diff options
Diffstat (limited to 'arch/s390/boot/startup.c')
| -rw-r--r-- | arch/s390/boot/startup.c | 512 |
1 files changed, 339 insertions, 173 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 6cf89314209a..da8337e63a3e 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -1,12 +1,18 @@ // SPDX-License-Identifier: GPL-2.0 +#define boot_fmt(fmt) "startup: " fmt #include <linux/string.h> #include <linux/elf.h> #include <asm/page-states.h> #include <asm/boot_data.h> +#include <asm/extmem.h> #include <asm/sections.h> +#include <asm/diag288.h> #include <asm/maccess.h> +#include <asm/machine.h> +#include <asm/sysinfo.h> #include <asm/cpu_mf.h> #include <asm/setup.h> +#include <asm/timex.h> #include <asm/kasan.h> #include <asm/kexec.h> #include <asm/sclp.h> @@ -18,7 +24,7 @@ #include "boot.h" #include "uv.h" -unsigned long __bootdata_preserved(__kaslr_offset); +struct vm_layout __bootdata_preserved(vm_layout); unsigned long __bootdata_preserved(__abs_lowcore); unsigned long __bootdata_preserved(__memcpy_real_area); pte_t *__bootdata_preserved(memcpy_real_ptep); @@ -29,61 +35,131 @@ 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); +unsigned long __bootdata_preserved(page_noexec_mask); +unsigned long __bootdata_preserved(segment_noexec_mask); +unsigned long __bootdata_preserved(region_noexec_mask); +union tod_clock __bootdata_preserved(tod_clock_base); +u64 __bootdata_preserved(clock_comparator_max) = -1UL; 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"); - + boot_emerg("%s\n", x); + boot_emerg(" -- System halted\n"); disabled_wait(); } +static char sysinfo_page[PAGE_SIZE] __aligned(PAGE_SIZE); + +static void detect_machine_type(void) +{ + struct sysinfo_3_2_2 *vmms = (struct sysinfo_3_2_2 *)&sysinfo_page; + + /* Check current-configuration-level */ + if (stsi(NULL, 0, 0, 0) <= 2) { + set_machine_feature(MFEATURE_LPAR); + return; + } + /* Get virtual-machine cpu information. */ + if (stsi(vmms, 3, 2, 2) || !vmms->count) + return; + /* Detect known hypervisors */ + if (!memcmp(vmms->vm[0].cpi, "\xd2\xe5\xd4", 3)) + set_machine_feature(MFEATURE_KVM); + else if (!memcmp(vmms->vm[0].cpi, "\xa9\x61\xe5\xd4", 4)) + set_machine_feature(MFEATURE_VM); +} + +static void detect_diag288(void) +{ + /* "BEGIN" in EBCDIC character set */ + static const char cmd[] = "\xc2\xc5\xc7\xc9\xd5"; + unsigned long action, len; + + action = machine_is_vm() ? (unsigned long)cmd : LPARWDT_RESTART; + len = machine_is_vm() ? sizeof(cmd) : 0; + if (__diag288(WDT_FUNC_INIT, MIN_INTERVAL, action, len)) + return; + __diag288(WDT_FUNC_CANCEL, 0, 0, 0); + set_machine_feature(MFEATURE_DIAG288); +} + +static void detect_diag9c(void) +{ + unsigned int cpu; + int rc = 1; + + cpu = stap(); + asm_inline volatile( + " diag %[cpu],%%r0,0x9c\n" + "0: lhi %[rc],0\n" + "1:\n" + EX_TABLE(0b, 1b) + : [rc] "+d" (rc) + : [cpu] "d" (cpu) + : "cc", "memory"); + if (!rc) + set_machine_feature(MFEATURE_DIAG9C); +} + +static void reset_tod_clock(void) +{ + union tod_clock clk; + + if (store_tod_clock_ext_cc(&clk) == 0) + return; + /* TOD clock not running. Set the clock to Unix Epoch. */ + if (set_tod_clock(TOD_UNIX_EPOCH) || store_tod_clock_ext_cc(&clk)) + disabled_wait(); + memset(&tod_clock_base, 0, sizeof(tod_clock_base)); + tod_clock_base.tod = TOD_UNIX_EPOCH; + get_lowcore()->last_update_clock = TOD_UNIX_EPOCH; +} + static void detect_facilities(void) { - if (test_facility(8)) { - machine.has_edat1 = 1; + if (cpu_has_edat1()) local_ctl_set_bit(0, CR0_EDAT_BIT); + page_noexec_mask = -1UL; + segment_noexec_mask = -1UL; + region_noexec_mask = -1UL; + if (!cpu_has_nx()) { + page_noexec_mask &= ~_PAGE_NOEXEC; + segment_noexec_mask &= ~_SEGMENT_ENTRY_NOEXEC; + region_noexec_mask &= ~_REGION_ENTRY_NOEXEC; + } + if (IS_ENABLED(CONFIG_PCI) && test_facility(153)) + set_machine_feature(MFEATURE_PCI_MIO); + reset_tod_clock(); + if (test_facility(139) && (tod_clock_base.tod >> 63)) { + /* Enable signed clock comparator comparisons */ + set_machine_feature(MFEATURE_SCC); + clock_comparator_max = -1UL >> 1; + local_ctl_set_bit(0, CR0_CLOCK_COMPARATOR_SIGN_BIT); } - if (test_facility(78)) - machine.has_edat2 = 1; - if (test_facility(130)) - machine.has_nx = 1; + if (test_facility(50) && test_facility(73)) { + set_machine_feature(MFEATURE_TX); + local_ctl_set_bit(0, CR0_TRANSACTIONAL_EXECUTION_BIT); + } + if (cpu_has_vx()) + local_ctl_set_bit(0, CR0_VECTOR_BIT); } static int cmma_test_essa(void) { - unsigned long reg1, reg2, tmp = 0; + unsigned long tmp = 0; int rc = 1; - psw_t old; /* Test ESSA_GET_STATE */ - asm volatile( - " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" - " epsw %[reg1],%[reg2]\n" - " st %[reg1],0(%[psw_pgm])\n" - " st %[reg2],4(%[psw_pgm])\n" - " larl %[reg1],1f\n" - " stg %[reg1],8(%[psw_pgm])\n" + asm_inline volatile( " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n" - " la %[rc],0\n" - "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" - : [reg1] "=&d" (reg1), - [reg2] "=&a" (reg2), - [rc] "+&d" (rc), - [tmp] "=&d" (tmp), - "+Q" (S390_lowcore.program_new_psw), - "=Q" (old) - : [psw_old] "a" (&old), - [psw_pgm] "a" (&S390_lowcore.program_new_psw), - [cmd] "i" (ESSA_GET_STATE) + "0: lhi %[rc],0\n" + "1:\n" + EX_TABLE(0b, 1b) + : [rc] "+d" (rc), [tmp] "+d" (tmp) + : [cmd] "i" (ESSA_GET_STATE) : "cc", "memory"); return rc; } @@ -102,16 +178,26 @@ static void cmma_init(void) static void setup_lpp(void) { - S390_lowcore.current_pid = 0; - S390_lowcore.lpp = LPP_MAGIC; + get_lowcore()->current_pid = 0; + get_lowcore()->lpp = LPP_MAGIC; if (test_facility(40)) - lpp(&S390_lowcore.lpp); + lpp(&get_lowcore()->lpp); } #ifdef CONFIG_KERNEL_UNCOMPRESSED -unsigned long mem_safe_offset(void) +static unsigned long mem_safe_offset(void) { - return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; + return (unsigned long)_compressed_start; +} + +static void deploy_kernel(void *output) +{ + void *uncompressed_start = (void *)_compressed_start; + + if (output == uncompressed_start) + return; + memmove(output, uncompressed_start, vmlinux.image_size); + memset(uncompressed_start, 0, vmlinux.image_size); } #endif @@ -127,7 +213,7 @@ static void rescue_initrd(unsigned long min, unsigned long max) return; old_addr = addr; physmem_free(RR_INITRD); - addr = physmem_alloc_top_down(RR_INITRD, size, 0); + addr = physmem_alloc_or_die(RR_INITRD, size, 0); memmove((void *)addr, (void *)old_addr, size); } @@ -141,67 +227,15 @@ static void copy_bootdata(void) memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size); } -#ifdef CONFIG_PIE_BUILD -static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, 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"); - } -} - -static void kaslr_adjust_got(unsigned long offset) {} -static void rescue_relocs(void) {} -static void free_relocs(void) {} -#else -static int *vmlinux_relocs_64_start; -static int *vmlinux_relocs_64_end; - -static void rescue_relocs(void) -{ - unsigned long size = __vmlinux_relocs_64_end - __vmlinux_relocs_64_start; - - vmlinux_relocs_64_start = (void *)physmem_alloc_top_down(RR_RELOC, size, 0); - vmlinux_relocs_64_end = (void *)vmlinux_relocs_64_start + size; - memmove(vmlinux_relocs_64_start, __vmlinux_relocs_64_start, size); -} - -static