Move context management code to common location
The upcoming Firmware Update feature needs transitioning across
Secure/Normal worlds to complete the FWU process and hence requires
context management code to perform this task.
Currently context management code is part of BL31 stage only.
This patch moves the code from (include)/bl31 to (include)/common.
Some function declarations/definitions and macros have also moved
to different files to help code sharing.
Change-Id: I3858b08aecdb76d390765ab2b099f457873f7b0c
diff --git a/common/context_mgmt.c b/common/context_mgmt.c
new file mode 100644
index 0000000..68ec894
--- /dev/null
+++ b/common/context_mgmt.c
@@ -0,0 +1,378 @@
+/*
+ * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <assert.h>
+#include <bl_common.h>
+#include <context.h>
+#include <context_mgmt.h>
+#include <interrupt_mgmt.h>
+#include <platform.h>
+#include <platform_def.h>
+#include <smcc_helpers.h>
+#include <string.h>
+
+
+/*******************************************************************************
+ * Context management library initialisation routine. This library is used by
+ * runtime services to share pointers to 'cpu_context' structures for the secure
+ * and non-secure states. Management of the structures and their associated
+ * memory is not done by the context management library e.g. the PSCI service
+ * manages the cpu context used for entry from and exit to the non-secure state.
+ * The Secure payload dispatcher service manages the context(s) corresponding to
+ * the secure state. It also uses this library to get access to the non-secure
+ * state cpu context pointers.
+ * Lastly, this library provides the api to make SP_EL3 point to the cpu context
+ * which will used for programming an entry into a lower EL. The same context
+ * will used to save state upon exception entry from that EL.
+ ******************************************************************************/
+void cm_init(void)
+{
+ /*
+ * The context management library has only global data to intialize, but
+ * that will be done when the BSS is zeroed out
+ */
+}
+
+/*******************************************************************************
+ * The following function initializes the cpu_context 'ctx' for
+ * first use, and sets the initial entrypoint state as specified by the
+ * entry_point_info structure.
+ *
+ * The security state to initialize is determined by the SECURE attribute
+ * of the entry_point_info. The function returns a pointer to the initialized
+ * context and sets this as the next context to return to.
+ *
+ * The EE and ST attributes are used to configure the endianess and secure
+ * timer availability for the new execution context.
+ *
+ * To prepare the register state for entry call cm_prepare_el3_exit() and
+ * el3_exit(). For Secure-EL1 cm_prepare_el3_exit() is equivalent to
+ * cm_e1_sysreg_context_restore().
+ ******************************************************************************/
+static void cm_init_context_common(cpu_context_t *ctx, const entry_point_info_t *ep)
+{
+ unsigned int security_state;
+ uint32_t scr_el3;
+ el3_state_t *state;
+ gp_regs_t *gp_regs;
+ unsigned long sctlr_elx;
+
+ assert(ctx);
+
+ security_state = GET_SECURITY_STATE(ep->h.attr);
+
+ /* Clear any residual register values from the context */
+ memset(ctx, 0, sizeof(*ctx));
+
+ /*
+ * Base the context SCR on the current value, adjust for entry point
+ * specific requirements and set trap bits from the IMF
+ * TODO: provide the base/global SCR bits using another mechanism?
+ */
+ scr_el3 = read_scr();
+ scr_el3 &= ~(SCR_NS_BIT | SCR_RW_BIT | SCR_FIQ_BIT | SCR_IRQ_BIT |
+ SCR_ST_BIT | SCR_HCE_BIT);
+
+ if (security_state != SECURE)
+ scr_el3 |= SCR_NS_BIT;
+
+ if (GET_RW(ep->spsr) == MODE_RW_64)
+ scr_el3 |= SCR_RW_BIT;
+
+ if (EP_GET_ST(ep->h.attr))
+ scr_el3 |= SCR_ST_BIT;
+
+#if IMAGE_BL31
+ /*
+ * IRQ/FIQ bits only need setting if interrupt routing
+ * model has been set up for BL31.
+ */
+ scr_el3 |= get_scr_el3_from_routing_model(security_state);
+#endif
+
+ /*
+ * Set up SCTLR_ELx for the target exception level:
+ * EE bit is taken from the entrpoint attributes
+ * M, C and I bits must be zero (as required by PSCI specification)
+ *
+ * The target exception level is based on the spsr mode requested.
+ * If execution is requested to EL2 or hyp mode, HVC is enabled
+ * via SCR_EL3.HCE.
