* [PATCH 0/2] make asm-generic/futex.h usable for more arch ports
@ 2016-10-10 0:03 Joel Porquet
2016-10-10 0:03 ` Joel Porquet
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw)
To: arnd, linux; +Cc: linux-arch, Joel Porquet, linux-kernel, linux-arm-kernel
Hi all,
I've had a patch on my shelf for a couple of years, from when I ported Linux on
a new processor architecture for an academic project, and thought I could send
it and let you decide if it's worth taking or not.
During my port, I basically modified the generic header "asm-generic/futex.h"
and made it into a more generic version so that I could include it in my code
and only redefine the necessary arch-specific bits.
Right now, most of the arch ports redefine their own "asm/futex.h" completely
although, for example for "futex_atomic_op_inuser()", they often share the exact
same preamble and epilogue and could benefit from some code refactoring.
My (short) series is made of two patches: 1/ refactoring "asm-generic/futex.h"
in order to make the arch-specific routines into overload-able macros that arch
ports can redefine when required, 2/ an example of how to use this refactoring
with the ARM port.
Let me know what you think.
Cheers,
Joël
Joel Porquet (2):
asm-generic/futex.h: code refactoring
arm: futex: Use asm-generic/futex.h instead of redefining the entire
header
arch/arm/include/asm/futex.h | 203 +++++++++++++++++----------------------
include/asm-generic/futex.h | 219 ++++++++++++++++++++++---------------------
2 files changed, 196 insertions(+), 226 deletions(-)
--
2.10.0
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^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 0/2] make asm-generic/futex.h usable for more arch ports 2016-10-10 0:03 [PATCH 0/2] make asm-generic/futex.h usable for more arch ports Joel Porquet @ 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` [PATCH 1/2] asm-generic/futex.h: code refactoring Joel Porquet 2016-10-10 0:03 ` [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header Joel Porquet 2 siblings, 0 replies; 6+ messages in thread From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw) To: arnd, linux; +Cc: linux-kernel, linux-arch, linux-arm-kernel, Joel Porquet Hi all, I've had a patch on my shelf for a couple of years, from when I ported Linux on a new processor architecture for an academic project, and thought I could send it and let you decide if it's worth taking or not. During my port, I basically modified the generic header "asm-generic/futex.h" and made it into a more generic version so that I could include it in my code and only redefine the necessary arch-specific bits. Right now, most of the arch ports redefine their own "asm/futex.h" completely although, for example for "futex_atomic_op_inuser()", they often share the exact same preamble and epilogue and could benefit from some code refactoring. My (short) series is made of two patches: 1/ refactoring "asm-generic/futex.h" in order to make the arch-specific routines into overload-able macros that arch ports can redefine when required, 2/ an example of how to use this refactoring with the ARM port. Let me know what you think. Cheers, Joël Joel Porquet (2): asm-generic/futex.h: code refactoring arm: futex: Use asm-generic/futex.h instead of redefining the entire header arch/arm/include/asm/futex.h | 203 +++++++++++++++++---------------------- include/asm-generic/futex.h | 219 ++++++++++++++++++++++--------------------- 2 files changed, 196 insertions(+), 226 deletions(-) -- 2.10.0 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/2] asm-generic/futex.h: code refactoring 2016-10-10 0:03 [PATCH 0/2] make asm-generic/futex.h usable for more arch ports Joel Porquet 2016-10-10 0:03 ` Joel Porquet @ 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header Joel Porquet 2 siblings, 1 reply; 6+ messages in thread From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw) To: arnd, linux; +Cc: linux-arch, Joel Porquet, linux-kernel, linux-arm-kernel The generic header "asm-generic/futex.h" defines the implementations of atomic functions "futex_atomic_op_inuser()" and "futex_atomic_cmpxchg_inatomic()". Currently, each of these functions is actually defined twice: once for uniprocessor machines and once for multiprocessor machines. However, these {smp,!smp} implementations, especially for "futex_atomic_op_inuser()", have some code in common that could be refactored. Furthermore, most