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![Paul Gortmaker](/assets/img/avatar_default.png)
Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance for the presence of either and replace as needed. Build testing revealed some implicit header usage that was fixed up accordingly. Note that some bool/obj-y instances remain since module.h is the header for some exception table entry stuff, and for things like __init_or_module (code that is tossed when MODULES=n). Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160714001901.31603-4-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
946 lines
26 KiB
C
946 lines
26 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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/*
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* Handle hardware traps and faults.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/context_tracking.h>
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#include <linux/interrupt.h>
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#include <linux/kallsyms.h>
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#include <linux/spinlock.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/kdebug.h>
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#include <linux/kgdb.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/ptrace.h>
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#include <linux/uprobes.h>
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#include <linux/string.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/kexec.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/init.h>
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#include <linux/bug.h>
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#include <linux/nmi.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/io.h>
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#ifdef CONFIG_EISA
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#include <linux/ioport.h>
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#include <linux/eisa.h>
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#endif
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#if defined(CONFIG_EDAC)
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#include <linux/edac.h>
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#endif
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#include <asm/kmemcheck.h>
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#include <asm/stacktrace.h>
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#include <asm/processor.h>
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#include <asm/debugreg.h>
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#include <linux/atomic.h>
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#include <asm/text-patching.h>
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#include <asm/ftrace.h>
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#include <asm/traps.h>
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#include <asm/desc.h>
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#include <asm/fpu/internal.h>
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#include <asm/mce.h>
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#include <asm/fixmap.h>
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#include <asm/mach_traps.h>
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#include <asm/alternative.h>
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#include <asm/fpu/xstate.h>
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#include <asm/trace/mpx.h>
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#include <asm/mpx.h>
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#include <asm/vm86.h>
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#ifdef CONFIG_X86_64
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#include <asm/x86_init.h>
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#include <asm/pgalloc.h>
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#include <asm/proto.h>
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/* No need to be aligned, but done to keep all IDTs defined the same way. */
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gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
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#else
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#include <asm/processor-flags.h>
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#include <asm/setup.h>
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#include <asm/proto.h>
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#endif
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/* Must be page-aligned because the real IDT is used in a fixmap. */
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gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
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DECLARE_BITMAP(used_vectors, NR_VECTORS);
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EXPORT_SYMBOL_GPL(used_vectors);
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static inline void cond_local_irq_enable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_enable();
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}
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static inline void cond_local_irq_disable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_disable();
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}
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/*
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* In IST context, we explicitly disable preemption. This serves two
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* purposes: it makes it much less likely that we would accidentally
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* schedule in IST context and it will force a warning if we somehow
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* manage to schedule by accident.
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*/
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void ist_enter(struct pt_regs *regs)
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{
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if (user_mode(regs)) {
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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} else {
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/*
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* We might have interrupted pretty much anything. In
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* fact, if we're a machine check, we can even interrupt
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* NMI processing. We don't want in_nmi() to return true,
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* but we need to notify RCU.
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*/
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rcu_nmi_enter();
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}
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preempt_disable();
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/* This code is a bit fragile. Test it. */
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
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}
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void ist_exit(struct pt_regs *regs)
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{
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preempt_enable_no_resched();
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if (!user_mode(regs))
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rcu_nmi_exit();
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}
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/**
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* ist_begin_non_atomic() - begin a non-atomic section in an IST exception
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* @regs: regs passed to the IST exception handler
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*
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* IST exception handlers normally cannot schedule. As a special
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* exception, if the exception interrupted userspace code (i.e.
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* user_mode(regs) would return true) and the exception was not
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* a double fault, it can be safe to schedule. ist_begin_non_atomic()
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* begins a non-atomic section within an ist_enter()/ist_exit() region.
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* Callers are responsible for enabling interrupts themselves inside
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* the non-atomic section, and callers must call ist_end_non_atomic()
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* before ist_exit().
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*/
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void ist_begin_non_atomic(struct pt_regs *regs)
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{
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BUG_ON(!user_mode(regs));
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/*
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* Sanity check: we need to be on the normal thread stack. This
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* will catch asm bugs and any attempt to use ist_preempt_enable
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* from double_fault.
