blob: 0104c4ed0881240d49afa139c11d7b1d5a0820fb [file] [log] [blame]
/*
* Copyright (c) 2013-2017, 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 <interrupt_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 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 */
zeromem(ctx, 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;
#ifndef HANDLE_EA_EL3_FIRST
/* Explicitly stop to trap aborts from lower exception levels. */
scr_el3 &= ~SCR_EA_BIT;
#endif
#ifdef 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 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 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;
/*
* If lower non-secure EL is AArch32, enable the CP15BEN, nTWI
* & nTWI bits. This aligns with SCTLR initialization on
* systems with an AArch32 EL3, where these bits
* architecturally reset to 1.
*/
if (security_state != SECURE)
sctlr_elx |= SCTLR_CP15BEN_BIT | SCTLR_NTWI_BIT
| SCTLR_NTWE_BIT;
}
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 (EL_IMPLEMENTED(2)) {
/* 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);
/*
* Avoid unexpected debug traps in case where MDCR_EL2
* is not completely reset by the hardware - set
* MDCR_EL2.HPMN to PMCR_EL0.N and zero the remaining
* bits.
* MDCR_EL2.HPMN and PMCR_EL0.N fields are the same size
* (5 bits) and HPMN is at offset zero within MDCR_EL2.
*/
write_mdcr_el2((read_pmcr_el0() & PMCR_EL0_N_BITS)
>> PMCR_EL0_N_SHIFT);
/*
* Avoid unexpected traps of non-secure access to
* certain system registers at EL1 or lower where
* HSTR_EL2 is not completely reset to zero by the
* hardware - zero the entire register.
*/
write_hstr_el2(0);
/*
* Reset CNTHP_CTL_EL2 to disable the EL2 physical timer
* and therefore prevent timer interrupts.
*/
write_cnthp_ctl_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, uintptr_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,
uintptr_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);
}