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* [PATCH 00/12] Introduce cmpxchg128() -- aka. the demise of cmpxchg_double()
@ 2023-05-31 13:08 Peter Zijlstra
  2023-05-31 13:08 ` [PATCH 01/12] cyrpto/b128ops: Remove struct u128 Peter Zijlstra
                   ` (12 more replies)
  0 siblings, 13 replies; 47+ messages in thread
From: Peter Zijlstra @ 2023-05-31 13:08 UTC (permalink / raw)
  To: torvalds
  Cc: corbet, will, peterz, boqun.feng, mark.rutland, catalin.marinas,
	dennis, tj, cl, hca, gor, agordeev, borntraeger, svens, tglx,
	mingo, bp, dave.hansen, x86, hpa, joro, suravee.suthikulpanit,
	robin.murphy, dwmw2, baolu.lu, Arnd Bergmann, Herbert Xu, davem,
	penberg, rientjes, iamjoonsoo.kim, Andrew Morton, vbabka,
	roman.gushchin, 42.hyeyoo, linux-doc, linux-kernel, linux-mm,
	linux-s390, iommu, linux-arch, linux-crypto, sfr, mpe,
	James.Bottomley, deller, linux-parisc

Hi!

After much breaking of things, find here the improved version.

Since v3:

 - unbreak everything that does *NOT* have cmpxchg128()

   Notably this_cpu_cmpxchg_double() is used unconditionally by SLUB
   which means that this_cpu_try_cmpxchg128() needs to be unconditionally
   available on all 64bit architectures.

 - fixed up x86/x86_64 cmpxchg{8,16}b emulation for this_cpu_cmpxchg{64,128}()

 - introduce {raw,this}_cpu_try_cmpxchg*()

 - add fallback for !__SIZEOF_INT128__ 64bit architectures

   Sadly there are supported 64bit architecture/compiler combinations that do
   not have __SIZEOF_INT128__, specifically it was found that HPPA64 only added
   this with GCC-11.

   this is yuck, and ideally we'd simply raise compiler requirements, but this
   'works'.

My plan is to re-add this to tip/locking/core and thus -next later this week.

Also available at:

  git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git locking/core

---
 Documentation/core-api/this_cpu_ops.rst     |   2 -
 arch/arm64/include/asm/atomic_ll_sc.h       |  56 +++---
 arch/arm64/include/asm/atomic_lse.h         |  39 ++---
 arch/arm64/include/asm/cmpxchg.h            |  48 ++----
 arch/arm64/include/asm/percpu.h             |  30 ++--
 arch/s390/include/asm/cmpxchg.h             |  32 +---
 arch/s390/include/asm/cpu_mf.h              |   2 +-
 arch/s390/include/asm/percpu.h              |  34 ++--
 arch/s390/kernel/perf_cpum_sf.c             |  16 +-
 arch/x86/include/asm/cmpxchg.h              |  25 ---
 arch/x86/include/asm/cmpxchg_32.h           |   2 +-
 arch/x86/include/asm/cmpxchg_64.h           |  63 ++++++-
 arch/x86/include/asm/percpu.h               | 102 ++++++-----
 arch/x86/lib/Makefile                       |   3 +-
 arch/x86/lib/cmpxchg16b_emu.S               |  43 +++--
 arch/x86/lib/cmpxchg8b_emu.S                |  67 ++++++--
 drivers/iommu/amd/amd_iommu_types.h         |   9 +-
 drivers/iommu/amd/iommu.c                   |  10 +-
 drivers/iommu/intel/irq_remapping.c         |   8 +-
 include/asm-generic/percpu.h                | 257 ++++++++++++++++++++++------
 include/crypto/b128ops.h                    |  14 +-
 include/linux/atomic/atomic-arch-fallback.h |  95 +++++++++-
 include/linux/atomic/atomic-instrumented.h  |  93 ++++++++--
 include/linux/dmar.h                        | 125 +++++++-------
 include/linux/percpu-defs.h                 |  45 ++---
 include/linux/slub_def.h                    |  12 +-
 include/linux/types.h                       |  12 ++
 include/uapi/linux/types.h                  |   4 +
 lib/crypto/curve25519-hacl64.c              |   2 -
 lib/crypto/poly1305-donna64.c               |   2 -
 mm/slab.h                                   |  53 +++++-
 mm/slub.c                                   | 139 +++++++++------
 scripts/atomic/gen-atomic-fallback.sh       |   4 +-
 scripts/atomic/gen-atomic-instrumented.sh   |  19 +-
 34 files changed, 952 insertions(+), 515 deletions(-)


