| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/set_memory.h> |
| #include <linux/ptdump.h> |
| #include <linux/seq_file.h> |
| #include <linux/debugfs.h> |
| #include <linux/mm.h> |
| #include <linux/kfence.h> |
| #include <linux/kasan.h> |
| #include <asm/ptdump.h> |
| #include <asm/kasan.h> |
| #include <asm/abs_lowcore.h> |
| #include <asm/nospec-branch.h> |
| #include <asm/sections.h> |
| #include <asm/maccess.h> |
| |
| static unsigned long max_addr; |
| |
| struct addr_marker { |
| unsigned long start_address; |
| const char *name; |
| }; |
| |
| enum address_markers_idx { |
| IDENTITY_BEFORE_NR = 0, |
| IDENTITY_BEFORE_END_NR, |
| AMODE31_START_NR, |
| AMODE31_END_NR, |
| KERNEL_START_NR, |
| KERNEL_END_NR, |
| #ifdef CONFIG_KFENCE |
| KFENCE_START_NR, |
| KFENCE_END_NR, |
| #endif |
| IDENTITY_AFTER_NR, |
| IDENTITY_AFTER_END_NR, |
| VMEMMAP_NR, |
| VMEMMAP_END_NR, |
| VMALLOC_NR, |
| VMALLOC_END_NR, |
| MODULES_NR, |
| MODULES_END_NR, |
| ABS_LOWCORE_NR, |
| ABS_LOWCORE_END_NR, |
| MEMCPY_REAL_NR, |
| MEMCPY_REAL_END_NR, |
| #ifdef CONFIG_KASAN |
| KASAN_SHADOW_START_NR, |
| KASAN_SHADOW_END_NR, |
| #endif |
| }; |
| |
| static struct addr_marker address_markers[] = { |
| [IDENTITY_BEFORE_NR] = {0, "Identity Mapping Start"}, |
| [IDENTITY_BEFORE_END_NR] = {(unsigned long)_stext, "Identity Mapping End"}, |
| [AMODE31_START_NR] = {0, "Amode31 Area Start"}, |
| [AMODE31_END_NR] = {0, "Amode31 Area End"}, |
| [KERNEL_START_NR] = {(unsigned long)_stext, "Kernel Image Start"}, |
| [KERNEL_END_NR] = {(unsigned long)_end, "Kernel Image End"}, |
| #ifdef CONFIG_KFENCE |
| [KFENCE_START_NR] = {0, "KFence Pool Start"}, |
| [KFENCE_END_NR] = {0, "KFence Pool End"}, |
| #endif |
| [IDENTITY_AFTER_NR] = {(unsigned long)_end, "Identity Mapping Start"}, |
| [IDENTITY_AFTER_END_NR] = {0, "Identity Mapping End"}, |
| [VMEMMAP_NR] = {0, "vmemmap Area Start"}, |
| [VMEMMAP_END_NR] = {0, "vmemmap Area End"}, |
| [VMALLOC_NR] = {0, "vmalloc Area Start"}, |
| [VMALLOC_END_NR] = {0, "vmalloc Area End"}, |
| [MODULES_NR] = {0, "Modules Area Start"}, |
| [MODULES_END_NR] = {0, "Modules Area End"}, |
| [ABS_LOWCORE_NR] = {0, "Lowcore Area Start"}, |
| [ABS_LOWCORE_END_NR] = {0, "Lowcore Area End"}, |
| [MEMCPY_REAL_NR] = {0, "Real Memory Copy Area Start"}, |
| [MEMCPY_REAL_END_NR] = {0, "Real Memory Copy Area End"}, |
| #ifdef CONFIG_KASAN |
| [KASAN_SHADOW_START_NR] = {KASAN_SHADOW_START, "Kasan Shadow Start"}, |
| [KASAN_SHADOW_END_NR] = {KASAN_SHADOW_END, "Kasan Shadow End"}, |
| #endif |
| { -1, NULL } |
| }; |
| |
| struct pg_state { |
| struct ptdump_state ptdump; |
| struct seq_file *seq; |
| int level; |
| unsigned int current_prot; |
| bool check_wx; |
| unsigned long wx_pages; |
| unsigned long start_address; |
| const struct addr_marker *marker; |
| }; |
| |
| #define pt_dump_seq_printf(m, fmt, args...) \ |
| ({ \ |
| struct seq_file *__m = (m); \ |
| \ |
| if (__m) \ |
| seq_printf(__m, fmt, ##args); \ |
| }) |
| |
| #define pt_dump_seq_puts(m, fmt) \ |
| ({ \ |
| struct seq_file *__m = (m); \ |
| \ |
| if (__m) \ |
| seq_printf(__m, fmt); \ |
| }) |
| |
| static void print_prot(struct seq_file *m, unsigned int pr, int level) |
| { |
| static const char * const level_name[] = |
| { "ASCE", "PGD", "PUD", "PMD", "PTE" }; |
| |
| pt_dump_seq_printf(m, "%s ", level_name[level]); |
