linux-kernel - [PATCH v2 10/10] s390/cpum_sf: Convert to cmpxchg128()

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Date:   Thu, 02 Feb 2023 15:50:40 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org
Cc:     corbet@....net, will@...nel.org, peterz@...radead.org,
        boqun.feng@...il.com, mark.rutland@....com,
        catalin.marinas@....com, dennis@...nel.org, tj@...nel.org,
        cl@...ux.com, hca@...ux.ibm.com, gor@...ux.ibm.com,
        agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
        svens@...ux.ibm.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, joro@...tes.org, suravee.suthikulpanit@....com,
        robin.murphy@....com, dwmw2@...radead.org,
        baolu.lu@...ux.intel.com, Arnd Bergmann <arnd@...db.de>,
        Herbert Xu <herbert@...dor.apana.org.au>, davem@...emloft.net,
        penberg@...nel.org, rientjes@...gle.com, iamjoonsoo.kim@....com,
        Andrew Morton <akpm@...ux-foundation.org>, vbabka@...e.cz,
        roman.gushchin@...ux.dev, 42.hyeyoo@...il.com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-s390@...r.kernel.org,
        iommu@...ts.linux.dev, linux-arch@...r.kernel.org,
        linux-crypto@...r.kernel.org
Subject: [PATCH v2 10/10] s390/cpum_sf: Convert to cmpxchg128()

Now that there is a cross arch u128 and cmpxchg128(), use those
instead of the custom CDSG helper.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/s390/include/asm/cpu_mf.h  |    2 +-
 arch/s390/kernel/perf_cpum_sf.c |   22 ++++++----------------
 2 files changed, 7 insertions(+), 17 deletions(-)

--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -141,7 +141,7 @@ union hws_trailer_header {
 		unsigned int dsdes:16;	/* 48-63: size of diagnostic SDE */
 		unsigned long long overflow; /* 64 - Overflow Count   */
 	};
-	__uint128_t val;
+	u128 val;
 };
 
 struct hws_trailer_entry {
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1228,16 +1228,6 @@ static void hw_collect_samples(struct pe
 	}
 }
 
-static inline __uint128_t __cdsg(__uint128_t *ptr, __uint128_t old, __uint128_t new)
-{
-	asm volatile(
-		"	cdsg	%[old],%[new],%[ptr]\n"
-		: [old] "+d" (old), [ptr] "+QS" (*ptr)
-		: [new] "d" (new)
-		: "memory", "cc");
-	return old;
-}
-
 /* hw_perf_event_update() - Process sampling buffer
  * @event:	The perf event
  * @flush_all:	Flag to also flush partially filled sample-data-blocks
@@ -1307,14 +1297,14 @@ static void hw_perf_event_update(struct
 
 		/* Reset trailer (using compare-double-and-swap) */
 		/* READ_ONCE() 16 byte header */
-		prev.val = __cdsg(&te->header.val, 0, 0);
+		prev.val = cmpxchg128(&te->header.val, 0, 0);
 		do {
 			old.val = prev.val;
 			new.val = prev.val;
 			new.f = 0;
 			new.a = 1;
 			new.overflow = 0;
-			prev.val = __cdsg(&te->header.val, old.val, new.val);
+			prev.val = cmpxchg128(&te->header.val, old.val, new.val);
 		} while (prev.val != old.val);
 
 		/* Advance to next sample-data-block */
@@ -1496,7 +1486,7 @@ static bool aux_set_alert(struct aux_buf
 
 	te = aux_sdb_trailer(aux, alert_index);
 	/* READ_ONCE() 16 byte header */
-	prev.val = __cdsg(&te->header.val, 0, 0);
+	prev.val = cmpxchg128(&te->header.val, 0, 0);
 	do {
 		old.val = prev.val;
 		new.val = prev.val;
@@ -1511,7 +1501,7 @@ static bool aux_set_alert(struct aux_buf
 		}
 		new.a = 1;
 		new.overflow = 0;
-		prev.val = __cdsg(&te->header.val, old.val, new.val);
+		prev.val = cmpxchg128(&te->header.val, old.val, new.val);
 	} while (prev.val != old.val);
 	return true;
 }
@@ -1575,7 +1565,7 @@ static bool aux_reset_buffer(struct aux_
 	for (i = 0; i < range_scan; i++, idx++) {
 		te = aux_sdb_trailer(aux, idx);
 		/* READ_ONCE() 16 byte header */
-		prev.val = __cdsg(&te->header.val, 0, 0);
+		prev.val = cmpxchg128(&te->header.val, 0, 0);
 		do {
 			old.val = prev.val;
 			new.val = prev.val;
@@ -1586,7 +1576,7 @@ static bool aux_reset_buffer(struct aux_
 				new.a = 1;
 			else
 				new.a = 0;
-			prev.val = __cdsg(&te->header.val, old.val, new.val);
+			prev.val = cmpxchg128(&te->header.val, old.val, new.val);
 		} while (prev.val != old.val);
 		*overflow += orig_overflow;
 	}