// SPDX-License-Identifier: GPL-2.0 #include <linux/string.h> #include <linux/elf.h> #include <asm/boot_data.h> #include <asm/sections.h> #include <asm/maccess.h> #include <asm/cpu_mf.h> #include <asm/setup.h> #include <asm/kasan.h> #include <asm/kexec.h> #include <asm/sclp.h> #include <asm/diag.h> #include <asm/uv.h> #include <asm/abs_lowcore.h> #include <asm/mem_detect.h> #include "decompressor.h" #include "boot.h" #include "uv.h" unsigned long __bootdata_preserved(__kaslr_offset); unsigned long __bootdata_preserved(__abs_lowcore); unsigned long __bootdata_preserved(__memcpy_real_area); pte_t *__bootdata_preserved(memcpy_real_ptep); unsigned long __bootdata(__amode31_base); unsigned long __bootdata_preserved(VMALLOC_START); unsigned long __bootdata_preserved(VMALLOC_END); struct page *__bootdata_preserved(vmemmap); unsigned long __bootdata_preserved(vmemmap_size); unsigned long __bootdata_preserved(MODULES_VADDR); unsigned long __bootdata_preserved(MODULES_END); unsigned long __bootdata(ident_map_size); int __bootdata(is_full_image) = 1; struct initrd_data __bootdata(initrd_data); u64 __bootdata_preserved(stfle_fac_list[16]); u64 __bootdata_preserved(alt_stfle_fac_list[16]); struct oldmem_data __bootdata_preserved(oldmem_data); struct machine_info machine; void error(char *x) { sclp_early_printk("\n\n"); sclp_early_printk(x); sclp_early_printk("\n\n -- System halted"); disabled_wait(); } static void detect_facilities(void) { if (test_facility(8)) { machine.has_edat1 = 1; __ctl_set_bit(0, 23); } if (test_facility(78)) machine.has_edat2 = 1; if (!noexec_disabled && test_facility(130)) { machine.has_nx = 1; __ctl_set_bit(0, 20); } } static void setup_lpp(void) { S390_lowcore.current_pid = 0; S390_lowcore.lpp = LPP_MAGIC; if (test_facility(40)) lpp(&S390_lowcore.lpp); } #ifdef CONFIG_KERNEL_UNCOMPRESSED unsigned long mem_safe_offset(void) { return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; } #endif static unsigned long rescue_initrd(unsigned long safe_addr) { if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) return safe_addr; if (!initrd_data.start || !initrd_data.size) return safe_addr; if (initrd_data.start < safe_addr) { memmove((void *)safe_addr, (void *)initrd_data.start, initrd_data.size); initrd_data.start = safe_addr; } return initrd_data.start + initrd_data.size; } static void copy_bootdata(void) { if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size) error(".boot.data section size mismatch"); memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size); if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size) error(".boot.preserved.data section size mismatch"); memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size); } static void handle_relocs(unsigned long offset) { Elf64_Rela *rela_start, *rela_end, *rela; int r_type, r_sym, rc; Elf64_Addr loc, val; Elf64_Sym *dynsym; rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start; rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end; dynsym = (Elf64_Sym *) vmlinux.dynsym_start; for (rela = rela_start; rela < rela_end; rela++) { loc = rela->r_offset + offset; val = rela->r_addend; r_sym = ELF64_R_SYM(rela->r_info); if (r_sym) { if (dynsym[r_sym].st_shndx != SHN_UNDEF) val += dynsym[r_sym].st_value + offset; } else { /* * 0 == undefined symbol table index (STN_UNDEF), * used for R_390_RELATIVE, only add KASLR offset */ val += offset; } r_type = ELF64_R_TYPE(rela->r_info); rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0); if (rc) error("Unknown relocation type"); } } /* * Merge information from several sources into a single ident_map_size value. * "ident_map_size" represents the upper limit of physical memory we may ever * reach. It might not be all online memory, but also include standby (offline) * memory. "ident_map_size" could be lower then actual standby or even online * memory present, due to limiting factors. We should never go above this limit. * It is the size of our identity mapping. * * Consider the following factors: * 1. max_physmem_end - end of physical memory online or standby. * Always <= end of the last online memory block (get_mem_detect_end()). * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the * kernel is able to support. * 3. "mem=" kernel command line option which limits physical memory usage. * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as * crash kernel. * 5. "hsa" size which is a memory limit when the kernel is executed during * zfcp/nvme dump. */ static void setup_ident_map_size(unsigned long max_physmem_end) { unsigned long hsa_size; ident_map_size = max_physmem_end; if (memory_limit) ident_map_size = min(ident_map_size, memory_limit); ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS); #ifdef CONFIG_CRASH_DUMP if (oldmem_data.start) { kaslr_enabled = 0; ident_map_size = min(ident_map_size, oldmem_data.size); } else if (ipl_block_valid && is_ipl_block_dump()) { kaslr_enabled = 0; if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) ident_map_size = min(ident_map_size, hsa_size); } #endif } static unsigned long setup_kernel_memory_layout(void) { unsigned long vmemmap_start; unsigned long asce_limit; unsigned long rte_size; unsigned long pages; unsigned long vmax; pages = ident_map_size / PAGE_SIZE; /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */ vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page); /* choose kernel address space layout: 4 or 3 levels. */ vmemmap_start = round_up(ident_map_size, _REGION3_SIZE); if (IS_ENABLED(CONFIG_KASAN) || vmalloc_size > _REGION2_SIZE || vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN > _REGION2_SIZE) { asce_limit = _REGION1_SIZE; rte_size = _REGION2_SIZE; } else { asce_limit = _REGION2_SIZE; rte_size = _REGION3_SIZE; } /* * forcing modules and vmalloc area under the ultravisor * secure storage limit, so that any vmalloc allocation * we do could be used to back secure guest storage. */ vmax = adjust_to_uv_max(asce_limit); #ifdef CONFIG_KASAN /* force vmalloc and modules below kasan shadow */ vmax = min(vmax, KASAN_SHADOW_START); #endif __memcpy_real_area = round_down(vmax - PAGE_SIZE, PAGE_SIZE); __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE, sizeof(struct lowcore)); MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE); MODULES_VADDR = MODULES_END - MODULES_LEN; VMALLOC_END = MODULES_VADDR; /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE)); VMALLOC_START = VMALLOC_END - vmalloc_size; /* split remaining virtual space between 1:1 mapping & vmemmap array */ pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page)); pages = SECTION_ALIGN_UP(pages); /* keep vmemmap_start aligned to a top level region table entry */ vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size); /* vmemmap_start is the future VMEM_MAX_PHYS, make sure it is within MAX_PHYSMEM */ vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); /* make sure identity map doesn't overlay with vmemmap */ ident_map_size = min(ident_map_size, vmemmap_start); vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page); /* make sure vmemmap doesn't overlay with vmalloc area */ VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START); vmemmap = (struct page *)vmemmap_start; return asce_limit; } /* * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's. */ static void clear_bss_section(void) { memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size); } /* * Set vmalloc area size to an 8th of (potential) physical memory * size, unless size has been set by kernel command line parameter. */ static void setup_vmalloc_size(void) { unsigned long size; if (vmalloc_size_set) return; size = round_up(ident_map_size / 8, _SEGMENT_SIZE); vmalloc_size = max(size, vmalloc_size); } static void offset_vmlinux_info(unsigned long offset) { vmlinux.default_lma += offset; *(unsigned long *)(&vmlinux.entry) += offset; vmlinux.bootdata_off += offset; vmlinux.bootdata_preserved_off += offset; vmlinux.rela_dyn_start += offset; vmlinux.rela_dyn_end += offset; vmlinux.dynsym_start += offset; vmlinux.init_mm_off += offset; vmlinux.swapper_pg_dir_off += offset; vmlinux.invalid_pg_dir_off += offset; } static unsigned long reserve_amode31(unsigned long safe_addr) { __amode31_base = PAGE_ALIGN(safe_addr); return __amode31_base + vmlinux.amode31_size; } void startup_kernel(void) { unsigned long max_physmem_end; unsigned long random_lma; unsigned long safe_addr; unsigned long asce_limit; void *img; psw_t psw; initrd_data.start = parmarea.initrd_start; initrd_data.size = parmarea.initrd_size; oldmem_data.start = parmarea.oldmem_base; oldmem_data.size = parmarea.oldmem_size; setup_lpp(); store_ipl_parmblock(); safe_addr = mem_safe_offset(); safe_addr = reserve_amode31(safe_addr); safe_addr = read_ipl_report(safe_addr); uv_query_info(); safe_addr = rescue_initrd(safe_addr); sclp_early_read_info(); setup_boot_command_line(); parse_boot_command_line(); detect_facilities(); sanitize_prot_virt_host(); max_physmem_end = detect_memory(&safe_addr); setup_ident_map_size(max_physmem_end); setup_vmalloc_size(); asce_limit = setup_kernel_memory_layout(); mem_detect_set_usable_limit(ident_map_size); if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) { random_lma = get_random_base(safe_addr); if (random_lma) { __kaslr_offset = random_lma - vmlinux.default_lma; img = (void *)vmlinux.default_lma; offset_vmlinux_info(__kaslr_offset); } } if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { img = decompress_kernel(); memmove((void *)vmlinux.default_lma, img, vmlinux.image_size); } else if (__kaslr_offset) memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size); /* * The order of the following operations is important: * * - handle_relocs() must follow clear_bss_section() to establish static * memory references to data in .bss to be used by setup_vmem() * (i.e init_mm.pgd) * * - setup_vmem() must follow handle_relocs() to be able using * static memory references to data in .bss (i.e init_mm.pgd) * * - copy_bootdata() must follow setup_vmem() to propagate changes to * bootdata made by setup_vmem() */ clear_bss_section(); handle_relocs(__kaslr_offset); setup_vmem(asce_limit); copy_bootdata(); if (__kaslr_offset) { /* * Save KASLR offset for early dumps, before vmcore_info is set. * Mark as uneven to distinguish from real vmcore_info pointer. */ S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL; /* Clear non-relocated kernel */ if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) memset(img, 0, vmlinux.image_size); } /* * Jump to the decompressed kernel entry point and switch DAT mode on. */ psw.addr = vmlinux.entry; psw.mask = PSW_KERNEL_BITS; __load_psw(psw); }