Re: [PATCH RFC 1/2] m68k: Add tracirqs

[Michael Schmitz]

Jean-Michel,

thanks for your patches!
Am 21.10.2024 um 22:44 schrieb Jean-Michel Hautbois:
The TRACE_IRQFLAGS_SUPPORT requires the architecture to call
trace_hardirqs_off() when interrupts are disabled and
trace_hardirqs_on() when they are enabled.
Add those calls to do_IRQ function.

You will also have to add these calls to the three sites in 
arch/m68k/coldfire/head.S where interrupts are enabled or disabled.

Here:
ENTRY(system_call)
        SAVE_ALL_SYS
        move    #0x2000,%sr             /* enable intrs again */
        GET_CURRENT(%d2)

and here:
ret_from_exception:
        move    #0x2700,%sr             /* disable intrs */
        btst    #5,%sp@(PT_OFF_SR)      /* check if returning to kernel */
        jeq     Luser_return            /* if so, skip resched, signals */

and here:
Lwork_to_do:
        movel   %a0@(TINFO_FLAGS),%d1   /* get thread_info->flags */
        move    #0x2000,%sr             /* enable intrs again */
        btst    #TIF_NEED_RESCHED,%d1
        jne     reschedule

There's one similar site in arch/m68k/kernel/head.S (ret_from_exception) 
where interrupts are enabled that would need a similar change, if you 
want to enable this for all m68k.

Registers %d0-%d5 and %a0-%a2 are saved on the stack at this point and 
can be clobbered if need be.

Cheers,

        Michael



Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautb...@yoseli.org>
---
 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);
 }