* Re: [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function
@ 2017-10-05 6:29 Greg Ungerer
2017-10-05 7:07 ` Paul Burton
0 siblings, 1 reply; 5+ messages in thread
From: Greg Ungerer @ 2017-10-05 6:29 UTC (permalink / raw)
To: Paul Burton; +Cc: Ralf Baechle, linux-mips
Hi Paul,
On Fri, 9 Jun 2017 17:26:38 -0700, Paul Burton wrote:
> Replace the macro definition of __cmpxchg() with an inline function,
> which is easier to read & modify. The cmpxchg() & cmpxchg_local() macros
> are adjusted to call the new __cmpxchg() function.
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> Cc: linux-mips@xxxxxxxxxxxxxx
I think this patch is breaking user space for me. I say "think"
because it is a bit tricky to bisect for the few patches previous
to this one since they won't compile cleanly for me (due to this
https://www.spinics.net/lists/mips/msg68727.html).
I have a Cavium Octeon 5010 MIPS64 CPU on a custom board, have been
running it for years running various kernel versions. Linux-4.13
breaks for me, and I bisected back to this change.
What I see is user space bomb strait after boot with console messages
like this:
mount[37] killed because of sig - 11
STACK DUMP:
CPU: 0 PID: 37 Comm: mount Not tainted 4.13.0-uc0 #8
task: 8000000007d14200 task.stack: 8000000007f18000
$ 0 : 0000000000000000 000000ffffd23f70 000000000000001a 000000000001a7d0
$ 4 : 0000000125af9760 0000000125af9718 0000000125af9748 0000000000000001
$ 8 : 2f2f2f2f2f2f2f2f 8101010101010100 0000000000000000 00000000ffffffff
$12 : 000000fff79f6000 000000fff7980f00 000000fff79887d8 0000000000000018
$16 : 0000000125af9718 0000000125af9760 0000000125af9748 0000000120054cd8
$20 : 000000012006f3a0 00000001200083ac 0000000120059fa0 000000012006f3a0
$24 : 00000000000001c8 000000fff798f7d0
$28 : 000000fff79f75e0 000000ffffd23fe0 0000000120010000 0000000120015820
Hi : 00000000000001b6
Lo : 000000000001b0b9
epc : 000000fff798f7f4 0x000000fff798f7f4
ra : 0000000120015820 0x0000000120015820
Status: 00008cf3 KX SX UX USER EXL IE
Cause : 00800020 (ExcCode 08)
PrId : 000d0601 (Cavium Octeon+)
000000ffffc9b000-000000ffffcbc000 rwxp 000000fffffdf000 00:00 0
I get a lot of them from various programs running from rc scripts.
It never manages to fully boot to login/shell.
If I take the linux-4.12 arch/mips/include/asm/cmpxchg.h and drop that
in place on a linux-4.13 (or even linux-4.14-rc3) I can compile and
run everything successfully.
Any thoughts?
Regards
Greg
> ---
>
> arch/mips/include/asm/cmpxchg.h | 59 ++++++++++++++++++++++-------------------
> 1 file changed, 32 insertions(+), 27 deletions(-)
>
> diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
> index e9c1e97bc29d..516cb66f066b 100644
> --- a/arch/mips/include/asm/cmpxchg.h
> +++ b/arch/mips/include/asm/cmpxchg.h
> @@ -34,7 +34,7 @@
> *
> * - Get an error at link-time due to the call to the missing function.
