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arch/riscv: Add SMP support for exception handler

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Change-Id: Ia1f97b82e329f6358061072f98278cf56b503618
Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68841
Reviewed-by: Philipp Hug <philipp@hug.cx>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: ron minnich <rminnich@gmail.com>
This commit is contained in:
Xiang Wang 2019-06-21 13:04:10 +08:00 committed by Martin L Roth
parent 5787a4c53b
commit 52b81845de
2 changed files with 117 additions and 114 deletions
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3
src/arch/riscv/payload.c
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@ -6,6 +6,7 @@
#include <arch/encoding.h> #include <arch/encoding.h>
#include <arch/smp/atomic.h> #include <arch/smp/atomic.h>
#include <console/console.h> #include <console/console.h>
#include <mcall.h>
#include <vm.h> #include <vm.h>
/* Run OpenSBI and let OpenSBI hand over control to the payload */ /* Run OpenSBI and let OpenSBI hand over control to the payload */
@ -47,6 +48,8 @@ void run_payload(struct prog *prog, void *fdt, int payload_mode)
write_csr(sie, 0); write_csr(sie, 0);
/* disable MMU */ /* disable MMU */
write_csr(satp, 0); write_csr(satp, 0);
/* save stack to mscratch so trap_entry can use that as exception stack */
write_csr(mscratch, MACHINE_STACK_TOP());
break; break;
case RISCV_PAYLOAD_MODE_M: case RISCV_PAYLOAD_MODE_M:
status = INSERT_FIELD(status, MSTATUS_MPP, PRV_M); status = INSERT_FIELD(status, MSTATUS_MPP, PRV_M);

228
src/arch/riscv/trap_util.S
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@ -7,129 +7,129 @@
#include <mcall.h> #include <mcall.h>
.macro restore_regs .macro restore_regs
# restore x registers # restore x registers
LOAD x1,1*REGBYTES(a0) LOAD x1, 1 * REGBYTES(sp)
LOAD x2,2*REGBYTES(a0) LOAD x3, 3 * REGBYTES(sp)
LOAD x3,3*REGBYTES(a0) LOAD x4, 4 * REGBYTES(sp)
LOAD x4,4*REGBYTES(a0) LOAD x5, 5 * REGBYTES(sp)
LOAD x5,5*REGBYTES(a0) LOAD x6, 6 * REGBYTES(sp)
LOAD x6,6*REGBYTES(a0) LOAD x7, 7 * REGBYTES(sp)
LOAD x7,7*REGBYTES(a0) LOAD x8, 8 * REGBYTES(sp)
LOAD x8,8*REGBYTES(a0) LOAD x9, 9 * REGBYTES(sp)
LOAD x9,9*REGBYTES(a0) LOAD x10, 10 * REGBYTES(sp)
LOAD x11,11*REGBYTES(a0) LOAD x11, 11 * REGBYTES(sp)
LOAD x12,12*REGBYTES(a0) LOAD x12, 12 * REGBYTES(sp)
LOAD x13,13*REGBYTES(a0) LOAD x13, 13 * REGBYTES(sp)
LOAD x14,14*REGBYTES(a0) LOAD x14, 14 * REGBYTES(sp)
LOAD x15,15*REGBYTES(a0) LOAD x15, 15 * REGBYTES(sp)
LOAD x16,16*REGBYTES(a0) LOAD x16, 16 * REGBYTES(sp)
LOAD x17,17*REGBYTES(a0) LOAD x17, 17 * REGBYTES(sp)
LOAD x18,18*REGBYTES(a0) LOAD x18, 18 * REGBYTES(sp)
