1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/string.h>
  3#include <linux/elf.h>
  4#include <asm/sections.h>
  5#include <asm/setup.h>
  6#include <asm/kexec.h>
  7#include <asm/sclp.h>
  8#include <asm/diag.h>
  9#include <asm/uv.h>
 10#include "compressed/decompressor.h"
 11#include "boot.h"
 12
 13extern char __boot_data_start[], __boot_data_end[];
 14extern char __boot_data_preserved_start[], __boot_data_preserved_end[];
 15unsigned long __bootdata_preserved(__kaslr_offset);
 16
 17/*
 18 * Some code and data needs to stay below 2 GB, even when the kernel would be
 19 * relocated above 2 GB, because it has to use 31 bit addresses.
 20 * Such code and data is part of the .dma section, and its location is passed
 21 * over to the decompressed / relocated kernel via the .boot.preserved.data
 22 * section.
 23 */
 24extern char _sdma[], _edma[];
 25extern char _stext_dma[], _etext_dma[];
 26extern struct exception_table_entry _start_dma_ex_table[];
 27extern struct exception_table_entry _stop_dma_ex_table[];
 28unsigned long __bootdata_preserved(__sdma) = __pa(&_sdma);
 29unsigned long __bootdata_preserved(__edma) = __pa(&_edma);
 30unsigned long __bootdata_preserved(__stext_dma) = __pa(&_stext_dma);
 31unsigned long __bootdata_preserved(__etext_dma) = __pa(&_etext_dma);
 32struct exception_table_entry *
 33	__bootdata_preserved(__start_dma_ex_table) = _start_dma_ex_table;
 34struct exception_table_entry *
 35	__bootdata_preserved(__stop_dma_ex_table) = _stop_dma_ex_table;
 36
 37int _diag210_dma(struct diag210 *addr);
 38int _diag26c_dma(void *req, void *resp, enum diag26c_sc subcode);
 39int _diag14_dma(unsigned long rx, unsigned long ry1, unsigned long subcode);
 40void _diag0c_dma(struct hypfs_diag0c_entry *entry);
 41void _diag308_reset_dma(void);
 42struct diag_ops __bootdata_preserved(diag_dma_ops) = {
 43	.diag210 = _diag210_dma,
 44	.diag26c = _diag26c_dma,
 45	.diag14 = _diag14_dma,
 46	.diag0c = _diag0c_dma,
 47	.diag308_reset = _diag308_reset_dma
 48};
 49static struct diag210 _diag210_tmp_dma __section(".dma.data");
 50struct diag210 *__bootdata_preserved(__diag210_tmp_dma) = &_diag210_tmp_dma;
 51void _swsusp_reset_dma(void);
 52unsigned long __bootdata_preserved(__swsusp_reset_dma) = __pa(_swsusp_reset_dma);
 53
 54void error(char *x)
 55{
 56	sclp_early_printk("\n\n");
 57	sclp_early_printk(x);
 58	sclp_early_printk("\n\n -- System halted");
 59
 60	disabled_wait();
 61}
 62
 63#ifdef CONFIG_KERNEL_UNCOMPRESSED
 64unsigned long mem_safe_offset(void)
 65{
 66	return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
 67}
 68#endif
 69
 70static void rescue_initrd(unsigned long addr)
 71{
 72	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
 73		return;
 74	if (!INITRD_START || !INITRD_SIZE)
 75		return;
 76	if (addr <= INITRD_START)
 77		return;
 78	memmove((void *)addr, (void *)INITRD_START, INITRD_SIZE);
 79	INITRD_START = addr;
 80}
 81
 82static void copy_bootdata(void)
 83{
 84	if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
 85		error(".boot.data section size mismatch");
 86	memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
 87	if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
 88		error(".boot.preserved.data section size mismatch");
 89	memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
 90}
 91
 92static void handle_relocs(unsigned long offset)
 93{
 94	Elf64_Rela *rela_start, *rela_end, *rela;
 95	int r_type, r_sym, rc;
 96	Elf64_Addr loc, val;
 97	Elf64_Sym *dynsym;
 98
 99	rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
100	rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
101	dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
102	for (rela = rela_start; rela < rela_end; rela++) {
103		loc = rela->r_offset + offset;
104		val = rela->r_addend;
105		r_sym = ELF64_R_SYM(rela->r_info);
106		if (r_sym) {
107			if (dynsym[r_sym].st_shndx != SHN_UNDEF)
108				val += dynsym[r_sym].st_value + offset;
109		} else {
110			/*
111			 * 0 == undefined symbol table index (STN_UNDEF),
112			 * used for R_390_RELATIVE, only add KASLR offset
113			 */
114			val += offset;
115		}
116		r_type = ELF64_R_TYPE(rela->r_info);
117		rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
118		if (rc)
119			error("Unknown relocation type");
120	}
121}
122
123static void clear_bss_section(void)
124{
125	memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
126}
127
128void startup_kernel(void)
129{
130	unsigned long random_lma;
131	unsigned long safe_addr;
132	void *img;
133
134	store_ipl_parmblock();
135	safe_addr = mem_safe_offset();
136	safe_addr = read_ipl_report(safe_addr);
137	uv_query_info();
138	rescue_initrd(safe_addr);
139	sclp_early_read_info();
140	setup_boot_command_line();
141	parse_boot_command_line();
142	setup_memory_end();
143	detect_memory();
144
145	random_lma = __kaslr_offset = 0;
146	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {
147		random_lma = get_random_base(safe_addr);
148		if (random_lma) {
149			__kaslr_offset = random_lma - vmlinux.default_lma;
150			img = (void *)vmlinux.default_lma;
151			vmlinux.default_lma += __kaslr_offset;
152			vmlinux.entry += __kaslr_offset;
153			vmlinux.bootdata_off += __kaslr_offset;
154			vmlinux.bootdata_preserved_off += __kaslr_offset;
155			vmlinux.rela_dyn_start += __kaslr_offset;
156			vmlinux.rela_dyn_end += __kaslr_offset;
157			vmlinux.dynsym_start += __kaslr_offset;
158		}
159	}
160
161	if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
162		img = decompress_kernel();
163		memmove((void *)vmlinux.default_lma, img, vmlinux.image_size);
164	} else if (__kaslr_offset)
165		memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size);
166
167	clear_bss_section();
168	copy_bootdata();
169	if (IS_ENABLED(CONFIG_RELOCATABLE))
170		handle_relocs(__kaslr_offset);
171
172	if (__kaslr_offset) {
173		/* Clear non-relocated kernel */
174		if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
175			memset(img, 0, vmlinux.image_size);
176	}
177	vmlinux.entry();
178}