^ permalink raw reply	[flat|nested] 47+ messages in thread
* [PATCH v3 05/11] percpu: Wire up cmpxchg128
@ 2023-05-15  7:57 Peter Zijlstra
  2023-05-20 10:49 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
  2023-05-22 10:27 ` tip-bot2 for Peter Zijlstra
  0 siblings, 2 replies; 47+ messages in thread
From: Peter Zijlstra @ 2023-05-15  7:57 UTC (permalink / raw)
  To: torvalds
  Cc: corbet, will, peterz, boqun.feng, mark.rutland, catalin.marinas,
	dennis, tj, cl, hca, gor, agordeev, borntraeger, svens, tglx,
	mingo, bp, dave.hansen, x86, hpa, joro, suravee.suthikulpanit,
	robin.murphy, dwmw2, baolu.lu, Arnd Bergmann, Herbert Xu, davem,
	penberg, rientjes, iamjoonsoo.kim, Andrew Morton, vbabka,
	roman.gushchin, 42.hyeyoo, linux-doc, linux-kernel, linux-mm,
	linux-s390, iommu, linux-arch, linux-crypto

In order to replace cmpxchg_double() with the newly minted
cmpxchg128() family of functions, wire it up in this_cpu_cmpxchg().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/arm64/include/asm/percpu.h |   20 +++++++++++++
 arch/s390/include/asm/percpu.h  |   16 ++++++++++
 arch/x86/include/asm/percpu.h   |   59 ++++++++++++++++++++++++++++++++++++++++
 include/asm-generic/percpu.h    |   16 ++++++++++
 4 files changed, 111 insertions(+)

--- a/arch/arm64/include/asm/percpu.h
+++ b/arch/arm64/include/asm/percpu.h
@@ -140,6 +140,10 @@ PERCPU_RET_OP(add, add, ldadd)
  * re-enabling preemption for preemptible kernels, but doing that in a way
  * which builds inside a module would mean messing directly with the preempt
  * count. If you do this, peterz and tglx will hunt you down.
+ *
+ * Not to mention it'll break the actual preemption model for missing a
+ * preemption point when TIF_NEED_RESCHED gets set while preemption is
+ * disabled.
  */
 #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)		\
 ({									\
@@ -240,6 +244,22 @@ PERCPU_RET_OP(add, add, ldadd)
 #define this_cpu_cmpxchg_8(pcp, o, n)	\
 	_pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
 
+#define this_cpu_cmpxchg64(pcp, o, n)	this_cpu_cmpxchg_8(pcp, o, n)
+
+#define this_cpu_cmpxchg128(pcp, o, n)					\
+({									\
+	typedef typeof(pcp) pcp_op_T__;					\
+	u128 old__, new__, ret__;					\
+	pcp_op_T__ *ptr__;						\
+	old__ = o;							\
+	new__ = n;							\
+	preempt_disable_notrace();					\
+	ptr__ = raw_cpu_ptr(&(pcp));					\
+	ret__ = cmpxchg128_local((void *)ptr__, old__, new__);		\
+	preempt_enable_notrace();					\
+	ret__;								\
+})
+
 #ifdef __KVM_NVHE_HYPERVISOR__
 extern unsigned long __hyp_per_cpu_offset(unsigned int cpu);
 #define __per_cpu_offset
--- a/arch/s390/include/asm/percpu.h
+++ b/arch/s390/include/asm/percpu.h
@@ -148,6 +148,22 @@
 #define this_cpu_cmpxchg_4(pcp, oval, nval) arch_this_cpu_cmpxchg(pcp, oval, nval)
 #define this_cpu_cmpxchg_8(pcp, oval, nval) arch_this_cpu_cmpxchg(pcp, oval, nval)
 
