diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mce/severity.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mce/severity.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c new file mode 100644 index 000000000..83df99131 --- /dev/null +++ b/arch/x86/kernel/cpu/mce/severity.c @@ -0,0 +1,492 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MCE grading rules. + * Copyright 2008, 2009 Intel Corporation. + * + * Author: Andi Kleen + */ +#include <linux/kernel.h> +#include <linux/seq_file.h> +#include <linux/init.h> +#include <linux/debugfs.h> +#include <linux/uaccess.h> + +#include <asm/mce.h> +#include <asm/intel-family.h> +#include <asm/traps.h> +#include <asm/insn.h> +#include <asm/insn-eval.h> + +#include "internal.h" + +/* + * Grade an mce by severity. In general the most severe ones are processed + * first. Since there are quite a lot of combinations test the bits in a + * table-driven way. The rules are simply processed in order, first + * match wins. + * + * Note this is only used for machine check exceptions, the corrected + * errors use much simpler rules. The exceptions still check for the corrected + * errors, but only to leave them alone for the CMCI handler (except for + * panic situations) + */ + +enum context { IN_KERNEL = 1, IN_USER = 2, IN_KERNEL_RECOV = 3 }; +enum ser { SER_REQUIRED = 1, NO_SER = 2 }; +enum exception { EXCP_CONTEXT = 1, NO_EXCP = 2 }; + +static struct severity { + u64 mask; + u64 result; + unsigned char sev; + unsigned char mcgmask; + unsigned char mcgres; + unsigned char ser; + unsigned char context; + unsigned char excp; + unsigned char covered; + unsigned char cpu_model; + unsigned char cpu_minstepping; + unsigned char bank_lo, bank_hi; + char *msg; +} severities[] = { +#define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c } +#define BANK_RANGE(l, h) .bank_lo = l, .bank_hi = h +#define MODEL_STEPPING(m, s) .cpu_model = m, .cpu_minstepping = s +#define KERNEL .context = IN_KERNEL +#define USER .context = IN_USER +#define KERNEL_RECOV .context = IN_KERNEL_RECOV +#define SER .ser = SER_REQUIRED +#define NOSER .ser = NO_SER +#define EXCP .excp = EXCP_CONTEXT +#define NOEXCP .excp = NO_EXCP +#define BITCLR(x) .mask = x, .result = 0 +#define BITSET(x) .mask = x, .result = x +#define MCGMASK(x, y) .mcgmask = x, .mcgres = y +#define MASK(x, y) .mask = x, .result = y +#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S) +#define MCI_UC_AR (MCI_STATUS_UC|MCI_STATUS_AR) +#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR) +#define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV) + + MCESEV( + NO, "Invalid", + BITCLR(MCI_STATUS_VAL) + ), + MCESEV( + NO, "Not enabled", + EXCP, BITCLR(MCI_STATUS_EN) + ), + MCESEV( + PANIC, "Processor context corrupt", + BITSET(MCI_STATUS_PCC) + ), + /* When MCIP is not set something is very confused */ + MCESEV( + PANIC, "MCIP not set in MCA handler", + EXCP, MCGMASK(MCG_STATUS_MCIP, 0) + ), + /* Neither return not error IP -- no chance to recover -> PANIC */ + MCESEV( + PANIC, "Neither restart nor error IP", + EXCP, MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0) + ), + MCESEV( + PANIC, "In kernel and no restart IP", + EXCP, KERNEL, MCGMASK(MCG_STATUS_RIPV, 0) + ), + MCESEV( + PANIC, "In kernel and no restart IP", + EXCP, KERNEL_RECOV, MCGMASK(MCG_STATUS_RIPV, 0) + ), + MCESEV( + KEEP, "Corrected error", + NOSER, BITCLR(MCI_STATUS_UC) + ), + /* + * known AO MCACODs reported via MCE or CMC: + * + * SRAO could be signaled either via a machine check exception or + * CMCI with the corresponding bit S 1 or 0. So we don't need to + * check bit S for SRAO. + */ + MCESEV( + AO, "Action optional: memory scrubbing error", + SER, MASK(MCI_UC_AR|MCACOD_SCRUBMSK, MCI_STATUS_UC|MCACOD_SCRUB) + ), + MCESEV( + AO, "Action optional: last level cache writeback error", + SER, MASK(MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB) + ), + /* + * Quirk for Skylake/Cascade Lake. Patrol scrubber may be configured + * to report uncorrected errors using CMCI with a special signature. + * UC=0, MSCOD=0x0010, MCACOD=binary(000X 0000 1100 XXXX) reported + * in one of the memory controller banks. + * Set severity to "AO" for same action as normal patrol scrub error. + */ + MCESEV( + AO, "Uncorrected Patrol Scrub Error", + SER, MASK(MCI_STATUS_UC|MCI_ADDR|0xffffeff0, MCI_ADDR|0x001000c0), + MODEL_STEPPING(INTEL_FAM6_SKYLAKE_X, 4), BANK_RANGE(13, 18) + ), + + /* ignore OVER for UCNA */ + MCESEV( + UCNA, "Uncorrected no action