void free_relocs(void) -{ - physmem_free(RR_RELOC); -} - -static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, unsigned long offset) +static void kaslr_adjust_relocs(unsigned long min_addr, unsigned long max_addr, + unsigned long offset, unsigned long phys_offset) { int *reloc; long loc; /* Adjust R_390_64 relocations */ - for (reloc = vmlinux_relocs_64_start; reloc < vmlinux_relocs_64_end; reloc++) { - loc = (long)*reloc + offset; + for (reloc = (int *)__vmlinux_relocs_64_start; reloc < (int *)__vmlinux_relocs_64_end; reloc++) { + loc = (long)*reloc + phys_offset; if (loc < min_addr || loc > max_addr) error("64-bit relocation outside of kernel!\n"); *(u64 *)loc += offset; @@ -213,24 +247,29 @@ static void kaslr_adjust_got(unsigned long offset) u64 *entry; /* - * Even without -fPIE, Clang still uses a global offset table for some - * reason. Adjust the GOT entries. + * Adjust GOT entries, except for ones for undefined weak symbols + * that resolved to zero. This also skips the first three reserved + * entries on s390x that are zero. */ - for (entry = (u64 *)vmlinux.got_start; entry < (u64 *)vmlinux.got_end; entry++) - *entry += offset; + for (entry = (u64 *)vmlinux.got_start; entry < (u64 *)vmlinux.got_end; entry++) { + if (*entry) + *entry += offset; + } } -#endif /* * 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 or memory areas reserved for other means (e.g., memory devices such as + * virtio-mem). + * + * "ident_map_size" could be lower then actual standby/reserved 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. + * 1. max_physmem_end - end of physical memory online, standby or reserved. * 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. @@ -253,17 +292,40 @@ static void setup_ident_map_size(unsigned long max_physmem_end) if (oldmem_data.start) { __kaslr_enabled = 0; ident_map_size = min(ident_map_size, oldmem_data.size); + boot_debug("kdump memory limit: 0x%016lx\n", 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) + if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) { ident_map_size = min(ident_map_size, hsa_size); + boot_debug("Stand-alone dump limit: 0x%016lx\n", hsa_size); + } } #endif + boot_debug("Identity map size: 0x%016lx\n", ident_map_size); } -static unsigned long setup_kernel_memory_layout(void) +#define FIXMAP_SIZE round_up(MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE, sizeof(struct lowcore)) + +static unsigned long get_vmem_size(unsigned long identity_size, + unsigned long vmemmap_size, + unsigned long vmalloc_size, + unsigned long rte_size) +{ + unsigned long max_mappable, vsize; + + max_mappable = max(identity_size, MAX_DCSS_ADDR); + vsize = round_up(SZ_2G + max_mappable, rte_size) + + round_up(vmemmap_size, rte_size) + + FIXMAP_SIZE + MODULES_LEN + KASLR_LEN; + if (IS_ENABLED(CONFIG_KMSAN)) + vsize += MODULES_LEN * 2; + return size_add(vsize, vmalloc_size); +} + +static unsigned long setup_kernel_memory_layout(unsigned long kernel_size) { unsigned long vmemmap_start; + unsigned long kernel_start; unsigned long asce_limit; unsigned long rte_size; unsigned long pages; @@ -275,12 +337,20 @@ static unsigned long setup_kernel_memory_layout(void) 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)) { + BUILD_BUG_ON(!IS_ALIGNED(TEXT_OFFSET, THREAD_SIZE)); + BUILD_BUG_ON(!IS_ALIGNED(__NO_KASLR_START_KERNEL, THREAD_SIZE)); + BUILD_BUG_ON(__NO_KASLR_END_KERNEL > _REGION1_SIZE); + vsize = get_vmem_size(ident_map_size, vmemmap_size, vmalloc_size, _REGION3_SIZE); + boot_debug("vmem size estimated: 0x%016lx\n", vsize); + if (IS_ENABLED(CONFIG_KASAN) || __NO_KASLR_END_KERNEL > _REGION2_SIZE || + (vsize > _REGION2_SIZE && kaslr_enabled())) { asce_limit = _REGION1_SIZE; - rte_size = _REGION2_SIZE; + if (__NO_KASLR_END_KERNEL > _REGION2_SIZE) { + rte_size = _REGION2_SIZE; + vsize = get_vmem_size(ident_map_size, vmemmap_size, vmalloc_size, _REGION2_SIZE); + } else { + rte_size = _REGION3_SIZE; + } } else { asce_limit = _REGION2_SIZE; rte_size = _REGION3_SIZE; @@ -290,38 +360,93 @@ static unsigned long setup_kernel_memory_layout(void) * 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. + * + * Assume the secure storage limit always exceeds _REGION2_SIZE, + * otherwise asce_limit and rte_size would have been adjusted. */ vmax = adjust_to_uv_max(asce_limit); + boot_debug("%d level paging 0x%016lx vmax\n", vmax == _REGION1_SIZE ? 4 : 3, vmax); #ifdef CONFIG_KASAN + BUILD_BUG_ON(__NO_KASLR_END_KERNEL > KASAN_SHADOW_START); + boot_debug("KASAN shadow area: 0x%016lx-0x%016lx\n", KASAN_SHADOW_START, KASAN_SHADOW_END); /* 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); + vsize = min(vsize, vmax); + if (kaslr_enabled()) { + unsigned long kernel_end, kaslr_len, slots, pos; + + kaslr_len = max(KASLR_LEN, vmax - vsize); + slots = DIV_ROUND_UP(kaslr_len - kernel_size, THREAD_SIZE); + if (get_random(slots, &pos)) + pos = 0; + kernel_end = vmax - pos * THREAD_SIZE; + kernel_start = round_down(kernel_end - kernel_size, THREAD_SIZE); + boot_debug("Randomization range: 0x%016lx-0x%016lx\n", vmax - kaslr_len, vmax); + boot_debug("kernel image: 0x%016lx-0x%016lx (kaslr)\n", kernel_start, + kernel_size + kernel_size); + } else if (vmax < __NO_KASLR_END_KERNEL || vsize > __NO_KASLR_END_KERNEL) { + kernel_start = round_down(vmax - kernel_size, THREAD_SIZE); + boot_debug("kernel image: 0x%016lx-0x%016lx (constrained)\n", kernel_start, + kernel_start + kernel_size); + } else { + kernel_start = __NO_KASLR_START_KERNEL; + boot_debug("kernel image: 0x%016lx-0x%016lx (nokaslr)\n", kernel_start, + kernel_start + kernel_size); + } + __kaslr_offset = kernel_start; + boot_debug("__kaslr_offset: 0x%016lx\n", __kaslr_offset); + + MODULES_END = round_down(kernel_start, _SEGMENT_SIZE); MODULES_VADDR = MODULES_END - MODULES_LEN; VMALLOC_END = MODULES_VADDR; + if (IS_ENABLED(CONFIG_KMSAN)) + VMALLOC_END -= MODULES_LEN * 2; + boot_debug("modules area: 0x%016lx-0x%016lx\n", MODULES_VADDR, MODULES_END); /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ - vsize = round_down(VMALLOC_END / 2, _SEGMENT_SIZE); + vsize = (VMALLOC_END - FIXMAP_SIZE) / 2; + vsize = round_down(vsize, _SEGMENT_SIZE); vmalloc_size = min(vmalloc_size, vsize); + if (IS_ENABLED(CONFIG_KMSAN)) { + /* take 2/3 of vmalloc area for KMSAN shadow and origins */ + vmalloc_size = round_down(vmalloc_size / 3, _SEGMENT_SIZE); + VMALLOC_END -= vmalloc_size * 2; + } VMALLOC_START = VMALLOC_END - vmalloc_size; + boot_debug("vmalloc area: 0x%016lx-0x%016lx\n", VMALLOC_START, VMALLOC_END); + + __memcpy_real_area = round_down(VMALLOC_START - MEMCPY_REAL_SIZE, PAGE_SIZE); + boot_debug("memcpy real area: 0x%016lx-0x%016lx\n", __memcpy_real_area, + __memcpy_real_area + MEMCPY_REAL_SIZE); + __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE, + sizeof(struct lowcore)); + boot_debug("abs lowcore: 0x%016lx-0x%016lx\n", __abs_lowcore, + __abs_lowcore + ABS_LOWCORE_MAP_SIZE); /* split remaining virtual space between 1:1 mapping & vmemmap array */ - pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page)); + pages = __abs_lowcore / (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; + vmemmap_start = round_down(__abs_lowcore - pages * sizeof(struct page), rte_size); /* 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); + /* make sure vmemmap doesn't overlay with absolute lowcore area */ + if (vmemmap_start + vmemmap_size > __abs_lowcore) { + vmemmap_size = SECTION_ALIGN_DOWN(ident_map_size / PAGE_SIZE) * sizeof(struct page); + ident_map_size = vmemmap_size / sizeof(struct page) * PAGE_SIZE; + } vmemmap = (struct page *)vmemmap_start; + /* maximum address for which linear mapping could be created (DCSS, memory) */ + BUILD_BUG_ON(MAX_DCSS_ADDR > (1UL << MAX_PHYSMEM_BITS)); + max_mappable = max(ident_map_size, MAX_DCSS_ADDR); + max_mappable = min(max_mappable, vmemmap_start); +#ifdef CONFIG_RANDOMIZE_IDENTITY_BASE + __identity_base = round_down(vmemmap_start - max_mappable, rte_size); +#endif + boot_debug("identity map: 0x%016lx-0x%016lx\n", __identity_base, + __identity_base + ident_map_size); return asce_limit; } @@ -329,9 +454,9 @@ static unsigned long setup_kernel_memory_layout(void) /* * 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) +static void clear_bss_section(unsigned long kernel_start) { - memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size); + memset((void *)kernel_start + vmlinux.image_size, 0, vmlinux.bss_size); } /* @@ -348,22 +473,17 @@ static void setup_vmalloc_size(void) vmalloc_size = max(size, vmalloc_size); } -static void kaslr_adjust_vmlinux_info(unsigned long offset) +static void kaslr_adjust_vmlinux_info(long offset) { - *(unsigned long *)(&vmlinux.entry) += offset; vmlinux.bootdata_off += offset; vmlinux.bootdata_preserved_off += offset; -#ifdef CONFIG_PIE_BUILD - vmlinux.rela_dyn_start += offset; - vmlinux.rela_dyn_end += offset; - vmlinux.dynsym_start += offset; -#else vmlinux.got_start += offset; vmlinux.got_end += offset; -#endif vmlinux.init_mm_off += offset; vmlinux.swapper_pg_dir_off += offset; vmlinux.invalid_pg_dir_off += offset; + vmlinux.alt_instructions += offset; + vmlinux.alt_instructions_end += offset; #ifdef CONFIG_KASAN vmlinux.kasan_early_shadow_page_off += offset; vmlinux.kasan_early_shadow_pte_off += offset; @@ -375,21 +495,32 @@ static void kaslr_adjust_vmlinux_info(unsigned long offset) void startup_kernel(void) { + unsigned long vmlinux_size = vmlinux.image_size + vmlinux.bss_size; + unsigned long nokaslr_text_lma, text_lma = 0, amode31_lma = 0; + unsigned long kernel_size = TEXT_OFFSET + vmlinux_size; + unsigned long kaslr_large_page_offset; 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(); + store_ipl_parmblock(); + uv_query_info(); + setup_boot_command_line(); + parse_boot_command_line(); /* - * 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). + * Non-randomized kernel physical start address must be _SEGMENT_SIZE + * aligned (see blow). + */ + nokaslr_text_lma = ALIGN(mem_safe_offset(), _SEGMENT_SIZE); + safe_addr = PAGE_ALIGN(nokaslr_text_lma + vmlinux_size); + + /* + * Reserve decompressor memory together with decompression heap, + * buffer and memory which might be occupied by uncompressed kernel + * (if KASLR is off or failed). */ physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr); if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size) @@ -397,52 +528,82 @@ void startup_kernel(void) 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(); + sclp_early_detect_machine_features(); detect_facilities(); + detect_diag9c(); + detect_machine_type(); + /* detect_diag288() needs machine type */ + detect_diag288(); cmma_init(); 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(); + asce_limit = setup_kernel_memory_layout(kernel_size); /* 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); - rescue_relocs(); + /* + * __kaslr_offset_phys must be _SEGMENT_SIZE aligned, so the lower + * 20 bits (the offset within a large page) are zero. Copy the last + * 20 bits of __kaslr_offset, which is THREAD_SIZE aligned, to + * __kaslr_offset_phys. + * + * With this the last 20 bits of __kaslr_offset_phys and __kaslr_offset + * are identical, which is required to allow for large mappings of the + * kernel image. + */ + kaslr_large_page_offset = __kaslr_offset & ~_SEGMENT_MASK; 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; - kaslr_adjust_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); + unsigned long size = vmlinux_size + kaslr_large_page_offset; + + text_lma = randomize_within_range(size, _SEGMENT_SIZE, TEXT_OFFSET, ident_map_size); } + if (!text_lma) + text_lma = nokaslr_text_lma; + text_lma |= kaslr_large_page_offset; + + /* + * [__kaslr_offset_phys..__kaslr_offset_phys + TEXT_OFFSET] region is + * never accessed via the kernel image mapping as per the linker script: + * + * . = TEXT_OFFSET; + * + * Therefore, this region could be used for something else and does + * not need to be reserved. See how it is skipped in setup_vmem(). + */ + __kaslr_offset_phys = text_lma - TEXT_OFFSET; + kaslr_adjust_vmlinux_info(__kaslr_offset_phys); + physmem_reserve(RR_VMLINUX, text_lma, vmlinux_size); + deploy_kernel((void *)text_lma); /* 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; + + /* + * In case KASLR is enabled the randomized location of .amode31 + * section might overlap with .vmlinux.relocs section. To avoid that + * the below randomize_within_range() could have been called with + * __vmlinux_relocs_64_end as the lower range address. However, + * .amode31 section is written to by the decompressed kernel - at + * that time the contents of .vmlinux.relocs is not needed anymore. + * Conversely, .vmlinux.relocs is read only by the decompressor, even + * before the kernel started. Therefore, in case the two sections + * overlap there is no risk of corrupting any data. + */ + if (kaslr_enabled()) { + unsigned long amode31_min; + + amode31_min = (unsigned long)_decompressor_end; + amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, amode31_min, SZ_2G); + } + if (!amode31_lma) + amode31_lma = text_lma - vmlinux.amode31_size; physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size); /* @@ -458,23 +619,28 @@ void startup_kernel(void) * - copy_bootdata() must follow setup_vmem() to propagate changes * to bootdata made by setup_vmem() */ - clear_bss_section(vmlinux_lma); - kaslr_adjust_relocs(vmlinux_lma, vmlinux_lma + vmlinux.image_size, __kaslr_offset); + clear_bss_section(text_lma); + kaslr_adjust_relocs(text_lma, text_lma + vmlinux.image_size, + __kaslr_offset, __kaslr_offset_phys); kaslr_adjust_got(__kaslr_offset); - free_relocs(); - setup_vmem(asce_limit); + setup_vmem(__kaslr_offset, __kaslr_offset + kernel_size, asce_limit); + dump_physmem_reserved(); copy_bootdata(); + __apply_alternatives((struct alt_instr *)_vmlinux_info.alt_instructions, + (struct alt_instr *)_vmlinux_info.alt_instructions_end, + ALT_CTX_EARLY); /* * 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; + get_lowcore()->vmcore_info = __kaslr_offset_phys ? __kaslr_offset_phys | 0x1UL : 0; /* * Jump to the decompressed kernel entry point and switch DAT mode on. */ - psw.addr = vmlinux.entry; + psw.addr = __kaslr_offset + vmlinux.entry; psw.mask = PSW_KERNEL_BITS; + boot_debug("Starting kernel at: 0x%016lx\n", psw.addr); __load_psw(psw); } |