301 lines
9.3 KiB
C
301 lines
9.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/string.h>
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#include <linux/elf.h>
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#include <asm/boot_data.h>
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#include <asm/sections.h>
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#include <asm/cpu_mf.h>
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#include <asm/setup.h>
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#include <asm/kasan.h>
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#include <asm/kexec.h>
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#include <asm/sclp.h>
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#include <asm/diag.h>
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#include <asm/uv.h>
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#include "compressed/decompressor.h"
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#include "boot.h"
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#include "uv.h"
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unsigned long __bootdata_preserved(__kaslr_offset);
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unsigned long __bootdata(__amode31_base);
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unsigned long __bootdata_preserved(VMALLOC_START);
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unsigned long __bootdata_preserved(VMALLOC_END);
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struct page *__bootdata_preserved(vmemmap);
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unsigned long __bootdata_preserved(vmemmap_size);
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unsigned long __bootdata_preserved(MODULES_VADDR);
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unsigned long __bootdata_preserved(MODULES_END);
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unsigned long __bootdata(ident_map_size);
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int __bootdata(is_full_image) = 1;
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struct initrd_data __bootdata(initrd_data);
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u64 __bootdata_preserved(stfle_fac_list[16]);
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u64 __bootdata_preserved(alt_stfle_fac_list[16]);
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struct oldmem_data __bootdata_preserved(oldmem_data);
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void error(char *x)
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{
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sclp_early_printk("\n\n");
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sclp_early_printk(x);
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sclp_early_printk("\n\n -- System halted");
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disabled_wait();
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}
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static void setup_lpp(void)
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{
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S390_lowcore.current_pid = 0;
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S390_lowcore.lpp = LPP_MAGIC;
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if (test_facility(40))
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lpp(&S390_lowcore.lpp);
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}
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#ifdef CONFIG_KERNEL_UNCOMPRESSED
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unsigned long mem_safe_offset(void)
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{
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return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
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}
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#endif
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static void rescue_initrd(unsigned long addr)
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{
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if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
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return;
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if (!initrd_data.start || !initrd_data.size)
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return;
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if (addr <= initrd_data.start)
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return;
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memmove((void *)addr, (void *)initrd_data.start, initrd_data.size);
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initrd_data.start = addr;
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}
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static void copy_bootdata(void)
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{
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if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
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error(".boot.data section size mismatch");
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memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
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if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
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error(".boot.preserved.data section size mismatch");
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memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
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}
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static void handle_relocs(unsigned long offset)
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{
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Elf64_Rela *rela_start, *rela_end, *rela;
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int r_type, r_sym, rc;
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Elf64_Addr loc, val;
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Elf64_Sym *dynsym;
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rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
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rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
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dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
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for (rela = rela_start; rela < rela_end; rela++) {
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loc = rela->r_offset + offset;
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val = rela->r_addend;
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r_sym = ELF64_R_SYM(rela->r_info);
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if (r_sym) {
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if (dynsym[r_sym].st_shndx != SHN_UNDEF)
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val += dynsym[r_sym].st_value + offset;
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} else {
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/*
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* 0 == undefined symbol table index (STN_UNDEF),
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* used for R_390_RELATIVE, only add KASLR offset
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*/
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val += offset;
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}
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r_type = ELF64_R_TYPE(rela->r_info);
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rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
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if (rc)
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error("Unknown relocation type");
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}
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}
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/*
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* Merge information from several sources into a single ident_map_size value.
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* "ident_map_size" represents the upper limit of physical memory we may ever
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* reach. It might not be all online memory, but also include standby (offline)
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* memory. "ident_map_size" could be lower then actual standby or even online
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* memory present, due to limiting factors. We should never go above this limit.
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* It is the size of our identity mapping.
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*
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* Consider the following factors:
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* 1. max_physmem_end - end of physical memory online or standby.
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* Always <= end of the last online memory block (get_mem_detect_end()).
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* 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
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* kernel is able to support.
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* 3. "mem=" kernel command line option which limits physical memory usage.
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* 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
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* crash kernel.
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* 5. "hsa" size which is a memory limit when the kernel is executed during
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* zfcp/nvme dump.