+ *
+ * Always compute the SCTLR_EL1 value and save in the cpu_context
+ * - the EL2 registers are set up by cm_preapre_ns_entry() as they
+ * are not part of the stored cpu_context
+ *
+ * TODO: In debug builds the spsr should be validated and checked
+ * against the CPU support, security state, endianess and pc
+ */
+ sctlr_elx = EP_GET_EE(ep->h.attr) ? SCTLR_EE_BIT : 0;
+ if (GET_RW(ep->spsr) == MODE_RW_64)
+ sctlr_elx |= SCTLR_EL1_RES1;
+ else
+ sctlr_elx |= SCTLR_AARCH32_EL1_RES1;
+ write_ctx_reg(get_sysregs_ctx(ctx), CTX_SCTLR_EL1, sctlr_elx);
+
+ if ((GET_RW(ep->spsr) == MODE_RW_64
+ && GET_EL(ep->spsr) == MODE_EL2)
+ || (GET_RW(ep->spsr) != MODE_RW_64
+ && GET_M32(ep->spsr) == MODE32_hyp)) {
+ scr_el3 |= SCR_HCE_BIT;
+ }
+
+ /* Populate EL3 state so that we've the right context before doing ERET */
+ state = get_el3state_ctx(ctx);
+ write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
+ write_ctx_reg(state, CTX_ELR_EL3, ep->pc);
+ write_ctx_reg(state, CTX_SPSR_EL3, ep->spsr);
+
+ /*
+ * Store the X0-X7 value from the entrypoint into the context
+ * Use memcpy as we are in control of the layout of the structures
+ */
+ gp_regs = get_gpregs_ctx(ctx);
+ memcpy(gp_regs, (void *)&ep->args, sizeof(aapcs64_params_t));
+}
+
+/*******************************************************************************
+ * The following function initializes the cpu_context for a CPU specified by
+ * its `cpu_idx` for first use, and sets the initial entrypoint state as
+ * specified by the entry_point_info structure.
+ ******************************************************************************/
+void cm_init_context_by_index(unsigned int cpu_idx,
+ const entry_point_info_t *ep)
+{
+ cpu_context_t *ctx;
+ ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
+ cm_init_context_common(ctx, ep);
+}
+
+/*******************************************************************************
+ * The following function initializes the cpu_context for the current CPU
+ * for first use, and sets the initial entrypoint state as specified by the
+ * entry_point_info structure.
+ ******************************************************************************/
+void cm_init_my_context(const entry_point_info_t *ep)
+{
+ cpu_context_t *ctx;
+ ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
+ cm_init_context_common(ctx, ep);
+}
+
+/*******************************************************************************
+ * Prepare the CPU system registers for first entry into secure or normal world
+ *
+ * If execution is requested to EL2 or hyp mode, SCTLR_EL2 is initialized
+ * If execution is requested to non-secure EL1 or svc mode, and the CPU supports
+ * EL2 then EL2 is disabled by configuring all necessary EL2 registers.
+ * For all entries, the EL1 registers are initialized from the cpu_context
+ ******************************************************************************/
+void cm_prepare_el3_exit(uint32_t security_state)
+{
+ uint32_t sctlr_elx, scr_el3, cptr_el2;
+ cpu_context_t *ctx = cm_get_context(security_state);
+
+ assert(ctx);
+
+ if (security_state == NON_SECURE) {
+ scr_el3 = read_ctx_reg(get_el3state_ctx(ctx), CTX_SCR_EL3);
+ if (scr_el3 & SCR_HCE_BIT) {
+ /* Use SCTLR_EL1.EE value to initialise sctlr_el2 */
+ sctlr_elx = read_ctx_reg(get_sysregs_ctx(ctx),
+ CTX_SCTLR_EL1);
+ sctlr_elx &= ~SCTLR_EE_BIT;
+ sctlr_elx |= SCTLR_EL2_RES1;
+ write_sctlr_el2(sctlr_elx);
+ } else if (read_id_aa64pfr0_el1() &
+ (ID_AA64PFR0_ELX_MASK << ID_AA64PFR0_EL2_SHIFT)) {
+ /* EL2 present but unused, need to disable safely */
+
+ /* HCR_EL2 = 0, except RW bit set to match SCR_EL3 */
+ write_hcr_el2((scr_el3 & SCR_RW_BIT) ? HCR_RW_BIT : 0);
+
+ /* SCTLR_EL2 : can be ignored when bypassing */
+
+ /* CPTR_EL2 : disable all traps TCPAC, TTA, TFP */
+ cptr_el2 = read_cptr_el2();
+ cptr_el2 &= ~(TCPAC_BIT | TTA_BIT | TFP_BIT);
+ write_cptr_el2(cptr_el2);
+
+ /* Enable EL1 access to timer */
+ write_cnthctl_el2(EL1PCEN_BIT | EL1PCTEN_BIT);
+
+ /* Reset CNTVOFF_EL2 */
+ write_cntvoff_el2(0);
+
+ /* Set VPIDR, VMPIDR to match MIDR, MPIDR */
+ write_vpidr_el2(read_midr_el1());
+ write_vmpidr_el2(read_mpidr_el1());
+
+ /*
+ * Reset VTTBR_EL2.
