diff options
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/Makefile | 3 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 7 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 34 | ||||
| -rw-r--r-- | arch/arm64/kernel/ftrace.c | 8 | ||||
| -rw-r--r-- | arch/arm64/kernel/head.S | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/hyp-stub.S | 10 | ||||
| -rw-r--r-- | arch/arm64/kernel/idreg-override.c | 25 | ||||
| -rw-r--r-- | arch/arm64/kernel/kaslr.c | 87 | ||||
| -rw-r--r-- | arch/arm64/kernel/module.c | 159 | ||||
| -rw-r--r-- | arch/arm64/kernel/setup.c | 2 |
10 files changed, 208 insertions, 129 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 7c2bb4e72476..3864a64e2b2b 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -42,8 +42,7 @@ obj-$(CONFIG_COMPAT) += sigreturn32.o obj-$(CONFIG_COMPAT_ALIGNMENT_FIXUPS) += compat_alignment.o obj-$(CONFIG_KUSER_HELPERS) += kuser32.o obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o -obj-$(CONFIG_MODULES) += module.o -obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o +obj-$(CONFIG_MODULES) += module.o module-plts.o obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_CPU_PM) += sleep.o suspend.o diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 307faa2b4395..be66e94a21bd 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -730,6 +730,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .cpu_enable = cpu_clear_bf16_from_user_emulation, }, #endif +#ifdef CONFIG_AMPERE_ERRATUM_AC03_CPU_38 + { + .desc = "AmpereOne erratum AC03_CPU_38", + .capability = ARM64_WORKAROUND_AMPERE_AC03_CPU_38, + ERRATA_MIDR_ALL_VERSIONS(MIDR_AMPERE1), + }, +#endif { } }; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 7d7128c65161..3d93147179a0 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -664,6 +664,8 @@ struct arm64_ftr_override __ro_after_init id_aa64smfr0_override; struct arm64_ftr_override __ro_after_init id_aa64isar1_override; struct arm64_ftr_override __ro_after_init id_aa64isar2_override; +struct arm64_ftr_override arm64_sw_feature_override; + static const struct __ftr_reg_entry { u32 sys_id; struct arm64_ftr_reg *reg; @@ -798,7 +800,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg, return reg; } -static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, +s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur) { s64 ret = 0; @@ -1996,6 +1998,19 @@ static bool has_nested_virt_support(const struct arm64_cpu_capabilities *cap, return true; } +static bool hvhe_possible(const struct arm64_cpu_capabilities *entry, + int __unused) +{ + u64 val; + + val = read_sysreg(id_aa64mmfr1_el1); + if (!cpuid_feature_extract_unsigned_field(val, ID_AA64MMFR1_EL1_VH_SHIFT)) + return false; + + val = arm64_sw_feature_override.val & arm64_sw_feature_override.mask; + return cpuid_feature_extract_unsigned_field(val, ARM64_SW_FEATURE_OVERRIDE_HVHE); +} + #ifdef CONFIG_ARM64_PAN static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused) { @@ -2641,6 +2656,23 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_enable_dit, ARM64_CPUID_FIELDS(ID_AA64PFR0_EL1, DIT, IMP) }, + { + .desc = "VHE for hypervisor only", + .capability = ARM64_KVM_HVHE, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = hvhe_possible, + }, + { + .desc = "Enhanced Virtualization Traps", + .capability = ARM64_HAS_EVT, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .sys_reg = SYS_ID_AA64MMFR2_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64MMFR2_EL1_EVT_SHIFT, + .field_width = 4, + .min_field_value = ID_AA64MMFR2_EL1_EVT_IMP, + .matches = has_cpuid_feature, + }, {}, }; diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 432626c866a8..a650f5e11fc5 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -197,7 +197,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) static struct plt_entry *get_ftrace_plt(struct module *mod) { -#ifdef CONFIG_ARM64_MODULE_PLTS +#ifdef CONFIG_MODULES struct plt_entry *plt = mod->arch.ftrace_trampolines; return &plt[FTRACE_PLT_IDX]; @@ -249,7 +249,7 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, * must use a PLT to reach it. We can only place PLTs for modules, and * only when module PLT support is built-in. */ - if (!IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) + if (!IS_ENABLED(CONFIG_MODULES)) return false; /* @@ -431,10 +431,8 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, * * Note: 