svn commit: r214835 - in head/sys: amd64/amd64 arm/arm i386/i386
ia64/ia64 mips/mips pc98/pc98 powerpc/aim powerpc/booke
sparc64/sparc64 sun4v/sun4v
John Baldwin
jhb at FreeBSD.org
Fri Nov 5 13:42:59 UTC 2010
Author: jhb
Date: Fri Nov 5 13:42:58 2010
New Revision: 214835
URL: http://svn.freebsd.org/changeset/base/214835
Log:
Adjust the order of operations in spinlock_enter() and spinlock_exit() to
work properly with single-stepping in a kernel debugger. Specifically,
these routines have always disabled interrupts before increasing the nesting
count and restored the prior state of interrupts after decreasing the nesting
count to avoid problems with a nested interrupt not disabling interrupts
when acquiring a spin lock. However, trap interrupts for single-stepping
can still occur even when interrupts are disabled. Now the saved state of
interrupts is not saved in the thread until after interrupts have been
disabled and the nesting count has been increased. Similarly, the saved
state from the thread cannot be read once the nesting count has been
decreased to zero. To fix this, use temporary variables to store interrupt
state and shuffle it between the thread's MD area and the appropriate
registers.
In cooperation with: bde
MFC after: 1 month
Modified:
head/sys/amd64/amd64/machdep.c
head/sys/arm/arm/machdep.c
head/sys/i386/i386/machdep.c
head/sys/ia64/ia64/machdep.c
head/sys/mips/mips/machdep.c
head/sys/pc98/pc98/machdep.c
head/sys/powerpc/aim/machdep.c
head/sys/powerpc/booke/machdep.c
head/sys/sparc64/sparc64/machdep.c
head/sys/sun4v/sun4v/machdep.c
Modified: head/sys/amd64/amd64/machdep.c
==============================================================================
--- head/sys/amd64/amd64/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/amd64/amd64/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -1762,11 +1762,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_flags = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ flags = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_flags = flags;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -1774,12 +1778,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
critical_exit();
+ flags = td->td_md.md_saved_flags;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_flags);
+ intr_restore(flags);
}
/*
Modified: head/sys/arm/arm/machdep.c
==============================================================================
--- head/sys/arm/arm/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/arm/arm/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -493,11 +493,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t cspr;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_cspr = disable_interrupts(I32_bit | F32_bit);
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ cspr = disable_interrupts(I32_bit | F32_bit);
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_cspr = cspr;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -505,12 +509,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t cspr;
td = curthread;
critical_exit();
+ cspr = td->td_md.md_saved_cspr;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- restore_interrupts(td->td_md.md_saved_cspr);
+ restore_interrupts(cspr);
}
/*
Modified: head/sys/i386/i386/machdep.c
==============================================================================
--- head/sys/i386/i386/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/i386/i386/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -2997,11 +2997,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_flags = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ flags = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_flags = flags;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -3009,12 +3013,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
critical_exit();
+ flags = td->td_md.md_saved_flags;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_flags);
+ intr_restore(flags);
}
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
Modified: head/sys/ia64/ia64/machdep.c
==============================================================================
--- head/sys/ia64/ia64/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/ia64/ia64/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -513,11 +513,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ int intr;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_intr = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ intr = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_intr = intr;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -525,12 +529,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ int intr;
td = curthread;
critical_exit();
+ intr = td->td_md.md_saved_intr;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_intr);
+ intr_restore(intr);
}
void
Modified: head/sys/mips/mips/machdep.c
==============================================================================
--- head/sys/mips/mips/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/mips/mips/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -450,11 +450,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t intr;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_intr = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ intr = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_intr = intr;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -462,12 +466,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t intr;
td = curthread;
critical_exit();
+ intr = td->td_md.md_saved_intr;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_intr);
+ intr_restore(intr);
}
/*
Modified: head/sys/pc98/pc98/machdep.c
==============================================================================
--- head/sys/pc98/pc98/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/pc98/pc98/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -2340,11 +2340,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_flags = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ flags = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_flags = flags;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -2352,12 +2356,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t flags;
td = curthread;
critical_exit();
+ flags = td->td_md.md_saved_flags;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_flags);
+ intr_restore(flags);
}
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
Modified: head/sys/powerpc/aim/machdep.c
==============================================================================
--- head/sys/powerpc/aim/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/powerpc/aim/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -751,11 +751,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t msr;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_msr = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ msr = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_msr = msr;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -763,12 +767,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t msr;
td = curthread;
critical_exit();
+ msr = td->td_md.md_saved_msr;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_msr);
+ intr_restore(msr);
}
/*
Modified: head/sys/powerpc/booke/machdep.c
==============================================================================
--- head/sys/powerpc/booke/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/powerpc/booke/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -516,11 +516,15 @@ void
spinlock_enter(void)
{
struct thread *td;
+ register_t msr;
td = curthread;
- if (td->td_md.md_spinlock_count == 0)
- td->td_md.md_saved_msr = intr_disable();
- td->td_md.md_spinlock_count++;
+ if (td->td_md.md_spinlock_count == 0) {
+ msr = intr_disable();
+ td->td_md.md_spinlock_count = 1;
+ td->td_md.md_saved_msr = msr;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -528,12 +532,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t msr;
td = curthread;
critical_exit();
+ msr = td->td_md.md_saved_msr;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- intr_restore(td->td_md.md_saved_msr);
+ intr_restore(msr);
}
/* Shutdown the CPU as much as possible. */
Modified: head/sys/sparc64/sparc64/machdep.c
==============================================================================
--- head/sys/sparc64/sparc64/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/sparc64/sparc64/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -224,9 +224,10 @@ spinlock_enter(void)
if (td->td_md.md_spinlock_count == 0) {
pil = rdpr(pil);
wrpr(pil, 0, PIL_TICK);
+ td->td_md.md_spinlock_count = 1;
td->td_md.md_saved_pil = pil;
- }
- td->td_md.md_spinlock_count++;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -234,12 +235,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t pil;
td = curthread;
critical_exit();
+ pil = td->td_md.md_saved_pil;
td->td_md.md_spinlock_count--;
if (td->td_md.md_spinlock_count == 0)
- wrpr(pil, td->td_md.md_saved_pil, 0);
+ wrpr(pil, pil, 0);
}
static phandle_t
Modified: head/sys/sun4v/sun4v/machdep.c
==============================================================================
--- head/sys/sun4v/sun4v/machdep.c Fri Nov 5 11:31:39 2010 (r214834)
+++ head/sys/sun4v/sun4v/machdep.c Fri Nov 5 13:42:58 2010 (r214835)
@@ -269,9 +269,10 @@ spinlock_enter(void)
td = curthread;
if (td->td_md.md_spinlock_count == 0) {
pil = intr_disable();
+ td->td_md.md_spinlock_count = 1;
td->td_md.md_saved_pil = pil;
- }
- td->td_md.md_spinlock_count++;
+ } else
+ td->td_md.md_spinlock_count++;
critical_enter();
}
@@ -279,14 +280,14 @@ void
spinlock_exit(void)
{
struct thread *td;
+ register_t pil;
td = curthread;
critical_exit();
+ pil = td->td_md.md_saved_pil;
td->td_md.md_spinlock_count--;
- if (td->td_md.md_spinlock_count == 0) {
- intr_restore(td->td_md.md_saved_pil);
- }
-
+ if (td->td_md.md_spinlock_count == 0)
+ intr_restore(pil);
}
unsigned
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