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*/
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BUG_ON((unsigned long)(current_top_of_stack() -
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current_stack_pointer()) >= THREAD_SIZE);
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preempt_enable_no_resched();
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}
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/**
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* ist_end_non_atomic() - begin a non-atomic section in an IST exception
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*
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* Ends a non-atomic section started with ist_begin_non_atomic().
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*/
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void ist_end_non_atomic(void)
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{
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preempt_disable();
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}
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static nokprobe_inline int
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do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
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struct pt_regs *regs, long error_code)
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{
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if (v8086_mode(regs)) {
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/*
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* Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
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* On nmi (interrupt 2), do_trap should not be called.
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*/
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if (trapnr < X86_TRAP_UD) {
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if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
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error_code, trapnr))
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return 0;
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}
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return -1;
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}
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if (!user_mode(regs)) {
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if (!fixup_exception(regs, trapnr)) {
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tsk->thread.error_code = error_code;
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tsk->thread.trap_nr = trapnr;
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die(str, regs, error_code);
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}
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return 0;
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}
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return -1;
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}
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static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
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siginfo_t *info)
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{
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unsigned long siaddr;
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int sicode;
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switch (trapnr) {
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default:
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return SEND_SIG_PRIV;
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case X86_TRAP_DE:
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sicode = FPE_INTDIV;
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siaddr = uprobe_get_trap_addr(regs);
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break;
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case X86_TRAP_UD:
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sicode = ILL_ILLOPN;
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siaddr = uprobe_get_trap_addr(regs);
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break;
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case X86_TRAP_AC:
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sicode = BUS_ADRALN;
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siaddr = 0;
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break;
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}
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info->si_signo = signr;
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info->si_errno = 0;
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info->si_code = sicode;
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info->si_addr = (void __user *)siaddr;
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return info;
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}
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static void
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do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
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long error_code, siginfo_t *info)
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{
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struct task_struct *tsk = current;
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if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
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return;
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/*
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* We want error_code and trap_nr set for userspace faults and
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* kernelspace faults which result in die(), but not
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* kernelspace faults which are fixed up. die() gives the
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* process no chance to handle the signal and notice the
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* kernel fault information, so that won't result in polluting
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* the information about previously queued, but not yet
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* delivered, faults. See also do_general_protection below.
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*/
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tsk->thread.error_code = error_code;
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tsk->thread.trap_nr = trapnr;
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if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
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printk_ratelimit()) {
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pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
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tsk->comm, tsk->pid, str,
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regs->ip, regs->sp, error_code);
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print_vma_addr(" in ", regs->ip);
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pr_cont("\n");
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}
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force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
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}
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NOKPROBE_SYMBOL(do_trap);
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static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
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unsigned long trapnr, int signr)
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{
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siginfo_t info;
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
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NOTIFY_STOP) {
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cond_local_irq_enable(regs);
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do_trap(trapnr, signr, str, regs, error_code,
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fill_trap_info(regs, signr, trapnr, &info));
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}
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}
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#define DO_ERROR(trapnr, signr, str, name) \
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dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
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{ \
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do_error_trap(regs, error_code, str, trapnr, signr); \
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}
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DO_ERROR(X86_TRAP_DE, SIGFPE, "divide error", divide_error)
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DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
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DO_ERROR(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op)
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DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",coprocessor_segment_overrun)
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DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
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DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
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DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
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DO_ERROR(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check)
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#ifdef CONFIG_X86_64
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/* Runs on IST stack */
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dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
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{
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static const char str[] = "double fault";
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struct task_struct *tsk = current;
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#ifdef CONFIG_X86_ESPFIX64
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extern unsigned char native_irq_return_iret[];
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/*
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* If IRET takes a non-IST fault on the espfix64 stack, then we
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* end up promoting it to a doublefault. In that case, modify
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* the stack to make it look like we just entered the #GP
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* handler from user space, similar to bad_iret.
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*
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* No need for ist_enter here because we don't use RCU.
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*/
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if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY &&
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regs->cs == __KERNEL_CS &&
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regs->ip == (unsigned long)native_irq_return_iret)
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{
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struct pt_regs *normal_regs = task_pt_regs(current);
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/* Fake a #GP(0) from userspace. */
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memmove(&normal_regs->ip, (void *)regs->sp, 5*8);
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normal_regs->orig_ax = 0; /* Missing (lost) #GP error code */
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regs->ip = (unsigned long)general_protection;
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regs->sp = (unsigned long)&normal_regs->orig_ax;
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return;
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}
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#endif
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ist_enter(regs);
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notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
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tsk->thread.error_code = error_code;
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tsk->thread.trap_nr = X86_TRAP_DF;
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#ifdef CONFIG_DOUBLEFAULT
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df_debug(regs, error_code);
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#endif
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/*
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* This is always a kernel trap and never fixable (and thus must
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* never return).
