diff options
| -rw-r--r-- | arch/i386/Kconfig.debug | 4 | ||||
| -rw-r--r-- | arch/i386/kernel/entry.S | 36 | ||||
| -rw-r--r-- | arch/i386/kernel/irq.c | 6 | ||||
| -rw-r--r-- | include/asm-i386/irqflags.h | 56 | ||||
| -rw-r--r-- | include/asm-i386/spinlock.h | 5 | ||||
| -rw-r--r-- | include/asm-i386/system.h | 20 |
6 files changed, 104 insertions, 23 deletions
diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug index b20ddd0..b31c080 100644 --- a/arch/i386/Kconfig.debug +++ b/arch/i386/Kconfig.debug @@ -1,5 +1,9 @@ menu "Kernel hacking" +config TRACE_IRQFLAGS_SUPPORT + bool + default y + source "lib/Kconfig.debug" config EARLY_PRINTK diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index 787190c..d9a260f 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -42,6 +42,7 @@ #include <linux/linkage.h> #include <asm/thread_info.h> +#include <asm/irqflags.h> #include <asm/errno.h> #include <asm/segment.h> #include <asm/smp.h> @@ -76,12 +77,21 @@ NT_MASK = 0x00004000 VM_MASK = 0x00020000 #ifdef CONFIG_PREEMPT -#define preempt_stop cli +#define preempt_stop cli; TRACE_IRQS_OFF #else #define preempt_stop #define resume_kernel restore_nocheck #endif +.macro TRACE_IRQS_IRET +#ifdef CONFIG_TRACE_IRQFLAGS + testl $IF_MASK,EFLAGS(%esp) # interrupts off? + jz 1f + TRACE_IRQS_ON +1: +#endif +.endm + #ifdef CONFIG_VM86 #define resume_userspace_sig check_userspace #else @@ -257,6 +267,10 @@ ENTRY(sysenter_entry) CFI_REGISTER esp, ebp movl TSS_sysenter_esp0(%esp),%esp sysenter_past_esp: + /* + * No need to follow this irqs on/off section: the syscall + * disabled irqs and here we enable it straight after entry: + */ sti pushl $(__USER_DS) CFI_ADJUST_CFA_OFFSET 4 @@ -303,6 +317,7 @@ sysenter_past_esp: call *sys_call_table(,%eax,4) movl %eax,EAX(%esp) cli + TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx jne syscall_exit_work @@ -310,6 +325,7 @@ sysenter_past_esp: movl EIP(%esp), %edx movl OLDESP(%esp), %ecx xorl %ebp,%ebp + TRACE_IRQS_ON sti sysexit CFI_ENDPROC @@ -339,6 +355,7 @@ syscall_exit: cli # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret + TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx # current->work jne syscall_exit_work @@ -355,12 +372,15 @@ restore_all: CFI_REMEMBER_STATE je ldt_ss # returning to user-space with LDT SS restore_nocheck: + TRACE_IRQS_IRET +restore_nocheck_notrace: RESTORE_REGS addl $4, %esp CFI_ADJUST_CFA_OFFSET -4 1: iret .section .fixup,"ax" iret_exc: + TRACE_IRQS_ON sti pushl $0 # no error code pushl $do_iret_error @@ -386,11 +406,13 @@ ldt_ss: subl $8, %esp # reserve space for switch16 pointer CFI_ADJUST_CFA_OFFSET 8 cli + TRACE_IRQS_OFF movl %esp, %eax /* Set up the 16bit stack frame with switch32 pointer on top, * and a switch16 pointer on top of the current frame. */ call setup_x86_bogus_stack CFI_ADJUST_CFA_OFFSET -8 # frame has moved + TRACE_IRQS_IRET RESTORE_REGS lss 20+4(%esp), %esp # switch to 16bit stack 1: iret @@ -411,6 +433,7 @@ work_resched: cli # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret + TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx andl $_TIF_WORK_MASK, %ecx # is there any work to be done other # than syscall tracing? @@ -462,6 +485,7 @@ syscall_trace_entry: syscall_exit_work: testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl jz work_pending + TRACE_IRQS_ON sti # could let do_syscall_trace() call # schedule() instead movl %esp, %eax @@ -535,9 +559,14 @@ ENTRY(irq_entries_start) vector=vector+1 .endr +/* + * the CPU automatically disables interrupts when executing an IRQ vector, + * so IRQ-flags tracing has to follow that: + */ ALIGN common_interrupt: SAVE_ALL + TRACE_IRQS_OFF movl %esp,%eax call do_IRQ jmp ret_from_intr @@ -549,9 +578,10 @@ ENTRY(name) \ pushl $~(nr); \ CFI_ADJUST_CFA_OFFSET 4; \ SAVE_ALL; \ + TRACE_IRQS_OFF \ movl %esp,%eax; \ call smp_/**/name; \ - jmp ret_from_intr; \ + jmp ret_from_intr; \ CFI_ENDPROC /* The include is where all of the SMP etc. interrupts come from */ @@ -726,7 +756,7 @@ nmi_stack_correct: xorl %edx,%edx # zero error code movl %esp,%eax # pt_regs pointer call do_nmi - jmp restore_all + jmp restore_nocheck_notrace CFI_ENDPROC nmi_stack_fixup: diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c index 16b4917..6cb529f 100644 --- a/arch/i386/kernel/irq.c +++ b/arch/i386/kernel/irq.c @@ -166,7 +166,7 @@ void irq_ctx_init(int cpu) irqctx->tinfo.task = NULL; irqctx->tinfo.exec_domain = NULL; irqctx->tinfo.cpu = cpu; - irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET; + irqctx->tinfo.preempt_count = 0; irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); softirq_ctx[cpu] = irqctx; @@ -211,6 +211,10 @@ asmlinkage void do_softirq(void) : "0"(isp) : "memory", "cc", "edx", "ecx", "eax" ); + /* + * Shouldnt happen, we returned above if in_interrupt(): + */ + WARN_ON_ONCE(softirq_count()); } local_irq_restore(flags); diff --git a/include/asm-i386/irqflags.h b/include/asm-i386/irqflags.h new file mode 100644 index 0000000..ca777e8 --- /dev/null +++ b/include/asm-i386/irqflags.h @@ -0,0 +1,56 @@ +/* + * include/asm-i386/irqflags.h + * + * IRQ flags handling + * + * This file gets included from lowlevel asm headers too, to provide + * wrapped versions of the local_irq_*() APIs, based on the + * raw_local_irq_*() macros from the lowlevel headers. + */ +#ifndef _ASM_IRQFLAGS_H +#define _ASM_IRQFLAGS_H + +#define raw_local_save_flags(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0) +#define raw_local_irq_restore(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0) +#define raw_local_irq_disable() __asm__ __volatile__("cli": : :"memory") +#define raw_local_irq_enable() __asm__ __volatile__("sti": : :"memory") +/* used in the idle loop; sti takes one instruction cycle to complete */ +#define raw_safe_halt() __asm__ __volatile__("sti; hlt": : :"memory") +/* used when interrupts are already enabled or to shutdown the processor */ +#define halt() __asm__ __volatile__("hlt": : :"memory") + +#define raw_irqs_disabled_flags(flags) (!((flags) & (1<<9))) + +/* For spinlocks etc */ +#define raw_local_irq_save(x) __asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory") + +/* + * Do the CPU's IRQ-state tracing from assembly code. We call a + * C function, so save all the C-clobbered registers: + */ +#ifdef CONFIG_TRACE_IRQFLAGS + +# define TRACE_IRQS_ON \ + pushl %eax; \ + pushl %ecx; \ + pushl %edx; \ + call trace_hardirqs_on; \ + popl %edx; \ + popl %ecx; \ + popl %eax; + +# define TRACE_IRQS_OFF \ + pushl %eax; \ + pushl %ecx; \ + pushl %edx; \ + call trace_hardirqs_off; \ + popl %edx; \ + popl %ecx; \ + popl %eax; + +#else +# define TRACE_IRQS_ON +# define TRACE_IRQS_OFF +#endif + +#endif diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h index 04ba302..7e29b51 100644 --- a/include/asm-i386/spinlock.h +++ b/include/asm-i386/spinlock.h @@ -31,6 +31,11 @@ "jmp 1b\n" \ "3:\n\t" +/* + * NOTE: there's an irqs-on section here, which normally would have to be + * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use + * __raw_spin_lock_string_flags(). + */ #define __raw_spin_lock_string_flags \ "\n1:\t" \ "lock ; decb %0\n\t" \ diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index cab0180..db398d8 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -456,25 +456,7 @@ static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long l #define set_wmb(var, value) do { var = value; wmb(); } while (0) -/* interrupt control.. */ -#define local_save_flags(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0) -#define local_irq_restore(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0) -#define local_irq_disable() __asm__ __volatile__("cli": : :"memory") -#define local_irq_enable() __asm__ __volatile__("sti": : :"memory") -/* used in the idle loop; sti takes one instruction cycle to complete */ -#define safe_halt() __asm__ __volatile__("sti; hlt": : :"memory") -/* used when interrupts are already enabled or to shutdown the processor */ -#define halt() __asm__ __volatile__("hlt": : :"memory") - -#define irqs_disabled() \ -({ \ - unsigned long flags; \ - local_save_flags(flags); \ - !(flags & (1<<9)); \ -}) - -/* For spinlocks etc */ -#define local_irq_save(x) __asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory") +#include <linux/irqflags.h> /* * disable hlt during certain critical i/o operations |