> */
> -extern void __cmpxchg_called_with_bad_pointer(void)
> +extern unsigned long __cmpxchg_called_with_bad_pointer(void)
> __compiletime_error("Bad argument size for cmpxchg");
> extern unsigned long __xchg_called_with_bad_pointer(void)
> __compiletime_error("Bad argument size for xchg");
> @@ -137,38 +137,43 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
> __ret; \
> })
>
> -#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
> +static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
> + unsigned long new, unsigned int size)
> +{
> + switch (size) {
> + case 4:
> + return __cmpxchg_asm("ll", "sc", (volatile u32 *)ptr, old, new);
> +
> + case 8:
> + /* lld/scd are only available for MIPS64 */
> + if (!IS_ENABLED(CONFIG_64BIT))
> + return __cmpxchg_called_with_bad_pointer();
> +
> + return __cmpxchg_asm("lld", "scd", (volatile u64 *)ptr, old, new);
> +
> + default:
> + return __cmpxchg_called_with_bad_pointer();
> + }
> +}
> +
> +#define cmpxchg_local(ptr, old, new) \
> + ((__typeof__(*(ptr))) \
> + __cmpxchg((ptr), \
> + (unsigned long)(__typeof__(*(ptr)))(old), \
> + (unsigned long)(__typeof__(*(ptr)))(new), \
> + sizeof(*(ptr))))
> +
> +#define cmpxchg(ptr, old, new) \
> ({ \
> - __typeof__(ptr) __ptr = (ptr); \
> - __typeof__(*(ptr)) __old = (old); \
> - __typeof__(*(ptr)) __new = (new); \
> - __typeof__(*(ptr)) __res = 0; \
> - \
> - pre_barrier; \
> - \
> - switch (sizeof(*(__ptr))) { \
> - case 4: \
> - __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
> - break; \
> - case 8: \
> - if (sizeof(long) == 8) { \
> - __res = __cmpxchg_asm("lld", "scd", __ptr, \
> - __old, __new); \
> - break; \
> - } \
> - default: \
> - __cmpxchg_called_with_bad_pointer(); \
> - break; \
> - } \
> + __typeof__(*(ptr)) __res; \
> \
> - post_barrier; \
> + smp_mb__before_llsc(); \
> + __res = cmpxchg_local((ptr), (old), (new)); \
> + smp_llsc_mb(); \
> \
> __res; \
> })
>
> -#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
> -#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
> -
> #ifdef CONFIG_64BIT
> #define cmpxchg64_local(ptr, o, n) \
> ({ \
> --
> 2.13.1
^ permalink raw reply [flat|nested] 5+ messages in thread* RE: [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function
2017-10-05 6:29 [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function Greg Ungerer
@ 2017-10-05 7:07 ` Paul Burton
2017-10-05 23:27 ` Greg Ungerer
0 siblings, 1 reply; 5+ messages in thread
From: Paul Burton @ 2017-10-05 7:07 UTC (permalink / raw)
To: Greg Ungerer, Ralf Baechle; +Cc: linux-mips
Hi Greg,
> On Fri, 9 Jun 2017 17:26:38 -0700, Paul Burton wrote:
> > Replace the macro definition of __cmpxchg() with an inline function,
> > which is easier to read & modify. The cmpxchg() & cmpxchg_local()
> > macros are adjusted to call the new __cmpxchg() function.
> >
> > Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> > Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> > Cc: linux-mips@xxxxxxxxxxxxxx
>
> I think this patch is breaking user space for me. I say "think"
> because it is a bit tricky to bisect for the few patches previous to this one
> since they won't compile cleanly for me (due to this
> https://www.spinics.net/lists/mips/msg68727.html).
>
> I have a Cavium Octeon 5010 MIPS64 CPU on a custom board, have been
> running it for years running various kernel versions. Linux-4.13 breaks for me,
> and I bisected back to this change.
>
> What I see is user space bomb strait after boot with console messages like
> this:
>
> mount[37] killed because of sig - 11
>
> STACK DUMP:
> <snip>
>
> I get a lot of them from various programs running from rc scripts.
> It never manages to fully boot to login/shell.
>
> If I take the linux-4.12 arch/mips/include/asm/cmpxchg.h and drop that in
> place on a linux-4.13 (or even linux-4.14-rc3) I can compile and run everything
> successfully.
>
> Any thoughts?
Are you running a uniprocessor/non-SMP kernel? Could you try this fix I submitted this fix 5 weeks ago:
https://patchwork.linux-mips.org/patch/17226/
Ralf: Could we get that merged please?
(Apologies if this email is formatted oddly.)
Thanks,
Paul
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function
2017-10-05 7:07 ` Paul Burton
@ 2017-10-05 23:27 ` Greg Ungerer
0 siblings, 0 replies; 5+ messages in thread
From: Greg Ungerer @ 2017-10-05 23:27 UTC (permalink / raw)
To: Paul Burton, Ralf Baechle; +Cc: linux-mips
Hi Paul,
On 05/10/17 17:07, Paul Burton wrote:
>> On Fri, 9 Jun 2017 17:26:38 -0700, Paul Burton wrote:
>>> Replace the macro definition of __cmpxchg() with an inline function,
>>> which is easier to read & modify. The cmpxchg() & cmpxchg_local()
>>> macros are adjusted to call the new __cmpxchg() function.
>>>
>>> Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
>>> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
>>> Cc: linux-mips@xxxxxxxxxxxxxx
>>
>> I think this patch is breaking user space for me. I say "think"
>> because it is a bit tricky to bisect for the few patches previous to this one
>> since they won't compile cleanly for me (due to this
>> https://www.spinics.net/lists/mips/msg68727.html).
>>
>> I have a Cavium Octeon 5010 MIPS64 CPU on a custom board, have been
>> running it for years running various kernel versions. Linux-4.13 breaks for me,
>> and I bisected back to this change.
