_tables_v2/, \ XLAT_TABLES_LIB_V2 := 1 $(eval $(call add_define,XLAT_TABLES_LIB_V2)) + +ifeq (${ALLOW_RO_XLAT_TABLES}, 1) + include lib/xlat_tables_v2/ro_xlat_tables.mk +endif diff --git a/lib/xlat_tables_v2/xlat_tables_context.c b/lib/xlat_tables_v2/xlat_tables_context.c index f4b64b33f..adca57875 100644 --- a/lib/xlat_tables_v2/xlat_tables_context.c +++ b/lib/xlat_tables_v2/xlat_tables_context.c @@ -1,9 +1,10 @@ /* - * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ +#include <arch_helpers.h> #include <assert.h> #include <platform_def.h> @@ -24,8 +25,14 @@ uint64_t mmu_cfg_params[MMU_CFG_PARAM_MAX]; * Allocate and initialise the default translation context for the BL image * currently executing. */ +#if PLAT_RO_XLAT_TABLES +REGISTER_XLAT_CONTEXT_RO_BASE_TABLE(tf, MAX_MMAP_REGIONS, MAX_XLAT_TABLES, + PLAT_VIRT_ADDR_SPACE_SIZE, PLAT_PHY_ADDR_SPACE_SIZE, + EL_REGIME_INVALID, "xlat_table"); +#else REGISTER_XLAT_CONTEXT(tf, MAX_MMAP_REGIONS, MAX_XLAT_TABLES, PLAT_VIRT_ADDR_SPACE_SIZE, PLAT_PHY_ADDR_SPACE_SIZE); +#endif void mmap_add_region(unsigned long long base_pa, uintptr_t base_va, size_t size, unsigned int attr) @@ -119,6 +126,75 @@ int xlat_change_mem_attributes(uintptr_t base_va, size_t size, uint32_t attr) return xlat_change_mem_attributes_ctx(&tf_xlat_ctx, base_va, size, attr); } +#if PLAT_RO_XLAT_TABLES +/* Change the memory attributes of the descriptors which resolve the address + * range that belongs to the translation tables themselves, which are by default + * mapped as part of read-write data in the BL image's memory. + * + * Since the translation tables map themselves via these level 3 (page) + * descriptors, any change applied to them with the MMU on would introduce a + * chicken and egg problem because of the break-before-make sequence. + * Eventually, it would reach the descriptor that resolves the very table it + * belongs to and the invalidation (break step) would cause the subsequent write + * (make step) to it to generate an MMU fault. Therefore, the MMU is disabled + * before making the change. + * + * No assumption is made about what data this function needs, therefore all the + * caches are flushed in order to ensure coherency. A future optimization would + * be to only flush the required data to main memory. + */ +int xlat_make_tables_readonly(void) +{ + assert(tf_xlat_ctx.initialized == true); +#ifdef __aarch64__ + if (tf_xlat_ctx.xlat_regime == EL1_EL0_REGIME) { + disable_mmu_el1(); + } else if (tf_xlat_ctx.xlat_regime == EL3_REGIME) { + disable_mmu_el3(); + } else { + assert(tf_xlat_ctx.xlat_regime == EL2_REGIME); + return -1; + } + + /* Flush all caches. */ + dcsw_op_all(DCCISW); +#else /* !__aarch64__ */ + assert(tf_xlat_ctx.xlat_regime == EL1_EL0_REGIME); + /* On AArch32, we flush the caches before disabling the MMU. The reason + * for this is that the dcsw_op_all AArch32 function pushes some + * registers onto the stack under the assumption that it is writing to + * cache, which is not true with the MMU off. This would result in the + * stack becoming corrupted and a wrong/junk value for the LR being + * restored at the end of the routine. + */ + dcsw_op_all(DC_OP_CISW); + disable_mmu_secure(); +#endif + + int rc = xlat_change_mem_attributes_ctx(&tf_xlat_ctx, + (uintptr_t)tf_xlat_ctx.tables, + tf_xlat_ctx.tables_num * XLAT_TABLE_SIZE, + MT_RO_DATA | MT_SECURE); + +#ifdef __aarch64__ + if (tf_xlat_ctx.xlat_regime == EL1_EL0_REGIME) { + enable_mmu_el1(0U); + } else { + assert(tf_xlat_ctx.xlat_regime == EL3_REGIME); + enable_mmu_el3(0U); + } +#else /* !__aarch64__ */ + enable_mmu_svc_mon(0U); +#endif + + if (rc == 0) { + tf_xlat_ctx.readonly_tables = true; + } + + return rc; +} +#endif /* PLAT_RO_XLAT_TABLES */ + /* * If dynamic allocation of new regions is disabled then by the time we call the * function enabling the MMU, we'll have registered all the memory regions to |