Excerpts from Christophe Leroy's message of February 5, 2021 6:09 pm:
>
>
> Le 30/01/2021 à 14:08, Nicholas Piggin a écrit :
>> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
>> ---
>
>> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
>> index f70d3f6174c8..7ff915aae8ec 100644
>> --- a/arch/powerpc/kernel/traps.c
>> +++ b/arch/powerpc/kernel/traps.c
>
>> @@ -1462,7 +1474,7 @@ static int emulate_math(struct pt_regs *regs)
>> static inline int emulate_math(struct pt_regs *regs) { return -1; }
>> #endif
>>
>> -void program_check_exception(struct pt_regs *regs)
>> +DEFINE_INTERRUPT_HANDLER(program_check_exception)
>> {
>> enum ctx_state prev_state = exception_enter();
>> unsigned int reason = get_reason(regs);
>> @@ -1587,14 +1599,14 @@ NOKPROBE_SYMBOL(program_check_exception);
>> * This occurs when running in hypervisor mode on POWER6 or later
>> * and an illegal instruction is encountered.
>> */
>> -void emulation_assist_interrupt(struct pt_regs *regs)
>> +DEFINE_INTERRUPT_HANDLER(emulation_assist_interrupt)
>> {
>> regs->msr |= REASON_ILLEGAL;
>> program_check_exception(regs);
>
> Is it correct that an INTERRUPT_HANDLER calls another INTERRUPT_HANDLER ?
No, here is a patch for it, should go any time before the interrupt
wrappers are introduced. It causes some conflicts later but are not
too complex. I can resend the series if necessary.
Thanks,
Nick
---
powerpc/traps: factor common code from program check and emulation assist
Move the program check handling into a function called by both, rather
than have the emulation assist handler call the program check handler.
This allows each of these handlers to be implemented with "interrupt
wrappers" in a later change.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/kernel/traps.c | 38 +++++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index f70d3f6174c8..2c5986109412 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1462,9 +1462,8 @@ static int emulate_math(struct pt_regs *regs)
static inline int emulate_math(struct pt_regs *regs) { return -1; }
#endif
-void program_check_exception(struct pt_regs *regs)
+static void do_program_check(struct pt_regs *regs)
{
- enum ctx_state prev_state = exception_enter();
unsigned int reason = get_reason(regs);
/* We can now get here via a FP Unavailable exception if the core
@@ -1473,22 +1472,22 @@ void program_check_exception(struct pt_regs *regs)
if (reason & REASON_FP) {
/* IEEE FP exception */
parse_fpe(regs);
- goto bail;
+ return;
}
if (reason & REASON_TRAP) {
unsigned long bugaddr;
/* Debugger is first in line to stop recursive faults in
* rcu_lock, notify_die, or atomic_notifier_call_chain */
if (debugger_bpt(regs))
- goto bail;
+ return;
if (kprobe_handler(regs))
- goto bail;
+ return;
/* trap exception */
if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
== NOTIFY_STOP)
- goto bail;
+ return;
bugaddr = regs->nip;
/*
@@ -1500,10 +1499,10 @@ void program_check_exception(struct pt_regs *regs)
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
- goto bail;
+ return;
}
_exception(SIGTRAP, regs, TRAP_BRKPT, regs->nip);
- goto bail;
+ return;
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (reason & REASON_TM) {
@@ -1524,7 +1523,7 @@ void program_check_exception(struct pt_regs *regs)
*/
if (user_mode(regs)) {
_exception(SIGILL, regs, ILL_ILLOPN, regs->nip);
- goto bail;
+ return;
} else {
printk(KERN_EMERG "Unexpected TM Bad Thing exception "
"at %lx (msr 0x%lx) tm_scratch=%llx\n",
@@ -1557,7 +1556,7 @@ void program_check_exception(struct pt_regs *regs)
* pattern to occurrences etc. -dgibson 31/Mar/2003
*/
if (!emulate_math(regs))
- goto bail;
+ return;
/* Try to emulate it if we should. */
if (reason & (REASON_ILLEGAL | REASON_PRIVILEGED)) {
@@ -1565,10 +1564,10 @@ void program_check_exception(struct pt_regs *regs)
case 0:
regs->nip += 4;
emulate_single_step(regs);
- goto bail;
+ return;
case -EFAULT:
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
- goto bail;
+ return;
}
}
@@ -1578,7 +1577,14 @@ void program_check_exception(struct pt_regs *regs)
else
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
-bail:
+}
+
+void program_check_exception(struct pt_regs *regs)
+{
+ enum ctx_state prev_state = exception_enter();
+
+ do_program_check(regs);
+
exception_exit(prev_state);
}
NOKPROBE_SYMBOL(program_check_exception);
@@ -1589,8 +1595,12 @@ NOKPROBE_SYMBOL(program_check_exception);
*/
void emulation_assist_interrupt(struct pt_regs *regs)
{
+ enum ctx_state prev_state = exception_enter();
+
regs->msr |= REASON_ILLEGAL;
- program_check_exception(regs);
+ do_program_check(regs);
+
+ exception_exit(prev_state);
}
NOKPROBE_SYMBOL(emulation_assist_interrupt);
--
2.23.0