+#define this_cpu_cmpxchg64(pcp, o, n)	this_cpu_cmpxchg_8(pcp, o, n)
+
+#define this_cpu_cmpxchg128(pcp, oval, nval)				\
+({									\
+	typedef typeof(pcp) pcp_op_T__;					\
+	u128 old__, new__, ret__;					\
+	pcp_op_T__ *ptr__;						\
+	old__ = oval;							\
+	new__ = nval;							\
+	preempt_disable_notrace();					\
+	ptr__ = raw_cpu_ptr(&(pcp));					\
+	ret__ = cmpxchg128((void *)ptr__, old__, new__);		\
+	preempt_enable_notrace();					\
+	ret__;								\
+})
+
 #define arch_this_cpu_xchg(pcp, nval)					\
 ({									\
 	typeof(pcp) *ptr__;						\
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -210,6 +210,65 @@ do {									\
 	(typeof(_var))(unsigned long) pco_old__;			\
 })
 
+#if defined(CONFIG_X86_32) && defined(CONFIG_X86_CMPXCHG64)
+#define percpu_cmpxchg64_op(size, qual, _var, _oval, _nval)		\
+({									\
+	union {								\
+		u64 var;						\
+		struct {						\
+			u32 low, high;					\
+		};							\
+	} old__, new__;							\
+									\
+	old__.var = _oval;						\
+	new__.var = _nval;						\
+									\
+	asm qual ("cmpxchg8b " __percpu_arg([var])			\
+		  : [var] "+m" (_var),					\
+		    "+a" (old__.low),					\
+		    "+d" (old__.high)					\
+		  : "b" (new__.low),					\
+		    "c" (new__.high)					\
+		  : "memory");						\
+									\
+	old__.var;							\
+})
+
+#define raw_cpu_cmpxchg64(pcp, oval, nval)	percpu_cmpxchg64_op(8,         , pcp, oval, nval)
+#define this_cpu_cmpxchg64(pcp, oval, nval)	percpu_cmpxchg64_op(8, volatile, pcp, oval, nval)
+#endif
+
+#ifdef CONFIG_X86_64
+#define raw_cpu_cmpxchg64(pcp, oval, nval)	percpu_cmpxchg_op(8,         , pcp, oval, nval);
+#define this_cpu_cmpxchg64(pcp, oval, nval)	percpu_cmpxchg_op(8, volatile, pcp, oval, nval);
+
+#define percpu_cmpxchg128_op(size, qual, _var, _oval, _nval)		\
+({									\
+	union {								\
+		u128 var;						\
+		struct {						\
+			u64 low, high;					\
+		};							\
+	} old__, new__;							\
+									\
+	old__.var = _oval;						\
+	new__.var = _nval;						\
+									\
+	asm qual ("cmpxchg16b " __percpu_arg([var])			\
+		  : [var] "+m" (_var),					\
+		    "+a" (old__.low),					\
+		    "+d" (old__.high)					\
+		  : "b" (new__.low),					\
+		    "c" (new__.high)					\
+		  : "memory");						\
+									\
+	old__.var;							\
+})
+
+#define raw_cpu_cmpxchg128(pcp, oval, nval)	percpu_cmpxchg128_op(16,         , pcp, oval, nval)
+#define this_cpu_cmpxchg128(pcp, oval, nval)	percpu_cmpxchg128_op(16, volatile, pcp, oval, nval)
+#endif
+
 /*
  * this_cpu_read() makes gcc load the percpu variable every time it is
  * accessed while this_cpu_read_stable() allows the value to be cached.
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -298,6 +298,14 @@ do {									\
 #define raw_cpu_cmpxchg_8(pcp, oval, nval) \
 	raw_cpu_generic_cmpxchg(pcp, oval, nval)
 #endif
+#ifndef raw_cpu_cmpxchg64
+#define raw_cpu_cmpxchg64(pcp, oval, nval) \
+	raw_cpu_generic_cmpxchg(pcp, oval, nval)
+#endif
+#ifndef raw_cpu_cmpxchg128
+#define raw_cpu_cmpxchg128(pcp, oval, nval) \
+	raw_cpu_generic_cmpxchg(pcp, oval, nval)
+#endif
 
