/*
* Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch.h>
#include <arch_helpers.h>
#include <assert.h>
#include <bl_common.h>
#include <context.h>
#include <context_mgmt.h>
#include <platform.h>
#include <platform_def.h>
#include <smcc_helpers.h>
#include <string.h>
#include <utils.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 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.
******************************************************************************/
void cm_init(void)
{
/*
* The context management library has only global data to initialize, 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 endianness 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, sctlr;
regs_t *reg_ctx;
assert(ctx);
security_state = GET_SECURITY_STATE(ep->h.attr);
/* Clear any residual register values from the context */
zeromem(ctx, sizeof(*ctx));
reg_ctx = get_regs_ctx(ctx);
/*
* Base the context SCR on the current value, adjust for entry point
* specific requirements
*/
scr = read_scr();
scr &= ~(SCR_NS_BIT | SCR_HCE_BIT);
if (security_state != SECURE)
scr |= SCR_NS_BIT;
if (security_state != SECURE) {
/*
* Set up SCTLR for the Non-secure context.
*
* SCTLR.EE: Endianness is taken from the entrypoint attributes.
*
* SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as
* required by PSCI specification)
*
* Set remaining SCTLR fields to their architecturally defined
* values. Some fields reset to an IMPLEMENTATION DEFINED value:
*
* SCTLR.TE: Set to zero so that exceptions to an Exception
* Level executing at PL1 are taken to A32 state.
*
* SCTLR.V: Set to zero to select the normal exception vectors
* with base address held in VBAR.
*/
assert(((ep->spsr >> SPSR_E_SHIFT) & SPSR_E_MASK) ==
(EP_GET_EE(ep->h.attr) >> EP_EE_SHIFT));
sctlr = EP_GET_EE(ep->h.attr) ? SCTLR_EE_BIT : 0;
sctlr |= (SCTLR_RESET_VAL & ~(SCTLR_TE_BIT | SCTLR_V_BIT));
write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr);
}
/*
* The target exception level is based on the spsr mode requested. If
* execution is requested to hyp mode, HVC is enabled via SCR.HCE.
*/
if (GET_M32(ep->spsr) == MODE32_hyp)
scr |= SCR_HCE_BIT;
/*
* Store the initialised values for SCTLR and SCR in the cpu_context.
* The Hyp mode registers are not part of the saved context and are
* set-up in cm_prepare_el3_exit().
*/
write_ctx_reg(reg_ctx, CTX_SCR, scr);
write_ctx_reg(reg_ctx, CTX_LR, ep->pc);
write_ctx_reg(reg_ctx, CTX_SPSR, ep->spsr);
/*
* Store the r0-r3 value from the entrypoint into the context
* Use memcpy as we are in control of the layout of the structures
*/
memcpy((void *)reg_ctx, (void *)&ep->args, sizeof(aapcs32_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 hyp mode, HSCTLR is initialized
* If execution is requested to non-secure PL1, and the CPU supports
* HYP mode then HYP mode is disabled by configuring all necessary HYP mode
* registers.
******************************************************************************/
void cm_prepare_el3_exit(uint32_t security_state)
{
uint32_t hsctlr, scr;
cpu_context_t *ctx = cm_get_context(security_state);
assert(ctx);
if (security_state == NON_SECURE) {
scr = read_ctx_reg(get_regs_ctx(ctx), CTX_SCR);
if (scr & SCR_HCE_BIT) {
/* Use SCTLR value to initialize HSCTLR */
hsctlr = read_ctx_reg(get_regs_ctx(ctx),
CTX_NS_SCTLR);
hsctlr |= HSCTLR_RES1;
/* Temporarily set the NS bit to access HSCTLR */
write_scr(read_scr() | SCR_NS_BIT);
/*
* Make sure the write to SCR is complete so that
* we can access HSCTLR
*/
isb();
write_hsctlr(hsctlr);
isb();
write_scr(read_scr() & ~SCR_NS_BIT);
isb();
} else if (read_id_pfr1() &
(ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) {
/*
* Set the NS bit to access NS copies of certain banked
* registers
*/
write_scr(read_scr() | SCR_NS_BIT);
isb();
/*
* Hyp / PL2 present but unused, need to disable safely.
* HSCTLR can be ignored in this case.
*
* Set HCR to its architectural reset value so that
* Non-secure operations do not trap to Hyp mode.
*/
write_hcr(HCR_RESET_VAL);
/*
* Set HCPTR to its architectural reset value so that
* Non-secure access from EL1 or EL0 to trace and to
* Advanced SIMD and floating point functionality does
* not trap to Hyp mode.
*/
write_hcptr(HCPTR_RESET_VAL);
/*
* Initialise CNTHCTL. All fields are architecturally
* UNKNOWN on reset and are set to zero except for
* field(s) listed below.
*
* CNTHCTL.PL1PCEN: Disable traps to Hyp mode of
* Non-secure EL0 and EL1 accessed to the physical
* timer registers.
*
* CNTHCTL.PL1PCTEN: Disable traps to Hyp mode of
* Non-secure EL0 and EL1 accessed to the physical
* counter registers.
*/
write_cnthctl(CNTHCTL_RESET_VAL |
PL1PCEN_BIT | PL1PCTEN_BIT);
/*
* Initialise CNTVOFF to zero as it resets to an
* IMPLEMENTATION DEFINED value.
*/
write64_cntvoff(0);
/*
* Set VPIDR and VMPIDR to match MIDR_EL1 and MPIDR
* respectively.
*/
write_vpidr(read_midr());
write_vmpidr(read_mpidr());
/*
* Initialise VTTBR, setting all fields rather than
* relying on the hw. Some fields are architecturally
* UNKNOWN at reset.
*
* VTTBR.VMID: Set to zero which is the architecturally
* defined reset value. Even though EL1&0 stage 2
* address translation is disabled, cache maintenance
* operations depend on the VMID.
*
* VTTBR.BADDR: Set to zero as EL1&0 stage 2 address
* translation is disabled.
*/
write64_vttbr(VTTBR_RESET_VAL &
~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));
/*
* Initialise HDCR, setting all the fields rather than
* relying on hw.
*
* HDCR.HPMN: Set to value of PMCR.N which is the
* architecturally-defined reset value.
*/
write_hdcr(HDCR_RESET_VAL |
((read_pmcr() & PMCR_N_BITS) >> PMCR_N_SHIFT));
/*
* Set HSTR to its architectural reset value so that
* access to system registers in the cproc=1111
* encoding space do not trap to Hyp mode.
*/
write_hstr(HSTR_RESET_VAL);
/*
* Set CNTHP_CTL to its architectural reset value to
* disable the EL2 physical timer and prevent timer
* interrupts. Some fields are architecturally UNKNOWN
* on reset and are set to zero.
*/
write_cnthp_ctl(CNTHP_CTL_RESET_VAL);
isb();
write_scr(read_scr() & ~SCR_NS_BIT);
isb();
}
}
}