* [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5???
@ 2014-01-12 8:46 Hugh Dickins
2014-01-12 12:34 ` Benjamin Herrenschmidt
2014-01-14 4:17 ` Benjamin Herrenschmidt
0 siblings, 2 replies; 3+ messages in thread
From: Hugh Dickins @ 2014-01-12 8:46 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: Mahesh Salgaonkar, linuxppc-dev
My PowerMac G5 cannot boot mmotm these days: different symptoms
(starting /sbin/init failed? or ATA errors and hang?), with unrelated
bugs adding to the confusion; but a bisection led to b5ff4211a829
"powerpc/book3s: Queue up and process delayed MCE events". Since that
series seems to be mostly about powernv, I tried changing BOOK3S_64
to POWERNV in entry_64.S, which has got it back to working for me.
Signed-off-by: Hugh Dickins <hughd@google.com>
just in case this happens to be right, but it's well beyond me!
---
arch/powerpc/kernel/entry_64.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- mmotm/arch/powerpc/kernel/entry_64.S 2014-01-10 18:24:56.940448828 -0800
+++ linux/arch/powerpc/kernel/entry_64.S 2014-01-10 18:29:24.276455182 -0800
@@ -184,7 +184,7 @@ syscall_exit:
bl .do_show_syscall_exit
ld r3,RESULT(r1)
#endif
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_POWERNV
BEGIN_FTR_SECTION
bl .machine_check_process_queued_event
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5???
2014-01-12 8:46 [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5??? Hugh Dickins
@ 2014-01-12 12:34 ` Benjamin Herrenschmidt
2014-01-14 4:17 ` Benjamin Herrenschmidt
1 sibling, 0 replies; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2014-01-12 12:34 UTC (permalink / raw)
To: Hugh Dickins; +Cc: Mahesh Salgaonkar, linuxppc-dev
On Sun, 2014-01-12 at 00:46 -0800, Hugh Dickins wrote:
> My PowerMac G5 cannot boot mmotm these days: different symptoms
> (starting /sbin/init failed? or ATA errors and hang?), with unrelated
> bugs adding to the confusion; but a bisection led to b5ff4211a829
> "powerpc/book3s: Queue up and process delayed MCE events". Since that
> series seems to be mostly about powernv, I tried changing BOOK3S_64
> to POWERNV in entry_64.S, which has got it back to working for me.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> just in case this happens to be right, but it's well beyond me!
Mahesh, I think that code is broken. It calls into C code after R3 is
loaded which will clobber it, thus clobbering the return from syscalls.
Also, are you really adding that overhead to every syscall in the
system ? That doesn't sound great...
Why do you do something in syscall_exit to begin with anyway ? That
doesn't seen like a great way to process delayed mchecks... When do you
want to process them ? Any interruptible code ? Task level ?
The former, you might be better off just shooting something like a local
doorbell and use some IPI message bit or similar to indicate the
presence of a pending mcheck. The local doorbell will trigger whenever
interrupts are enabled.
Ben.
> ---
>
> arch/powerpc/kernel/entry_64.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- mmotm/arch/powerpc/kernel/entry_64.S 2014-01-10 18:24:56.940448828 -0800
> +++ linux/arch/powerpc/kernel/entry_64.S 2014-01-10 18:29:24.276455182 -0800
> @@ -184,7 +184,7 @@ syscall_exit:
> bl .do_show_syscall_exit
> ld r3,RESULT(r1)
> #endif
> -#ifdef CONFIG_PPC_BOOK3S_64
> +#ifdef CONFIG_PPC_POWERNV
> BEGIN_FTR_SECTION
> bl .machine_check_process_queued_event
> END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5???
2014-01-12 8:46 [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5??? Hugh Dickins
2014-01-12 12:34 ` Benjamin Herrenschmidt
@ 2014-01-14 4:17 ` Benjamin Herrenschmidt
1 sibling, 0 replies; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2014-01-14 4:17 UTC (permalink / raw)
To: Hugh Dickins; +Cc: Mahesh Salgaonkar, linuxppc-dev
On Sun, 2014-01-12 at 00:46 -0800, Hugh Dickins wrote:
> My PowerMac G5 cannot boot mmotm these days: different symptoms
> (starting /sbin/init failed? or ATA errors and hang?), with unrelated
> bugs adding to the confusion; but a bisection led to b5ff4211a829
> "powerpc/book3s: Queue up and process delayed MCE events". Since that
> series seems to be mostly about powernv, I tried changing BOOK3S_64
> to POWERNV in entry_64.S, which has got it back to working for me.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> just in case this happens to be right, but it's well beyond me!
> ---
Do that help instead ?
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 770d6d6..9820d36 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -187,6 +187,7 @@ syscall_exit:
#ifdef CONFIG_PPC_BOOK3S_64
BEGIN_FTR_SECTION
bl .machine_check_process_queued_event
+ ld r3,RESULT(r1)
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
#endif
CURRENT_THREAD_INFO(r12, r1)
Cheers,
Ben.
>
> arch/powerpc/kernel/entry_64.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- mmotm/arch/powerpc/kernel/entry_64.S 2014-01-10 18:24:56.940448828 -0800
> +++ linux/arch/powerpc/kernel/entry_64.S 2014-01-10 18:29:24.276455182 -0800
> @@ -184,7 +184,7 @@ syscall_exit:
> bl .do_show_syscall_exit
> ld r3,RESULT(r1)
> #endif
> -#ifdef CONFIG_PPC_BOOK3S_64
> +#ifdef CONFIG_PPC_POWERNV
> BEGIN_FTR_SECTION
> bl .machine_check_process_queued_event
> END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2014-01-12 8:46 [PATCH mmotm/next] powerpc: fix powernv boot breakage on G5??? Hugh Dickins
2014-01-12 12:34 ` Benjamin Herrenschmidt
2014-01-14 4:17 ` Benjamin Herrenschmidt
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