payload.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <program_loading.h>
#include <stdint.h>
#include <arch/boot.h>
#include <arch/encoding.h>
#include <arch/smp/atomic.h>
#include <console/console.h>
#include <vm.h>
 
/* Run OpenSBI and let OpenSBI hand over control to the payload */
void run_payload_opensbi(struct prog *prog, void *fdt, struct prog *opensbi, int payload_mode)
{
        int hart_id = read_csr(mhartid);
        uintptr_t status = read_csr(mstatus);
        status = INSERT_FIELD(status, MSTATUS_MPIE, 0);
 
        /*
         * In case of OpenSBI we always run it in M-Mode.
         * OpenSBI will switch to payload_mode when done.
         */
 
        status = INSERT_FIELD(status, MSTATUS_MPP, PRV_M);
        /* Trap vector base address point to the payload */
        write_csr(mtvec, prog_entry(opensbi));
        /* disable M-Mode interrupt */
        write_csr(mie, 0);
        write_csr(mstatus, status);
 
        run_opensbi(hart_id, fdt, prog_entry(opensbi), prog_entry(prog), payload_mode);
}
 
/* Runs the payload without OpenSBI integration */
void run_payload(struct prog *prog, void *fdt, int payload_mode)
{
        void (*doit)(int hart_id, void *fdt) = prog_entry(prog);
        int hart_id = read_csr(mhartid);
        uintptr_t status = read_csr(mstatus);
        status = INSERT_FIELD(status, MSTATUS_MPIE, 0);
 
        switch (payload_mode) {
        case RISCV_PAYLOAD_MODE_U:
                status = INSERT_FIELD(status, MSTATUS_MPP, PRV_U);
                /* Trap vector base address point to the payload */
                write_csr(utvec, doit);
                /* disable U-Mode interrupt */
                write_csr(uie, 0);
                break;
        case RISCV_PAYLOAD_MODE_S:
                status = INSERT_FIELD(status, MSTATUS_MPP, PRV_S);
                /* Trap vector base address point to the payload */
                write_csr(stvec, doit);
                /* disable S-Mode interrupt */
                write_csr(sie, 0);
                /* disable MMU */
                write_csr(satp, 0);
                break;
        case RISCV_PAYLOAD_MODE_M:
                status = INSERT_FIELD(status, MSTATUS_MPP, PRV_M);
                /* Trap vector base address point to the payload */
                write_csr(mtvec, doit);
                /* disable M-Mode interrupt */
                write_csr(mie, 0);
                break;
        default:
                die("wrong privilege level for payload");
                break;
        }
        write_csr(mstatus, status);
        write_csr(mepc, doit);
        asm volatile(
                "mv a0, %0\n\t"
                "mv a1, %1\n\t"
                "mret" ::"r"(hart_id),
                "r"(fdt)
                : "a0", "a1");
}