the arch ports usually redefine their own "asm/futex.h" header completely, instead of using the generic header even though a good chunk of the code is shared (once again, especially for 'futex_atomic_op_inuser()'). This patch refactors the uniprocessor and multiprocessor implementations of both functions into a single implementation, making the machine-specific part a customizable macro. As a (hopefully good) side-effect, this makes it possible for arch ports to start including this generic header, instead of redefining it completely, and only overload the macros with arch-specific routines. Signed-off-by: Joel Porquet <joel@porquet.org> --- include/asm-generic/futex.h | 219 ++++++++++++++++++++++---------------------- 1 file changed, 112 insertions(+), 107 deletions(-) diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h index bf2d34c..a72b36b 100644 --- a/include/asm-generic/futex.h +++ b/include/asm-generic/futex.h @@ -6,12 +6,114 @@ #include <asm/errno.h> #ifndef CONFIG_SMP + /* - * The following implementation only for uniprocessor machines. - * It relies on preempt_disable() ensuring mutual exclusion. - * + * The following implementations are for uniprocessor machines. + * They rely on preempt_disable() to ensure mutual exclusion. */ +#ifndef __futex_atomic_op_inuser +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret; \ + u32 tmp; \ + \ + preempt_disable(); \ + pagefault_disable(); \ + \ + __ret = -EFAULT; \ + if (unlikely(get_user(oldval, uaddr) != 0)) \ + goto out_pagefault_enable; \ + \ + __ret = 0; \ + tmp = oldval; \ + \ + switch (op) { \ + case FUTEX_OP_SET: \ + tmp = oparg; \ + break; \ + case FUTEX_OP_ADD: \ + tmp += oparg; \ + break; \ + case FUTEX_OP_OR: \ + tmp |= oparg; \ + break; \ + case FUTEX_OP_ANDN: \ + tmp &= ~oparg; \ + break; \ + case FUTEX_OP_XOR: \ + tmp ^= oparg; \ + break; \ + default: \ + __ret = -ENOSYS; \ + } \ + \ + if (__ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ +out_pagefault_enable: \ + pagefault_enable(); \ + preempt_enable(); \ + \ + __ret; \ +}) +#endif + +#ifndef __futex_atomic_cmpxchg_inatomic +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret = 0; \ + u32 tmp; \ + \ + preempt_disable(); \ + if (unlikely(get_user(tmp, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ + if (__ret == 0 && tmp == oldval && \ + unlikely(put_user(newval, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ + *uval = tmp; \ + preempt_enable(); \ + \ + __ret; \ +}) +#endif + +#else + +/* + * For multiprocessor machines, these macro should be overloaded with + * implementations based on arch-specific atomic instructions to ensure proper + * mutual exclusion + */ +#ifndef __futex_atomic_op_inuser +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret; \ + switch (op) { \ + case FUTEX_OP_SET: \ + case FUTEX_OP_ADD: \ + case FUTEX_OP_OR: \ + case FUTEX_OP_ANDN: \ + case FUTEX_OP_XOR: \ + default: \ + __ret = -ENOSYS; \ + } \ + __ret; \ +}) +#endif + +#ifndef __futex_atomic_cmpxchg_inatomic +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret = -ENOSYS; \ + __ret; \ +}) +#endif + +#endif + /** * futex_atomic_op_inuser() - Atomic arithmetic operation with constant * argument and comparison of the previous @@ -31,48 +133,15 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; - int oldval, ret; - u32 tmp; + int oldval = 0, ret; if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; - preempt_disable(); - pagefault_disable(); + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; - ret = -EFAULT; - if (unlikely(get_user(oldval, uaddr) != 0)) - goto out_pagefault_enable; - - ret = 0; - tmp = oldval; - - switch (op) { - case FUTEX_OP_SET: - tmp = oparg; - break; - case FUTEX_OP_ADD: - tmp += oparg; - break; - case FUTEX_OP_OR: - tmp |= oparg; - break; - case FUTEX_OP_ANDN: - tmp &= ~oparg; - break; - case FUTEX_OP_XOR: - tmp ^= oparg; - break; - default: - ret = -ENOSYS; - } - - if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) - ret = -EFAULT; - -out_pagefault_enable: - pagefault_enable(); - preempt_enable(); + ret = __futex_atomic_op_inuser(op, oldval, uaddr, oparg); if (ret == 0) { switch (cmp) { @@ -103,76 +172,12 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) */ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) + u32 oldval, u32 newval) { - u32 val; - - preempt_disable(); - if (unlikely(get_user(val, uaddr) != 0)) { - preempt_enable(); - return -EFAULT; - } - - if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { - preempt_enable(); - return -EFAULT; - } - - *uval = val; - preempt_enable(); - - return 0; -} - -#else -static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) -{ - int op = (encoded_op >> 28) & 7; - int cmp = (encoded_op >> 24) & 15; - int oparg = (encoded_op << 8) >> 20; - int cmparg = (encoded_op << 20) >> 20; - int oldval = 0, ret; - if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) - oparg = 1 << oparg; - - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; - pagefault_disable(); - - switch (op) { - case FUTEX_OP_SET: - case FUTEX_OP_ADD: - case FUTEX_OP_OR: - case FUTEX_OP_ANDN: - case FUTEX_OP_XOR: - default: - ret = -ENOSYS; - } - - pagefault_enable(); - - if (!ret) { - switch (cmp) { - case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; - case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; - case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; - case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; - case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; - case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; - default: ret = -ENOSYS; - } - } - return ret; -} - -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - return -ENOSYS; + return __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval); } -#endif /* CONFIG_SMP */ #endif -- 2.10.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 1/2] asm-generic/futex.h: code refactoring 2016-10-10 0:03 ` [PATCH 1/2] asm-generic/futex.h: code refactoring Joel Porquet @ 2016-10-10 0:03 ` Joel Porquet 0 siblings, 0 replies; 6+ messages in thread From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw) To: arnd, linux; +Cc: linux-kernel, linux-arch, linux-arm-kernel, Joel Porquet The generic header "asm-generic/futex.h" defines the implementations of atomic functions "futex_atomic_op_inuser()" and "futex_atomic_cmpxchg_inatomic()". Currently, each of these functions is actually defined twice: once for uniprocessor machines and once for multiprocessor machines. However, these {smp,!smp} implementations, especially for "futex_atomic_op_inuser()", have some code in common that could be refactored. Furthermore, most the arch ports usually redefine their own "asm/futex.h" header completely, instead of using the generic header even though a good chunk of the code is shared (once again, especially for 'futex_atomic_op_inuser()'). This patch refactors the uniprocessor and multiprocessor implementations of both functions into a single implementation, making the machine-specific part a customizable macro. As a (hopefully good) side-effect, this makes it possible for arch ports to start including this generic header, instead of redefining it completely, and only overload the macros with arch-specific routines. Signed-off-by: Joel Porquet <joel@porquet.org> --- include/asm-generic/futex.h | 219 ++++++++++++++++++++++---------------------- 1 file changed, 112 insertions(+), 107 deletions(-) diff --git a/include/asm-generic/futex.h b/include/asm-generic/futex.h index bf2d34c..a72b36b 100644 --- a/include/asm-generic/futex.h +++ b/include/asm-generic/futex.h @@ -6,12 +6,114 @@ #include <asm/errno.h> #ifndef CONFIG_SMP + /* - * The following implementation only for uniprocessor machines. - * It relies on preempt_disable() ensuring mutual exclusion. - * + * The following implementations are for uniprocessor machines. + * They rely on preempt_disable() to ensure mutual exclusion. */ +#ifndef __futex_atomic_op_inuser +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret; \ + u32 tmp; \ + \ + preempt_disable(); \ + pagefault_disable(); \ + \ + __ret = -EFAULT; \ + if (unlikely(get_user(oldval, uaddr) != 0)) \ + goto out_pagefault_enable; \ + \ + __ret = 0; \ + tmp = oldval; \ + \ + switch (op) { \ + case FUTEX_OP_SET: \ + tmp = oparg; \ + break; \ + case FUTEX_OP_ADD: \ + tmp += oparg; \ + break; \ + case FUTEX_OP_OR: \ + tmp |= oparg; \ + break; \ + case FUTEX_OP_ANDN: \ + tmp &= ~oparg; \ + break; \ + case FUTEX_OP_XOR: \ + tmp ^= oparg; \ + break; \ + default: \ + __ret = -ENOSYS; \ + } \ + \ + if (__ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ +out_pagefault_enable: \ + pagefault_enable(); \ + preempt_enable(); \ + \ + __ret; \ +}) +#endif + +#ifndef __futex_atomic_cmpxchg_inatomic +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret = 0; \ + u32 tmp; \ + \ + preempt_disable(); \ + if (unlikely(get_user(tmp, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ + if (__ret == 0 && tmp == oldval && \ + unlikely(put_user(newval, uaddr) != 0)) \ + __ret = -EFAULT; \ + \ + *uval = tmp; \ + preempt_enable(); \ + \ + __ret; \ +}) +#endif + +#else + +/* + * For multiprocessor machines, these macro should be overloaded with + * implementations based on arch-specific atomic instructions to ensure proper + * mutual exclusion + */ +#ifndef __futex_atomic_op_inuser +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret; \ + switch (op) { \ + case FUTEX_OP_SET: \ + case FUTEX_OP_ADD: \ + case FUTEX_OP_OR: \ + case FUTEX_OP_ANDN: \ + case FUTEX_OP_XOR: \ + default: \ + __ret = -ENOSYS; \ + } \ + __ret; \ +}) +#endif + +#ifndef __futex_atomic_cmpxchg_inatomic +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret = -ENOSYS; \ + __ret; \ +}) +#endif + +#endif + /** * futex_atomic_op_inuser() - Atomic arithmetic operation with constant * argument and comparison of the previous @@ -31,48 +133,15 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; - int oldval, ret; - u32 tmp; + int oldval = 0, ret; if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; - preempt_disable(); - pagefault_disable(); + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; - ret = -EFAULT; - if (unlikely(get_user(oldval, uaddr) != 0)) - goto out_pagefault_enable; - - ret = 0; - tmp = oldval; - - switch (op) { - case FUTEX_OP_SET: - tmp = oparg; - break; - case FUTEX_OP_ADD: - tmp += oparg; - break; - case FUTEX_OP_OR: - tmp |= oparg; - break; - case FUTEX_OP_ANDN: - tmp &= ~oparg; - break; - case FUTEX_OP_XOR: - tmp ^= oparg; - break; - default: - ret = -ENOSYS; - } - - if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0)) - ret = -EFAULT; - -out_pagefault_enable: - pagefault_enable(); - preempt_enable(); + ret = __futex_atomic_op_inuser(op, oldval, uaddr, oparg); if (ret == 0) { switch (cmp) { @@ -103,76 +172,12 @@ futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) */ static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) + u32 oldval, u32 newval) { - u32 val; - - preempt_disable(); - if (unlikely(get_user(val, uaddr) != 0)) { - preempt_enable(); - return -EFAULT; - } - - if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { - preempt_enable(); - return -EFAULT; - } - - *uval = val; - preempt_enable(); - - return 0; -} - -#else -static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) -{ - int op = (encoded_op >> 28) & 7; - int cmp = (encoded_op >> 24) & 15; - int oparg = (encoded_op << 8) >> 20; - int cmparg = (encoded_op << 20) >> 20; - int oldval = 0, ret; - if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) - oparg = 1 << oparg; - - if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; - pagefault_disable(); - - switch (op) { - case FUTEX_OP_SET: - case FUTEX_OP_ADD: - case FUTEX_OP_OR: - case FUTEX_OP_ANDN: - case FUTEX_OP_XOR: - default: - ret = -ENOSYS; - } - - pagefault_enable(); - - if (!ret) { - switch (cmp) { - case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; - case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; - case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; - case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; - case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; - case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; - default: ret = -ENOSYS; - } - } - return ret; -} - -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - return -ENOSYS; + return __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval); } -#endif /* CONFIG_SMP */ #endif -- 2.10.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header 2016-10-10 0:03 [PATCH 0/2] make asm-generic/futex.h usable for more arch ports Joel Porquet 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` [PATCH 1/2] asm-generic/futex.h: code refactoring Joel Porquet @ 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` Joel Porquet 2 siblings, 1 reply; 6+ messages in thread From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw) To: arnd, linux; +Cc: linux-arch, Joel Porquet, linux-kernel, linux-arm-kernel "asm-generic/futex.h" was refactored and now allows arch ports to only define arch-specific macros instead of redefining the entire header file. This patch adapts "asm/futex.h" for ARM by only defining the macros required by the generic header (ie __futex_atomic_op_inuser() and __futex_atomic_cmpxchg_inatomic()). Compiled (SMP and !SMP) and booted on QEMU with a minimal busybox-based system. Signed-off-by: Joel Porquet <joel@porquet.org> --- arch/arm/include/asm/futex.h | 203 ++++++++++++++++++------------------------- 1 file changed, 84 insertions(+), 119 deletions(-) diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 6795368..d3db562 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -39,41 +39,30 @@ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ : "cc", "memory"); \ uaccess_restore(__ua_flags); \ + smp_mb(); \ }) -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - unsigned int __ua_flags; - int ret; - u32 val; - - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - - smp_mb(); - /* Prefetching cannot fault */ - prefetchw(uaddr); - __ua_flags = uaccess_save_and_enable(); - __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" - "1: ldrex %1, [%4]\n" - " teq %1, %2\n" - " ite eq @ explicit IT needed for the 2b label\n" - "2: strexeq %0, %3, [%4]\n" - " movne %0, #0\n" - " teq %0, #0\n" - " bne 1b\n" - __futex_atomic_ex_table("%5") - : "=&r" (ret), "=&r" (val) - : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) - : "cc", "memory"); - uaccess_restore(__ua_flags); - smp_mb(); - - *uval = val; - return ret; -} +#define __futex_atomic_cmpxchg_op(ret, val, uaddr, oldval, newval) \ +({ \ + unsigned int __ua_flags; \ + smp_mb(); \ + prefetchw(uaddr); \ + __ua_flags = uaccess_save_and_enable(); \ + __asm__ __volatile__( \ + "1: ldrex %1, [%4]\n" \ + " teq %1, %2\n" \ + " ite eq @ explicit IT needed for the 2b label\n" \ + "2: strexeq %0, %3, [%4]\n" \ + " movne %0, #0\n" \ + " teq %0, #0\n" \ + " bne 1b\n" \ + __futex_atomic_ex_table("%5") \ + : "=&r" (ret), "=&r" (val) \ + : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) \ + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ + smp_mb(); \ +}) #else /* !SMP, we can work around lack of atomic ops by disabling preemption */ @@ -82,7 +71,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ ({ \ - unsigned int __ua_flags = uaccess_save_and_enable(); \ + unsigned int __ua_flags; \ + preempt_disable(); \ + __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: " TUSER(ldr) " %1, [%3]\n" \ " " insn "\n" \ @@ -93,98 +84,72 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ : "cc", "memory"); \ uaccess_restore(__ua_flags); \ + preempt_disable(); \ }) -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - unsigned int __ua_flags; - int ret = 0; - u32 val; - - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - - preempt_disable(); - __ua_flags = uaccess_save_and_enable(); - __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" - "1: " TUSER(ldr) " %1, [%4]\n" - " teq %1, %2\n" - " it eq @ explicit IT needed for the 2b label\n" - "2: " TUSER(streq) " %3, [%4]\n" - __futex_atomic_ex_table("%5") - : "+r" (ret), "=&r" (val) - : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) - : "cc", "memory"); - uaccess_restore(__ua_flags); - - *uval = val; - preempt_enable(); - - return ret; -} +#define __futex_atomic_cmpxchg_op(ret, val, uaddr, oldval, newval) \ +({ \ + unsigned int __ua_flags; \ + preempt_disable(); \ + __ua_flags = uaccess_save_and_enable(); \ + __asm__ __volatile__( \ + "@futex_atomic_cmpxchg_inatomic\n" \ + "1: " TUSER(ldr) " %1, [%4]\n" \ + " teq %1, %2\n" \ + " it eq @ explicit IT needed for the 2b label\n" \ + "2: " TUSER(streq) " %3, [%4]\n" \ + __futex_atomic_ex_table("%5") \ + : "+r" (ret), "=&r" (val) \ + : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) \ + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ + preempt_enable(); \ +}) #endif /* !SMP */ -static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) -{ - int op = (encoded_op >> 28) & 7; - int cmp = (encoded_op >> 24) & 15; - int oparg = (encoded_op << 8) >> 20; - int cmparg = (encoded_op << 20) >> 20; - int oldval = 0, ret, tmp; +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret, tmp; \ + pagefault_disable(); \ + switch (op) { \ + case FUTEX_OP_SET: \ + __futex_atomic_op("mov %0, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_ADD: \ + __futex_atomic_op("add %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_OR: \ + __futex_atomic_op("orr %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_ANDN: \ + __futex_atomic_op("and %0, %1, %4", \ + __ret, oldval, tmp, uaddr, ~oparg); \ + break; \ + case FUTEX_OP_XOR: \ + __futex_atomic_op("eor %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + default: \ + ret = -ENOSYS; \ + } \ + pagefault_enable(); \ + __ret; \ +}) - if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) - oparg = 1 << oparg; +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret; \ + u32 val; \ + __futex_atomic_cmpxchg_op(__ret, val, uaddr, oldval, newval); \ + *uval = val; \ + __ret; \ +}) - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - -#ifndef CONFIG_SMP - preempt_disable(); -#endif - pagefault_disable(); - - switch (op) { - case FUTEX_OP_SET: - __futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_ADD: - __futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_OR: - __futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_ANDN: - __futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg); - break; - case FUTEX_OP_XOR: - __futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - default: - ret = -ENOSYS; - } - - pagefault_enable(); -#ifndef CONFIG_SMP - preempt_enable(); -#endif - - if (!ret) { - switch (cmp) { - case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; - case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; - case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; - case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; - case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; - case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; - default: ret = -ENOSYS; - } - } - return ret; -} +#include <asm-generic/futex.h> #endif /* __KERNEL__ */ #endif /* _ASM_ARM_FUTEX_H */ -- 2.10.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header 2016-10-10 0:03 ` [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header Joel Porquet @ 2016-10-10 0:03 ` Joel Porquet 0 siblings, 0 replies; 6+ messages in thread From: Joel Porquet @ 2016-10-10 0:03 UTC (permalink / raw) To: arnd, linux; +Cc: linux-kernel, linux-arch, linux-arm-kernel, Joel Porquet "asm-generic/futex.h" was refactored and now allows arch ports to only define arch-specific macros instead of redefining the entire header file. This patch adapts "asm/futex.h" for ARM by only defining the macros required by the generic header (ie __futex_atomic_op_inuser() and __futex_atomic_cmpxchg_inatomic()). Compiled (SMP and !SMP) and booted on QEMU with a minimal busybox-based system. Signed-off-by: Joel Porquet <joel@porquet.org> --- arch/arm/include/asm/futex.h | 203 ++++++++++++++++++------------------------- 1 file changed, 84 insertions(+), 119 deletions(-) diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 6795368..d3db562 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -39,41 +39,30 @@ : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ : "cc", "memory"); \ uaccess_restore(__ua_flags); \ + smp_mb(); \ }) -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - unsigned int __ua_flags; - int ret; - u32 val; - - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - - smp_mb(); - /* Prefetching cannot fault */ - prefetchw(uaddr); - __ua_flags = uaccess_save_and_enable(); - __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" - "1: ldrex %1, [%4]\n" - " teq %1, %2\n" - " ite eq @ explicit IT needed for the 2b label\n" - "2: strexeq %0, %3, [%4]\n" - " movne %0, #0\n" - " teq %0, #0\n" - " bne 1b\n" - __futex_atomic_ex_table("%5") - : "=&r" (ret), "=&r" (val) - : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) - : "cc", "memory"); - uaccess_restore(__ua_flags); - smp_mb(); - - *uval = val; - return ret; -} +#define __futex_atomic_cmpxchg_op(ret, val, uaddr, oldval, newval) \ +({ \ + unsigned int __ua_flags; \ + smp_mb(); \ + prefetchw(uaddr); \ + __ua_flags = uaccess_save_and_enable(); \ + __asm__ __volatile__( \ + "1: ldrex %1, [%4]\n" \ + " teq %1, %2\n" \ + " ite eq @ explicit IT needed for the 2b label\n" \ + "2: strexeq %0, %3, [%4]\n" \ + " movne %0, #0\n" \ + " teq %0, #0\n" \ + " bne 1b\n" \ + __futex_atomic_ex_table("%5") \ + : "=&r" (ret), "=&r" (val) \ + : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) \ + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ + smp_mb(); \ +}) #else /* !SMP, we can work around lack of atomic ops by disabling preemption */ @@ -82,7 +71,9 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ ({ \ - unsigned int __ua_flags = uaccess_save_and_enable(); \ + unsigned int __ua_flags; \ + preempt_disable(); \ + __ua_flags = uaccess_save_and_enable(); \ __asm__ __volatile__( \ "1: " TUSER(ldr) " %1, [%3]\n" \ " " insn "\n" \ @@ -93,98 +84,72 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ : "cc", "memory"); \ uaccess_restore(__ua_flags); \ + preempt_disable(); \ }) -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - unsigned int __ua_flags; - int ret = 0; - u32 val; - - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - - preempt_disable(); - __ua_flags = uaccess_save_and_enable(); - __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" - "1: " TUSER(ldr) " %1, [%4]\n" - " teq %1, %2\n" - " it eq @ explicit IT needed for the 2b label\n" - "2: " TUSER(streq) " %3, [%4]\n" - __futex_atomic_ex_table("%5") - : "+r" (ret), "=&r" (val) - : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) - : "cc", "memory"); - uaccess_restore(__ua_flags); - - *uval = val; - preempt_enable(); - - return ret; -} +#define __futex_atomic_cmpxchg_op(ret, val, uaddr, oldval, newval) \ +({ \ + unsigned int __ua_flags; \ + preempt_disable(); \ + __ua_flags = uaccess_save_and_enable(); \ + __asm__ __volatile__( \ + "@futex_atomic_cmpxchg_inatomic\n" \ + "1: " TUSER(ldr) " %1, [%4]\n" \ + " teq %1, %2\n" \ + " it eq @ explicit IT needed for the 2b label\n" \ + "2: " TUSER(streq) " %3, [%4]\n" \ + __futex_atomic_ex_table("%5") \ + : "+r" (ret), "=&r" (val) \ + : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) \ + : "cc", "memory"); \ + uaccess_restore(__ua_flags); \ + preempt_enable(); \ +}) #endif /* !SMP */ -static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) -{ - int op = (encoded_op >> 28) & 7; - int cmp = (encoded_op >> 24) & 15; - int oparg = (encoded_op << 8) >> 20; - int cmparg = (encoded_op << 20) >> 20; - int oldval = 0, ret, tmp; +#define __futex_atomic_op_inuser(op, oldval, uaddr, oparg) \ +({ \ + int __ret, tmp; \ + pagefault_disable(); \ + switch (op) { \ + case FUTEX_OP_SET: \ + __futex_atomic_op("mov %0, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_ADD: \ + __futex_atomic_op("add %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_OR: \ + __futex_atomic_op("orr %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + case FUTEX_OP_ANDN: \ + __futex_atomic_op("and %0, %1, %4", \ + __ret, oldval, tmp, uaddr, ~oparg); \ + break; \ + case FUTEX_OP_XOR: \ + __futex_atomic_op("eor %0, %1, %4", \ + __ret, oldval, tmp, uaddr, oparg); \ + break; \ + default: \ + ret = -ENOSYS; \ + } \ + pagefault_enable(); \ + __ret; \ +}) - if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) - oparg = 1 << oparg; +#define __futex_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval) \ +({ \ + int __ret; \ + u32 val; \ + __futex_atomic_cmpxchg_op(__ret, val, uaddr, oldval, newval); \ + *uval = val; \ + __ret; \ +}) - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) - return -EFAULT; - -#ifndef CONFIG_SMP - preempt_disable(); -#endif - pagefault_disable(); - - switch (op) { - case FUTEX_OP_SET: - __futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_ADD: - __futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_OR: - __futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - case FUTEX_OP_ANDN: - __futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg); - break; - case FUTEX_OP_XOR: - __futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg); - break; - default: - ret = -ENOSYS; - } - - pagefault_enable(); -#ifndef CONFIG_SMP - preempt_enable(); -#endif - - if (!ret) { - switch (cmp) { - case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; - case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; - case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; - case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; - case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; - case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; - default: ret = -ENOSYS; - } - } - return ret; -} +#include <asm-generic/futex.h> #endif /* __KERNEL__ */ #endif /* _ASM_ARM_FUTEX_H */ -- 2.10.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-10-10 3:40 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-10-10 0:03 [PATCH 0/2] make asm-generic/futex.h usable for more arch ports Joel Porquet 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` [PATCH 1/2] asm-generic/futex.h: code refactoring Joel Porquet 2016-10-10 0:03 ` Joel Porquet 2016-10-10 0:03 ` [PATCH 2/2] arm: futex: Use asm-generic/futex.h instead of redefining the entire header Joel Porquet 2016-10-10 0:03 ` Joel Porquet
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