| if (pr & _PAGE_INVALID) { |
| pt_dump_seq_printf(m, "I\n"); |
| return; |
| } |
| pt_dump_seq_puts(m, (pr & _PAGE_PROTECT) ? "RO " : "RW "); |
| pt_dump_seq_puts(m, (pr & _PAGE_NOEXEC) ? "NX\n" : "X\n"); |
| } |
| |
| static void note_prot_wx(struct pg_state *st, unsigned long addr) |
| { |
| #ifdef CONFIG_DEBUG_WX |
| if (!st->check_wx) |
| return; |
| if (st->current_prot & _PAGE_INVALID) |
| return; |
| if (st->current_prot & _PAGE_PROTECT) |
| return; |
| if (st->current_prot & _PAGE_NOEXEC) |
| return; |
| /* |
| * The first lowcore page is W+X if spectre mitigations are using |
| * trampolines or the BEAR enhancements facility is not installed, |
| * in which case we have two lpswe instructions in lowcore that need |
| * to be executable. |
| */ |
| if (addr == PAGE_SIZE && (nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear))) |
| return; |
| WARN_ONCE(1, "s390/mm: Found insecure W+X mapping at address %pS\n", |
| (void *)st->start_address); |
| st->wx_pages += (addr - st->start_address) / PAGE_SIZE; |
| #endif /* CONFIG_DEBUG_WX */ |
| } |
| |
| static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, u64 val) |
| { |
| int width = sizeof(unsigned long) * 2; |
| static const char units[] = "KMGTPE"; |
| const char *unit = units; |
| unsigned long delta; |
| struct pg_state *st; |
| struct seq_file *m; |
| unsigned int prot; |
| |
| st = container_of(pt_st, struct pg_state, ptdump); |
| m = st->seq; |
| prot = val & (_PAGE_PROTECT | _PAGE_NOEXEC); |
| if (level == 4 && (val & _PAGE_INVALID)) |
| prot = _PAGE_INVALID; |
| /* For pmd_none() & friends val gets passed as zero. */ |
| if (level != 4 && !val) |
| prot = _PAGE_INVALID; |
| /* Final flush from generic code. */ |
| if (level == -1) |
| addr = max_addr; |
| if (st->level == -1) { |
| pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name); |
| st->start_address = addr; |
| st->current_prot = prot; |
| st->level = level; |
| } else if (prot != st->current_prot || level != st->level || |
| addr >= st->marker[1].start_address) { |
| note_prot_wx(st, addr); |
| pt_dump_seq_printf(m, "0x%0*lx-0x%0*lx ", |
| width, st->start_address, |
| width, addr); |
| delta = (addr - st->start_address) >> 10; |
| while (!(delta & 0x3ff) && unit[1]) { |
| delta >>= 10; |
| unit++; |
| } |
| pt_dump_seq_printf(m, "%9lu%c ", delta, *unit); |
| print_prot(m, st->current_prot, st->level); |
| while (addr >= st->marker[1].start_address) { |
| st->marker++; |
| pt_dump_seq_printf(m, "---[ %s ]---\n", st->marker->name); |
| } |
| st->start_address = addr; |
| st->current_prot = prot; |
| st->level = level; |
| } |
| } |
| |
| #ifdef CONFIG_DEBUG_WX |
| void ptdump_check_wx(void) |
| { |
| struct pg_state st = { |
| .ptdump = { |
| .note_page = note_page, |
| .range = (struct ptdump_range[]) { |
| {.start = 0, .end = max_addr}, |
| {.start = 0, .end = 0}, |
| } |
| }, |
| .seq = NULL, |
| .level = -1, |
| .current_prot = 0, |
| .check_wx = true, |
| .wx_pages = 0, |
| .start_address = 0, |
| .marker = (struct addr_marker[]) { |
| { .start_address = 0, .name = NULL}, |
| { .start_address = -1, .name = NULL}, |
| }, |
| }; |
| |
| if (!MACHINE_HAS_NX) |
| return; |
| ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); |
| if (st.wx_pages) |
| pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n", st.wx_pages); |
