[RFC PATCH 02/13] m68k: Fix mutual exclusion in arch_gettimeoffset
From: Finn Thain
Date: Sun Nov 11 2018 - 23:47:30 EST
Implementations of arch_gettimeoffset are generally not re-entrant
and assume that interrupts have been disabled. Unfortunately this
pre-condition got broken in v2.6.32.
Cc: Philip Blundell <philb@xxxxxxx>
Cc: Michael Schmitz <schmitzmic@xxxxxxxxx>
Cc: Joshua Thompson <funaho@xxxxxxxxx>
Fixes: 4ad4c76b7afb ("m68k: convert to use arch_gettimeoffset()")
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
---
arch/m68k/amiga/config.c | 6 +++++-
arch/m68k/atari/time.c | 6 +++++-
arch/m68k/bvme6000/config.c | 10 +++++++---
arch/m68k/hp300/time.c | 8 +++++++-
arch/m68k/mac/via.c | 5 +++++
arch/m68k/mvme147/config.c | 6 +++++-
arch/m68k/mvme16x/config.c | 1 -
7 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index 65f63a457130..5ec3687984a9 100644
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -492,12 +492,14 @@ static void __init amiga_sched_init(irq_handler_t timer_routine)
#define TICK_SIZE 10000
-/* This is always executed with interrupts disabled. */
static u32 amiga_gettimeoffset(void)
{
+ unsigned long flags;
unsigned short hi, lo, hi2;
u32 ticks, offset = 0;
+ local_irq_save(flags);
+
/* read CIA B timer A current value */
hi = ciab.tahi;
lo = ciab.talo;
@@ -515,6 +517,8 @@ static u32 amiga_gettimeoffset(void)
if (cia_set_irq(&ciab_base, 0) & CIA_ICR_TA)
offset = 10000;
+ local_irq_restore(flags);
+
ticks = jiffy_ticks - ticks;
ticks = (10000 * ticks) / jiffy_ticks;
diff --git a/arch/m68k/atari/time.c b/arch/m68k/atari/time.c
index 9cca64286464..4765e9a58293 100644
--- a/arch/m68k/atari/time.c
+++ b/arch/m68k/atari/time.c
@@ -40,11 +40,13 @@ atari_sched_init(irq_handler_t timer_routine)
#define TICK_SIZE 10000
-/* This is always executed with interrupts disabled. */
u32 atari_gettimeoffset(void)
{
+ unsigned long flags;
u32 ticks, offset = 0;
+ local_irq_save(flags);
+
/* read MFP timer C current value */
ticks = st_mfp.tim_dt_c;
/* The probability of underflow is less than 2% */
@@ -53,6 +55,8 @@ u32 atari_gettimeoffset(void)
if (st_mfp.int_pn_b & (1 << 5))
offset = TICK_SIZE;
+ local_irq_restore(flags);
+
ticks = INT_TICKS - ticks;
ticks = ticks * 10000L / INT_TICKS;
diff --git a/arch/m68k/bvme6000/config.c b/arch/m68k/bvme6000/config.c
index 143ee9fa3893..0afdef10a5a4 100644
--- a/arch/m68k/bvme6000/config.c
+++ b/arch/m68k/bvme6000/config.c
@@ -206,8 +206,6 @@ void bvme6000_sched_init (irq_handler_t timer_routine)
}
-/* This is always executed with interrupts disabled. */
-
/*
* NOTE: Don't accept any readings within 5us of rollover, as
* the T1INT bit may be a little slow getting set. There is also
@@ -217,12 +215,16 @@ void bvme6000_sched_init (irq_handler_t timer_routine)
u32 bvme6000_gettimeoffset(void)
{
+ unsigned long flags;
volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
volatile PitRegsPtr pit = (PitRegsPtr)BVME_PIT_BASE;