LOAD x19,19*REGBYTES(a0) LOAD x19, 19 * REGBYTES(sp)
LOAD x20,20*REGBYTES(a0) LOAD x20, 20 * REGBYTES(sp)
LOAD x21,21*REGBYTES(a0) LOAD x21, 21 * REGBYTES(sp)
LOAD x22,22*REGBYTES(a0) LOAD x22, 22 * REGBYTES(sp)
LOAD x23,23*REGBYTES(a0) LOAD x23, 23 * REGBYTES(sp)
LOAD x24,24*REGBYTES(a0) LOAD x24, 24 * REGBYTES(sp)
LOAD x25,25*REGBYTES(a0) LOAD x25, 25 * REGBYTES(sp)
LOAD x26,26*REGBYTES(a0) LOAD x26, 26 * REGBYTES(sp)
LOAD x27,27*REGBYTES(a0) LOAD x27, 27 * REGBYTES(sp)
LOAD x28,28*REGBYTES(a0) LOAD x28, 28 * REGBYTES(sp)
LOAD x29,29*REGBYTES(a0) LOAD x29, 29 * REGBYTES(sp)
LOAD x30,30*REGBYTES(a0) LOAD x30, 30 * REGBYTES(sp)
LOAD x31,31*REGBYTES(a0) LOAD x31, 31 * REGBYTES(sp)
# restore a0 last .endm
LOAD x10,10*REGBYTES(a0)
.endm
.macro save_tf .macro save_tf
# save gprs # save general purpose registers
STORE x1,1*REGBYTES(x2) # no point in saving x0 since it is always 0
STORE x3,3*REGBYTES(x2) STORE x1, 1 * REGBYTES(sp)
STORE x4,4*REGBYTES(x2) # x2 is our stack pointer and is saved further below
STORE x5,5*REGBYTES(x2) STORE x3, 3 * REGBYTES(sp)
STORE x6,6*REGBYTES(x2) STORE x4, 4 * REGBYTES(sp)
STORE x7,7*REGBYTES(x2) STORE x5, 5 * REGBYTES(sp)
STORE x8,8*REGBYTES(x2) STORE x6, 6 * REGBYTES(sp)
STORE x9,9*REGBYTES(x2) STORE x7, 7 * REGBYTES(sp)
STORE x10,10*REGBYTES(x2) STORE x8, 8 * REGBYTES(sp)
STORE x11,11*REGBYTES(x2) STORE x9, 9 * REGBYTES(sp)
STORE x12,12*REGBYTES(x2) STORE x10, 10 * REGBYTES(sp)
STORE x13,13*REGBYTES(x2) STORE x11, 11 * REGBYTES(sp)
STORE x14,14*REGBYTES(x2) STORE x12, 12 * REGBYTES(sp)
STORE x15,15*REGBYTES(x2) STORE x13, 13 * REGBYTES(sp)
STORE x16,16*REGBYTES(x2) STORE x14, 14 * REGBYTES(sp)
STORE x17,17*REGBYTES(x2) STORE x15, 15 * REGBYTES(sp)
STORE x18,18*REGBYTES(x2) STORE x16, 16 * REGBYTES(sp)
STORE x19,19*REGBYTES(x2) STORE x17, 17 * REGBYTES(sp)
STORE x20,20*REGBYTES(x2) STORE x18, 18 * REGBYTES(sp)
STORE x21,21*REGBYTES(x2) STORE x19, 19 * REGBYTES(sp)
STORE x22,22*REGBYTES(x2) STORE x20, 20 * REGBYTES(sp)
STORE x23,23*REGBYTES(x2) STORE x21, 21 * REGBYTES(sp)
STORE x24,24*REGBYTES(x2) STORE x22, 22 * REGBYTES(sp)
STORE x25,25*REGBYTES(x2) STORE x23, 23 * REGBYTES(sp)
STORE x26,26*REGBYTES(x2) STORE x24, 24 * REGBYTES(sp)
STORE x27,27*REGBYTES(x2) STORE x25, 25 * REGBYTES(sp)
STORE x28,28*REGBYTES(x2) STORE x26, 26 * REGBYTES(sp)
STORE x29,29*REGBYTES(x2) STORE x27, 27 * REGBYTES(sp)
STORE x30,30*REGBYTES(x2) STORE x28, 28 * REGBYTES(sp)
STORE x31,31*REGBYTES(x2) STORE x29, 29 * REGBYTES(sp)
STORE x30, 30 * REGBYTES(sp)
STORE x31, 31 * REGBYTES(sp)
# get sr, epc, badvaddr, cause # get sr, epc, badvaddr, cause
csrrw t0,mscratch,x0 csrr t0, mscratch
csrr s0,mstatus bnez t0, 1f # t0 == 0, trap come from coreboot
