fix(gpt_rme): rework delegating/undelegating sequence
The previous delegating/undelegating sequence was incorrect as per the
specification DDI0615, "Architecture Reference Manual Supplement, The
Realm Management Extension (RME), for Armv9-A" Sections A1.1.1 and
A1.1.2
Off topic:
- cleaning the gpt_is_gpi_valid and gpt_check_pass_overlap
Change-Id: Idb64d0a2e6204f1708951137062847938ab5e0ac
Signed-off-by: Robert Wakim <robert.wakim@arm.com>
diff --git a/lib/gpt_rme/gpt_rme.c b/lib/gpt_rme/gpt_rme.c
index e424fe2..d6fbc04 100644
--- a/lib/gpt_rme/gpt_rme.c
+++ b/lib/gpt_rme/gpt_rme.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -95,9 +95,8 @@
if ((gpi == GPT_GPI_NO_ACCESS) || (gpi == GPT_GPI_ANY) ||
((gpi >= GPT_GPI_SECURE) && (gpi <= GPT_GPI_REALM))) {
return true;
- } else {
- return false;
}
+ return false;
}
/*
@@ -117,9 +116,8 @@
{
if (((base_1 + size_1) > base_2) && ((base_2 + size_2) > base_1)) {
return true;
- } else {
- return false;
}
+ return false;
}
/*
@@ -434,14 +432,14 @@
gpt_desc = GPT_L0_BLK_DESC(GPT_PAS_ATTR_GPI(pas->attrs));
/* Start index of this region in L0 GPTs */
- idx = pas->base_pa >> GPT_L0_IDX_SHIFT;
+ idx = GPT_L0_IDX(pas->base_pa);
/*
* Determine number of L0 GPT descriptors covered by
* this PAS region and use the count to populate these
* descriptors.
*/
- end_idx = (pas->base_pa + pas->size) >> GPT_L0_IDX_SHIFT;
+ end_idx = GPT_L0_IDX(pas->base_pa + pas->size);
/* Generate the needed block descriptors. */
for (; idx < end_idx; idx++) {
@@ -471,8 +469,8 @@
uintptr_t cur_idx;
uintptr_t end_idx;
- cur_idx = cur_pa >> GPT_L0_IDX_SHIFT;
- end_idx = end_pa >> GPT_L0_IDX_SHIFT;
+ cur_idx = GPT_L0_IDX(cur_pa);
+ end_idx = GPT_L0_IDX(end_pa);
assert(cur_idx <= end_idx);
@@ -770,7 +768,7 @@
/* Validate other parameters. */
ret = gpt_validate_l0_params(pps, l0_mem_base, l0_mem_size);
- if (ret < 0) {
+ if (ret != 0) {
return ret;
}
@@ -849,7 +847,7 @@
if (l1_gpt_cnt > 0) {
ret = gpt_validate_l1_params(l1_mem_base, l1_mem_size,
l1_gpt_cnt);
- if (ret < 0) {
+ if (ret != 0) {
return ret;
}
@@ -958,55 +956,170 @@
static spinlock_t gpt_lock;
/*
- * Check if caller is allowed to transition a PAS.
+ * A helper to write the value (target_pas << gpi_shift) to the index of
+ * the gpt_l1_addr
+ */
+static inline void write_gpt(uint64_t *gpt_l1_desc, uint64_t *gpt_l1_addr,
+ unsigned int gpi_shift, unsigned int idx,
+ unsigned int target_pas)
+{
+ *gpt_l1_desc &= ~(GPT_L1_GRAN_DESC_GPI_MASK << gpi_shift);
+ *gpt_l1_desc |= ((uint64_t)target_pas << gpi_shift);
+ gpt_l1_addr[idx] = *gpt_l1_desc;
+}
+
+/*
+ * Helper to retrieve the gpt_l1_* information from the base address
+ * returned in gpi_info
+ */
+static int get_gpi_params(uint64_t base, gpi_info_t *gpi_info)
+{
+ uint64_t gpt_l0_desc, *gpt_l0_base;
+
+ gpt_l0_base = (uint64_t *)gpt_config.plat_gpt_l0_base;
+ gpt_l0_desc = gpt_l0_base[GPT_L0_IDX(base)];
+ if (GPT_L0_TYPE(gpt_l0_desc) != GPT_L0_TYPE_TBL_DESC) {
+ VERBOSE("[GPT] Granule is not covered by a table descriptor!\n");
+ VERBOSE(" Base=0x%" PRIx64 "\n", base);
+ return -EINVAL;
+ }
+
+ /* Get the table index and GPI shift from PA. */
+ gpi_info->gpt_l1_addr = GPT_L0_TBLD_ADDR(gpt_l0_desc);
+ gpi_info->idx = GPT_L1_IDX(gpt_config.p, base);
+ gpi_info->gpi_shift = GPT_L1_GPI_IDX(gpt_config.p, base) << 2;
+
+ gpi_info->gpt_l1_desc = (gpi_info->gpt_l1_addr)[gpi_info->idx];
+ gpi_info->gpi = (gpi_info->gpt_l1_desc >> gpi_info->gpi_shift) &
+ GPT_L1_GRAN_DESC_GPI_MASK;
+ return 0;
+}
+
+/*
+ * This function is the granule transition delegate service. When a granule
+ * transition request occurs it is routed to this function to have the request,
+ * if valid, fulfilled following A1.1.1 Delegate of RME supplement
*
- * - Secure world caller can only request S <-> NS transitions on a
- * granule that is already in either S or NS PAS.