| else |
| pr_info("Checked W+X mappings: passed, no %sW+X pages found\n", |
| (nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)) ? |
| "unexpected " : ""); |
| } |
| #endif /* CONFIG_DEBUG_WX */ |
| |
| #ifdef CONFIG_PTDUMP_DEBUGFS |
| static int ptdump_show(struct seq_file *m, void *v) |
| { |
| struct pg_state st = { |
| .ptdump = { |
| .note_page = note_page, |
| .range = (struct ptdump_range[]) { |
| {.start = 0, .end = max_addr}, |
| {.start = 0, .end = 0}, |
| } |
| }, |
| .seq = m, |
| .level = -1, |
| .current_prot = 0, |
| .check_wx = false, |
| .wx_pages = 0, |
| .start_address = 0, |
| .marker = address_markers, |
| }; |
| |
| get_online_mems(); |
| mutex_lock(&cpa_mutex); |
| ptdump_walk_pgd(&st.ptdump, &init_mm, NULL); |
| mutex_unlock(&cpa_mutex); |
| put_online_mems(); |
| return 0; |
| } |
| DEFINE_SHOW_ATTRIBUTE(ptdump); |
| #endif /* CONFIG_PTDUMP_DEBUGFS */ |
| |
| /* |
| * Heapsort from lib/sort.c is not a stable sorting algorithm, do a simple |
| * insertion sort to preserve the original order of markers with the same |
| * start address. |
| */ |
| static void sort_address_markers(void) |
| { |
| struct addr_marker tmp; |
| int i, j; |
| |
| for (i = 1; i < ARRAY_SIZE(address_markers) - 1; i++) { |
| tmp = address_markers[i]; |
| for (j = i - 1; j >= 0 && address_markers[j].start_address > tmp.start_address; j--) |
| address_markers[j + 1] = address_markers[j]; |
| address_markers[j + 1] = tmp; |
| } |
| } |
| |
| static int pt_dump_init(void) |
| { |
| #ifdef CONFIG_KFENCE |
| unsigned long kfence_start = (unsigned long)__kfence_pool; |
| #endif |
| /* |
| * Figure out the maximum virtual address being accessible with the |
| * kernel ASCE. We need this to keep the page table walker functions |
| * from accessing non-existent entries. |
| */ |
| max_addr = (S390_lowcore.kernel_asce & _REGION_ENTRY_TYPE_MASK) >> 2; |
| max_addr = 1UL << (max_addr * 11 + 31); |
| address_markers[IDENTITY_AFTER_END_NR].start_address = ident_map_size; |
| address_markers[AMODE31_START_NR].start_address = __samode31; |
| address_markers[AMODE31_END_NR].start_address = __eamode31; |
| address_markers[MODULES_NR].start_address = MODULES_VADDR; |
| address_markers[MODULES_END_NR].start_address = MODULES_END; |
| address_markers[ABS_LOWCORE_NR].start_address = __abs_lowcore; |
| address_markers[ABS_LOWCORE_END_NR].start_address = __abs_lowcore + ABS_LOWCORE_MAP_SIZE; |
| address_markers[MEMCPY_REAL_NR].start_address = __memcpy_real_area; |
| address_markers[MEMCPY_REAL_END_NR].start_address = __memcpy_real_area + MEMCPY_REAL_SIZE; |
| address_markers[VMEMMAP_NR].start_address = (unsigned long) vmemmap; |
| address_markers[VMEMMAP_END_NR].start_address = (unsigned long)vmemmap + vmemmap_size; |
| address_markers[VMALLOC_NR].start_address = VMALLOC_START; |
| address_markers[VMALLOC_END_NR].start_address = VMALLOC_END; |
| #ifdef CONFIG_KFENCE |
| address_markers[KFENCE_START_NR].start_address = kfence_start; |
| address_markers[KFENCE_END_NR].start_address = kfence_start + KFENCE_POOL_SIZE; |
| #endif |
| sort_address_markers(); |
| #ifdef CONFIG_PTDUMP_DEBUGFS |
| debugfs_create_file("kernel_page_tables", 0400, NULL, NULL, &ptdump_fops); |
| #endif /* CONFIG_PTDUMP_DEBUGFS */ |
| return 0; |
| } |
| device_initcall(pt_dump_init); |