>>
>> What I see is user space bomb strait after boot with console messages like
>> this:
>>
>> mount[37] killed because of sig - 11
>>
>> STACK DUMP:
>> <snip>
>>
>> I get a lot of them from various programs running from rc scripts.
>> It never manages to fully boot to login/shell.
>>
>> If I take the linux-4.12 arch/mips/include/asm/cmpxchg.h and drop that in
>> place on a linux-4.13 (or even linux-4.14-rc3) I can compile and run everything
>> successfully.
>>
>> Any thoughts?
>
> Are you running a uniprocessor/non-SMP kernel?
Yes, CONFIG_SMP not set.
> Could you try this fix I submitted this fix 5 weeks ago:
>
> https://patchwork.linux-mips.org/patch/17226/
Yep, that fixes it. Thanks for the quick response.
> Ralf: Could we get that merged please?
Since this is a problem in linux-4.13 then a candidate for linux-4.13 stable too?
Regards
Greg
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 00/11] MIPS: cmpxchg(), xchg() fixes & queued locks
@ 2017-06-10 0:26 Paul Burton
2017-06-10 0:26 ` Paul Burton
0 siblings, 1 reply; 5+ messages in thread
From: Paul Burton @ 2017-06-10 0:26 UTC (permalink / raw)
To: linux-mips; +Cc: Ralf Baechle, Paul Burton
This series makes a bunch of cleanups & improvements to the cmpxchg() &
xchg() macros & functions, allowing them to be used on values smaller
than 4 bytes, then switches MIPS over to use generic queued spinlocks &
queued read/write locks.
Applies atop v4.12-rc4.
Paul Burton (11):
MIPS: cmpxchg: Unify R10000_LLSC_WAR & non-R10000_LLSC_WAR cases
MIPS: cmpxchg: Pull xchg() asm into a macro
MIPS: cmpxchg: Use __compiletime_error() for bad cmpxchg() pointers
MIPS: cmpxchg: Error out on unsupported xchg() calls
MIPS: cmpxchg: Drop __xchg_u{32,64} functions
MIPS: cmpxchg: Implement __cmpxchg() as a function
MIPS: cmpxchg: Implement 1 byte & 2 byte xchg()
MIPS: cmpxchg: Implement 1 byte & 2 byte cmpxchg()
MIPS: cmpxchg: Rearrange __xchg() arguments to match xchg()
MIPS: Use queued read/write locks (qrwlock)
MIPS: Use queued spinlocks (qspinlock)
arch/mips/Kconfig | 2 +
arch/mips/include/asm/Kbuild | 2 +
arch/mips/include/asm/cmpxchg.h | 280 ++++++++++------------
arch/mips/include/asm/spinlock.h | 426 +--------------------------------
arch/mips/include/asm/spinlock_types.h | 34 +--
arch/mips/kernel/Makefile | 2 +-
arch/mips/kernel/cmpxchg.c | 109 +++++++++
7 files changed, 239 insertions(+), 616 deletions(-)
create mode 100644 arch/mips/kernel/cmpxchg.c
--
2.13.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function
@ 2017-06-10 0:26 ` Paul Burton
0 siblings, 0 replies; 5+ messages in thread
From: Paul Burton @ 2017-06-10 0:26 UTC (permalink / raw)
To: linux-mips; +Cc: Ralf Baechle, Paul Burton
Replace the macro definition of __cmpxchg() with an inline function,
which is easier to read & modify. The cmpxchg() & cmpxchg_local() macros
are adjusted to call the new __cmpxchg() function.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
---
arch/mips/include/asm/cmpxchg.h | 59 ++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index e9c1e97bc29d..516cb66f066b 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -34,7 +34,7 @@
*
* - Get an error at link-time due to the call to the missing function.
