+++ /dev/null
-// 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));
- }
-}
projects / linux-2.6-microblaze.git / blobdiff