diff options
Diffstat (limited to 'kernel/head.S')
| -rw-r--r-- | kernel/head.S | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/kernel/head.S b/kernel/head.S index 638e5e8..45e66a8 100644 --- a/kernel/head.S +++ b/kernel/head.S @@ -71,11 +71,6 @@ _start_kernel: amoadd.w a3, a2, (a3) bnez a3, .Lhart_wait - // 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) - // Explicitely nullify the 'gp' and 'sscratch' registers, as they are a bit // special but we are not using them. For the rest of the registers, we // explicitely do not care to reset them. @@ -90,12 +85,12 @@ _start_kernel: // Point 'sp' the our global stack. See fbos/sched.h for more details. la sp, stack + STACK_SIZE - // The `start_kernel` function requires an argument to be passed, which is - // the pointer to the `fdt` blob. The bootloader puts this on the `a1` - // register, so let's move it now to `a0`. - mv a0, a1 - - // Start the kernel. + // Start the kernel. Notice that both 'a0' and 'a1' have been left + // untouched. This is no coincidence as the values as passed from the + // bootloader for both these two registers will be passed down to the kernel + // as is. As with the Linux kernel these two registers contain: + // - a0: boot hart id. + // - a1: pointer to the flattened device tree blob. tail start_kernel // We really shouldn't reach this point. If so, at least mask again all |