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*/
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for (;;)
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die(str, regs, error_code);
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}
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#endif
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dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
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{
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const struct mpx_bndcsr *bndcsr;
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siginfo_t *info;
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
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if (notify_die(DIE_TRAP, "bounds", regs, error_code,
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X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
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return;
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cond_local_irq_enable(regs);
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if (!user_mode(regs))
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die("bounds", regs, error_code);
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if (!cpu_feature_enabled(X86_FEATURE_MPX)) {
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/* The exception is not from Intel MPX */
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goto exit_trap;
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}
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/*
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* We need to look at BNDSTATUS to resolve this exception.
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* A NULL here might mean that it is in its 'init state',
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* which is all zeros which indicates MPX was not
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* responsible for the exception.
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*/
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bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);
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if (!bndcsr)
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goto exit_trap;
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trace_bounds_exception_mpx(bndcsr);
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/*
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* The error code field of the BNDSTATUS register communicates status
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* information of a bound range exception #BR or operation involving
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* bound directory.
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*/
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switch (bndcsr->bndstatus & MPX_BNDSTA_ERROR_CODE) {
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case 2: /* Bound directory has invalid entry. */
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if (mpx_handle_bd_fault())
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goto exit_trap;
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break; /* Success, it was handled */
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case 1: /* Bound violation. */
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info = mpx_generate_siginfo(regs);
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if (IS_ERR(info)) {
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/*
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* We failed to decode the MPX instruction. Act as if
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* the exception was not caused by MPX.
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*/
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goto exit_trap;
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}
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/*
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* Success, we decoded the instruction and retrieved
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* an 'info' containing the address being accessed
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* which caused the exception. This information
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* allows and application to possibly handle the
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* #BR exception itself.
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*/
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do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, info);
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kfree(info);
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break;
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case 0: /* No exception caused by Intel MPX operations. */
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goto exit_trap;
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default:
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die("bounds", regs, error_code);
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}
|
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return;
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|
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exit_trap:
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/*
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* This path out is for all the cases where we could not
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* handle the exception in some way (like allocating a
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* table or telling userspace about it. We will also end
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* up here if the kernel has MPX turned off at compile
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* time..
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*/
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do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);
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}
|
|
|
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dotraplinkage void
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do_general_protection(struct pt_regs *regs, long error_code)
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{
|
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struct task_struct *tsk;
|
|
|
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RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
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cond_local_irq_enable(regs);
|
|
|
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if (v8086_mode(regs)) {
|
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local_irq_enable();
|
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handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
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return;
|
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}
|
|
|
|
tsk = current;
|
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if (!user_mode(regs)) {
|
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if (fixup_exception(regs, X86_TRAP_GP))
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return;
|
|
|
|
tsk->thread.error_code = error_code;
|
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tsk->thread.trap_nr = X86_TRAP_GP;
|
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if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
|
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X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
|
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die("general protection fault", regs, error_code);
|
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return;
|
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}
|
|
|
|
tsk->thread.error_code = error_code;
|
|
tsk->thread.trap_nr = X86_TRAP_GP;
|
|
|
|
if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
|
|
printk_ratelimit()) {
|
|
pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
|
|
tsk->comm, task_pid_nr(tsk),
|
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regs->ip, regs->sp, error_code);
|
|
print_vma_addr(" in ", regs->ip);
|
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pr_cont("\n");
|
|
}
|
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|
|
force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
|
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}
|
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NOKPROBE_SYMBOL(do_general_protection);
|
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|
|
/* May run on IST stack. */
|
|
dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
|
|
{
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
/*
|
|
* ftrace must be first, everything else may cause a recursive crash.
