* [PATCH] csky: Move to generic ticket-spinlock
@ 2022-03-18 8:34 guoren
2022-03-18 10:57 ` Arnd Bergmann
2022-03-18 22:48 ` Palmer Dabbelt
0 siblings, 2 replies; 6+ messages in thread
From: guoren @ 2022-03-18 8:34 UTC (permalink / raw)
To: palmer; +Cc: linux-csky, linux-arch, linux-kernel, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
There is no benefit from custom implementation for ticket-spinlock,
so move to generic ticket-spinlock for easy maintenance.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
---
arch/csky/include/asm/Kbuild | 2 +
arch/csky/include/asm/spinlock.h | 82 +-------------------------
arch/csky/include/asm/spinlock_types.h | 20 +------
3 files changed, 4 insertions(+), 100 deletions(-)
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 904a18a818be..d94434288c31 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -3,6 +3,8 @@ generic-y += asm-offsets.h
generic-y += extable.h
generic-y += gpio.h
generic-y += kvm_para.h
+generic-y += ticket-lock.h
+generic-y += ticket-lock-types.h
generic-y += qrwlock.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
index 69f5aa249c5f..8bc179ba0d8d 100644
--- a/arch/csky/include/asm/spinlock.h
+++ b/arch/csky/include/asm/spinlock.h
@@ -3,87 +3,7 @@
#ifndef __ASM_CSKY_SPINLOCK_H
#define __ASM_CSKY_SPINLOCK_H
-#include <linux/spinlock_types.h>
-#include <asm/barrier.h>
-
-/*
- * Ticket-based spin-locking.
- */
-static inline void arch_spin_lock(arch_spinlock_t *lock)
-{
- arch_spinlock_t lockval;
- u32 ticket_next = 1 << TICKET_NEXT;
- u32 *p = &lock->lock;
- u32 tmp;
-
- asm volatile (
- "1: ldex.w %0, (%2) \n"
- " mov %1, %0 \n"
- " add %0, %3 \n"
- " stex.w %0, (%2) \n"
- " bez %0, 1b \n"
- : "=&r" (tmp), "=&r" (lockval)
- : "r"(p), "r"(ticket_next)
- : "cc");
-
- while (lockval.tickets.next != lockval.tickets.owner)
- lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
-
- smp_mb();
-}
-
-static inline int arch_spin_trylock(arch_spinlock_t *lock)
-{
- u32 tmp, contended, res;
- u32 ticket_next = 1 << TICKET_NEXT;
- u32 *p = &lock->lock;
-
- do {
- asm volatile (
- " ldex.w %0, (%3) \n"
- " movi %2, 1 \n"
- " rotli %1, %0, 16 \n"
- " cmpne %1, %0 \n"
- " bt 1f \n"
- " movi %2, 0 \n"
- " add %0, %0, %4 \n"
- " stex.w %0, (%3) \n"
- "1: \n"
- : "=&r" (res), "=&r" (tmp), "=&r" (contended)
- : "r"(p), "r"(ticket_next)
- : "cc");
- } while (!res);
-
- if (!contended)
- smp_mb();
-
- return !contended;
-}
-
-static inline void arch_spin_unlock(arch_spinlock_t *lock)
-{
- smp_mb();
- WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
-}
-
-static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
-{
- return lock.tickets.owner == lock.tickets.next;
-}
-
-static inline int arch_spin_is_locked(arch_spinlock_t *lock)
-{
- return !arch_spin_value_unlocked(READ_ONCE(*lock));
-}
-
-static inline int arch_spin_is_contended(arch_spinlock_t *lock)
-{
- struct __raw_tickets tickets = READ_ONCE(lock->tickets);
-
- return (tickets.next - tickets.owner) > 1;
-}
-#define arch_spin_is_contended arch_spin_is_contended
-
+#include <asm/ticket-lock.h>
#include <asm/qrwlock.h>
#endif /* __ASM_CSKY_SPINLOCK_H */
diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
index db87a12c3827..0bb7f6022a3b 100644
--- a/arch/csky/include/asm/spinlock_types.h
+++ b/arch/csky/include/asm/spinlock_types.h
@@ -3,25 +3,7 @@
#ifndef __ASM_CSKY_SPINLOCK_TYPES_H
#define __ASM_CSKY_SPINLOCK_TYPES_H
-#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
-# error "please don't include this file directly"
-#endif
-
-#define TICKET_NEXT 16
-
-typedef struct {
- union {
- u32 lock;
- struct __raw_tickets {
- /* little endian */
- u16 owner;
- u16 next;
- } tickets;
- };
