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Diffstat (limited to 'arch')
-rw-r--r--arch/x86_64/Kconfig.debug4
-rw-r--r--arch/x86_64/ia32/ia32entry.S19
-rw-r--r--arch/x86_64/kernel/entry.S188
-rw-r--r--arch/x86_64/kernel/irq.c4
4 files changed, 161 insertions, 54 deletions
diff --git a/arch/x86_64/Kconfig.debug b/arch/x86_64/Kconfig.debug
index 1d92ab56c0f9..775d211a5cf9 100644
--- a/arch/x86_64/Kconfig.debug
+++ b/arch/x86_64/Kconfig.debug
@@ -1,5 +1,9 @@
menu "Kernel hacking"
+config TRACE_IRQFLAGS_SUPPORT
+ bool
+ default y
+
source "lib/Kconfig.debug"
config DEBUG_RODATA
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index c536fa98ea37..9b5bb413a6e9 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -13,6 +13,7 @@
#include <asm/thread_info.h>
#include <asm/segment.h>
#include <asm/vsyscall32.h>
+#include <asm/irqflags.h>
#include <linux/linkage.h>
#define IA32_NR_syscalls ((ia32_syscall_end - ia32_sys_call_table)/8)
@@ -75,6 +76,10 @@ ENTRY(ia32_sysenter_target)
swapgs
movq %gs:pda_kernelstack, %rsp
addq $(PDA_STACKOFFSET),%rsp
+ /*
+ * No need to follow this irqs on/off section: the syscall
+ * disabled irqs, here we enable it straight after entry:
+ */
sti
movl %ebp,%ebp /* zero extension */
pushq $__USER32_DS
@@ -118,6 +123,7 @@ sysenter_do_call:
movq %rax,RAX-ARGOFFSET(%rsp)
GET_THREAD_INFO(%r10)
cli
+ TRACE_IRQS_OFF
testl $_TIF_ALLWORK_MASK,threadinfo_flags(%r10)
jnz int_ret_from_sys_call
andl $~TS_COMPAT,threadinfo_status(%r10)
@@ -132,6 +138,7 @@ sysenter_do_call:
CFI_REGISTER rsp,rcx
movl $VSYSCALL32_SYSEXIT,%edx /* User %eip */
CFI_REGISTER rip,rdx
+ TRACE_IRQS_ON
swapgs
sti /* sti only takes effect after the next instruction */
/* sysexit */
@@ -186,6 +193,10 @@ ENTRY(ia32_cstar_target)
movl %esp,%r8d
CFI_REGISTER rsp,r8
movq %gs:pda_kernelstack,%rsp
+ /*
+ * No need to follow this irqs on/off section: the syscall
+ * disabled irqs and here we enable it straight after entry:
+ */
sti
SAVE_ARGS 8,1,1
movl %eax,%eax /* zero extension */
@@ -220,6 +231,7 @@ cstar_do_call:
movq %rax,RAX-ARGOFFSET(%rsp)
GET_THREAD_INFO(%r10)
cli
+ TRACE_IRQS_OFF
testl $_TIF_ALLWORK_MASK,threadinfo_flags(%r10)
jnz int_ret_from_sys_call
andl $~TS_COMPAT,threadinfo_status(%r10)
@@ -228,6 +240,7 @@ cstar_do_call:
CFI_REGISTER rip,rcx
movl EFLAGS-ARGOFFSET(%rsp),%r11d
/*CFI_REGISTER rflags,r11*/
+ TRACE_IRQS_ON
movl RSP-ARGOFFSET(%rsp),%esp
CFI_RESTORE rsp
swapgs
@@ -286,7 +299,11 @@ ENTRY(ia32_syscall)
/*CFI_REL_OFFSET rflags,EFLAGS-RIP*/
/*CFI_REL_OFFSET cs,CS-RIP*/
CFI_REL_OFFSET rip,RIP-RIP
- swapgs
+ swapgs
+ /*
+ * No need to follow this irqs on/off section: the syscall
+ * disabled irqs and here we enable it straight after entry:
+ */
sti
movl %eax,%eax
pushq %rax
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index ed92c2983606..d464dded68c0 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -41,13 +41,24 @@
#include <asm/thread_info.h>
#include <asm/hw_irq.h>
#include <asm/page.h>
+#include <asm/irqflags.h>
.code64
