SPM: Move shim layer to TTBR1_EL1
This gives each Secure Partition complete freedom on its address space.
Previously, the memory used by the exception vectors was reserved and
couldn't be used. Also, it always had to be mapped, forcing SPM to
generate translation tables that included the exception vectors as well
as the Partition memory regions. With this change, partitions can reduce
their address space size easily.
Change-Id: I67fb5e9bdf2870b73347f23bff702fab0a8f8711
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/services/std_svc/spm/spm_setup.c b/services/std_svc/spm/spm_setup.c
index 3aabc20..6cbbc5b 100644
--- a/services/std_svc/spm/spm_setup.c
+++ b/services/std_svc/spm/spm_setup.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -77,12 +77,24 @@
write_ctx_reg(get_sysregs_ctx(ctx), CTX_MAIR_EL1,
mmu_cfg_params[MMU_CFG_MAIR]);
+ /* Enable translations using TTBR1_EL1 */
+ int t1sz = 64 - __builtin_ctzll(SPM_SHIM_XLAT_VIRT_ADDR_SPACE_SIZE);
+ mmu_cfg_params[MMU_CFG_TCR] &= ~TCR_EPD1_BIT;
+ mmu_cfg_params[MMU_CFG_TCR] |=
+ ((uint64_t)t1sz << TCR_T1SZ_SHIFT) |
+ TCR_SH1_INNER_SHAREABLE |
+ TCR_RGN1_OUTER_WBA | TCR_RGN1_INNER_WBA |
+ TCR_TG1_4K;
+
write_ctx_reg(get_sysregs_ctx(ctx), CTX_TCR_EL1,
mmu_cfg_params[MMU_CFG_TCR]);
write_ctx_reg(get_sysregs_ctx(ctx), CTX_TTBR0_EL1,
mmu_cfg_params[MMU_CFG_TTBR0]);
+ write_ctx_reg(get_sysregs_ctx(ctx), CTX_TTBR1_EL1,
+ (uint64_t)spm_exceptions_xlat_get_base_table());
+
/* Setup SCTLR_EL1 */
u_register_t sctlr_el1 = read_ctx_reg(get_sysregs_ctx(ctx), CTX_SCTLR_EL1);
@@ -122,9 +134,14 @@
* ----------------------------
*/
- /* Shim Exception Vector Base Address */
+ /*
+ * Shim exception vector base address. It is mapped at the start of the
+ * address space accessed by TTBR1_EL1, which means that the base
+ * address of the exception vectors depends on the size of the address
+ * space specified in TCR_EL1.T1SZ.
+ */
write_ctx_reg(get_sysregs_ctx(ctx), CTX_VBAR_EL1,
- SPM_SHIM_EXCEPTIONS_PTR);
+ UINT64_MAX - (SPM_SHIM_XLAT_VIRT_ADDR_SPACE_SIZE - 1ULL));
/*
* FPEN: Allow the Secure Partition to access FP/SIMD registers.