'mod' is only set at module load time. */ - if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) && - IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && mod) { + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) && mod) return aarch64_insn_patch_text_nosync((void *)pc, new); - } if (!ftrace_find_callable_addr(rec, mod, &addr)) return -EINVAL; diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index e92caebff46a..23955050da73 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -603,6 +603,8 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) msr sctlr_el1, x1 mov x2, xzr 2: + __init_el2_nvhe_prepare_eret + mov w0, #BOOT_CPU_MODE_EL2 orr x0, x0, x2 eret diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 9439240c3fcf..5c71e1019545 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -82,7 +82,15 @@ SYM_CODE_START_LOCAL(__finalise_el2) tbnz x1, #0, 1f // Needs to be VHE capable, obviously - check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 2f 1f x1 x2 + check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 0f 1f x1 x2 + +0: // Check whether we only want the hypervisor to run VHE, not the kernel + adr_l x1, arm64_sw_feature_override + ldr x2, [x1, FTR_OVR_VAL_OFFSET] + ldr x1, [x1, FTR_OVR_MASK_OFFSET] + and x2, x2, x1 + ubfx x2, x2, #ARM64_SW_FEATURE_OVERRIDE_HVHE, #4 + cbz x2, 2f 1: mov_q x0, HVC_STUB_ERR eret diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 370ab84fd06e..c553d30089e5 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -138,15 +138,22 @@ static const struct ftr_set_desc smfr0 __initconst = { }, }; -extern struct arm64_ftr_override kaslr_feature_override; +static bool __init hvhe_filter(u64 val) +{ + u64 mmfr1 = read_sysreg(id_aa64mmfr1_el1); + + return (val == 1 && + lower_32_bits(__boot_status) == BOOT_CPU_MODE_EL2 && + cpuid_feature_extract_unsigned_field(mmfr1, + ID_AA64MMFR1_EL1_VH_SHIFT)); +} -static const struct ftr_set_desc kaslr __initconst = { - .name = "kaslr", -#ifdef CONFIG_RANDOMIZE_BASE - .override = &kaslr_feature_override, -#endif +static const struct ftr_set_desc sw_features __initconst = { + .name = "arm64_sw", + .override = &arm64_sw_feature_override, .fields = { - FIELD("disabled", 0, NULL), + FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL), + FIELD("hvhe", ARM64_SW_FEATURE_OVERRIDE_HVHE, hvhe_filter), {} }, }; @@ -158,7 +165,7 @@ static const struct ftr_set_desc * const regs[] __initconst = { &isar1, &isar2, &smfr0, - &kaslr, + &sw_features, }; static const struct { @@ -175,7 +182,7 @@ static const struct { "id_aa64isar1.api=0 id_aa64isar1.apa=0 " "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0" }, { "arm64.nomte", "id_aa64pfr1.mte=0" }, - { "nokaslr", "kaslr.disabled=1" }, + { "nokaslr", "arm64_sw.nokaslr=1" }, }; static int __init parse_nokaslr(char *unused) diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index e7477f21a4c9..94a269cd1f07 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -4,90 +4,35 @@ */ #include <linux/cache.h> -#include <linux/crc32.h> #include <linux/init.h> -#include <linux/libfdt.h> -#include <linux/mm_types.h> -#include <linux/sched.h> -#include <linux/types.h> -#include <linux/pgtable.h> -#include <linux/random.h> +#include <linux/printk.h> -#include <asm/fixmap.h> -#include <asm/kernel-pgtable.h> +#include <asm/cpufeature.h> #include <asm/memory.h> -#include <asm/mmu.h> -#include <asm/sections.h> -#include <asm/setup.h> -u64 __ro_after_init module_alloc_base; u16 __initdata memstart_offset_seed; -struct arm64_ftr_override kaslr_feature_override __initdata; +bool __ro_after_init __kaslr_is_enabled = false; -static int __init kaslr_init(void) +void __init kaslr_init(void) { - u64 module_range; - u32 seed; - - /* - * Set a reasonable default for module_alloc_base in case - * we end up running with module randomization disabled. - */ - module_alloc_base = (u64)_etext - MODULES_VSIZE; - - if (kaslr_feature_override.val & kaslr_feature_override.mask & 0xf) { + if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val & + arm64_sw_feature_override.mask, + ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) { pr_info("KASLR disabled on command line\n"); - return 0; - } - - if (!kaslr_enabled()) { - pr_warn("KASLR disabled due to lack of seed\n"); - return 0; + return; } - pr_info("KASLR enabled\n"); - /* - * KASAN without KASAN_VMALLOC does not expect the module region to - * intersect the vmalloc region, since shadow memory is allocated for - * each module at load time, whereas the vmalloc region will already be - * shadowed by KASAN zero pages. + * The KASLR offset modulo MIN_KIMG_ALIGN is taken from the physical + * placement of the image rather than from the seed, so a displacement + * of less than MIN_KIMG_ALIGN means that no seed was provided. */ - BUILD_BUG_ON((IS_ENABLED(CONFIG_KASAN_GENERIC) || - IS_ENABLED(CONFIG_KASAN_SW_TAGS)) && - !IS_ENABLED(CONFIG_KASAN_VMALLOC)); - - seed = get_random_u32(); - - if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) { - /* - * Randomize the module region over a 2 GB window covering the - * kernel. This reduces the risk of modules leaking information - * about the address of the kernel itself, but results in - * branches between modules and the core kernel that are - * resolved via PLTs. (Branches between modules will be - * resolved normally.) - */ - module_range = SZ_2G - (u64)(_end - _stext); - module_alloc_base = max((u64)_end - SZ_2G, (u64)MODULES_VADDR); - } else { - /* - * Randomize the module region by setting module_alloc_base to - * a PAGE_SIZE multiple in the range [_etext - MODULES_VSIZE, - * _stext) . This guarantees that the resulting region still - * covers [_stext, _etext], and that all relative branches can - * be resolved without veneers unless this region is exhausted - * and we fall back to a larger 2GB window in module_alloc() - * when ARM64_MODULE_PLTS is enabled. - */ - module_range = MODULES_VSIZE - (u64)(_etext - _stext); + if (kaslr_offset() < MIN_KIMG_ALIGN) { + pr_warn("KASLR disabled due to lack of seed\n"); + return; } - /* use the lower 21 bits to randomize the base of the module region */ - module_alloc_base += (module_range * (seed & ((1 << 21) - 1))) >> 21; - module_alloc_base &= PAGE_MASK; - - return 0; + pr_info("KASLR enabled\n"); + __kaslr_is_enabled = true; } -subsys_initcall(kaslr_init) diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index 5af4975caeb5..dd851297596e 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -7,6 +7,8 @@ * Author: Will Deacon <will.deacon@arm.com> */ +#define pr_fmt(fmt) "Modules: " fmt + #include <linux/bitops.h> #include <linux/elf.h> #include <linux/ftrace.h> @@ -15,52 +17,131 @@ #include <linux/kernel.h> #include <linux/mm.h> #include <linux/moduleloader.h> +#include <linux/random.h> #include <linux/scs.h> #include <linux/vmalloc.h> + #include <asm/alternative.h> #include <asm/insn.h> #include <asm/scs.h> #include <asm/sections.h> +static u64 module_direct_base __ro_after_init = 0; +static u64 module_plt_base __ro_after_init = 0; + +/* + * Choose a random page-aligned base address for a window of 'size' bytes which + * entirely contains the interval [start, end - 1]. + */ +static u64 __init random_bounding_box(u64 size, u64 start, u64 end) +{ + u64 max_pgoff, pgoff; + + if ((end - start) >= size) + return 0; + + max_pgoff = (size - (end - start)) / PAGE_SIZE; + pgoff = get_random_u32_inclusive(0, max_pgoff); + + return start - pgoff * PAGE_SIZE; +} + +/* + * Modules may directly reference data and text anywhere within the kernel + * image and other modules. References using PREL32 relocations have a +/-2G + * range, and so we need to ensure that the entire kernel image and all modules + * fall within a 2G window such that these are always within range. + * + * Modules may directly branch to functions and code within the kernel text, + * and to functions and code within other modules. These branches will use + * CALL26/JUMP26 relocations with a +/-128M range. Without PLTs, we must ensure + * that the entire kernel text and all module text falls within a 128M window + * such that these are always within range. With PLTs, we can expand this to a + * 2G window. + * + * We chose the 128M region to surround the entire kernel image (rather than + * just the text) as using the same bounds for the 128M and 2G regions ensures + * by construction that we never select a 128M region that is not a subset of + * the 2G region. For very large and unusual kernel configurations this means + * we may fall back to PLTs where they could have been avoided, but this keeps + * the logic significantly simpler. + */ +static int __init module_init_limits(void) +{ + u64 kernel_end = (u64)_end; + u64 kernel_start = (u64)_text; + u64 kernel_size = kernel_end - kernel_start; + + /* + * The