Make the doublefault exception handler unconditional on 32-bit. Yes,
it is important to be able to catch #DF exceptions instead of silent
reboots. Yes, the code size increase is worth every byte. And one less
CONFIG symbol is just the cherry on top.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200404083646.8897-1-bp@alien8.de
If in doubt, say "Y".
-config DOUBLEFAULT
- default y
- bool "Enable doublefault exception handler" if EXPERT && X86_32
- ---help---
- This option allows trapping of rare doublefault exceptions that
- would otherwise cause a system to silently reboot. Disabling this
- option saves about 4k and might cause you much additional grey
- hair.
-
config DEBUG_TLBFLUSH
bool "Set upper limit of TLB entries to flush one-by-one"
depends on DEBUG_KERNEL
jmp common_exception
SYM_CODE_END(debug)
-#ifdef CONFIG_DOUBLEFAULT
SYM_CODE_START(double_fault)
1:
/*
hlt
jmp 1b
SYM_CODE_END(double_fault)
-#endif
/*
* NMI is doubly nasty. It can happen on the first instruction of
#ifndef _ASM_X86_DOUBLEFAULT_H
#define _ASM_X86_DOUBLEFAULT_H
-#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT)
+#ifdef CONFIG_X86_32
extern void doublefault_init_cpu_tss(void);
#else
static inline void doublefault_init_cpu_tss(void)
dotraplinkage void do_bounds(struct pt_regs *regs, long error_code);
dotraplinkage void do_invalid_op(struct pt_regs *regs, long error_code);
dotraplinkage void do_device_not_available(struct pt_regs *regs, long error_code);
-#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT)
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
-#endif
dotraplinkage void do_coprocessor_segment_overrun(struct pt_regs *regs, long error_code);
dotraplinkage void do_invalid_TSS(struct pt_regs *regs, long error_code);
dotraplinkage void do_segment_not_present(struct pt_regs *regs, long error_code);
obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
obj-y += kprobes/
obj-$(CONFIG_MODULES) += module.o
-ifeq ($(CONFIG_X86_32),y)
-obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o
-endif
+obj-$(CONFIG_X86_32) += doublefault_32.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_VM86) += vm86_32.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
{
-#ifdef CONFIG_DOUBLEFAULT
struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
struct doublefault_stack *ss = &cea->doublefault_stack;
info->next_sp = (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
return true;
-#else
- return false;
-#endif
}
}
#endif
-#if defined(CONFIG_X86_64) || defined(CONFIG_DOUBLEFAULT)
/*
* Runs on an IST stack for x86_64 and on a special task stack for x86_32.
*
die("double fault", regs, error_code);
panic("Machine halted.");
}
-#endif
dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
{
DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks);
#endif
-#if defined(CONFIG_X86_32) && defined(CONFIG_DOUBLEFAULT)
+#ifdef CONFIG_X86_32
DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack);
#endif
#else
static inline void percpu_setup_exception_stacks(unsigned int cpu)
{
-#ifdef CONFIG_DOUBLEFAULT
struct cpu_entry_area *cea = get_cpu_entry_area(cpu);
cea_map_percpu_pages(&cea->doublefault_stack,
&per_cpu(doublefault_stack, cpu), 1, PAGE_KERNEL);
-#endif
}
#endif
CONFIG_USER_STACKTRACE_SUPPORT=y
CONFIG_DEBUG_SG=y
CONFIG_DEBUG_NOTIFIERS=y
-CONFIG_DOUBLEFAULT=y
CONFIG_X86_DEBUG_FPU=y
CONFIG_DEBUG_SECTION_MISMATCH=y
CONFIG_DEBUG_PAGEALLOC=y