csrr t1,mepc # t0 != 0, t0 is saved old sp
csrr t2,mtval add t0, sp, MENTRY_FRAME_SIZE
csrr t3,mcause 1:
STORE t0,2*REGBYTES(x2) csrr s0, mstatus
STORE s0,32*REGBYTES(x2) csrr t1, mepc
STORE t1,33*REGBYTES(x2) csrr t2, mtval
STORE t2,34*REGBYTES(x2) csrr t3, mcause
STORE t3,35*REGBYTES(x2) STORE t0, 2 * REGBYTES(sp)
STORE s0, 32 * REGBYTES(sp)
STORE t1, 33 * REGBYTES(sp)
STORE t2, 34 * REGBYTES(sp)
STORE t3, 35 * REGBYTES(sp)
# get faulting insn, if it wasn't a fetch-related trap # get faulting insn, if it wasn't a fetch-related trap
li x5,-1 li x5, -1
STORE x5,36*REGBYTES(x2) STORE x5, 36 * REGBYTES(sp)
.endm
.endm .text
.global trap_entry
.globl estack .align 2 # four byte alignment, as required by mtvec
.text
.global trap_entry
.align 2 # four byte alignment, as required by mtvec
trap_entry: trap_entry:
csrw mscratch, sp # mscratch is initialized to 0
# when exiting coreboot, write sp to mscratch
# before jumping to m-mode firmware we always set trap vector to the entry point of the
# payload and we don't care about mscratch anymore. mscratch is only ever used as
# exception stack if whatever coreboot jumps to is in s-mode.
#TODO we could check MPP field in mstatus to see if come from unpriviledged code. That
# way we could still use mscratch for other purposes inside the code base.
#TODO In case we got called from s-mode firmware we need to protect our stack and trap
# handler with a PMP region.
csrrw sp, mscratch, sp
# sp == 0 => trap came from coreboot
# sp != 0 => trap came from s-mode payload
bnez sp, 1f
csrrw sp, mscratch, sp
1:
addi sp, sp, -MENTRY_FRAME_SIZE
save_tf
# SMP isn't supported yet, to avoid overwriting the same stack with different mv a0,sp # put trapframe as first argument
# harts that handle traps at the same time.
# someday this gets fixed.
//csrr sp, mhartid
csrr sp, 0xf14
.Lsmp_hang:
bnez sp, .Lsmp_hang
# Use a different stack than in the main context, to avoid overwriting LOAD t0, trap_handler
# stack data. jalr t0
# TODO: Maybe use the old stack pointer (plus an offset) instead. But only if
# the previous mode was M, because it would be a very bad idea to use a stack
# pointer provided by unprivileged code!
la sp, _estack
addi sp, sp, -2048 # 2 KiB is half of the stack space
addi sp, sp, -MENTRY_FRAME_SIZE
save_tf
move a0,sp
# store pointer to stack frame (moved out from trap_handler)
csrw mscratch, sp
LOAD t0, trap_handler
jalr t0
trap_return: trap_return:
csrr a0, mscratch
restore_regs restore_regs
# go back to the previous mode addi sp, sp, MENTRY_FRAME_SIZE
# restore original stack pointer (either sp or mscratch)
csrrw sp, mscratch, sp
bnez sp, 1f
csrrw sp, mscratch, sp
1:
mret mret