diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index aaabb5883ab8..e566affeed7f 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -193,6 +193,9 @@ Debugging kstack=N Print that many words from the kernel stack in oops dumps. + pagefaulttrace Dump all page faults. Only useful for extreme debugging + and will create a lot of output. + Misc noreplacement Don't replace instructions with more appropiate ones diff --git a/arch/x86_64/Kconfig.debug b/arch/x86_64/Kconfig.debug index 9cf1410d2f5a..3ccf6f4d1068 100644 --- a/arch/x86_64/Kconfig.debug +++ b/arch/x86_64/Kconfig.debug @@ -2,15 +2,6 @@ menu "Kernel hacking" source "lib/Kconfig.debug" -# !SMP for now because the context switch early causes GPF in segment reloading -# and the GS base checking does the wrong thing then, causing a hang. -config CHECKING - bool "Additional run-time checks" - depends on DEBUG_KERNEL && !SMP - help - Enables some internal consistency checks for kernel debugging. - You should normally say N. - config INIT_DEBUG bool "Debug __init statements" depends on DEBUG_KERNEL diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 4a836384dd0f..bf337f493189 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -428,19 +428,6 @@ static void __kprobes do_trap(int trapnr, int signr, char *str, { conditional_sti(regs); -#ifdef CONFIG_CHECKING - { - unsigned long gs; - struct x8664_pda *pda = cpu_pda + safe_smp_processor_id(); - rdmsrl(MSR_GS_BASE, gs); - if (gs != (unsigned long)pda) { - wrmsrl(MSR_GS_BASE, pda); - printk("%s: wrong gs %lx expected %p rip %lx\n", str, gs, pda, - regs->rip); - } - } -#endif - if (user_mode(regs)) { struct task_struct *tsk = current; @@ -513,20 +500,6 @@ asmlinkage void __kprobes do_general_protection(struct pt_regs * regs, { conditional_sti(regs); -#ifdef CONFIG_CHECKING - { - unsigned long gs; - struct x8664_pda *pda = cpu_pda + safe_smp_processor_id(); - rdmsrl(MSR_GS_BASE, gs); - if (gs != (unsigned long)pda) { - wrmsrl(MSR_GS_BASE, pda); - oops_in_progress++; - printk("general protection handler: wrong gs %lx expected %p\n", gs, pda); - oops_in_progress--; - } - } -#endif - if (user_mode(regs)) { struct task_struct *tsk = current; @@ -665,19 +638,6 @@ asmlinkage void __kprobes do_debug(struct pt_regs * regs, struct task_struct *tsk = current; siginfo_t info; -#ifdef CONFIG_CHECKING - { - /* RED-PEN interaction with debugger - could destroy gs */ - unsigned long gs; - struct x8664_pda *pda = cpu_pda + safe_smp_processor_id(); - rdmsrl(MSR_GS_BASE, gs); - if (gs != (unsigned long)pda) { - wrmsrl(MSR_GS_BASE, pda); - printk("debug handler: wrong gs %lx expected %p\n", gs, pda); - } - } -#endif - get_debugreg(condition, 6); if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code, diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c index b75b872ec154..3a63707a698b 100644 --- a/arch/x86_64/mm/fault.c +++ b/arch/x86_64/mm/fault.c @@ -308,18 +308,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, unsigned long flags; siginfo_t info; -#ifdef CONFIG_CHECKING - { - unsigned long gs; - struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); - rdmsrl(MSR_GS_BASE, gs); - if (gs != (unsigned long)pda) { - wrmsrl(MSR_GS_BASE, pda); - printk("page_fault: wrong gs %lx expected %p\n", gs, pda); - } - } -#endif - /* get the address */ __asm__("movq %%cr2,%0":"=r" (address)); if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, @@ -571,3 +559,10 @@ do_sigbus: force_sig_info(SIGBUS, &info, tsk); return; } + +static int __init enable_pagefaulttrace(char *str) +{ + page_fault_trace = 1; + return 0; +} +__setup("pagefaulttrace", enable_pagefaulttrace); diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c index 854a41b8372b..286f6a624c3a 100644 --- a/arch/x86_64/mm/init.c +++ b/arch/x86_64/mm/init.c @@ -565,10 +565,6 @@ extern int exception_trace, page_fault_trace; static ctl_table debug_table2[] = { { 99, "exception-trace", &exception_trace, sizeof(int), 0644, NULL, proc_dointvec }, -#ifdef CONFIG_CHECKING - { 100, "page-fault-trace", &page_fault_trace, sizeof(int), 0644, NULL, - proc_dointvec }, -#endif { 0, } };