|
|
* See note by declaration of modifying_ftrace_code in ftrace.c
|
|
*/
|
|
if (unlikely(atomic_read(&modifying_ftrace_code)) &&
|
|
ftrace_int3_handler(regs))
|
|
return;
|
|
#endif
|
|
if (poke_int3_handler(regs))
|
|
return;
|
|
|
|
ist_enter(regs);
|
|
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
|
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
|
|
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
|
|
SIGTRAP) == NOTIFY_STOP)
|
|
goto exit;
|
|
#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
|
|
|
|
#ifdef CONFIG_KPROBES
|
|
if (kprobe_int3_handler(regs))
|
|
goto exit;
|
|
#endif
|
|
|
|
if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
|
|
SIGTRAP) == NOTIFY_STOP)
|
|
goto exit;
|
|
|
|
/*
|
|
* Let others (NMI) know that the debug stack is in use
|
|
* as we may switch to the interrupt stack.
|
|
*/
|
|
debug_stack_usage_inc();
|
|
preempt_disable();
|
|
cond_local_irq_enable(regs);
|
|
do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
|
|
cond_local_irq_disable(regs);
|
|
preempt_enable_no_resched();
|
|
debug_stack_usage_dec();
|
|
exit:
|
|
ist_exit(regs);
|
|
}
|
|
NOKPROBE_SYMBOL(do_int3);
|
|
|
|
#ifdef CONFIG_X86_64
|
|
/*
|
|
* Help handler running on IST stack to switch off the IST stack if the
|
|
* interrupted code was in user mode. The actual stack switch is done in
|
|
* entry_64.S
|
|
*/
|
|
asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
|
|
{
|
|
struct pt_regs *regs = task_pt_regs(current);
|
|
*regs = *eregs;
|
|
return regs;
|
|
}
|
|
NOKPROBE_SYMBOL(sync_regs);
|
|
|
|
struct bad_iret_stack {
|
|
void *error_entry_ret;
|
|
struct pt_regs regs;
|
|
};
|
|
|
|
asmlinkage __visible notrace
|
|
struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
|
|
{
|
|
/*
|
|
* This is called from entry_64.S early in handling a fault
|
|
* caused by a bad iret to user mode. To handle the fault
|
|
* correctly, we want move our stack frame to task_pt_regs
|
|
* and we want to pretend that the exception came from the
|
|
* iret target.
|
|
*/
|
|
struct bad_iret_stack *new_stack =
|
|
container_of(task_pt_regs(current),
|
|
struct bad_iret_stack, regs);
|
|
|
|
/* Copy the IRET target to the new stack. */
|
|
memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8);
|
|
|
|
/* Copy the remainder of the stack from the current stack. */
|
|
memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip));
|
|
|
|
BUG_ON(!user_mode(&new_stack->regs));
|
|
return new_stack;
|
|
}
|
|
NOKPROBE_SYMBOL(fixup_bad_iret);
|
|
#endif
|
|
|
|
static bool is_sysenter_singlestep(struct pt_regs *regs)
|
|
{
|
|
/*
|
|
* We don't try for precision here. If we're anywhere in the region of
|
|
* code that can be single-stepped in the SYSENTER entry path, then
|
|
* assume that this is a useless single-step trap due to SYSENTER
|
|
* being invoked with TF set. (We don't know in advance exactly
|
|
* which instructions will be hit because BTF could plausibly
|
|
* be set.)
|
|
*/
|
|
#ifdef CONFIG_X86_32
|
|
return (regs->ip - (unsigned long)__begin_SYSENTER_singlestep_region) <
|
|
(unsigned long)__end_SYSENTER_singlestep_region -
|
|
(unsigned long)__begin_SYSENTER_singlestep_region;
|
|
#elif defined(CONFIG_IA32_EMULATION)
|
|
return (regs->ip - (unsigned long)entry_SYSENTER_compat) <
|
|
(unsigned long)__end_entry_SYSENTER_compat -
|
|
(unsigned long)entry_SYSENTER_compat;
|
|
#else
|
|
return false;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Our handling of the processor debug registers is non-trivial.
|
|
* We do not clear them on entry and exit from the kernel. Therefore
|
|
* it is possible to get a watchpoint trap here from inside the kernel.
|
|
* However, the code in ./ptrace.c has ensured that the user can
|
|
* only set watchpoints on userspace addresses. Therefore the in-kernel
|
|
* watchpoint trap can only occur in code which is reading/writing
|
|
* from user space. Such code must not hold kernel locks (since it
|
|
* can equally take a page fault), therefore it is safe to call
|
|
* force_sig_info even though that claims and releases locks.