 #ifndef raw_cpu_cmpxchg_double_1
 #define raw_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \
@@ -423,6 +431,14 @@ do {									\
 #define this_cpu_cmpxchg_8(pcp, oval, nval) \
 	this_cpu_generic_cmpxchg(pcp, oval, nval)
 #endif
+#ifndef this_cpu_cmpxchg64
+#define this_cpu_cmpxchg64(pcp, oval, nval) \
+	this_cpu_generic_cmpxchg(pcp, oval, nval)
+#endif
+#ifndef this_cpu_cmpxchg128
+#define this_cpu_cmpxchg128(pcp, oval, nval) \
+	this_cpu_generic_cmpxchg(pcp, oval, nval)
+#endif
 
 #ifndef this_cpu_cmpxchg_double_1
 #define this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \



^ permalink raw reply	[flat|nested] 47+ messages in thread

end of thread, other threads:[~2023-06-09 16:20 UTC | newest]

Thread overview: 47+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-31 13:08 [PATCH 00/12] Introduce cmpxchg128() -- aka. the demise of cmpxchg_double() Peter Zijlstra
2023-05-31 13:08 ` [PATCH 01/12] cyrpto/b128ops: Remove struct u128 Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 02/12] types: Introduce [us]128 Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 03/12] arch: Introduce arch_{,try_}_cmpxchg128{,_local}() Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 04/12] instrumentation: Wire up cmpxchg128() Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 05/12] percpu: Add {raw,this}_cpu_try_cmpxchg() Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-06-09 16:10   ` [PATCH v2 5/12] " Konrad Dybcio
2023-06-09 16:13     ` Nathan Chancellor
2023-06-09 16:20       ` Konrad Dybcio
2023-05-31 13:08 ` [PATCH 06/12] percpu: Wire up cmpxchg128 Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 07/12] percpu: #ifndef __SIZEOF_INT128__ Peter Zijlstra
2023-05-31 14:21   ` Arnd Bergmann
2023-05-31 15:50     ` Peter Zijlstra
2023-06-01 10:14     ` [PATCH v2 07/12] parisc/percpu: Work around the lack of __SIZEOF_INT128__ Peter Zijlstra
2023-06-01 10:32       ` Helge Deller
2023-06-01 10:50         ` Peter Zijlstra
2023-06-01 21:08           ` Sam James
2023-06-01 13:29         ` Linus Torvalds
2023-06-01 17:38           ` Masahiro Yamada
2023-06-02 14:39           ` Peter Zijlstra
2023-06-02 14:50             ` Mark Rutland
2023-06-02 16:09             ` Linus Torvalds
2023-06-02 17:00             ` H. Peter Anvin
2023-06-02 19:10               ` Peter Zijlstra
2023-06-02 19:20                 ` H. Peter Anvin
2023-06-02 19:40                   ` Peter Zijlstra
2023-06-02 19:57                     ` Linus Torvalds
2023-06-02 20:42             ` Helge Deller
2023-05-31 13:08 ` [PATCH 08/12] x86,amd_iommu: Replace cmpxchg_double() Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 09/12] x86,intel_iommu: " Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 10/12] slub: " Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 11/12] arch: Remove cmpxchg_double Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 13:08 ` [PATCH 12/12] s390/cpum_sf: Convert to cmpxchg128() Peter Zijlstra
2023-06-05  7:42   ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-31 14:47 ` [PATCH 00/12] Introduce cmpxchg128() -- aka. the demise of cmpxchg_double() Mark Rutland
  -- strict thread matches above, loose matches on Subject: below --
2023-05-15  7:57 [PATCH v3 05/11] percpu: Wire up cmpxchg128 Peter Zijlstra
2023-05-20 10:49 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2023-05-22 10:27 ` tip-bot2 for Peter Zijlstra

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