-} arch_spinlock_t;
-
-#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
-
+#include <asm/ticket-lock-types.h>
#include <asm-generic/qrwlock_types.h>
#endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] csky: Move to generic ticket-spinlock
2022-03-18 8:34 [PATCH] csky: Move to generic ticket-spinlock guoren
@ 2022-03-18 10:57 ` Arnd Bergmann
2022-03-19 3:58 ` Guo Ren
2022-03-18 22:48 ` Palmer Dabbelt
1 sibling, 1 reply; 6+ messages in thread
From: Arnd Bergmann @ 2022-03-18 10:57 UTC (permalink / raw)
To: Guo Ren
Cc: Palmer Dabbelt, linux-csky, linux-arch,
Linux Kernel Mailing List, Guo Ren
On Fri, Mar 18, 2022 at 9:34 AM <guoren@kernel.org> wrote:
> @@ -3,6 +3,8 @@ generic-y += asm-offsets.h
> generic-y += extable.h
> generic-y += gpio.h
> generic-y += kvm_para.h
> +generic-y += ticket-lock.h
> +generic-y += ticket-lock-types.h
> generic-y += qrwlock.h
> generic-y += user.h
> generic-y += vmlinux.lds.h
If these headers are not included from architecture-independent code,
they should
not be marked as generic-y, same as for the qrwlock.h header
> +#include <asm/ticket-lock.h>
> #include <asm/qrwlock.h>
>
> ...
> +#include <asm/ticket-lock-types.h>
> #include <asm-generic/qrwlock_types.h>
>
So these should all become
#include <asm-generic/...h>
It would however make sense to have the trivial two-line version
of the two header files and put them into asm-generic/spinlock.h
and asm-generic/spinlock-types.h, replacing the current version.
If you do that, then you need a 'generic-y' line for spinlock.h,
but not for the other ones.
Arnd
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] csky: Move to generic ticket-spinlock
2022-03-18 8:34 [PATCH] csky: Move to generic ticket-spinlock guoren
2022-03-18 10:57 ` Arnd Bergmann
@ 2022-03-18 22:48 ` Palmer Dabbelt
2022-03-19 4:01 ` Guo Ren
1 sibling, 1 reply; 6+ messages in thread
From: Palmer Dabbelt @ 2022-03-18 22:48 UTC (permalink / raw)
To: guoren; +Cc: linux-csky, linux-arch, linux-kernel, guoren
On Fri, 18 Mar 2022 01:34:21 PDT (-0700), guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> There is no benefit from custom implementation for ticket-spinlock,
> so move to generic ticket-spinlock for easy maintenance.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Cc: Palmer Dabbelt <palmer@rivosinc.com>
Thanks, one less port to look at ;)
Looks like there were a few comments on the v1, and I wasn't going to
target this at the upcoming merge window anyway because I wanted to give
the various RISC-V vendors time to test stuff. LMK if you want me to
add this to the others, but I was planning on posting a stable tag
either way so no big deal on my end.
> ---
> arch/csky/include/asm/Kbuild | 2 +
> arch/csky/include/asm/spinlock.h | 82 +-------------------------
> arch/csky/include/asm/spinlock_types.h | 20 +------
> 3 files changed, 4 insertions(+), 100 deletions(-)
>
> diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
> index 904a18a818be..d94434288c31 100644
> --- a/arch/csky/include/asm/Kbuild
> +++ b/arch/csky/include/asm/Kbuild
> @@ -3,6 +3,8 @@ generic-y += asm-offsets.h
> generic-y += extable.h
> generic-y += gpio.h
> generic-y += kvm_para.h
> +generic-y += ticket-lock.h
> +generic-y += ticket-lock-types.h
> generic-y += qrwlock.h
> generic-y += user.h
> generic-y += vmlinux.lds.h
> diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
> index 69f5aa249c5f..8bc179ba0d8d 100644
> --- a/arch/csky/include/asm/spinlock.h
> +++ b/arch/csky/include/asm/spinlock.h
> @@ -3,87 +3,7 @@
> #ifndef __ASM_CSKY_SPINLOCK_H
> #define __ASM_CSKY_SPINLOCK_H
>
> -#include <linux/spinlock_types.h>
> -#include <asm/barrier.h>
> -
> -/*
> - * Ticket-based spin-locking.