*/
-extern void __cmpxchg_called_with_bad_pointer(void)
+extern unsigned long __cmpxchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for cmpxchg");
extern unsigned long __xchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for xchg");
@@ -137,38 +137,43 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
__ret; \
})
-#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
+static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+ unsigned long new, unsigned int size)
+{
+ switch (size) {
+ case 4:
+ return __cmpxchg_asm("ll", "sc", (volatile u32 *)ptr, old, new);
+
+ case 8:
+ /* lld/scd are only available for MIPS64 */
+ if (!IS_ENABLED(CONFIG_64BIT))
+ return __cmpxchg_called_with_bad_pointer();
+
+ return __cmpxchg_asm("lld", "scd", (volatile u64 *)ptr, old, new);
+
+ default:
+ return __cmpxchg_called_with_bad_pointer();
+ }
+}
+
+#define cmpxchg_local(ptr, old, new) \
+ ((__typeof__(*(ptr))) \
+ __cmpxchg((ptr), \
+ (unsigned long)(__typeof__(*(ptr)))(old), \
+ (unsigned long)(__typeof__(*(ptr)))(new), \
+ sizeof(*(ptr))))
+
+#define cmpxchg(ptr, old, new) \
({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(*(ptr)) __old = (old); \
- __typeof__(*(ptr)) __new = (new); \
- __typeof__(*(ptr)) __res = 0; \
- \
- pre_barrier; \
- \
- switch (sizeof(*(__ptr))) { \
- case 4: \
- __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
- break; \
- case 8: \
- if (sizeof(long) == 8) { \
- __res = __cmpxchg_asm("lld", "scd", __ptr, \
- __old, __new); \
- break; \
- } \
- default: \
- __cmpxchg_called_with_bad_pointer(); \
- break; \
- } \
+ __typeof__(*(ptr)) __res; \
\
- post_barrier; \
+ smp_mb__before_llsc(); \
+ __res = cmpxchg_local((ptr), (old), (new)); \
+ smp_llsc_mb(); \
\
__res; \
})
-#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
-#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
-
#ifdef CONFIG_64BIT
#define cmpxchg64_local(ptr, o, n) \
({ \
--
2.13.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function
@ 2017-06-10 0:26 ` Paul Burton
0 siblings, 0 replies; 5+ messages in thread
From: Paul Burton @ 2017-06-10 0:26 UTC (permalink / raw)
To: linux-mips; +Cc: Ralf Baechle, Paul Burton
Replace the macro definition of __cmpxchg() with an inline function,
which is easier to read & modify. The cmpxchg() & cmpxchg_local() macros
are adjusted to call the new __cmpxchg() function.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
---
arch/mips/include/asm/cmpxchg.h | 59 ++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 27 deletions(-)
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index e9c1e97bc29d..516cb66f066b 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -34,7 +34,7 @@
*
* - Get an error at link-time due to the call to the missing function.
*/
-extern void __cmpxchg_called_with_bad_pointer(void)
+extern unsigned long __cmpxchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for cmpxchg");
extern unsigned long __xchg_called_with_bad_pointer(void)
__compiletime_error("Bad argument size for xchg");
@@ -137,38 +137,43 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
__ret; \
})
-#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
+static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+ unsigned long new, unsigned int size)
+{
+ switch (size) {
+ case 4:
+ return __cmpxchg_asm("ll", "sc", (volatile u32 *)ptr, old, new);
+
+ case 8:
+ /* lld/scd are only available for MIPS64 */
+ if (!IS_ENABLED(CONFIG_64BIT))
+ return __cmpxchg_called_with_bad_pointer();
+
+ return __cmpxchg_asm("lld", "scd", (volatile u64 *)ptr, old, new);
+
+ default:
+ return __cmpxchg_called_with_bad_pointer();
+ }
+}
+
+#define cmpxchg_local(ptr, old, new) \
+ ((__typeof__(*(ptr))) \
+ __cmpxchg((ptr), \
+ (unsigned long)(__typeof__(*(ptr)))(old), \
+ (unsigned long)(__typeof__(*(ptr)))(new), \
+ sizeof(*(ptr))))
+
+#define cmpxchg(ptr, old, new) \
({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(*(ptr)) __old = (old); \
- __typeof__(*(ptr)) __new = (new); \
- __typeof__(*(ptr)) __res = 0; \
- \
- pre_barrier; \
- \
- switch (sizeof(*(__ptr))) { \
- case 4: \
- __res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
- break; \
- case 8: \
- if (sizeof(long) == 8) { \
- __res = __cmpxchg_asm("lld", "scd", __ptr, \
- __old, __new); \
- break; \
- } \
- default: \
- __cmpxchg_called_with_bad_pointer(); \
- break; \
- } \
+ __typeof__(*(ptr)) __res; \
\
- post_barrier; \
+ smp_mb__before_llsc(); \
+ __res = cmpxchg_local((ptr), (old), (new)); \
+ smp_llsc_mb(); \
\
__res; \
})
-#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
-#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
-
#ifdef CONFIG_64BIT
#define cmpxchg64_local(ptr, o, n) \
({ \
--
2.13.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2017-06-10 0:26 [PATCH 00/11] MIPS: cmpxchg(), xchg() fixes & queued locks Paul Burton
2017-06-10 0:26 ` [PATCH 06/11] MIPS: cmpxchg: Implement __cmpxchg() as a function Paul Burton
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