diff options
Diffstat (limited to 'arch/arm64/kernel/idreg-override.c')
-rw-r--r-- | arch/arm64/kernel/idreg-override.c | 375 |
1 files changed, 0 insertions, 375 deletions
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c deleted file mode 100644 index e30fd9e32e..0000000000 --- a/arch/arm64/kernel/idreg-override.c +++ /dev/null @@ -1,375 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Early cpufeature override framework - * - * Copyright (C) 2020 Google LLC - * Author: Marc Zyngier <maz@kernel.org> - */ - -#include <linux/ctype.h> -#include <linux/kernel.h> -#include <linux/libfdt.h> - -#include <asm/cacheflush.h> -#include <asm/cpufeature.h> -#include <asm/setup.h> - -#define FTR_DESC_NAME_LEN 20 -#define FTR_DESC_FIELD_LEN 10 -#define FTR_ALIAS_NAME_LEN 30 -#define FTR_ALIAS_OPTION_LEN 116 - -static u64 __boot_status __initdata; - -// temporary __prel64 related definitions -// to be removed when this code is moved under pi/ - -#define __prel64_initconst __initconst - -#define PREL64(type, name) union { type *name; } - -#define prel64_pointer(__d) (__d) - -typedef bool filter_t(u64 val); - -struct ftr_set_desc { - char name[FTR_DESC_NAME_LEN]; - PREL64(struct arm64_ftr_override, override); - struct { - char name[FTR_DESC_FIELD_LEN]; - u8 shift; - u8 width; - PREL64(filter_t, filter); - } fields[]; -}; - -#define FIELD(n, s, f) { .name = n, .shift = s, .width = 4, .filter = f } - -static bool __init mmfr1_vh_filter(u64 val) -{ - /* - * If we ever reach this point while running VHE, we're - * guaranteed to be on one of these funky, VHE-stuck CPUs. If - * the user was trying to force nVHE on us, proceed with - * attitude adjustment. - */ - return !(__boot_status == (BOOT_CPU_FLAG_E2H | BOOT_CPU_MODE_EL2) && - val == 0); -} - -static const struct ftr_set_desc mmfr1 __prel64_initconst = { - .name = "id_aa64mmfr1", - .override = &id_aa64mmfr1_override, - .fields = { - FIELD("vh", ID_AA64MMFR1_EL1_VH_SHIFT, mmfr1_vh_filter), - {} - }, -}; - -static bool __init pfr0_sve_filter(u64 val) -{ - /* - * Disabling SVE also means disabling all the features that - * are associated with it. The easiest way to do it is just to - * override id_aa64zfr0_el1 to be 0. - */ - if (!val) { - id_aa64zfr0_override.val = 0; - id_aa64zfr0_override.mask = GENMASK(63, 0); - } - - return true; -} - -static const struct ftr_set_desc pfr0 __prel64_initconst = { - .name = "id_aa64pfr0", - .override = &id_aa64pfr0_override, - .fields = { - FIELD("sve", ID_AA64PFR0_EL1_SVE_SHIFT, pfr0_sve_filter), - {} - }, -}; - -static bool __init pfr1_sme_filter(u64 val) -{ - /* - * Similarly to SVE, disabling SME also means disabling all - * the features that are associated with it. Just set - * id_aa64smfr0_el1 to 0 and don't look back. - */ - if (!val) { - id_aa64smfr0_override.val = 0; - id_aa64smfr0_override.mask = GENMASK(63, 0); - } - - return true; -} - -static const struct ftr_set_desc pfr1 __prel64_initconst = { - .name = "id_aa64pfr1", - .override = &id_aa64pfr1_override, - .fields = { - FIELD("bt", ID_AA64PFR1_EL1_BT_SHIFT, NULL ), - FIELD("mte", ID_AA64PFR1_EL1_MTE_SHIFT, NULL), - FIELD("sme", ID_AA64PFR1_EL1_SME_SHIFT, pfr1_sme_filter), - {} - }, -}; - -static const struct ftr_set_desc isar1 __prel64_initconst = { - .name = "id_aa64isar1", - .override = &id_aa64isar1_override, - .fields = { - FIELD("gpi", ID_AA64ISAR1_EL1_GPI_SHIFT, NULL), - FIELD("gpa", ID_AA64ISAR1_EL1_GPA_SHIFT, NULL), - FIELD("api", ID_AA64ISAR1_EL1_API_SHIFT, NULL), - FIELD("apa", ID_AA64ISAR1_EL1_APA_SHIFT, NULL), - {} - }, -}; - -static const struct ftr_set_desc isar2 __prel64_initconst = { - .name = "id_aa64isar2", - .override = &id_aa64isar2_override, - .fields = { - FIELD("gpa3", ID_AA64ISAR2_EL1_GPA3_SHIFT, NULL), - FIELD("apa3", ID_AA64ISAR2_EL1_APA3_SHIFT, NULL), - FIELD("mops", ID_AA64ISAR2_EL1_MOPS_SHIFT, NULL), - {} - }, -}; - -static const struct ftr_set_desc smfr0 __prel64_initconst = { - .name = "id_aa64smfr0", - .override = &id_aa64smfr0_override, - .fields = { - FIELD("smever", ID_AA64SMFR0_EL1_SMEver_SHIFT, NULL), - /* FA64 is a one bit field... :-/ */ - { "fa64", ID_AA64SMFR0_EL1_FA64_SHIFT, 1, }, - {} - }, -}; - -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 sw_features __prel64_initconst = { - .name = "arm64_sw", - .override = &arm64_sw_feature_override, - .fields = { - FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL), - FIELD("hvhe", ARM64_SW_FEATURE_OVERRIDE_HVHE, hvhe_filter), - {} - }, -}; - -static const -PREL64(const struct ftr_set_desc, reg) regs[] __prel64_initconst = { - { &mmfr1 }, - { &pfr0 }, - { &pfr1 }, - { &isar1 }, - { &isar2 }, - { &smfr0 }, - { &sw_features }, -}; - -static const struct { - char alias[FTR_ALIAS_NAME_LEN]; - char feature[FTR_ALIAS_OPTION_LEN]; -} aliases[] __initconst = { - { "kvm_arm.mode=nvhe", "id_aa64mmfr1.vh=0" }, - { "kvm_arm.mode=protected", "id_aa64mmfr1.vh=0" }, - { "arm64.nosve", "id_aa64pfr0.sve=0" }, - { "arm64.nosme", "id_aa64pfr1.sme=0" }, - { "arm64.nobti", "id_aa64pfr1.bt=0" }, - { "arm64.nopauth", - "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 " - "id_aa64isar1.api=0 id_aa64isar1.apa=0 " - "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0" }, - { "arm64.nomops", "id_aa64isar2.mops=0" }, - { "arm64.nomte", "id_aa64pfr1.mte=0" }, - { "nokaslr", "arm64_sw.nokaslr=1" }, -}; - -static int __init parse_hexdigit(const char *p, u64 *v) -{ - // skip "0x" if it comes next - if (p[0] == '0' && tolower(p[1]) == 'x') - p += 2; - - // check whether the RHS is a single hex digit - if (!isxdigit(p[0]) || (p[1] && !isspace(p[1]))) - return -EINVAL; - - *v = tolower(*p) - (isdigit(*p) ? '0' : 'a' - 10); - return 0; -} - -static int __init find_field(const char *cmdline, char *opt, int len, - const struct ftr_set_desc *reg, int f, u64 *v) -{ - int flen = strlen(reg->fields[f].name); - - // append '<fieldname>=' to obtain '<name>.