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*/
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static void setup_ident_map_size(unsigned long max_physmem_end)
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{
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unsigned long hsa_size;
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ident_map_size = max_physmem_end;
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if (memory_limit)
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ident_map_size = min(ident_map_size, memory_limit);
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ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS);
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#ifdef CONFIG_CRASH_DUMP
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if (oldmem_data.start) {
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kaslr_enabled = 0;
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ident_map_size = min(ident_map_size, oldmem_data.size);
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} else if (ipl_block_valid && is_ipl_block_dump()) {
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kaslr_enabled = 0;
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if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size)
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ident_map_size = min(ident_map_size, hsa_size);
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}
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#endif
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}
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static void setup_kernel_memory_layout(void)
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{
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unsigned long vmemmap_start;
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unsigned long rte_size;
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unsigned long pages;
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pages = ident_map_size / PAGE_SIZE;
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/* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
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vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page);
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/* choose kernel address space layout: 4 or 3 levels. */
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vmemmap_start = round_up(ident_map_size, _REGION3_SIZE);
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if (IS_ENABLED(CONFIG_KASAN) ||
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vmalloc_size > _REGION2_SIZE ||
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vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN >
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_REGION2_SIZE) {
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MODULES_END = _REGION1_SIZE;
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rte_size = _REGION2_SIZE;
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} else {
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MODULES_END = _REGION2_SIZE;
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rte_size = _REGION3_SIZE;
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}
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/*
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* forcing modules and vmalloc area under the ultravisor
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* secure storage limit, so that any vmalloc allocation
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* we do could be used to back secure guest storage.
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*/
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adjust_to_uv_max(&MODULES_END);
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#ifdef CONFIG_KASAN
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/* force vmalloc and modules below kasan shadow */
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MODULES_END = min(MODULES_END, KASAN_SHADOW_START);
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#endif
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MODULES_VADDR = MODULES_END - MODULES_LEN;
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VMALLOC_END = MODULES_VADDR;
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/* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */
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vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE));
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VMALLOC_START = VMALLOC_END - vmalloc_size;
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/* split remaining virtual space between 1:1 mapping & vmemmap array */
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pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
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pages = SECTION_ALIGN_UP(pages);
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/* keep vmemmap_start aligned to a top level region table entry */
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vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size);
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/* vmemmap_start is the future VMEM_MAX_PHYS, make sure it is within MAX_PHYSMEM */
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vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS);
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/* make sure identity map doesn't overlay with vmemmap */
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ident_map_size = min(ident_map_size, vmemmap_start);
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vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
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/* make sure vmemmap doesn't overlay with vmalloc area */
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VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START);
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vmemmap = (struct page *)vmemmap_start;
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}
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/*
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* This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
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*/
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static void clear_bss_section(void)
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{
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memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
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}
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/*
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* Set vmalloc area size to an 8th of (potential) physical memory
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* size, unless size has been set by kernel command line parameter.
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*/
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static void setup_vmalloc_size(void)
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{
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unsigned long size;
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if (vmalloc_size_set)
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return;
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size = round_up(ident_map_size / 8, _SEGMENT_SIZE);
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vmalloc_size = max(size, vmalloc_size);
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}
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static void offset_vmlinux_info(unsigned long offset)
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{
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vmlinux.default_lma += offset;
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*(unsigned long *)(&vmlinux.entry) += offset;
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vmlinux.bootdata_off += offset;
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vmlinux.bootdata_preserved_off += offset;
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vmlinux.rela_dyn_start += offset;
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vmlinux.rela_dyn_end += offset;
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vmlinux.dynsym_start += offset;
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}
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static unsigned long reserve_amode31(unsigned long safe_addr)
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{
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__amode31_base = PAGE_ALIGN(safe_addr);
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return safe_addr + vmlinux.amode31_size;
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}
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void startup_kernel(void)
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{
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unsigned long random_lma;
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unsigned long safe_addr;
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void *img;
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initrd_data.start = parmarea.initrd_start;
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initrd_data.size = parmarea.initrd_size;
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oldmem_data.start = parmarea.oldmem_base;
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oldmem_data.size = parmarea.oldmem_size;
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setup_lpp();
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store_ipl_parmblock();
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safe_addr = mem_safe_offset();
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safe_addr = reserve_amode31(safe_addr);
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safe_addr = read_ipl_report(safe_addr);
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uv_query_info();
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rescue_initrd(safe_addr);
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sclp_early_read_info();
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setup_boot_command_line();
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parse_boot_command_line();
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sanitize_prot_virt_host();
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setup_ident_map_size(detect_memory());
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setup_vmalloc_size();
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setup_kernel_memory_layout();
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if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {
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random_lma = get_random_base(safe_addr);
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if (random_lma) {
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__kaslr_offset = random_lma - vmlinux.default_lma;
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img = (void *)vmlinux.default_lma;
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offset_vmlinux_info(__kaslr_offset);
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}
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}
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if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
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img = decompress_kernel();
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memmove((void *)vmlinux.default_lma, img, vmlinux.image_size);
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} else if (__kaslr_offset)
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memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size);
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clear_bss_section();
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copy_bootdata();
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if (IS_ENABLED(CONFIG_RELOCATABLE))
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handle_relocs(__kaslr_offset);
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if (__kaslr_offset) {
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/*
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* Save KASLR offset for early dumps, before vmcore_info is set.
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* Mark as uneven to distinguish from real vmcore_info pointer.
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*/
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S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
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/* Clear non-relocated kernel */
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if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
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memset(img, 0, vmlinux.image_size);
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}
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vmlinux.entry();
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}
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