default modules region is placed immediately below the kernel + * image, and is large enough to use the full 2G relocation range. + */ + BUILD_BUG_ON(KIMAGE_VADDR != MODULES_END); + BUILD_BUG_ON(MODULES_VSIZE < SZ_2G); + + if (!kaslr_enabled()) { + if (kernel_size < SZ_128M) + module_direct_base = kernel_end - SZ_128M; + if (kernel_size < SZ_2G) + module_plt_base = kernel_end - SZ_2G; + } else { + u64 min = kernel_start; + u64 max = kernel_end; + + if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) { + pr_info("2G module region forced by RANDOMIZE_MODULE_REGION_FULL\n"); + } else { + module_direct_base = random_bounding_box(SZ_128M, min, max); + if (module_direct_base) { + min = module_direct_base; + max = module_direct_base + SZ_128M; + } + } + + module_plt_base = random_bounding_box(SZ_2G, min, max); + } + + pr_info("%llu pages in range for non-PLT usage", + module_direct_base ? (SZ_128M - kernel_size) / PAGE_SIZE : 0); + pr_info("%llu pages in range for PLT usage", + module_plt_base ? (SZ_2G - kernel_size) / PAGE_SIZE : 0); + + return 0; +} +subsys_initcall(module_init_limits); + void *module_alloc(unsigned long size) { - u64 module_alloc_end = module_alloc_base + MODULES_VSIZE; - gfp_t gfp_mask = GFP_KERNEL; - void *p; - - /* Silence the initial allocation */ - if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) - gfp_mask |= __GFP_NOWARN; - - if (IS_ENABLED(CONFIG_KASAN_GENERIC) || - IS_ENABLED(CONFIG_KASAN_SW_TAGS)) - /* don't exceed the static module region - see below */ - module_alloc_end = MODULES_END; - - p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, - module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK, - NUMA_NO_NODE, __builtin_return_address(0)); - - if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && - (IS_ENABLED(CONFIG_KASAN_VMALLOC) || - (!IS_ENABLED(CONFIG_KASAN_GENERIC) && - !IS_ENABLED(CONFIG_KASAN_SW_TAGS)))) - /* - * KASAN without KASAN_VMALLOC can only deal with module - * allocations being served from the reserved module region, - * since the remainder of the vmalloc region is already - * backed by zero shadow pages, and punching holes into it - * is non-trivial. Since the module region is not randomized - * when KASAN is enabled without KASAN_VMALLOC, it is even - * less likely that the module region gets exhausted, so we - * can simply omit this fallback in that case. - */ - p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, - module_alloc_base + SZ_2G, GFP_KERNEL, - PAGE_KERNEL, 0, NUMA_NO_NODE, - __builtin_return_address(0)); + void *p = NULL; + + /* + * Where possible, prefer to allocate within direct branch range of the + * kernel such that no PLTs are necessary. + */ + if (module_direct_base) { + p = __vmalloc_node_range(size, MODULE_ALIGN, + module_direct_base, + module_direct_base + SZ_128M, + GFP_KERNEL | __GFP_NOWARN, + PAGE_KERNEL, 0, NUMA_NO_NODE, + __builtin_return_address(0)); + } - if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) { + if (!p && module_plt_base) { + p = __vmalloc_node_range(size, MODULE_ALIGN, + module_plt_base, + module_plt_base + SZ_2G, + GFP_KERNEL | __GFP_NOWARN, + PAGE_KERNEL, 0, NUMA_NO_NODE, + __builtin_return_address(0)); + } + + if (!p) { + pr_warn_ratelimited("%s: unable to allocate memory\n", + __func__); + } + + if (p && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) { vfree(p); return NULL; } @@ -448,9 +529,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, case R_AARCH64_CALL26: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26, AARCH64_INSN_IMM_26); - - if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && - ovf == -ERANGE) { + if (ovf == -ERANGE) { val = module_emit_plt_entry(me, sechdrs, loc, &rel[i], sym); if (!val) return -ENOEXEC; @@ -487,7 +566,7 @@ static int module_init_ftrace_plt(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { -#if defined(CONFIG_ARM64_MODULE_PLTS) && defined(CONFIG_DYNAMIC_FTRACE) +#if defined(CONFIG_DYNAMIC_FTRACE) const Elf_Shdr *s; struct plt_entry *plts; diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index b8ec7b3ac9cb..417a8a86b2db 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -296,6 +296,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) *cmdline_p = boot_command_line; + kaslr_init(); + /* * If know now we are going to need KPTI then use non-global * mappings from the start, avoiding the cost of rewriting |