|
|
*
|
|
* Code in ./signal.c ensures that the debug control register
|
|
* is restored before we deliver any signal, and therefore that
|
|
* user code runs with the correct debug control register even though
|
|
* we clear it here.
|
|
*
|
|
* Being careful here means that we don't have to be as careful in a
|
|
* lot of more complicated places (task switching can be a bit lazy
|
|
* about restoring all the debug state, and ptrace doesn't have to
|
|
* find every occurrence of the TF bit that could be saved away even
|
|
* by user code)
|
|
*
|
|
* May run on IST stack.
|
|
*/
|
|
dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
int user_icebp = 0;
|
|
unsigned long dr6;
|
|
int si_code;
|
|
|
|
ist_enter(regs);
|
|
|
|
get_debugreg(dr6, 6);
|
|
/*
|
|
* The Intel SDM says:
|
|
*
|
|
* Certain debug exceptions may clear bits 0-3. The remaining
|
|
* contents of the DR6 register are never cleared by the
|
|
* processor. To avoid confusion in identifying debug
|
|
* exceptions, debug handlers should clear the register before
|
|
* returning to the interrupted task.
|
|
*
|
|
* Keep it simple: clear DR6 immediately.
|
|
*/
|
|
set_debugreg(0, 6);
|
|
|
|
/* Filter out all the reserved bits which are preset to 1 */
|
|
dr6 &= ~DR6_RESERVED;
|
|
|
|
/*
|
|
* The SDM says "The processor clears the BTF flag when it
|
|
* generates a debug exception." Clear TIF_BLOCKSTEP to keep
|
|
* TIF_BLOCKSTEP in sync with the hardware BTF flag.
|
|
*/
|
|
clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
|
|
|
|
if (unlikely(!user_mode(regs) && (dr6 & DR_STEP) &&
|
|
is_sysenter_singlestep(regs))) {
|
|
dr6 &= ~DR_STEP;
|
|
if (!dr6)
|
|
goto exit;
|
|
/*
|
|
* else we might have gotten a single-step trap and hit a
|
|
* watchpoint at the same time, in which case we should fall
|
|
* through and handle the watchpoint.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* If dr6 has no reason to give us about the origin of this trap,
|
|
* then it's very likely the result of an icebp/int01 trap.
|
|
* User wants a sigtrap for that.
|
|
*/
|
|
if (!dr6 && user_mode(regs))
|
|
user_icebp = 1;
|
|
|
|
/* Catch kmemcheck conditions! */
|
|
if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
|
|
goto exit;
|
|
|
|
/* Store the virtualized DR6 value */
|
|
tsk->thread.debugreg6 = dr6;
|
|
|
|
#ifdef CONFIG_KPROBES
|
|
if (kprobe_debug_handler(regs))
|
|
goto exit;
|
|
#endif
|
|
|
|
if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
|
|
SIGTRAP) == NOTIFY_STOP)
|
|
goto exit;
|
|
|
|
/*
|
|
* Let others (NMI) know that the debug stack is in use
|
|
* as we may switch to the interrupt stack.
|
|
*/
|
|
debug_stack_usage_inc();
|
|
|
|
/* It's safe to allow irq's after DR6 has been saved */
|
|
preempt_disable();
|
|
cond_local_irq_enable(regs);
|
|
|
|
if (v8086_mode(regs)) {
|
|
handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
|
|
X86_TRAP_DB);
|
|
cond_local_irq_disable(regs);
|
|
preempt_enable_no_resched();
|
|
debug_stack_usage_dec();
|
|
goto exit;
|
|
}
|
|
|
|
if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) {
|
|
/*
|
|
* Historical junk that used to handle SYSENTER single-stepping.
|
|
* This should be unreachable now. If we survive for a while
|
|
* without anyone hitting this warning, we'll turn this into
|
|
* an oops.