#ifndef CONFIG_PREEMPT
#define retint_kernel retint_restore_args
#endif
-
+
+
+.macro TRACE_IRQS_IRETQ offset=ARGOFFSET
+#ifdef CONFIG_TRACE_IRQFLAGS
+ bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
+ jnc 1f
+ TRACE_IRQS_ON
+1:
+#endif
+.endm
+
/*
* C code is not supposed to know about undefined top of stack. Every time
* a C function with an pt_regs argument is called from the SYSCALL based
@@ -194,6 +205,10 @@ ENTRY(system_call)
swapgs
movq %rsp,%gs:pda_oldrsp
movq %gs:pda_kernelstack,%rsp
+ /*
+ * No need to follow this irqs off/on section - it's straight
+ * and short:
+ */
sti
SAVE_ARGS 8,1
movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
@@ -219,10 +234,15 @@ ret_from_sys_call:
sysret_check:
GET_THREAD_INFO(%rcx)
cli
+ TRACE_IRQS_OFF
movl threadinfo_flags(%rcx),%edx
andl %edi,%edx
CFI_REMEMBER_STATE
jnz sysret_careful
+ /*
+ * sysretq will re-enable interrupts:
+ */
+ TRACE_IRQS_ON
movq RIP-ARGOFFSET(%rsp),%rcx
CFI_REGISTER rip,rcx
RESTORE_ARGS 0,-ARG_SKIP,1
@@ -237,6 +257,7 @@ sysret_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc sysret_signal
+ TRACE_IRQS_ON
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
@@ -247,6 +268,7 @@ sysret_careful:
/* Handle a signal */
sysret_signal:
+ TRACE_IRQS_ON
sti
testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
jz 1f
@@ -261,6 +283,7 @@ sysret_signal:
/* Use IRET because user could have changed frame. This
works because ptregscall_common has called FIXUP_TOP_OF_STACK. */
cli
+ TRACE_IRQS_OFF
jmp int_with_check
badsys:
@@ -309,6 +332,7 @@ ENTRY(int_ret_from_sys_call)
CFI_REL_OFFSET r10,R10-ARGOFFSET
CFI_REL_OFFSET r11,R11-ARGOFFSET
cli
+ TRACE_IRQS_OFF
testl $3,CS-ARGOFFSET(%rsp)
je retint_restore_args
movl $_TIF_ALLWORK_MASK,%edi
@@ -327,6 +351,7 @@ int_with_check:
int_careful:
bt $TIF_NEED_RESCHED,%edx
jnc int_very_careful
+ TRACE_IRQS_ON
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
@@ -334,10 +359,12 @@ int_careful:
popq %rdi
CFI_ADJUST_CFA_OFFSET -8
cli
+ TRACE_IRQS_OFF
jmp int_with_check
/* handle signals and tracing -- both require a full stack frame */
int_very_careful:
+ TRACE_IRQS_ON
sti
SAVE_REST
/* Check for syscall exit trace */
@@ -351,6 +378,7 @@ int_very_careful:
CFI_ADJUST_CFA_OFFSET -8
andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi
cli
+ TRACE_IRQS_OFF
jmp int_restore_rest
int_signal:
@@ -363,6 +391,7 @@ int_signal:
int_restore_rest:
RESTORE_REST
cli
+ TRACE_IRQS_OFF
jmp int_with_check
CFI_ENDPROC
END(int_ret_from_sys_call)
@@ -484,6 +513,10 @@ END(stub_rt_sigreturn)
swapgs
1: incl %gs:pda_irqcount # RED-PEN should check preempt count
cmoveq %gs:pda_irqstackptr,%rsp
+ /*
+ * We entered an interrupt context - irqs are off:
+ */
+ TRACE_IRQS_OFF
call \func
.endm
@@ -493,6 +526,7 @@ ENTRY(common_interrupt)
/* 0(%rsp): oldrsp-ARGOFFSET */
ret_from_intr:
cli
+ TRACE_IRQS_OFF
decl %gs:pda_irqcount
leaveq
CFI_DEF_CFA_REGISTER rsp
@@ -515,9 +549,21 @@ retint_check:
CFI_REMEMBER_STATE
jnz retint_careful
retint_swapgs:
+ /*