- *
- * - Realm world caller can only request R <-> NS transitions on a
- * granule that is already in either R or NS PAS.
+ * TODO: implement support for transitioning multiple granules at once.
*
* Parameters
+ * base Base address of the region to transition, must be
+ * aligned to granule size.
+ * size Size of region to transition, must be aligned to granule
+ * size.
* src_sec_state Security state of the caller.
- * current_gpi Current GPI of the granule.
- * target_gpi Requested new GPI for the granule.
*
* Return
* Negative Linux error code in the event of a failure, 0 for success.
*/
-static int gpt_check_transition_gpi(unsigned int src_sec_state,
- unsigned int current_gpi,
- unsigned int target_gpi)
+int gpt_delegate_pas(uint64_t base, size_t size, unsigned int src_sec_state)
{
- unsigned int check_gpi;
+ gpi_info_t gpi_info;
+ uint64_t nse;
+ int res;
+ unsigned int target_pas;
- /* Cannot transition a granule to the state it is already in. */
- if (current_gpi == target_gpi) {
+ /* Ensure that the tables have been set up before taking requests. */
+ assert(gpt_config.plat_gpt_l0_base != 0UL);
+
+ /* Ensure that caches are enabled. */
+ assert((read_sctlr_el3() & SCTLR_C_BIT) != 0UL);
+
+ /* Delegate request can only come from REALM or SECURE */
+ assert(src_sec_state == SMC_FROM_REALM ||
+ src_sec_state == SMC_FROM_SECURE);
+
+ /* See if this is a single or a range of granule transition. */
+ if (size != GPT_PGS_ACTUAL_SIZE(gpt_config.p)) {
return -EINVAL;
}
- /* Check security state, only secure and realm can transition. */
- if (src_sec_state == SMC_FROM_REALM) {
- check_gpi = GPT_GPI_REALM;
- } else if (src_sec_state == SMC_FROM_SECURE) {
- check_gpi = GPT_GPI_SECURE;
+ /* Check that base and size are valid */
+ if ((ULONG_MAX - base) < size) {
+ VERBOSE("[GPT] Transition request address overflow!\n");
+ VERBOSE(" Base=0x%" PRIx64 "\n", base);
+ VERBOSE(" Size=0x%lx\n", size);
+ return -EINVAL;
+ }
+
+ /* Make sure base and size are valid. */
+ if (((base & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0UL) ||
+ ((size & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0UL) ||
+ (size == 0UL) ||
+ ((base + size) >= GPT_PPS_ACTUAL_SIZE(gpt_config.t))) {
+ VERBOSE("[GPT] Invalid granule transition address range!\n");
+ VERBOSE(" Base=0x%" PRIx64 "\n", base);
+ VERBOSE(" Size=0x%lx\n", size);
+ return -EINVAL;
+ }
+
+ target_pas = GPT_GPI_REALM;
+ if (src_sec_state == SMC_FROM_SECURE) {
+ target_pas = GPT_GPI_SECURE;
+ }
+
+ /*
+ * Access to L1 tables is controlled by a global lock to ensure
+ * that no more than one CPU is allowed to make changes at any
+ * given time.