> - */
> -static inline void arch_spin_lock(arch_spinlock_t *lock)
> -{
> - arch_spinlock_t lockval;
> - u32 ticket_next = 1 << TICKET_NEXT;
> - u32 *p = &lock->lock;
> - u32 tmp;
> -
> - asm volatile (
> - "1: ldex.w %0, (%2) \n"
> - " mov %1, %0 \n"
> - " add %0, %3 \n"
> - " stex.w %0, (%2) \n"
> - " bez %0, 1b \n"
> - : "=&r" (tmp), "=&r" (lockval)
> - : "r"(p), "r"(ticket_next)
> - : "cc");
> -
> - while (lockval.tickets.next != lockval.tickets.owner)
> - lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
> -
> - smp_mb();
> -}
> -
> -static inline int arch_spin_trylock(arch_spinlock_t *lock)
> -{
> - u32 tmp, contended, res;
> - u32 ticket_next = 1 << TICKET_NEXT;
> - u32 *p = &lock->lock;
> -
> - do {
> - asm volatile (
> - " ldex.w %0, (%3) \n"
> - " movi %2, 1 \n"
> - " rotli %1, %0, 16 \n"
> - " cmpne %1, %0 \n"
> - " bt 1f \n"
> - " movi %2, 0 \n"
> - " add %0, %0, %4 \n"
> - " stex.w %0, (%3) \n"
> - "1: \n"
> - : "=&r" (res), "=&r" (tmp), "=&r" (contended)
> - : "r"(p), "r"(ticket_next)
> - : "cc");
> - } while (!res);
> -
> - if (!contended)
> - smp_mb();
> -
> - return !contended;
> -}
> -
> -static inline void arch_spin_unlock(arch_spinlock_t *lock)
> -{
> - smp_mb();
> - WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
> -}
> -
> -static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
> -{
> - return lock.tickets.owner == lock.tickets.next;
> -}
> -
> -static inline int arch_spin_is_locked(arch_spinlock_t *lock)
> -{
> - return !arch_spin_value_unlocked(READ_ONCE(*lock));
> -}
> -
> -static inline int arch_spin_is_contended(arch_spinlock_t *lock)
> -{
> - struct __raw_tickets tickets = READ_ONCE(lock->tickets);
> -
> - return (tickets.next - tickets.owner) > 1;
> -}
> -#define arch_spin_is_contended arch_spin_is_contended
> -
> +#include <asm/ticket-lock.h>
> #include <asm/qrwlock.h>
>
> #endif /* __ASM_CSKY_SPINLOCK_H */
> diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
> index db87a12c3827..0bb7f6022a3b 100644
> --- a/arch/csky/include/asm/spinlock_types.h
> +++ b/arch/csky/include/asm/spinlock_types.h
> @@ -3,25 +3,7 @@
> #ifndef __ASM_CSKY_SPINLOCK_TYPES_H
> #define __ASM_CSKY_SPINLOCK_TYPES_H
>
> -#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
> -# error "please don't include this file directly"
> -#endif
> -
> -#define TICKET_NEXT 16
> -
> -typedef struct {
> - union {
> - u32 lock;
> - struct __raw_tickets {
> - /* little endian */
> - u16 owner;
> - u16 next;
> - } tickets;
> - };
> -} arch_spinlock_t;
> -
> -#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
> -
> +#include <asm/ticket-lock-types.h>
> #include <asm-generic/qrwlock_types.h>
>
> #endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] csky: Move to generic ticket-spinlock
2022-03-18 10:57 ` Arnd Bergmann
@ 2022-03-19 3:58 ` Guo Ren
0 siblings, 0 replies; 6+ messages in thread
From: Guo Ren @ 2022-03-19 3:58 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Palmer Dabbelt, linux-csky, linux-arch,
Linux Kernel Mailing List, Guo Ren
Hi Arnd,
On Fri, Mar 18, 2022 at 6:58 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, Mar 18, 2022 at 9:34 AM <guoren@kernel.org> wrote:
> > @@ -3,6 +3,8 @@ generic-y += asm-offsets.h
> > generic-y += extable.h
> > generic-y += gpio.h
> > generic-y += kvm_para.h
> > +generic-y += ticket-lock.h
> > +generic-y += ticket-lock-types.h
> > generic-y += qrwlock.h
> > generic-y += user.h
> > generic-y += vmlinux.lds.h
>
> If these headers are not included from architecture-independent code,
> they should
> not be marked as generic-y, same as for the qrwlock.h header
>
> > +#include <asm/ticket-lock.h>
> > #include <asm/qrwlock.h>
> >
> > ...
