/*-
* Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com>
* All rights reserved.
*
* Portions of this software were developed by SRI International and the
* University of Cambridge Computer Laboratory under DARPA/AFRL contract
* FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
*
* Portions of this software were developed by the University of Cambridge
* Computer Laboratory as part of the CTSRD Project, with support from the
* UK Higher Education Innovation Fund (HEIF).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include "assym.inc"
#include <sys/syscall.h>
#include <machine/asm.h>
#include <machine/param.h>
#include <machine/trap.h>
#include <machine/riscvreg.h>
#include <machine/pte.h>
.globl kernbase
.set kernbase, KERNBASE
.text
/*
* Alternate entry point. Used when booting via SBI firmware. It must be placed
* at the beginning of the .text section. Arguments are as follows:
* - a0 = hart ID
* - a1 = dtbp
*
* Multiple CPUs might enter from this point, so we perform a hart lottery and
* send the losers to mpentry.
*/
.globl _alt_start
_alt_start:
/* Set the global pointer */
.option push
.option norelax
lla gp, __global_pointer$
.option pop
/* Pick a hart to run the boot process. */
lla t0, hart_lottery
li t1, 1
amoadd.w t0, t1, 0(t0)
/*
* We must jump to mpentry in the non-BSP case because the offset is
* too large to fit in a 12-bit branch immediate.
*/
beqz t0, 1f
j mpentry
1:
/* Store the boot hart */
lla t0, boot_hart
sw a0, 0(t0)
/* Load zero as modulep */
mv a0, zero
j pagetables
/*
* Main entry point. This routine is marked as the ELF entry, and is where
* loader(8) will enter the kernel. Arguments are as follows:
* - a0 = modulep
* - a1 = ???
*
* It is expected that only a single CPU will enter here.
*/
.globl _start
_start:
/* Set the global pointer */
.option push
.option norelax
lla gp, __global_pointer$
.option pop
/*
* Zero a1 to indicate that we have no DTB pointer. It is already
* included in the loader(8) metadata.
*/
mv a1, zero
/*
* Page tables setup
* a0 - modulep or zero
* a1 - zero or dtbp
*/
pagetables:
/* Get the kernel's load address */
jal get_physmem
/* Add L1 entry for kernel */
lla s1, pagetable_l1
lla s2, pagetable_l2 /* Link to next level PN */
srli s2, s2, PAGE_SHIFT
li a5, KERNBASE
srli a5, a5, L1_SHIFT /* >> L1_SHIFT */
andi a5, a5, 0x1ff /* & 0x1ff */
li t4, PTE_V
slli t5, s2, PTE_PPN0_S /* (s2 << PTE_PPN0_S) */
or t6, t4, t5
/* Store L1 PTE entry to position */
li a6, PTE_SIZE
mulw a5, a5, a6
add t0, s1, a5
sd t6, (t0)
/* Level 2 superpages (512 x 2MiB) */
lla s1, pagetable_l2
srli t4, s9, L2_SHIFT /* Div physmem base by 2 MiB */
li t2, 512 /* Build 512 entries */
add t3, t4, t2
li t0, (PTE_KERN | PTE_X)
1:
slli t2, t4, PTE_PPN1_S /* << PTE_PPN1_S */
or t5, t0, t2
sd t5, (s1) /* Store PTE entry to position */
addi s1, s1, PTE_SIZE
addi t4, t4, 1
bltu t4, t3, 1b
/* Create an L1 page for early devmap */
lla s1, pagetable_l1
lla s2, pagetable_l2_devmap /* Link to next level PN */
srli s2, s2, PAGE_SHIFT
li a5, (VM_MAX_KERNEL_ADDRESS - L2_SIZE)
srli a5, a5, L1_SHIFT /* >> L1_SHIFT */
andi a5, a5, 0x1ff /* & 0x1ff */
li t4, PTE_V
slli t5, s2, PTE_PPN0_S /* (s2 << PTE_PPN0_S) */
or t6, t4, t5
/* Store single level1 PTE entry to position */
li a6, PTE_SIZE
mulw a5, a5, a6
add t0, s1, a5
sd t6, (t0)
/* Check if we have a DTB that needs to be mapped */
beqz a1, 2f
/* Create an L2 page superpage for DTB */
lla s1, pagetable_l2_devmap
mv s2, a1
srli s2, s2, PAGE_SHIFT
/* Mask off any bits that aren't aligned */
andi s2, s2, ~((1 << (PTE_PPN1_S - PTE_PPN0_S)) - 1)
li t0, (PTE_KERN)