+ */
+ spin_lock(&gpt_lock);
+ res = get_gpi_params(base, &gpi_info);
+ if (res != 0) {
+ spin_unlock(&gpt_lock);
+ return res;
+ }
+
+ /* Check that the current address is in NS state */
+ if (gpi_info.gpi != GPT_GPI_NS) {
+ VERBOSE("[GPT] Only Granule in NS state can be delegated.\n");
+ VERBOSE(" Caller: %u, Current GPI: %u\n", src_sec_state,
+ gpi_info.gpi);
+ spin_unlock(&gpt_lock);
+ return -EINVAL;
+ }
+
+ if (src_sec_state == SMC_FROM_SECURE) {
+ nse = (uint64_t)GPT_NSE_SECURE << GPT_NSE_SHIFT;
} else {
- return -EINVAL;
+ nse = (uint64_t)GPT_NSE_REALM << GPT_NSE_SHIFT;
}
- /* Make sure security state is allowed to make the transition. */
- if ((target_gpi != check_gpi) && (target_gpi != GPT_GPI_NS)) {
- return -EINVAL;
- }
- if ((current_gpi != check_gpi) && (current_gpi != GPT_GPI_NS)) {
- return -EINVAL;
- }
+ /*
+ * In order to maintain mutual distrust between Realm and Secure
+ * states, remove any data speculatively fetched into the target
+ * physical address space. Issue DC CIPAPA over address range
+ */
+ flush_dcache_to_popa_range(nse | base,
+ GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+
+ write_gpt(&gpi_info.gpt_l1_desc, gpi_info.gpt_l1_addr,
+ gpi_info.gpi_shift, gpi_info.idx, target_pas);
+ dsboshst();
+
+ gpt_tlbi_by_pa_ll(base, GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+ dsbosh();
+
+ nse = (uint64_t)GPT_NSE_NS << GPT_NSE_SHIFT;
+
+ flush_dcache_to_popa_range(nse | base,
+ GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+
+ /* Unlock access to the L1 tables. */
+ spin_unlock(&gpt_lock);
+
+ /*
+ * The isb() will be done as part of context
+ * synchronization when returning to lower EL
+ */
+ VERBOSE("[GPT] Granule 0x%" PRIx64 ", GPI 0x%x->0x%x\n",
+ base, gpi_info.gpi, target_pas);
return 0;
}
/*
- * This function is the core of the granule transition service. When a granule
+ * This function is the granule transition undelegate service. When a granule
* transition request occurs it is routed to this function where the request is
* validated then fulfilled if possible.
*
@@ -1018,29 +1131,32 @@
* size Size of region to transition, must be aligned to granule
* size.
* src_sec_state Security state of the caller.
- * target_pas Target PAS of the specified memory region.
*
* Return
* Negative Linux error code in the event of a failure, 0 for success.
*/
-int gpt_transition_pas(uint64_t base, size_t size, unsigned int src_sec_state,
- unsigned int target_pas)
+int gpt_undelegate_pas(uint64_t base, size_t size, unsigned int src_sec_state)
{
- int idx;
- unsigned int gpi_shift;
- unsigned int gpi;
- uint64_t gpt_l0_desc;
- uint64_t gpt_l1_desc;
- uint64_t *gpt_l1_addr;
- uint64_t *gpt_l0_base;
+ gpi_info_t gpi_info;
+ uint64_t nse;
+ int res;
/* Ensure that the tables have been set up before taking requests. */
- assert(gpt_config.plat_gpt_l0_base != 0U);
+ assert(gpt_config.plat_gpt_l0_base != 0UL);
- /* Ensure that MMU and data caches are enabled. */
- assert((read_sctlr_el3() & SCTLR_C_BIT) != 0U);
+ /* Ensure that MMU and caches are enabled. */
+ assert((read_sctlr_el3() & SCTLR_C_BIT) != 0UL);
- /* Check for address range overflow. */
+ /* Delegate request can only come from REALM or SECURE */
+ assert(src_sec_state == SMC_FROM_REALM ||
+ src_sec_state == SMC_FROM_SECURE);
+
+ /* See if this is a single or a range of granule transition. */
+ if (size != GPT_PGS_ACTUAL_SIZE(gpt_config.p)) {
+ return -EINVAL;
+ }
+
+ /* Check that base and size are valid */
if ((ULONG_MAX - base) < size) {
VERBOSE("[GPT] Transition request address overflow!\n");
VERBOSE(" Base=0x%" PRIx64 "\n", base);
@@ -1049,9 +1165,9 @@
}
/* Make sure base and size are valid. */
- if (((base & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0U) ||
- ((size & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0U) ||
- (size == 0U) ||
+ if (((base & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0UL) ||
+ ((size & (GPT_PGS_ACTUAL_SIZE(gpt_config.p) - 1)) != 0UL) ||
+ (size == 0UL) ||
((base + size) >= GPT_PPS_ACTUAL_SIZE(gpt_config.t))) {
VERBOSE("[GPT] Invalid granule transition address range!\n");
VERBOSE(" Base=0x%" PRIx64 "\n", base);
@@ -1059,66 +1175,81 @@
return -EINVAL;
}
- /* See if this is a single granule transition or a range of granules. */
- if (size != GPT_PGS_ACTUAL_SIZE(gpt_config.p)) {
- /*
- * TODO: Add support for transitioning multiple granules with a
- * single call to this function.