> > +#include <asm/ticket-lock-types.h>
> > #include <asm-generic/qrwlock_types.h>
> >
>
> So these should all become
>
> #include <asm-generic/...h>
>
> It would however make sense to have the trivial two-line version
> of the two header files and put them into asm-generic/spinlock.h
> and asm-generic/spinlock-types.h, replacing the current version.
>
> If you do that, then you need a 'generic-y' line for spinlock.h,
> but not for the other ones.
Thx for the suggestion, I've sent V2 based on Palmer's series to make
the ticket spinlock more generic.
Please have a look:
https://lore.kernel.org/linux-arch/20220319035457.2214979-1-guoren@kernel.org/T/#t
>
> Arnd
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] csky: Move to generic ticket-spinlock
2022-03-18 22:48 ` Palmer Dabbelt
@ 2022-03-19 4:01 ` Guo Ren
2022-03-22 17:48 ` Palmer Dabbelt
0 siblings, 1 reply; 6+ messages in thread
From: Guo Ren @ 2022-03-19 4:01 UTC (permalink / raw)
To: Palmer Dabbelt; +Cc: linux-csky, linux-arch, Linux Kernel Mailing List, Guo Ren
Hi Palmer,
On Sat, Mar 19, 2022 at 6:48 AM Palmer Dabbelt <palmer@rivosinc.com> wrote:
>
> On Fri, 18 Mar 2022 01:34:21 PDT (-0700), guoren@kernel.org wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > There is no benefit from custom implementation for ticket-spinlock,
> > so move to generic ticket-spinlock for easy maintenance.
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Cc: Palmer Dabbelt <palmer@rivosinc.com>
>
> Thanks, one less port to look at ;)
>
> Looks like there were a few comments on the v1, and I wasn't going to
> target this at the upcoming merge window anyway because I wanted to give
Agree, we needn't so hurry.
> the various RISC-V vendors time to test stuff. LMK if you want me to
> add this to the others, but I was planning on posting a stable tag
> either way so no big deal on my end.
Yes, I hope csky's could be in the series. And I updated V2 with
Arnd's suggestion, please have a look:
https://lore.kernel.org/linux-arch/20220319035457.2214979-1-guoren@kernel.org/T/#t
>
> > ---
> > arch/csky/include/asm/Kbuild | 2 +
> > arch/csky/include/asm/spinlock.h | 82 +-------------------------
> > arch/csky/include/asm/spinlock_types.h | 20 +------
> > 3 files changed, 4 insertions(+), 100 deletions(-)
> >
> > diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
> > index 904a18a818be..d94434288c31 100644
> > --- a/arch/csky/include/asm/Kbuild
> > +++ b/arch/csky/include/asm/Kbuild
> > @@ -3,6 +3,8 @@ generic-y += asm-offsets.h
> > generic-y += extable.h
> > generic-y += gpio.h
> > generic-y += kvm_para.h
> > +generic-y += ticket-lock.h
> > +generic-y += ticket-lock-types.h
> > generic-y += qrwlock.h
> > generic-y += user.h
> > generic-y += vmlinux.lds.h
> > diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
> > index 69f5aa249c5f..8bc179ba0d8d 100644
> > --- a/arch/csky/include/asm/spinlock.h
> > +++ b/arch/csky/include/asm/spinlock.h
> > @@ -3,87 +3,7 @@
> > #ifndef __ASM_CSKY_SPINLOCK_H
> > #define __ASM_CSKY_SPINLOCK_H
> >
> > -#include <linux/spinlock_types.h>
> > -#include <asm/barrier.h>
> > -
> > -/*
> > - * Ticket-based spin-locking.
