diff options
Diffstat (limited to 'kernel/head.S')
| -rw-r--r-- | kernel/head.S | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/head.S b/kernel/head.S index 74f83d8..b175b89 100644 --- a/kernel/head.S +++ b/kernel/head.S @@ -63,6 +63,23 @@ _start_kernel: // Flush the instruction cache fence.i + // Run the hart lottery. If this is not the first time that it happens, then + // stall this hart forever: on this simple kernel we only want one hart + // available to avoid SMP shenanigans. See explanation on fbos/init.h. + la a3, hart_lottery + li a2, 1 + amoadd.w a3, a2, (a3) + beqz a3, .Lhart_proceed +.Lhart_wait: + wfi + j .Lhart_wait + +.Lhart_proceed: + // Store the hart id as we will tamper with the 'a0' register later when + // performing the call to `start_kernel`. + la a3, hart_id + sw a0, 0(a3) + // Reset all registers except ra, a0, a1. li sp, 0 li gp, 0 |