On Wed, 23 Oct 2024 10:59:42 +0200
Jean-Michel Hautbois <jeanmichel.hautbois@xxxxxxxxxx> wrote:
Sadly, not that straightforward.
I have this patch right now:
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index b2a3093af677..fc4a2d124514 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -41,6 +41,7 @@ config M68K
select ZONE_DMA
select ARCH_SUPPORTS_RT
select IRQ_FORCED_THREADING
+ select TRACE_IRQFLAGS_SUPPORT
config CPU_BIG_ENDIAN
def_bool y
diff --git a/arch/m68k/coldfire/entry.S b/arch/m68k/coldfire/entry.S
index 4ea08336e2fb..fbdc4404f29e 100644
--- a/arch/m68k/coldfire/entry.S
+++ b/arch/m68k/coldfire/entry.S
@@ -57,6 +57,9 @@ enosys:
ENTRY(system_call)
SAVE_ALL_SYS
move #0x2000,%sr /* enable intrs again */
+#ifdef CONFIG_TRACE_IRQFLAGS
+ jbsr trace_hardirqs_on
+#endif
Note, the trace_hardirqs_on/off() needs to be done when interrupts are
disabled. That is:
__local_irq_disable();
trace_hardirqs_off();
[..]
trace_hardirqs_on();
__local_irq_enable();
I don't know the m68k assembly, but from the comments it looks like you
are calling these with interrupts enabled.
-- Steve
GET_CURRENT(%d2)
cmpl #NR_syscalls,%d0
@@ -99,6 +102,9 @@ ENTRY(system_call)
addql #4,%sp
ret_from_exception:
+#ifdef CONFIG_TRACE_IRQFLAGS
+ jbsr trace_hardirqs_off
+#endif
move #0x2700,%sr /* disable intrs */
btst #5,%sp@(PT_OFF_SR) /* check if returning to kernel */
jeq Luser_return /* if so, skip resched, signals */
@@ -140,6 +146,9 @@ Lreturn:
Lwork_to_do:
movel %a0@(TINFO_FLAGS),%d1 /* get thread_info->flags */
move #0x2000,%sr /* enable intrs again */
+#ifdef CONFIG_TRACE_IRQFLAGS
+ jbsr trace_hardirqs_on
+#endif
btst #TIF_NEED_RESCHED,%d1
jne reschedule
But it fails when init is called:
[ 5.313000] Run /bin/bash as init process
[ 5.314000] with arguments:
[ 5.315000] /bin/bash
[ 5.316000] with environment:
[ 5.317000] HOME=/
[ 5.318000] TERM=linux
[ 5.684000] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0000000b
[ 5.684000] CPU: 0 UID: 0 PID: 1 Comm: bash Not tainted
6.12.0-rc4-00049-g4393ca34ead3 #364
[ 5.684000] Stack from 41a03e18:
[ 5.684000] 41a03e18 41540187 41540187 0000000a ffffffff
415a8fb4 4140dd90 41416588
[ 5.684000] 41540187 4140d5de 4102ba84 4100b19c 4100b1a8
00000000 41a38000 4102ba3a
[ 5.684000] 41a03ea0 4100c34a 4150e87e 0000000b 0000000b
41a03f80 0000000a 41a3c0d4
[ 5.684000] 41a02000 400004d8 41a08000 4102ba3a 4102ba84
00000000 00000000 000000ff
[ 5.684000] 00000000 00000000 41a03ef4 4100cb82 0000000b
0000000b 41a03f80 41a03f6c
[ 5.684000] 41016cd2 0000000b 41a03f6c 0000001d 00000026
0000048c ffffffff 00000006
[ 5.684000] Call Trace: [<4140dd90>] _printk+0x0/0x18
[ 5.684000] [<41416588>] dump_stack+0xc/0x10
[ 5.684000] [<4140d5de>] panic+0xf2/0x2d4
[ 5.684000] [<4102ba84>] preempt_count_sub+0x0/0x2e
[ 5.684000] [<4100b19c>] arch_local_irq_enable+0x0/0xc
[ 5.684000] [<4100b1a8>] arch_irqs_disabled+0x0/0x10
[ 5.684000] [<4102ba3a>] preempt_count_add+0x0/0x1e
[ 5.684000] [<4100c34a>] do_exit+0x266/0x930
[ 5.684000] [<4102ba3a>] preempt_count_add+0x0/0x1e
[ 5.684000] [<4102ba84>] preempt_count_sub+0x0/0x2e
[ 5.684000] [<4100cb82>] do_group_exit+0x26/0xba
[ 5.684000] [<41016cd2>] get_signal+0x60e/0x76c
[ 5.684000] [<410044e8>] test_ti_thread_flag+0x0/0x14
[ 5.684000] [<4102ba94>] preempt_count_sub+0x10/0x2e
[ 5.684000] [<41004b68>] do_notify_resume+0x3a/0x4c6
[ 5.684000] [<41015d52>] force_sig_fault_to_task+0x32/0x3e
[ 5.684000] [<41015d72>] force_sig_fault+0x14/0x1a
[ 5.684000] [<41005606>] buserr_c+0x9a/0x188
[ 5.684000] [<410065fc>] Lsignal_return+0x14/0x24
[ 5.684000] [<410065de>] Lwork_to_do+0xe/0x18
[ 5.684000]
[ 5.684000] ---[ end Kernel panic - not syncing: Attempted to kill
init! exitcode=0x0000000b ]---
JM
Registers %d0-%d5 and %a0-%a2 are saved on the stack at this point and
can be clobbered if need be.
I don't know if they need to be clobbered...
I meant to say that if you need registers to prepare function arguments
for trace_irqs_on/off() on the stack, these can be used. But that may
not be necessary in this case.
Cheers,
Michael
Thanks,
JM
Cheers,
Michael
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@xxxxxxxxxx>
---
arch/m68k/Kconfig | 1 +
arch/m68k/kernel/irq.c | 2 ++
2 files changed, 3 insertions(+)
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index
cc26df907bfe3c8143a931d259eceabb16af7411..ab3375475721fa63418c40d4ba6ac76679ebc77d
100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -39,6 +39,7 @@ config M68K
select OLD_SIGSUSPEND3
select UACCESS_MEMCPY if !MMU
select ZONE_DMA
+ select TRACE_IRQFLAGS_SUPPORT
config CPU_BIG_ENDIAN
def_bool y
diff --git a/arch/m68k/kernel/irq.c b/arch/m68k/kernel/irq.c
index
9ab4f550342e5de11c528f55781432675ffd66bf..74cf60ebbc4bca51f3caa4046dbd2bdb02355711
100644
--- a/arch/m68k/kernel/irq.c
+++ b/arch/m68k/kernel/irq.c
@@ -21,9 +21,11 @@ asmlinkage void do_IRQ(int irq, struct pt_regs
*regs)
{
struct pt_regs *oldregs = set_irq_regs(regs);
+ trace_hardirqs_off();
irq_enter();
generic_handle_irq(irq);
irq_exit();
+ trace_hardirqs_on();
set_irq_regs(oldregs);
}
