limine/common/sys/smp_trampoline.asm_riscv64
2023-06-20 13:24:49 +02:00

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.section .text
.global smp_trampoline_start
smp_trampoline_start:
// The AP begins executing here with the following state:
// satp = 0
// sstatus.SIE = 0
// a0 = hartid
// a1 = struct trampoline_passed_info *
//
// All other registers are undefined.
ld a0, 16(a1)
ld t0, 8(a1)
csrw satp, t0
// Tell the BSP we've started.
li t0, 1
fence rw, w
sd t0, (a1)
// Zero all the things.
// Preserve a0
mv a1, zero
mv a2, zero
mv a3, zero
mv a4, zero
mv a5, zero
mv a6, zero
mv a7, zero
mv s0, zero
mv s1, zero
mv s2, zero
mv s3, zero
mv s4, zero
mv s5, zero
mv s6, zero
mv s7, zero
mv s8, zero
mv s9, zero
mv s10, zero
mv s11, zero
mv t1, zero
mv t2, zero
mv t3, zero
mv t4, zero
mv t5, zero
mv t6, zero
mv tp, zero
mv ra, zero
csrw sie, zero
csrw stvec, zero
// Wait for kernel to tell us where to go.
0: .insn i 0x0F, 0, x0, x0, 0x010 // pause
ld t0, 24(a0)
fence r, rw
beqz t0, 0b
// Load sp from reserved field of info struct
ld sp, 16(a0)
jr t0