+ * The iretq could re-enable interrupts:
+ */
+ cli
+ TRACE_IRQS_IRETQ
swapgs
+ jmp restore_args
+
retint_restore_args:
cli
+ /*
+ * The iretq could re-enable interrupts:
+ */
+ TRACE_IRQS_IRETQ
+restore_args:
RESTORE_ARGS 0,8,0
iret_label:
iretq
@@ -530,6 +576,7 @@ iret_label:
/* running with kernel gs */
bad_iret:
movq $11,%rdi /* SIGSEGV */
+ TRACE_IRQS_ON
sti
jmp do_exit
.previous
@@ -539,6 +586,7 @@ retint_careful:
CFI_RESTORE_STATE
bt $TIF_NEED_RESCHED,%edx
jnc retint_signal
+ TRACE_IRQS_ON
sti
pushq %rdi
CFI_ADJUST_CFA_OFFSET 8
@@ -547,11 +595,13 @@ retint_careful:
CFI_ADJUST_CFA_OFFSET -8
GET_THREAD_INFO(%rcx)
cli
+ TRACE_IRQS_OFF
jmp retint_check
retint_signal:
testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
jz retint_swapgs
+ TRACE_IRQS_ON
sti
SAVE_REST
movq $-1,ORIG_RAX(%rsp)
@@ -560,6 +610,7 @@ retint_signal:
call do_notify_resume
RESTORE_REST
cli
+ TRACE_IRQS_OFF
movl $_TIF_NEED_RESCHED,%edi
GET_THREAD_INFO(%rcx)
jmp retint_check
@@ -666,7 +717,7 @@ END(spurious_interrupt)
/* error code is on the stack already */
/* handle NMI like exceptions that can happen everywhere */
- .macro paranoidentry sym, ist=0
+ .macro paranoidentry sym, ist=0, irqtrace=1
SAVE_ALL
cld
movl $1,%ebx
@@ -691,8 +742,73 @@ END(spurious_interrupt)
addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
.endif
cli
+ .if \irqtrace
+ TRACE_IRQS_OFF
+ .endif
.endm
-
+
+ /*
+ * "Paranoid" exit path from exception stack.
+ * Paranoid because this is used by NMIs and cannot take
+ * any kernel state for granted.
+ * We don't do kernel preemption checks here, because only
+ * NMI should be common and it does not enable IRQs and
+ * cannot get reschedule ticks.
+ *
+ * "trace" is 0 for the NMI handler only, because irq-tracing
+ * is fundamentally NMI-unsafe. (we cannot change the soft and
+ * hard flags at once, atomically)
+ */
+ .macro paranoidexit trace=1
+ /* ebx: no swapgs flag */
+paranoid_exit\trace:
+ testl %ebx,%ebx /* swapgs needed? */
+ jnz paranoid_restore\trace
+ testl $3,CS(%rsp)
+ jnz paranoid_userspace\trace
+paranoid_swapgs\trace:
+ TRACE_IRQS_IRETQ 0
+ swapgs
+paranoid_restore\trace:
+ RESTORE_ALL 8
+ iretq
+paranoid_userspace\trace:
+ GET_THREAD_INFO(%rcx)
+ movl threadinfo_flags(%rcx),%ebx
+ andl $_TIF_WORK_MASK,%ebx
+ jz paranoid_swapgs\trace
+ movq %rsp,%rdi /* &pt_regs */
+ call sync_regs
+ movq %rax,%rsp /* switch stack for scheduling */
+ testl $_TIF_NEED_RESCHED,%ebx
+ jnz paranoid_schedule\trace
+ movl %ebx,%edx /* arg3: thread flags */
+ .if \trace
+ TRACE_IRQS_ON
+ .endif
+ sti
+ xorl %esi,%esi /* arg2: oldset */
+ movq %rsp,%rdi /* arg1: &pt_regs */
+ call do_notify_resume
+ cli
+ .if \trace
+ TRACE_IRQS_OFF
+ .endif
+ jmp paranoid_userspace\trace
+paranoid_schedule\trace:
+ .if \trace
+ TRACE_IRQS_ON
+ .endif
+ sti
+ call schedule
+ cli
+ .if \trace
+ TRACE_IRQS_OFF
+ .endif
+ jmp paranoid_userspace\trace
+ CFI_ENDPROC
+ .endm
+
/*
* Exception entry point. This expects an error code/orig_rax on the stack
* and the exception handler in %rax.
