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-rw-r--r--arch/i386/Kconfig.debug4
-rw-r--r--arch/i386/kernel/entry.S36
-rw-r--r--arch/i386/kernel/irq.c6
-rw-r--r--include/asm-i386/irqflags.h56
-rw-r--r--include/asm-i386/spinlock.h5
-rw-r--r--include/asm-i386/system.h20
6 files changed, 104 insertions, 23 deletions
diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug
index b20ddd04f3d8..b31c0802e1cc 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 787190c45fdb..d9a260f2efb4 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 16b491703967..6cb529f60dcc 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 000000000000..ca777e894c92
--- /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 04ba30234c48..7e29b51bcaa0 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 cab0180567f9..db398d88b1d9 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
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.