- */
- panic();
- }
-
- /* Get the L0 descriptor and make sure it is for a table. */
- gpt_l0_base = (uint64_t *)gpt_config.plat_gpt_l0_base;
- gpt_l0_desc = gpt_l0_base[GPT_L0_IDX(base)];
- if (GPT_L0_TYPE(gpt_l0_desc) != GPT_L0_TYPE_TBL_DESC) {
- VERBOSE("[GPT] Granule is not covered by a table descriptor!\n");
- VERBOSE(" Base=0x%" PRIx64 "\n", base);
- return -EINVAL;
- }
-
- /* Get the table index and GPI shift from PA. */
- gpt_l1_addr = GPT_L0_TBLD_ADDR(gpt_l0_desc);
- idx = GPT_L1_IDX(gpt_config.p, base);
- gpi_shift = GPT_L1_GPI_IDX(gpt_config.p, base) << 2;
-
/*
* Access to L1 tables is controlled by a global lock to ensure
* that no more than one CPU is allowed to make changes at any
* given time.
*/
spin_lock(&gpt_lock);
- gpt_l1_desc = gpt_l1_addr[idx];
- gpi = (gpt_l1_desc >> gpi_shift) & GPT_L1_GRAN_DESC_GPI_MASK;
- /* Make sure caller state and source/target PAS are allowed. */
- if (gpt_check_transition_gpi(src_sec_state, gpi, target_pas) < 0) {
+ res = get_gpi_params(base, &gpi_info);
+ if (res != 0) {
spin_unlock(&gpt_lock);
- VERBOSE("[GPT] Invalid caller state and PAS combo!\n");
- VERBOSE(" Caller: %u, Current GPI: %u, Target GPI: %u\n",
- src_sec_state, gpi, target_pas);
- return -EPERM;
+ return res;
}
- /* Clear existing GPI encoding and transition granule. */
- gpt_l1_desc &= ~(GPT_L1_GRAN_DESC_GPI_MASK << gpi_shift);
- gpt_l1_desc |= ((uint64_t)target_pas << gpi_shift);
- gpt_l1_addr[idx] = gpt_l1_desc;
+ /* Check that the current address is in the delegated state */
+ if ((src_sec_state == SMC_FROM_REALM &&
+ gpi_info.gpi != GPT_GPI_REALM) ||
+ (src_sec_state == SMC_FROM_SECURE &&
+ gpi_info.gpi != GPT_GPI_SECURE)) {
+ VERBOSE("[GPT] Only Granule in REALM or SECURE state can be undelegated.\n");
+ VERBOSE(" Caller: %u, Current GPI: %u\n", src_sec_state,
+ gpi_info.gpi);
+ spin_unlock(&gpt_lock);
+ return -EINVAL;
+ }
- /* Ensure that the write operation will be observed by GPC */
- dsbishst();
+
+ /* In order to maintain mutual distrust between Realm and Secure
+ * states, remove access now, in order to guarantee that writes
+ * to the currently-accessible physical address space will not
+ * later become observable.
+ */
+ write_gpt(&gpi_info.gpt_l1_desc, gpi_info.gpt_l1_addr,
+ gpi_info.gpi_shift, gpi_info.idx, GPT_GPI_NO_ACCESS);
+ dsboshst();
+
+ gpt_tlbi_by_pa_ll(base, GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+ dsbosh();
+
+ if (src_sec_state == SMC_FROM_SECURE) {
+ nse = (uint64_t)GPT_NSE_SECURE << GPT_NSE_SHIFT;
+ } else {
+ nse = (uint64_t)GPT_NSE_REALM << GPT_NSE_SHIFT;
+ }
+
+ /* Ensure that the scrubbed data has made it past the PoPA */
+ flush_dcache_to_popa_range(nse | base,
+ GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+
+ /*
+ * Remove any data loaded speculatively
+ * in NS space from before the scrubbing
+ */
+ nse = (uint64_t)GPT_NSE_NS << GPT_NSE_SHIFT;
+
+ flush_dcache_to_popa_range(nse | base,
+ GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+
+ /* Clear existing GPI encoding and transition granule. */
+ write_gpt(&gpi_info.gpt_l1_desc, gpi_info.gpt_l1_addr,
+ gpi_info.gpi_shift, gpi_info.idx, GPT_GPI_NS);
+ dsboshst();
+
+ /* Ensure that all agents observe the new NS configuration */
+ gpt_tlbi_by_pa_ll(base, GPT_PGS_ACTUAL_SIZE(gpt_config.p));
+ dsbosh();
/* Unlock access to the L1 tables. */
spin_unlock(&gpt_lock);
- gpt_tlbi_by_pa(base, GPT_PGS_ACTUAL_SIZE(gpt_config.p));
- dsbishst();
/*
* The isb() will be done as part of context
* synchronization when returning to lower EL
*/
- VERBOSE("[GPT] Granule 0x%" PRIx64 ", GPI 0x%x->0x%x\n", base, gpi,
- target_pas);
+ VERBOSE("[GPT] Granule 0x%" PRIx64 ", GPI 0x%x->0x%x\n",
+ base, gpi_info.gpi, GPT_GPI_NS);
return 0;
}