+ * Needed because cache maintenance operations depend on
+ * the VMID even when non-secure EL1&0 stage 2 address
+ * translation are disabled.
+ */
+ write_vttbr_el2(0);
+ }
+ }
+
+ el1_sysregs_context_restore(get_sysregs_ctx(ctx));
+
+ cm_set_next_context(ctx);
+}
+
+/*******************************************************************************
+ * The next four functions are used by runtime services to save and restore
+ * EL1 context on the 'cpu_context' structure for the specified security
+ * state.
+ ******************************************************************************/
+void cm_el1_sysregs_context_save(uint32_t security_state)
+{
+ cpu_context_t *ctx;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ el1_sysregs_context_save(get_sysregs_ctx(ctx));
+}
+
+void cm_el1_sysregs_context_restore(uint32_t security_state)
+{
+ cpu_context_t *ctx;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ el1_sysregs_context_restore(get_sysregs_ctx(ctx));
+}
+
+/*******************************************************************************
+ * This function populates ELR_EL3 member of 'cpu_context' pertaining to the
+ * given security state with the given entrypoint
+ ******************************************************************************/
+void cm_set_elr_el3(uint32_t security_state, uint64_t entrypoint)
+{
+ cpu_context_t *ctx;
+ el3_state_t *state;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ /* Populate EL3 state so that ERET jumps to the correct entry */
+ state = get_el3state_ctx(ctx);
+ write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
+}
+
+/*******************************************************************************
+ * This function populates ELR_EL3 and SPSR_EL3 members of 'cpu_context'
+ * pertaining to the given security state
+ ******************************************************************************/
+void cm_set_elr_spsr_el3(uint32_t security_state,
+ uint64_t entrypoint, uint32_t spsr)
+{
+ cpu_context_t *ctx;
+ el3_state_t *state;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ /* Populate EL3 state so that ERET jumps to the correct entry */
+ state = get_el3state_ctx(ctx);
+ write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
+ write_ctx_reg(state, CTX_SPSR_EL3, spsr);
+}
+
+/*******************************************************************************
+ * This function updates a single bit in the SCR_EL3 member of the 'cpu_context'
+ * pertaining to the given security state using the value and bit position
+ * specified in the parameters. It preserves all other bits.
+ ******************************************************************************/
+void cm_write_scr_el3_bit(uint32_t security_state,
+ uint32_t bit_pos,
+ uint32_t value)
+{
+ cpu_context_t *ctx;
+ el3_state_t *state;
+ uint32_t scr_el3;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ /* Ensure that the bit position is a valid one */
+ assert((1 << bit_pos) & SCR_VALID_BIT_MASK);
+
+ /* Ensure that the 'value' is only a bit wide */
+ assert(value <= 1);
+
+ /*
+ * Get the SCR_EL3 value from the cpu context, clear the desired bit
+ * and set it to its new value.
+ */
+ state = get_el3state_ctx(ctx);
+ scr_el3 = read_ctx_reg(state, CTX_SCR_EL3);
+ scr_el3 &= ~(1 << bit_pos);
+ scr_el3 |= value << bit_pos;
+ write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
+}
+
+/*******************************************************************************
+ * This function retrieves SCR_EL3 member of 'cpu_context' pertaining to the
+ * given security state.
+ ******************************************************************************/
+uint32_t cm_get_scr_el3(uint32_t security_state)
+{
+ cpu_context_t *ctx;
+ el3_state_t *state;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ /* Populate EL3 state so that ERET jumps to the correct entry */
+ state = get_el3state_ctx(ctx);
+ return read_ctx_reg(state, CTX_SCR_EL3);
+}
+
+/*******************************************************************************
+ * This function is used to program the context that's used for exception
+ * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
+ * the required security state
+ ******************************************************************************/
+void cm_set_next_eret_context(uint32_t security_state)
+{
+ cpu_context_t *ctx;
+
+ ctx = cm_get_context(security_state);
+ assert(ctx);
+
+ cm_set_next_context(ctx);
+}