> > - */
> > -static inline void arch_spin_lock(arch_spinlock_t *lock)
> > -{
> > - arch_spinlock_t lockval;
> > - u32 ticket_next = 1 << TICKET_NEXT;
> > - u32 *p = &lock->lock;
> > - u32 tmp;
> > -
> > - asm volatile (
> > - "1: ldex.w %0, (%2) \n"
> > - " mov %1, %0 \n"
> > - " add %0, %3 \n"
> > - " stex.w %0, (%2) \n"
> > - " bez %0, 1b \n"
> > - : "=&r" (tmp), "=&r" (lockval)
> > - : "r"(p), "r"(ticket_next)
> > - : "cc");
> > -
> > - while (lockval.tickets.next != lockval.tickets.owner)
> > - lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
> > -
> > - smp_mb();
> > -}
> > -
> > -static inline int arch_spin_trylock(arch_spinlock_t *lock)
> > -{
> > - u32 tmp, contended, res;
> > - u32 ticket_next = 1 << TICKET_NEXT;
> > - u32 *p = &lock->lock;
> > -
> > - do {
> > - asm volatile (
> > - " ldex.w %0, (%3) \n"
> > - " movi %2, 1 \n"
> > - " rotli %1, %0, 16 \n"
> > - " cmpne %1, %0 \n"
> > - " bt 1f \n"
> > - " movi %2, 0 \n"
> > - " add %0, %0, %4 \n"
> > - " stex.w %0, (%3) \n"
> > - "1: \n"
> > - : "=&r" (res), "=&r" (tmp), "=&r" (contended)
> > - : "r"(p), "r"(ticket_next)
> > - : "cc");
> > - } while (!res);
> > -
> > - if (!contended)
> > - smp_mb();
> > -
> > - return !contended;
> > -}
> > -
> > -static inline void arch_spin_unlock(arch_spinlock_t *lock)
> > -{
> > - smp_mb();
> > - WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
> > -}
> > -
> > -static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
> > -{
> > - return lock.tickets.owner == lock.tickets.next;
> > -}
> > -
> > -static inline int arch_spin_is_locked(arch_spinlock_t *lock)
> > -{
> > - return !arch_spin_value_unlocked(READ_ONCE(*lock));
> > -}
> > -
> > -static inline int arch_spin_is_contended(arch_spinlock_t *lock)
> > -{
> > - struct __raw_tickets tickets = READ_ONCE(lock->tickets);
> > -
> > - return (tickets.next - tickets.owner) > 1;
> > -}
> > -#define arch_spin_is_contended arch_spin_is_contended
> > -
> > +#include <asm/ticket-lock.h>
> > #include <asm/qrwlock.h>
> >
> > #endif /* __ASM_CSKY_SPINLOCK_H */
> > diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
> > index db87a12c3827..0bb7f6022a3b 100644
> > --- a/arch/csky/include/asm/spinlock_types.h
> > +++ b/arch/csky/include/asm/spinlock_types.h
> > @@ -3,25 +3,7 @@
> > #ifndef __ASM_CSKY_SPINLOCK_TYPES_H
> > #define __ASM_CSKY_SPINLOCK_TYPES_H
> >
> > -#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
> > -# error "please don't include this file directly"
> > -#endif
> > -
> > -#define TICKET_NEXT 16
> > -
> > -typedef struct {
> > - union {
> > - u32 lock;
> > - struct __raw_tickets {
> > - /* little endian */
> > - u16 owner;
> > - u16 next;
> > - } tickets;
> > - };
> > -} arch_spinlock_t;
> > -
> > -#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
> > -
> > +#include <asm/ticket-lock-types.h>
> > #include <asm-generic/qrwlock_types.h>
> >
> > #endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] csky: Move to generic ticket-spinlock
2022-03-19 4:01 ` Guo Ren
@ 2022-03-22 17:48 ` Palmer Dabbelt
0 siblings, 0 replies; 6+ messages in thread
From: Palmer Dabbelt @ 2022-03-22 17:48 UTC (permalink / raw)
To: guoren; +Cc: linux-csky, linux-arch, linux-kernel, guoren
On Fri, 18 Mar 2022 21:01:49 PDT (-0700), guoren@kernel.org wrote:
> Hi Palmer,
>
> On Sat, Mar 19, 2022 at 6:48 AM Palmer Dabbelt <palmer@rivosinc.com> wrote:
>>
>> On Fri, 18 Mar 2022 01:34:21 PDT (-0700), guoren@kernel.org wrote:
>> > From: Guo Ren <guoren@linux.alibaba.com>
>> >
>> > There is no benefit from custom implementation for ticket-spinlock,
>> > so move to generic ticket-spinlock for easy maintenance.