- unsigned char msr = rtc->msr & 0xc0;
+ unsigned char msr;
unsigned char t1int, t1op;
u32 v = 800000, ov;
+ local_irq_save(flags);
+
+ msr = rtc->msr & 0xc0;
rtc->msr = 0; /* Ensure timer registers accessible */
do {
@@ -245,6 +247,8 @@ u32 bvme6000_gettimeoffset(void)
v += 10000; /* Int pending, + 10ms */
rtc->msr = msr;
+ local_irq_restore(flags);
+
return v * 1000;
}
diff --git a/arch/m68k/hp300/time.c b/arch/m68k/hp300/time.c
index 289d928a46cb..5cf711fd0858 100644
--- a/arch/m68k/hp300/time.c
+++ b/arch/m68k/hp300/time.c
@@ -49,16 +49,22 @@ static irqreturn_t hp300_tick(int irq, void *dev_id)
u32 hp300_gettimeoffset(void)
{
- /* Read current timer 1 value */
+ unsigned long flags;
unsigned char lsb, msb1, msb2;
unsigned short ticks;
+ local_irq_save(flags);
+
+ /* Read current timer 1 value */
msb1 = in_8(CLOCKBASE + 5);
lsb = in_8(CLOCKBASE + 7);
msb2 = in_8(CLOCKBASE + 5);
if (msb1 != msb2)
/* A carry happened while we were reading. Read it again */
lsb = in_8(CLOCKBASE + 7);
+
+ local_irq_restore(flags);
+
ticks = INTVAL - ((msb2 << 8) | lsb);
return ((USECS_PER_JIFFY * ticks) / INTVAL) * 1000;
}
diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index e4facff0c1f3..e5dff74f59b3 100644
--- a/arch/m68k/mac/via.c
+++ b/arch/m68k/mac/via.c
@@ -318,8 +318,11 @@ void via_debug_dump(void)
u32 mac_gettimeoffset(void)
{
+ unsigned long flags;
unsigned long ticks, offset = 0;
+ local_irq_save(flags);
+
/* read VIA1 timer 2 current value */
ticks = via1[vT1CL] | (via1[vT1CH] << 8);
/* The probability of underflow is less than 2% */
@@ -327,6 +330,8 @@ u32 mac_gettimeoffset(void)
/* Check for pending timer interrupt in VIA1 IFR */
if (via1[vIFR] & 0x40) offset = TICK_SIZE;
+ local_irq_restore(flags);
+
ticks = MAC_CLOCK_TICK - ticks;
ticks = ticks * 10000L / MAC_CLOCK_TICK;
diff --git a/arch/m68k/mvme147/config.c b/arch/m68k/mvme147/config.c
index adea549d240e..8074940b0aa1 100644
--- a/arch/m68k/mvme147/config.c
+++ b/arch/m68k/mvme147/config.c
@@ -125,17 +125,21 @@ void mvme147_sched_init (irq_handler_t timer_routine)
m147_pcc->t1_int_cntrl = PCC_INT_ENAB|PCC_LEVEL_TIMER1;
}
-/* This is always executed with interrupts disabled. */
/* XXX There are race hazards in this code XXX */
u32 mvme147_gettimeoffset(void)
{
+ unsigned long flags;
volatile unsigned short *cp = (volatile unsigned short *)0xfffe1012;
unsigned short n;
+ local_irq_save(flags);
+
n = *cp;
while (n != *cp)
n = *cp;
+ local_irq_restore(flags);
+
n -= PCC_TIMER_PRELOAD;
return ((unsigned long)n * 25 / 4) * 1000;
}
diff --git a/arch/m68k/mvme16x/config.c b/arch/m68k/mvme16x/config.c
index 6ee36a5b528d..d4aec717e688 100644
--- a/arch/m68k/mvme16x/config.c
+++ b/arch/m68k/mvme16x/config.c
@@ -381,7 +381,6 @@ void mvme16x_sched_init (irq_handler_t timer_routine)
}
-/* This is always executed with interrupts disabled. */
u32 mvme16x_gettimeoffset(void)
{
return (*(volatile u32 *)0xfff42008) * 1000;
--
2.18.1