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.section ".text.init"
// entrypoint for boot hart(s). a0: hartid, a1: *fdt
.globl _start
// entrypoint for other harts. a0: hartid, a1: unused for now
.global _mpentry
_start:
/* disable interrupts and paging */
csrw satp, zero
csrw sie, zero
csrw sip, zero
.option push
.option norelax
la gp, __global_pointer$
.option pop
/* setup stack.
* stack grows toward lower address so sp will mark end of frame.
*/
addi t0, a0, 1
li t1, PAGE_SIZE
la sp, __stack_start
mul t1, t1, t0
add sp, sp, t1
/* setup thread pointer */
mv tp, a0
/* the label _boot_hart is shared between threads. after the first atomic swap, all other harts will branch to mpentry */
li a2, 1
lla a3, _boot_hart
amoswap.w a3, a2, (a3)
bnez a3, _mpentry
/* clear the bss section */
la a2, __bss_start
la a3, __bss_end
1:
sd zero, (a2)
addi a2, a2, __SIZEOF_POINTER__
blt a2, a3, 1b
2:
call init
j _spin
_mpentry:
/* satp = 0, sstatus.sie = 0, a0 = hartid, a1 = opaque */
call mpinit
/* shouldn't reach this point */
j _spin
_spin:
wfi
j _spin
.section ".data"
_boot_hart:
.word 0
.section ".rodata"
/* linker imports */
.globl HEAP_START
HEAP_START: .dword __heap_start
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