required", + SER, MASK(MCI_UC_SAR, MCI_STATUS_UC) + ), + MCESEV( + PANIC, "Illegal combination (UCNA with AR=1)", + SER, + MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR) + ), + MCESEV( + KEEP, "Non signalled machine check", + SER, BITCLR(MCI_STATUS_S) + ), + + MCESEV( + PANIC, "Action required with lost events", + SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR) + ), + + /* known AR MCACODs: */ +#ifdef CONFIG_MEMORY_FAILURE + MCESEV( + KEEP, "Action required but unaffected thread is continuable", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR, MCI_UC_SAR|MCI_ADDR), + MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, MCG_STATUS_RIPV) + ), + MCESEV( + AR, "Action required: data load in error recoverable area of kernel", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA), + KERNEL_RECOV + ), + MCESEV( + AR, "Action required: data load error in a user process", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA), + USER + ), + MCESEV( + AR, "Action required: instruction fetch error in a user process", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR), + USER + ), + MCESEV( + PANIC, "Data load in unrecoverable area of kernel", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA), + KERNEL + ), + MCESEV( + PANIC, "Instruction fetch error in kernel", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR), + KERNEL + ), +#endif + MCESEV( + PANIC, "Action required: unknown MCACOD", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR) + ), + + MCESEV( + SOME, "Action optional: unknown MCACOD", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S) + ), + MCESEV( + SOME, "Action optional with lost events", + SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S) + ), + + MCESEV( + PANIC, "Overflowed uncorrected", + BITSET(MCI_STATUS_OVER|MCI_STATUS_UC) + ), + MCESEV( + UC, "Uncorrected", + BITSET(MCI_STATUS_UC) + ), + MCESEV( + SOME, "No match", + BITSET(0) + ) /* always matches. keep at end */ +}; + +#define mc_recoverable(mcg) (((mcg) & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) == \ + (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) + +static bool is_copy_from_user(struct pt_regs *regs) +{ + u8 insn_buf[MAX_INSN_SIZE]; + struct insn insn; + unsigned long addr; + + if (copy_from_kernel_nofault(insn_buf, (void *)regs->ip, MAX_INSN_SIZE)) + return false; + + kernel_insn_init(&insn, insn_buf, MAX_INSN_SIZE); + insn_get_opcode(&insn); + if (!insn.opcode.got) + return false; + + switch (insn.opcode.value) { + /* MOV mem,reg */ + case 0x8A: case 0x8B: + /* MOVZ mem,reg */ + case 0xB60F: case 0xB70F: + insn_get_modrm(&insn); + insn_get_sib(&insn); + if (!insn.modrm.got || !insn.sib.got) + return false; + addr = (unsigned long)insn_get_addr_ref(&insn, regs); + break; + /* REP MOVS */ + case 0xA4: case 0xA5: + addr = regs->si; + break; + default: + return false; + } + + if (fault_in_kernel_space(addr)) + return false; + + current->mce_vaddr = (void __user *)addr; + + return true; +} + +/* + * If mcgstatus indicated that ip/cs on the stack were + * no good, then "m->cs" will be zero and we will have + * to assume the worst case (IN_KERNEL) as we actually + * have no idea what we were executing when the machine + * check hit. + * If we do have a good "m->cs" (or a faked one in the + * case we were executing in VM86 mode) we can use it to + * distinguish an exception taken in user from from one + * taken in the kernel. + */ +static int error_context(struct mce *m, struct pt_regs *regs) +{ + enum handler_type t; + + if ((m->cs & 3) == 3) + return IN_USER; + if (!mc_recoverable(m->mcgstatus)) + return IN_KERNEL; + + t = ex_get_fault_handler_type(m->ip); + if (t == EX_HANDLER_FAULT) { + m->kflags |= MCE_IN_KERNEL_RECOV; + return IN_KERNEL_RECOV; + } + if (t == EX_HANDLER_UACCESS && regs && is_copy_from_user(regs)) { + m->kflags |= MCE_IN_KERNEL_RECOV; + m->kflags |= MCE_IN_KERNEL_COPYIN; + return IN_KERNEL_RECOV; + } + + return IN_KERNEL; +} + +static int mce_severity_amd_smca(struct mce *m, enum context err_ctx) +{ + u32 addr = MSR_AMD64_SMCA_MCx_CONFIG(m->bank); + u32 low, high; + + /* + * We need to look at the following bits: + * - "succor" bit (data poisoning support), and + * - TCC bit (Task Context Corrupt) + * in MCi_STATUS to determine error severity. + */ + if (!mce_flags.succor) + return MCE_PANIC_SEVERITY; + + if (rdmsr_safe(addr, &low, &high)) + return MCE_PANIC_SEVERITY; + + /* TCC (Task context corrupt). If set and if IN_KERNEL, panic. */ + if ((low & MCI_CONFIG_MCAX) && + (m->status & MCI_STATUS_TCC) && + (err_ctx == IN_KERNEL)) + return MCE_PANIC_SEVERITY; + + /* ...otherwise invoke hwpoison handler. */ + return MCE_AR_SEVERITY; +} + +/* + * See AMD Error Scope Hierarchy table in a newer BKDG. For example + * 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features" + */ +static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant, + char **msg, bool is_excp) +{ + enum context ctx = error_context(m, regs); + + /* Processor Context Corrupt, no need to fumble too much, die! */ + if (m->status & MCI_STATUS_PCC) + return MCE_PANIC_SEVERITY; + + if (m->status & MCI_STATUS_UC) { + + if (ctx == IN_KERNEL) + return MCE_PANIC_SEVERITY; + + /* + * On older systems where overflow_recov flag is not present, we + * should simply panic if an error overflow occurs. If + * overflow_recov flag is present and set, then software can try + * to at least kill process to prolong system operation. + */ + if (mce_flags.overflow_recov) { + if (mce_flags.smca) + return mce_severity_amd_smca(m, ctx); + + /* kill current process */ + return MCE_AR_SEVERITY; + } else { + /* at least one error was not logged */ + if (m->status & MCI_STATUS_OVER) + return MCE_PANIC_SEVERITY; + } + + /* + * For any other case, return MCE_UC_SEVERITY so that we log the + * error and exit #MC handler. + */ + return MCE_UC_SEVERITY; + } + + /* + * deferred error: poll handler catches these and adds to mce_ring so + * memory-failure can take recovery actions. + */ + if (m->status & MCI_STATUS_DEFERRED) + return MCE_DEFERRED_SEVERITY; + + /* + * corrected error: poll handler catches these and passes responsibility + * of decoding the error to EDAC + */ + return MCE_KEEP_SEVERITY; +} + +static int mce_severity_intel(struct mce *m, struct pt_regs *regs, + int tolerant, char **msg, bool is_excp) +{ + enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP); + enum context ctx = error_context(m, regs); + struct severity *s; + + for (s = severities;; s++) { + if ((m->status & s->mask) != s->result) + continue; + if ((m->mcgstatus & s->mcgmask) != s->mcgres) + continue; + if (s->ser == SER_REQUIRED && !mca_cfg.ser) + continue; + if (s->ser == NO_SER && mca_cfg.ser) + continue; + if (s->context && ctx != s->context) + continue; + if (s->excp && excp != s->excp) + continue; + if (s->cpu_model && boot_cpu_data.x86_model != s->cpu_model) + continue; + if (s->cpu_minstepping && boot_cpu_data.x86_stepping < s->cpu_minstepping) + continue; + if (s->bank_lo && (m->bank < s->bank_lo || m->bank > s->bank_hi)) + continue; + if (msg) + *msg = s->msg; + s->covered = 1; + if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) { + if (tolerant < 1) + return MCE_PANIC_SEVERITY; + } + return s->sev; + } +} + +/* Default to mce_severity_intel */ +int (*mce_severity)(struct mce *m, struct pt_regs *regs, int tolerant, char **msg, bool is_excp) = + mce_severity_intel; + +void __init mcheck_vendor_init_severity(void) +{ + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) + mce_severity = mce_severity_amd; +} + +#ifdef CONFIG_DEBUG_FS +static void *s_start(struct seq_file *f, loff_t *pos) +{ + if (*pos >= ARRAY_SIZE(severities)) + return NULL; + return &severities[*pos]; +} + +static void *s_next(struct seq_file *f, void *data, loff_t *pos) +{ + if (++(*pos) >= ARRAY_SIZE(severities)) + return NULL; + return &severities[*pos]; +} + +static void s_stop(struct seq_file *f, void *data) +{ +} + +static int s_show(struct seq_file *f, void *data) +{ + struct severity *ser = data; + seq_printf(f, "%d\t%s\n", ser->covered, ser->msg); + return 0; +} + +static const struct seq_operations severities_seq_ops = { + .start = s_start, + .next = s_next, + .stop = s_stop, + .show = s_show, +}; + +static int severities_coverage_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &severities_seq_ops); +} + +static ssize_t severities_coverage_write(struct file *file, + const char __user *ubuf, + size_t count, loff_t *ppos) +{ + int i; + for (i = 0; i < ARRAY_SIZE(severities); i++) + severities[i].covered = 0; + return count; +} + +static const struct file_operations severities_coverage_fops = { + .open = severities_coverage_open, + .release = seq_release, + .read = seq_read, + .write = severities_coverage_write, + .llseek = seq_lseek, +}; + +static int __init severities_debugfs_init(void) +{ + struct dentry *dmce; + + dmce = mce_get_debugfs_dir(); + + debugfs_create_file("severities-coverage", 0444, dmce, NULL, + &severities_coverage_fops); + return 0; +} +late_initcall(severities_debugfs_init); +#endif /* CONFIG_DEBUG_FS */ |