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/*
* 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;
/*
* Set up SCTLR for the Non Secure context.
* EE bit is taken from the entrypoint 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 hyp mode, HVC is enabled
* via SCR.HCE.
*
* Always compute the SCTLR_EL1 value and save in the cpu_context
* - the HYP 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, endianness and pc
*/
if (security_state != SECURE) {
sctlr = EP_GET_EE(ep->h.attr) ? SCTLR_EE_BIT : 0;
/*
* In addition to SCTLR_RES1, set the CP15_BEN, nTWI & nTWE
* bits that architecturally reset to 1.
*/
sctlr |= SCTLR_RES1 | SCTLR_CP15BEN_BIT |
SCTLR_NTWI_BIT | SCTLR_NTWE_BIT;
write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr);
}
if (GET_M32(ep->spsr) == MODE32_hyp)
scr |= SCR_HCE_BIT;
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 sctlr, scr, hcptr;
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 */
sctlr = read_ctx_reg(get_regs_ctx(ctx),
CTX_NS_SCTLR);
sctlr |= 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(sctlr);
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();
/* PL2 present but unused, need to disable safely */
write_hcr(0);
/* HSCTLR : can be ignored when bypassing */
/* HCPTR : disable all traps TCPAC, TTA, TCP */
hcptr = read_hcptr();
hcptr &= ~(TCPAC_BIT | TTA_BIT | TCP11_BIT | TCP10_BIT);
write_hcptr(hcptr);
/* Enable EL1 access to timer */
write_cnthctl(PL1PCEN_BIT | PL1PCTEN_BIT);
/* Reset CNTVOFF_EL2 */
write64_cntvoff(0);
/* Set VPIDR, VMPIDR to match MIDR, MPIDR */
write_vpidr(read_midr());
write_vmpidr(read_mpidr());
/*
* Reset VTTBR.
* Needed because cache maintenance operations depend on
* the VMID even when non-secure EL1&0 stage 2 address
* translation are disabled.
*/
write64_vttbr(0);
/*
* Avoid unexpected debug traps in case where HDCR
* is not completely reset by the hardware - set
* HDCR.HPMN to PMCR.N and zero the remaining bits.
* The HDCR.HPMN and PMCR.N fields are the same size
* (5 bits) and HPMN is at offset zero within HDCR.
*/
write_hdcr((read_pmcr() & PMCR_N_BITS) >> PMCR_N_SHIFT);
/*
* Reset CNTHP_CTL to disable the EL2 physical timer and
* therefore prevent timer interrupts.
*/
write_cnthp_ctl(0);
isb();
write_scr(read_scr() & ~SCR_NS_BIT);
isb();
}
}
}
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