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/* SPDX-License-Identifier: GPL-2.0-only */
#include <arch/cache.h>
#include <arch/lib_helpers.h>
#include <arch/mmu.h>
#include <arch/transition.h>
#include <assert.h>
void __weak exc_dispatch(struct exc_state *exc_state, uint64_t id)
{
/* Default weak implementation does nothing. */
}
void exc_entry(struct exc_state *exc_state, uint64_t id)
{
struct elx_state *elx = &exc_state->elx;
struct regs *regs = &exc_state->regs;
uint8_t elx_mode;
elx->spsr = raw_read_spsr_el3();
elx_mode = get_mode_from_spsr(elx->spsr);
if (elx_mode == SPSR_USE_H)
regs->sp = (uint64_t)&exc_state[1];
else
regs->sp = raw_read_sp_el0();
elx->elr = raw_read_elr_el3();
exc_dispatch(exc_state, id);
}
void transition_to_el2(void *entry, void *arg, uint64_t spsr)
{
struct exc_state exc_state;
struct elx_state *elx = &exc_state.elx;
struct regs *regs = &exc_state.regs;
regs->x[X0_INDEX] = (uint64_t)arg;
elx->elr = (uint64_t)entry;
elx->spsr = spsr;
/*
* Policies enforced:
* 1. We support only transitions to EL2
* 2. We support transitions to Aarch64 mode only
*
* If any of the above conditions holds false, then we need a proper way
* to update SCR/HCR before removing the checks below
*/
assert(get_el_from_spsr(spsr) == EL2 && !(spsr & SPSR_ERET_32));
/* Initialize SCR with defaults for running without secure monitor
(disable all traps, enable all instructions, run NS at AArch64). */
raw_write_scr_el3(SCR_FIEN | SCR_API | SCR_APK | SCR_ST | SCR_RW |
SCR_HCE | SCR_SMD | SCR_RES1 | SCR_NS);
/* Initialize CPTR to not trap anything to EL3. */
raw_write_cptr_el3(CPTR_EL3_TCPAC_DISABLE | CPTR_EL3_TTA_DISABLE |
CPTR_EL3_TFP_DISABLE);
/* ELR/SPSR: Write entry point and processor state of program */
raw_write_elr_el3(elx->elr);
raw_write_spsr_el3(elx->spsr);
/* SCTLR: Initialize EL with everything disabled */
raw_write_sctlr_el2(SCTLR_RES1);
/* SP_ELx: Initialize stack pointer */
raw_write_sp_el2(elx->sp_elx);
/* Payloads expect to be entered with MMU disabled. Includes an ISB. */
mmu_disable();
/* Eret to the entry point */
trans_switch(regs);
}
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