|
|
*/
|
|
tsk->thread.debugreg6 &= ~DR_STEP;
|
|
set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
|
|
regs->flags &= ~X86_EFLAGS_TF;
|
|
}
|
|
si_code = get_si_code(tsk->thread.debugreg6);
|
|
if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
|
|
send_sigtrap(tsk, regs, error_code, si_code);
|
|
cond_local_irq_disable(regs);
|
|
preempt_enable_no_resched();
|
|
debug_stack_usage_dec();
|
|
|
|
exit:
|
|
#if defined(CONFIG_X86_32)
|
|
/*
|
|
* This is the most likely code path that involves non-trivial use
|
|
* of the SYSENTER stack. Check that we haven't overrun it.
|
|
*/
|
|
WARN(this_cpu_read(cpu_tss.SYSENTER_stack_canary) != STACK_END_MAGIC,
|
|
"Overran or corrupted SYSENTER stack\n");
|
|
#endif
|
|
ist_exit(regs);
|
|
}
|
|
NOKPROBE_SYMBOL(do_debug);
|
|
|
|
/*
|
|
* Note that we play around with the 'TS' bit in an attempt to get
|
|
* the correct behaviour even in the presence of the asynchronous
|
|
* IRQ13 behaviour
|
|
*/
|
|
static void math_error(struct pt_regs *regs, int error_code, int trapnr)
|
|
{
|
|
struct task_struct *task = current;
|
|
struct fpu *fpu = &task->thread.fpu;
|
|
siginfo_t info;
|
|
char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
|
|
"simd exception";
|
|
|
|
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
|
|
return;
|
|
cond_local_irq_enable(regs);
|
|
|
|
if (!user_mode(regs)) {
|
|
if (!fixup_exception(regs, trapnr)) {
|
|
task->thread.error_code = error_code;
|
|
task->thread.trap_nr = trapnr;
|
|
die(str, regs, error_code);
|
|
}
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Save the info for the exception handler and clear the error.
|
|
*/
|
|
fpu__save(fpu);
|
|
|
|
task->thread.trap_nr = trapnr;
|
|
task->thread.error_code = error_code;
|
|
info.si_signo = SIGFPE;
|
|
info.si_errno = 0;
|
|
info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
|
|
|
|
info.si_code = fpu__exception_code(fpu, trapnr);
|
|
|
|
/* Retry when we get spurious exceptions: */
|
|
if (!info.si_code)
|
|
return;
|
|
|
|
force_sig_info(SIGFPE, &info, task);
|
|
}
|
|
|
|
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
|
|
{
|
|
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
|
math_error(regs, error_code, X86_TRAP_MF);
|
|
}
|
|
|
|
dotraplinkage void
|
|
do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
|
|
{
|
|
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
|
math_error(regs, error_code, X86_TRAP_XF);
|
|
}
|
|
|
|
dotraplinkage void
|
|
do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
|
|
{
|
|
cond_local_irq_enable(regs);
|
|
}
|
|
|
|
dotraplinkage void
|
|
do_device_not_available(struct pt_regs *regs, long error_code)
|
|
{
|
|
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
|
|
|
#ifdef CONFIG_MATH_EMULATION
|
|
if (!boot_cpu_has(X86_FEATURE_FPU) && (read_cr0() & X86_CR0_EM)) {
|
|
struct math_emu_info info = { };
|
|
|
|
cond_local_irq_enable(regs);
|
|
|
|
info.regs = regs;
|
|
math_emulate(&info);
|
|
return;
|
|
}
|
|
#endif
|
|
fpu__restore(¤t->thread.fpu); /* interrupts still off */
|
|
#ifdef CONFIG_X86_32
|
|
cond_local_irq_enable(regs);
|
|
#endif
|
|
}
|
|
NOKPROBE_SYMBOL(do_device_not_available);
|
|
|
|
#ifdef CONFIG_X86_32
|
|
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
|
|
{
|
|
siginfo_t info;
|
|
|
|
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
|
|
local_irq_enable();
|
|
|
|
info.si_signo = SIGILL;
|
|
info.si_errno = 0;
|
|
info.si_code = ILL_BADSTK;
|
|
info.si_addr = NULL;
|
|
if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
|
|
X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
|
|
do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
|
|
&info);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Set of traps needed for early debugging. */
|
|
void __init early_trap_init(void)
|
|
{
|
|
/*
|
|
* Don't use IST to set DEBUG_STACK as it doesn't work until TSS
|
|
* is ready in cpu_init() <-- trap_init(). Before trap_init(),
|
|
* CPU runs at ring 0 so it is impossible to hit an invalid
|
|
* stack. Using the original stack works well enough at this
|
|
* early stage. DEBUG_STACK will be equipped after cpu_init() in
|
|
* trap_init().