@@ -748,6 +864,7 @@ error_exit:
movl %ebx,%eax
RESTORE_REST
cli
+ TRACE_IRQS_OFF
GET_THREAD_INFO(%rcx)
testl %eax,%eax
jne retint_kernel
@@ -755,6 +872,10 @@ error_exit:
movl $_TIF_WORK_MASK,%edi
andl %edi,%edx
jnz retint_careful
+ /*
+ * The iret might restore flags:
+ */
+ TRACE_IRQS_IRETQ
swapgs
RESTORE_ARGS 0,8,0
jmp iret_label
@@ -916,8 +1037,7 @@ KPROBE_ENTRY(debug)
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_debug, DEBUG_STACK
- jmp paranoid_exit
- CFI_ENDPROC
+ paranoidexit
END(debug)
.previous .text
@@ -926,49 +1046,13 @@ KPROBE_ENTRY(nmi)
INTR_FRAME
pushq $-1
CFI_ADJUST_CFA_OFFSET 8
- paranoidentry do_nmi
- /*
- * "Paranoid" exit path from exception stack.
- * Paranoid because this is used by NMIs and cannot take
- * any kernel state for granted.
- * We don't do kernel preemption checks here, because only
- * NMI should be common and it does not enable IRQs and
- * cannot get reschedule ticks.
- */
- /* ebx: no swapgs flag */
-paranoid_exit:
- testl %ebx,%ebx /* swapgs needed? */
- jnz paranoid_restore
- testl $3,CS(%rsp)
- jnz paranoid_userspace
-paranoid_swapgs:
- swapgs
-paranoid_restore:
- RESTORE_ALL 8
- iretq
-paranoid_userspace:
- GET_THREAD_INFO(%rcx)
- movl threadinfo_flags(%rcx),%ebx
- andl $_TIF_WORK_MASK,%ebx
- jz paranoid_swapgs
- movq %rsp,%rdi /* &pt_regs */
- call sync_regs
- movq %rax,%rsp /* switch stack for scheduling */
- testl $_TIF_NEED_RESCHED,%ebx
- jnz paranoid_schedule
- movl %ebx,%edx /* arg3: thread flags */
- sti
- xorl %esi,%esi /* arg2: oldset */
- movq %rsp,%rdi /* arg1: &pt_regs */
- call do_notify_resume
- cli
- jmp paranoid_userspace
-paranoid_schedule:
- sti
- call schedule
- cli
- jmp paranoid_userspace
- CFI_ENDPROC
+ paranoidentry do_nmi, 0, 0
+#ifdef CONFIG_TRACE_IRQFLAGS
+ paranoidexit 0
+#else
+ jmp paranoid_exit1
+ CFI_ENDPROC
+#endif
END(nmi)
.previous .text
@@ -977,7 +1061,7 @@ KPROBE_ENTRY(int3)
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_int3, DEBUG_STACK
- jmp paranoid_exit
+ jmp paranoid_exit1
CFI_ENDPROC
END(int3)
.previous .text
@@ -1006,7 +1090,7 @@ END(reserved)
ENTRY(double_fault)
XCPT_FRAME
paranoidentry do_double_fault
- jmp paranoid_exit
+ jmp paranoid_exit1
CFI_ENDPROC
END(double_fault)
@@ -1022,7 +1106,7 @@ END(segment_not_present)
ENTRY(stack_segment)
XCPT_FRAME
paranoidentry do_stack_segment
- jmp paranoid_exit
+ jmp paranoid_exit1
CFI_ENDPROC
END(stack_segment)
@@ -1050,7 +1134,7 @@ ENTRY(machine_check)
pushq $0
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_machine_check
- jmp paranoid_exit
+ jmp paranoid_exit1
CFI_ENDPROC
END(machine_check)
#endif
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index a1f1df5f7bfc..5221a53e90c1 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -177,8 +177,10 @@ asmlinkage void do_softirq(void)
local_irq_save(flags);
pending = local_softirq_pending();
/* Switch to interrupt stack */
- if (pending)
+ if (pending) {
call_softirq();
+ WARN_ON_ONCE(softirq_count());
+ }
local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-22 23:16:43 +0300