| // 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/physmem_info.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_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_preserved(max_mappable); |
| unsigned long __bootdata(ident_map_size); |
| |
| 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 void rescue_initrd(unsigned long min, unsigned long max) |
| { |
| unsigned long old_addr, addr, size; |
| |
| if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) |
| return; |
| if (!get_physmem_reserved(RR_INITRD, &addr, &size)) |
| return; |
| if (addr >= min && addr + size <= max) |
| return; |
| old_addr = addr; |
| physmem_free(RR_INITRD); |
| addr = physmem_alloc_top_down(RR_INITRD, size, 0); |
| memmove((void *)addr, (void *)old_addr, 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 range (get_physmem_online_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 vsize; |
| 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. */ |
| vsize = round_up(ident_map_size, _REGION3_SIZE) + vmemmap_size + |
| MODULES_LEN + MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE; |
| vsize = size_add(vsize, vmalloc_size); |
| if (IS_ENABLED(CONFIG_KASAN) || (vsize > _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 - MEMCPY_REAL_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 = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); |
| /* maximum mappable address as seen by arch_get_mappable_range() */ |
| max_mappable = vmemmap_start; |
| /* 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(unsigned long vmlinux_lma) |
| { |
| memset((void *)vmlinux_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) |
| { |
| *(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; |
| #ifdef CONFIG_KASAN |
| vmlinux.kasan_early_shadow_page_off += offset; |
| vmlinux.kasan_early_shadow_pte_off += offset; |
| vmlinux.kasan_early_shadow_pmd_off += offset; |
| vmlinux.kasan_early_shadow_pud_off += offset; |
| vmlinux.kasan_early_shadow_p4d_off += offset; |
| #endif |
| } |
| |
| void startup_kernel(void) |
| { |
| unsigned long max_physmem_end; |
| unsigned long vmlinux_lma = 0; |
| unsigned long amode31_lma = 0; |
| unsigned long asce_limit; |
| unsigned long safe_addr; |
| void *img; |
| psw_t psw; |
| |
| setup_lpp(); |
| safe_addr = mem_safe_offset(); |
| |
| /* |
| * Reserve decompressor memory together with decompression heap, buffer and |
| * memory which might be occupied by uncompressed kernel at default 1Mb |
| * position (if KASLR is off or failed). |
| */ |
| physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr); |
| if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size) |
| physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size); |
| oldmem_data.start = parmarea.oldmem_base; |
| oldmem_data.size = parmarea.oldmem_size; |
| |
| store_ipl_parmblock(); |
| read_ipl_report(); |
| uv_query_info(); |
| sclp_early_read_info(); |
| setup_boot_command_line(); |
| parse_boot_command_line(); |
| detect_facilities(); |
| sanitize_prot_virt_host(); |
| max_physmem_end = detect_max_physmem_end(); |
| setup_ident_map_size(max_physmem_end); |
| setup_vmalloc_size(); |
| asce_limit = setup_kernel_memory_layout(); |
| /* got final ident_map_size, physmem allocations could be performed now */ |
| physmem_set_usable_limit(ident_map_size); |
| detect_physmem_online_ranges(max_physmem_end); |
| save_ipl_cert_comp_list(); |
| rescue_initrd(safe_addr, ident_map_size); |
| |
| if (kaslr_enabled()) { |
| vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size, |
| THREAD_SIZE, vmlinux.default_lma, |
| ident_map_size); |
| if (vmlinux_lma) { |
| __kaslr_offset = vmlinux_lma - vmlinux.default_lma; |
| offset_vmlinux_info(__kaslr_offset); |
| } |
| } |
| vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma; |
| physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size); |
| |
| if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { |
| img = decompress_kernel(); |
| memmove((void *)vmlinux_lma, img, vmlinux.image_size); |
| } else if (__kaslr_offset) { |
| img = (void *)vmlinux.default_lma; |
| memmove((void *)vmlinux_lma, img, vmlinux.image_size); |
| memset(img, 0, vmlinux.image_size); |
| } |
| |
| /* vmlinux decompression is done, shrink reserved low memory */ |
| physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end); |
| if (kaslr_enabled()) |
| amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G); |
| amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size; |
| physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_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(vmlinux_lma); |
| handle_relocs(__kaslr_offset); |
| setup_vmem(asce_limit); |
| copy_bootdata(); |
| |
| /* |
| * 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 ? __kaslr_offset | 0x1UL : 0; |
| |
| /* |
| * Jump to the decompressed kernel entry point and switch DAT mode on. |
| */ |
| psw.addr = vmlinux.entry; |
| psw.mask = PSW_KERNEL_BITS; |
| __load_psw(psw); |
| } |