xref: /linux/arch/powerpc/kernel/early_32.c (revision b77e0ce62d63a761ffb7f7245a215a49f5921c2f)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 /*
4  * Early init before relocation
5  */
6 
7 #include <linux/init.h>
8 #include <linux/kernel.h>
9 #include <asm/setup.h>
10 #include <asm/sections.h>
11 #include <asm/asm-prototypes.h>
12 
13 /*
14  * We're called here very early in the boot.
15  *
16  * Note that the kernel may be running at an address which is different
17  * from the address that it was linked at, so we must use RELOC/PTRRELOC
18  * to access static data (including strings).  -- paulus
19  */
20 notrace unsigned long __init early_init(unsigned long dt_ptr)
21 {
22 	unsigned long kva, offset = reloc_offset();
23 
24 	kva = *PTRRELOC(&kernstart_virt_addr);
25 
26 	/* First zero the BSS */
27 	if (kva == KERNELBASE)
28 		memset(PTRRELOC(&__bss_start), 0, __bss_stop - __bss_start);
29 
30 	/*
31 	 * Identify the CPU type and fix up code sections
32 	 * that depend on which cpu we have.
33 	 */
34 	identify_cpu(offset, mfspr(SPRN_PVR));
35 
36 	apply_feature_fixups();
37 
38 	return kva + offset;
39 }
40