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Zeroing all registers in kernel entry code

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Imbus 2024-08-07 11:26:45 +02:00
parent ad34ff9b86
commit a1b9321a74
1 changed files with 43 additions and 5 deletions
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48
kernel/entry.S
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@ -11,17 +11,55 @@
.section .text
.global _entry
_entry:
# Clear all the registers.
li x1, 0x0
li x2, 0x0
li x3, 0x0
li x4, 0x0
li x5, 0x0
li x6, 0x0
li x7, 0x0
li x8, 0x0
li x9, 0x0
li x10, 0x0
li x11, 0x0
li x12, 0x0
li x13, 0x0
li x14, 0x0
li x15, 0x0
li x16, 0x0
li x17, 0x0
li x18, 0x0
li x19, 0x0
li x20, 0x0
li x21, 0x0
li x22, 0x0
li x23, 0x0
li x24, 0x0
li x25, 0x0
li x26, 0x0
li x27, 0x0
li x28, 0x0
li x29, 0x0
li x30, 0x0
li x31, 0x0
# set up a stack for C.
# stack0 is declared in start.c,
# with a 4096-byte stack per CPU.
# sp = stack0 + (hartid * 4096)
la sp, stack0
li a0, 1024*4
csrr a1, mhartid
addi a1, a1, 1
mul a0, a0, a1
add sp, sp, a0
li a0, 1024*4 # a0 = 4096
# Control and Status Register Read
csrr a1, mhartid # a1 = unique hart (core) id
addi a1, a1, 1 # a1 += 1
mul a0, a0, a1 # a0 *= a1, aka a0 = 4096 * (hartid + 1), the base of the stack for this hart
add sp, sp, a0 # sp += a0, stack pointer is now properly configured
# jump to start() in start.c
call start
# Infinite spin loop.
spin:
j spin