>> >
>> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
>> > Cc: Palmer Dabbelt <palmer@rivosinc.com>
>>
>> Thanks, one less port to look at ;)
>>
>> Looks like there were a few comments on the v1, and I wasn't going to
>> target this at the upcoming merge window anyway because I wanted to give
> Agree, we needn't so hurry.
>
>> the various RISC-V vendors time to test stuff. LMK if you want me to
>> add this to the others, but I was planning on posting a stable tag
>> either way so no big deal on my end.
> Yes, I hope csky's could be in the series. And I updated V2 with
> Arnd's suggestion, please have a look:
> https://lore.kernel.org/linux-arch/20220319035457.2214979-1-guoren@kernel.org/T/#t
Thanks, I'll include the csky stuff next time I re-spin this.
Looks like there's been some other comments from folks that didn't make
your v2, most notably the SOB lines which makes this a bit funny. I'm
also not sure I like merging the two RISC-V patches together, as they'd
be nice to be able to test on their own.
I'll go poke around with this some once I'm a bit father into the merge
window. I think we can both keep Arnd's generic header idea and let
folks mix/match spin/rw lock flavors, which might also help with some of
the other ports.
>
>>
>> > ---
>> > arch/csky/include/asm/Kbuild | 2 +
>> > arch/csky/include/asm/spinlock.h | 82 +-------------------------
>> > arch/csky/include/asm/spinlock_types.h | 20 +------
>> > 3 files changed, 4 insertions(+), 100 deletions(-)
>> >
>> > diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
>> > index 904a18a818be..d94434288c31 100644
>> > --- a/arch/csky/include/asm/Kbuild
>> > +++ b/arch/csky/include/asm/Kbuild
>> > @@ -3,6 +3,8 @@ generic-y += asm-offsets.h
>> > generic-y += extable.h
>> > generic-y += gpio.h
>> > generic-y += kvm_para.h
>> > +generic-y += ticket-lock.h
>> > +generic-y += ticket-lock-types.h
>> > generic-y += qrwlock.h
>> > generic-y += user.h
>> > generic-y += vmlinux.lds.h
>> > diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
>> > index 69f5aa249c5f..8bc179ba0d8d 100644
>> > --- a/arch/csky/include/asm/spinlock.h
>> > +++ b/arch/csky/include/asm/spinlock.h
>> > @@ -3,87 +3,7 @@
>> > #ifndef __ASM_CSKY_SPINLOCK_H
>> > #define __ASM_CSKY_SPINLOCK_H
>> >
>> > -#include <linux/spinlock_types.h>
>> > -#include <asm/barrier.h>
>> > -
>> > -/*
>> > - * Ticket-based spin-locking.