<fieldname>=' - memcpy(opt + len, reg->fields[f].name, flen); - len += flen; - opt[len++] = '='; - - if (memcmp(cmdline, opt, len)) - return -1; - - return parse_hexdigit(cmdline + len, v); -} - -static void __init match_options(const char *cmdline) -{ - char opt[FTR_DESC_NAME_LEN + FTR_DESC_FIELD_LEN + 2]; - int i; - - for (i = 0; i < ARRAY_SIZE(regs); i++) { - const struct ftr_set_desc *reg = prel64_pointer(regs[i].reg); - struct arm64_ftr_override *override; - int len = strlen(reg->name); - int f; - - override = prel64_pointer(reg->override); - - // set opt[] to '<name>.' - memcpy(opt, reg->name, len); - opt[len++] = '.'; - - for (f = 0; reg->fields[f].name[0] != '\0'; f++) { - u64 shift = reg->fields[f].shift; - u64 width = reg->fields[f].width ?: 4; - u64 mask = GENMASK_ULL(shift + width - 1, shift); - bool (*filter)(u64 val); - u64 v; - - if (find_field(cmdline, opt, len, reg, f, &v)) - continue; - - /* - * If an override gets filtered out, advertise - * it by setting the value to the all-ones while - * clearing the mask... Yes, this is fragile. - */ - filter = prel64_pointer(reg->fields[f].filter); - if (filter && !filter(v)) { - override->val |= mask; - override->mask &= ~mask; - continue; - } - - override->val &= ~mask; - override->val |= (v << shift) & mask; - override->mask |= mask; - - return; - } - } -} - -static __init void __parse_cmdline(const char *cmdline, bool parse_aliases) -{ - do { - char buf[256]; - size_t len; - int i; - - cmdline = skip_spaces(cmdline); - - /* terminate on "--" appearing on the command line by itself */ - if (cmdline[0] == '-' && cmdline[1] == '-' && isspace(cmdline[2])) - return; - - for (len = 0; cmdline[len] && !isspace(cmdline[len]); len++) { - if (len >= sizeof(buf) - 1) - break; - if (cmdline[len] == '-') - buf[len] = '_'; - else - buf[len] = cmdline[len]; - } - if (!len) - return; - - buf[len] = 0; - - cmdline += len; - - match_options(buf); - - for (i = 0; parse_aliases && i < ARRAY_SIZE(aliases); i++) - if (!memcmp(buf, aliases[i].alias, len + 1)) - __parse_cmdline(aliases[i].feature, false); - } while (1); -} - -static __init const u8 *get_bootargs_cmdline(void) -{ - const u8 *prop; - void *fdt; - int node; - - fdt = get_early_fdt_ptr(); - if (!fdt) - return NULL; - - node = fdt_path_offset(fdt, "/chosen"); - if (node < 0) - return NULL; - - prop = fdt_getprop(fdt, node, "bootargs", NULL); - if (!prop) - return NULL; - - return strlen(prop) ? prop : NULL; -} - -static __init void parse_cmdline(void) -{ - const u8 *prop = get_bootargs_cmdline(); - - if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !prop) - __parse_cmdline(CONFIG_CMDLINE, true); - - if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && prop) - __parse_cmdline(prop, true); -} - -/* Keep checkers quiet */ -void init_feature_override(u64 boot_status); - -asmlinkage void __init init_feature_override(u64 boot_status) -{ - struct arm64_ftr_override *override; - const struct ftr_set_desc *reg; - int i; - - for (i = 0; i < ARRAY_SIZE(regs); i++) { - reg = prel64_pointer(regs[i].reg); - override = prel64_pointer(reg->override); - - override->val = 0; - override->mask = 0; - } - - __boot_status = boot_status; - - parse_cmdline(); - - for (i = 0; i < ARRAY_SIZE(regs); i++) { - reg = prel64_pointer(regs[i].reg); - override = prel64_pointer(reg->override); - dcache_clean_inval_poc((unsigned long)override, - (unsigned long)(override + 1)); - } -} |