slli t2, s2, PTE_PPN0_S /* << PTE_PPN0_S */
or t0, t0, t2
/* Store PTE entry to position */
li a6, PTE_SIZE
li a5, 510
mulw a5, a5, a6
add t1, s1, a5
sd t0, (t1)
/* Page tables END */
/* Setup supervisor trap vector */
2:
lla t0, va
sub t0, t0, s9
li t1, KERNBASE
add t0, t0, t1
csrw stvec, t0
/* Set page tables base register */
lla s2, pagetable_l1
srli s2, s2, PAGE_SHIFT
li t0, SATP_MODE_SV39
or s2, s2, t0
sfence.vma
csrw satp, s2
.align 2
va:
/* Set the global pointer again, this time with the virtual address. */
.option push
.option norelax
lla gp, __global_pointer$
.option pop
/* Setup supervisor trap vector */
la t0, cpu_exception_handler
csrw stvec, t0
/* Ensure sscratch is zero */
li t0, 0
csrw sscratch, t0
/* Initialize stack pointer */
la sp, initstack_end
/* Clear frame pointer */
mv s0, zero
/* Allocate space for thread0 PCB and riscv_bootparams */
addi sp, sp, -(PCB_SIZE + RISCV_BOOTPARAMS_SIZE) & ~STACKALIGNBYTES
/* Clear BSS */
la t0, _C_LABEL(__bss_start)
la t1, _C_LABEL(_end)
1:
sd zero, 0(t0)
addi t0, t0, 8
bltu t0, t1, 1b
/* Fill riscv_bootparams */
la t0, pagetable_l1
sd t0, RISCV_BOOTPARAMS_KERN_L1PT(sp)
sd s9, RISCV_BOOTPARAMS_KERN_PHYS(sp)
la t0, initstack
sd t0, RISCV_BOOTPARAMS_KERN_STACK(sp)
li t0, (VM_EARLY_DTB_ADDRESS)
/* Add offset of DTB within superpage */
li t1, (L2_OFFSET)
and t1, a1, t1
add t0, t0, t1
sd t0, RISCV_BOOTPARAMS_DTBP_VIRT(sp)
sd a1, RISCV_BOOTPARAMS_DTBP_PHYS(sp)
sd a0, RISCV_BOOTPARAMS_MODULEP(sp)
mv a0, sp
call _C_LABEL(initriscv) /* Off we go */
call _C_LABEL(mi_startup)
/* We should never reach here, but if so just hang. */
2:
wfi
j 2b
/*
* Get the physical address the kernel is loaded to. Returned in s9.
*/
get_physmem:
lla t0, virt_map /* physical address of virt_map */
ld t1, 0(t0) /* virtual address of virt_map */
sub t1, t1, t0 /* calculate phys->virt delta */
li t2, KERNBASE
sub s9, t2, t1 /* s9 = physmem base */
ret
.align 4
initstack:
.space (PAGE_SIZE * KSTACK_PAGES)
initstack_end:
ENTRY(sigcode)
mv a0, sp
addi a0, a0, SF_UC
1:
li t0, SYS_sigreturn
ecall
/* sigreturn failed, exit */
li t0, SYS_exit
ecall
j 1b
END(sigcode)
/* This may be copied to the stack, keep it 16-byte aligned */
.align 3
esigcode:
.data
.align 3
.global szsigcode
szsigcode:
.quad esigcode - sigcode
.align 12
pagetable_l1:
.space PAGE_SIZE
pagetable_l2:
.space PAGE_SIZE
pagetable_l2_devmap:
.space PAGE_SIZE
.align 3
virt_map:
.quad virt_map
hart_lottery:
.space 4
.globl init_pt_va
init_pt_va:
.quad pagetable_l2 /* XXX: Keep page tables VA */
#ifndef SMP
ENTRY(mpentry)
1:
wfi
j 1b
END(mpentry)
#else
/*
* mpentry(unsigned long)
*
* Called by a core when it is being brought online.
*/
ENTRY(mpentry)
/*
* Calculate the offset to __riscv_boot_ap
* for the current core, cpuid is in a0.
*/
li t1, 4
mulw t1, t1, a0
/* Get the pointer */
lla t0, __riscv_boot_ap
add t0, t0, t1
1:
/* Wait the kernel to be ready */
lw t1, 0(t0)
beqz t1, 1b
/* Setup stack pointer */
lla t0, bootstack
ld sp, 0(t0)
/* Get the kernel's load address */
jal get_physmem
/* Setup supervisor trap vector */
lla t0, mpva
sub t0, t0, s9
li t1, KERNBASE
add t0, t0, t1
csrw stvec, t0
/* Set page tables base register */
lla s2, pagetable_l1
srli s2, s2, PAGE_SHIFT
li t0, SATP_MODE_SV39
or s2, s2, t0
sfence.vma
csrw satp, s2
.align 2
mpva:
/* Set the global pointer again, this time with the virtual address. */
.option push
.option norelax
lla gp, __global_pointer$
.option pop
/* Setup supervisor trap vector */
la t0, cpu_exception_handler
csrw stvec, t0
/* Ensure sscratch is zero */
li t0, 0
csrw sscratch, t0
call init_secondary
END(mpentry)
#endif