>> > - */
>> > -static inline void arch_spin_lock(arch_spinlock_t *lock)
>> > -{
>> > - arch_spinlock_t lockval;
>> > - u32 ticket_next = 1 << TICKET_NEXT;
>> > - u32 *p = &lock->lock;
>> > - u32 tmp;
>> > -
>> > - asm volatile (
>> > - "1: ldex.w %0, (%2) \n"
>> > - " mov %1, %0 \n"
>> > - " add %0, %3 \n"
>> > - " stex.w %0, (%2) \n"
>> > - " bez %0, 1b \n"
>> > - : "=&r" (tmp), "=&r" (lockval)
>> > - : "r"(p), "r"(ticket_next)
>> > - : "cc");
>> > -
>> > - while (lockval.tickets.next != lockval.tickets.owner)
>> > - lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
>> > -
>> > - smp_mb();
>> > -}
>> > -
>> > -static inline int arch_spin_trylock(arch_spinlock_t *lock)
>> > -{
>> > - u32 tmp, contended, res;
>> > - u32 ticket_next = 1 << TICKET_NEXT;
>> > - u32 *p = &lock->lock;
>> > -
>> > - do {
>> > - asm volatile (
>> > - " ldex.w %0, (%3) \n"
>> > - " movi %2, 1 \n"
>> > - " rotli %1, %0, 16 \n"
>> > - " cmpne %1, %0 \n"
>> > - " bt 1f \n"
>> > - " movi %2, 0 \n"
>> > - " add %0, %0, %4 \n"
>> > - " stex.w %0, (%3) \n"
>> > - "1: \n"
>> > - : "=&r" (res), "=&r" (tmp), "=&r" (contended)
>> > - : "r"(p), "r"(ticket_next)
>> > - : "cc");
>> > - } while (!res);
>> > -
>> > - if (!contended)
>> > - smp_mb();
>> > -
>> > - return !contended;
>> > -}
>> > -
>> > -static inline void arch_spin_unlock(arch_spinlock_t *lock)
>> > -{
>> > - smp_mb();
>> > - WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
>> > -}
>> > -
>> > -static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
>> > -{
>> > - return lock.tickets.owner == lock.tickets.next;
>> > -}
>> > -
>> > -static inline int arch_spin_is_locked(arch_spinlock_t *lock)
>> > -{
>> > - return !arch_spin_value_unlocked(READ_ONCE(*lock));
>> > -}
>> > -
>> > -static inline int arch_spin_is_contended(arch_spinlock_t *lock)
>> > -{
>> > - struct __raw_tickets tickets = READ_ONCE(lock->tickets);
>> > -
>> > - return (tickets.next - tickets.owner) > 1;
>> > -}
>> > -#define arch_spin_is_contended arch_spin_is_contended
>> > -
>> > +#include <asm/ticket-lock.h>
>> > #include <asm/qrwlock.h>
>> >
>> > #endif /* __ASM_CSKY_SPINLOCK_H */
>> > diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
>> > index db87a12c3827..0bb7f6022a3b 100644
>> > --- a/arch/csky/include/asm/spinlock_types.h
>> > +++ b/arch/csky/include/asm/spinlock_types.h
>> > @@ -3,25 +3,7 @@
>> > #ifndef __ASM_CSKY_SPINLOCK_TYPES_H
>> > #define __ASM_CSKY_SPINLOCK_TYPES_H
>> >
>> > -#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
>> > -# error "please don't include this file directly"
>> > -#endif
>> > -
>> > -#define TICKET_NEXT 16
>> > -
>> > -typedef struct {
>> > - union {
>> > - u32 lock;
>> > - struct __raw_tickets {
>> > - /* little endian */
>> > - u16 owner;
>> > - u16 next;
>> > - } tickets;
>> > - };
>> > -} arch_spinlock_t;
>> > -
>> > -#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
>> > -
>> > +#include <asm/ticket-lock-types.h>
>> > #include <asm-generic/qrwlock_types.h>
>> >
>> > #endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-03-22 17:48 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-18 8:34 [PATCH] csky: Move to generic ticket-spinlock guoren
2022-03-18 10:57 ` Arnd Bergmann
2022-03-19 3:58 ` Guo Ren
2022-03-18 22:48 ` Palmer Dabbelt
2022-03-19 4:01 ` Guo Ren
2022-03-22 17:48 ` Palmer Dabbelt
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