|
|
*
|
|
* We don't need to set trace_idt_table like set_intr_gate(),
|
|
* since we don't have trace_debug and it will be reset to
|
|
* 'debug' in trap_init() by set_intr_gate_ist().
|
|
*/
|
|
set_intr_gate_notrace(X86_TRAP_DB, debug);
|
|
/* int3 can be called from all */
|
|
set_system_intr_gate(X86_TRAP_BP, &int3);
|
|
#ifdef CONFIG_X86_32
|
|
set_intr_gate(X86_TRAP_PF, page_fault);
|
|
#endif
|
|
load_idt(&idt_descr);
|
|
}
|
|
|
|
void __init early_trap_pf_init(void)
|
|
{
|
|
#ifdef CONFIG_X86_64
|
|
set_intr_gate(X86_TRAP_PF, page_fault);
|
|
#endif
|
|
}
|
|
|
|
void __init trap_init(void)
|
|
{
|
|
int i;
|
|
|
|
#ifdef CONFIG_EISA
|
|
void __iomem *p = early_ioremap(0x0FFFD9, 4);
|
|
|
|
if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
|
|
EISA_bus = 1;
|
|
early_iounmap(p, 4);
|
|
#endif
|
|
|
|
set_intr_gate(X86_TRAP_DE, divide_error);
|
|
set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
|
|
/* int4 can be called from all */
|
|
set_system_intr_gate(X86_TRAP_OF, &overflow);
|
|
set_intr_gate(X86_TRAP_BR, bounds);
|
|
set_intr_gate(X86_TRAP_UD, invalid_op);
|
|
set_intr_gate(X86_TRAP_NM, device_not_available);
|
|
#ifdef CONFIG_X86_32
|
|
set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
|
|
#else
|
|
set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
|
|
#endif
|
|
set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
|
|
set_intr_gate(X86_TRAP_TS, invalid_TSS);
|
|
set_intr_gate(X86_TRAP_NP, segment_not_present);
|
|
set_intr_gate(X86_TRAP_SS, stack_segment);
|
|
set_intr_gate(X86_TRAP_GP, general_protection);
|
|
set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
|
|
set_intr_gate(X86_TRAP_MF, coprocessor_error);
|
|
set_intr_gate(X86_TRAP_AC, alignment_check);
|
|
#ifdef CONFIG_X86_MCE
|
|
set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
|
|
#endif
|
|
set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
|
|
|
|
/* Reserve all the builtin and the syscall vector: */
|
|
for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
|
|
set_bit(i, used_vectors);
|
|
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
set_system_intr_gate(IA32_SYSCALL_VECTOR, entry_INT80_compat);
|
|
set_bit(IA32_SYSCALL_VECTOR, used_vectors);
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_32
|
|
set_system_intr_gate(IA32_SYSCALL_VECTOR, entry_INT80_32);
|
|
set_bit(IA32_SYSCALL_VECTOR, used_vectors);
|
|
#endif
|
|
|
|
/*
|
|
* Set the IDT descriptor to a fixed read-only location, so that the
|
|
* "sidt" instruction will not leak the location of the kernel, and
|
|
* to defend the IDT against arbitrary memory write vulnerabilities.
|
|
* It will be reloaded in cpu_init() */
|
|
__set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
|
|
idt_descr.address = fix_to_virt(FIX_RO_IDT);
|
|
|
|
/*
|
|
* Should be a barrier for any external CPU state:
|
|
*/
|
|
cpu_init();
|
|
|
|
/*
|
|
* X86_TRAP_DB and X86_TRAP_BP have been set
|
|
* in early_trap_init(). However, ITS works only after
|
|
* cpu_init() loads TSS. See comments in early_trap_init().
|
|
*/
|
|
set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
|
|
/* int3 can be called from all */
|
|
set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
|
|
|
|
x86_init.irqs.trap_init();
|
|
|
|
#ifdef CONFIG_X86_64
|
|
memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
|
|
set_nmi_gate(X86_TRAP_DB, &debug);
|
|
set_nmi_gate(X86_TRAP_BP, &int3);
|
|
#endif
|
|
}
|