From: Heiko Carstens <hca@linux.ibm.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Mete Durlu <meted@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Juergen Christ <jchrist@linux.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: [PATCH v3 05/11] s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines
Date: Mon, 21 Sep 2026 10:39:59 +0200 [thread overview]
Message-ID: <20260921084005.4022574-6-hca@linux.ibm.com> (raw)
In-Reply-To: <20260921084005.4022574-1-hca@linux.ibm.com>
Define LC_PERCPU_OFFSET and LC_PERCPU_REGISTER offset defines and use
them in percpu code. This shortens the percpu inline assemblies and makes
them a bit more readable.
Note that because of header dependencies it is not possible to use
asm-offsets. However to avoid adding more dependencies to asm-offsets
it seems to be preferable to use the current approach in any way.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/include/asm/entry-percpu.h | 2 +-
arch/s390/include/asm/lowcore.h | 3 ++
arch/s390/include/asm/percpu.h | 47 ++++++++++------------------
3 files changed, 20 insertions(+), 32 deletions(-)
diff --git a/arch/s390/include/asm/entry-percpu.h b/arch/s390/include/asm/entry-percpu.h
index 4ef47265cfce..89c9e44f6f83 100644
--- a/arch/s390/include/asm/entry-percpu.h
+++ b/arch/s390/include/asm/entry-percpu.h
@@ -49,7 +49,7 @@ static __always_inline bool percpu_code_check(struct pt_regs *regs)
}
if ((insn & 0xff0f) != 0xe300)
return true;
- disp = offsetof(struct lowcore, percpu_offset);
+ disp = LC_PERCPU_OFFSET;
if (machine_has_relocated_lowcore())
disp += LOWCORE_ALT_ADDRESS;
insn = (disp & 0xff000) >> 4 | (disp & 0x00fff) << 16 | 0x8;
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index f0364a9f8a19..f4517bbe405b 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -222,6 +222,9 @@ struct lowcore {
__u8 pad_0x1900[0x2000-0x1900]; /* 0x1900 */
} __packed __aligned(8192);
+#define LC_PERCPU_OFFSET offsetof(struct lowcore, percpu_offset)
+#define LC_PERCPU_REGISTER offsetof(struct lowcore, percpu_register)
+
static __always_inline struct lowcore *get_lowcore(void)
{
struct lowcore *lc;
diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h
index 3bc448c4c2dd..770fe4be65dc 100644
--- a/arch/s390/include/asm/percpu.h
+++ b/arch/s390/include/asm/percpu.h
@@ -14,17 +14,16 @@
#define arch_raw_cpu_ptr(_ptr) \
({ \
- unsigned long lc_percpu, tcp_ptr__; \
+ unsigned long tcp_ptr__; \
\
tcp_ptr__ = (__force unsigned long)(_ptr); \
- lc_percpu = offsetof(struct lowcore, percpu_offset); \
asm_inline volatile( \
ALTERNATIVE("ag %[__ptr__],%[offzero](%%r0)\n", \
"ag %[__ptr__],%[offalt](%%r0)\n", \
ALT_FEATURE(MFEATURE_LOWCORE)) \
: [__ptr__] "+d" (tcp_ptr__) \
- : [offzero] "i" (lc_percpu), \
- [offalt] "i" (lc_percpu + LOWCORE_ALT_ADDRESS), \
+ : [offzero] "i" (LC_PERCPU_OFFSET), \
+ [offalt] "i" (LC_PERCPU_OFFSET + LOWCORE_ALT_ADDRESS), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
(TYPEOF_UNQUAL(*(_ptr)) __force __kernel *)tcp_ptr__; \
@@ -144,13 +143,10 @@
#define arch_this_cpu_add(pcp, val, op1, op2, szcast) \
do { \
- unsigned long lc_pcpr, lc_pcpo; \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
\
- lc_pcpr = offsetof(struct lowcore, percpu_register); \
- lc_pcpo = offsetof(struct lowcore, percpu_offset); \
ptr__ = PERCPU_PTR(&(pcp)); \
if (__builtin_constant_p(val__) && \
((szcast)val__ > -129) && ((szcast)val__ < 128)) { \
@@ -162,8 +158,8 @@ do { \
: [ptr__] "+&a" (ptr__), "+m" (*ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
: [val__] "i" ((szcast)val__), \
- [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
} else { \
@@ -176,8 +172,8 @@ do { \
[ptr__] "+&a" (ptr__), "+m" (*ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
: [val__] "d" (val__), \
- [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
} \
@@ -188,13 +184,10 @@ do { \
#define arch_this_cpu_add_return(pcp, val, op) \
({ \
- unsigned long lc_pcpr, lc_pcpo; \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
\
- lc_pcpr = offsetof(struct lowcore, percpu_register); \
- lc_pcpo = offsetof(struct lowcore, percpu_offset); \
ptr__ = PERCPU_PTR(&(pcp)); \
asm_inline volatile( \
MVIY_PERCPU("%[disppcpr]","%[ptr__]") \
@@ -205,8 +198,8 @@ do { \
[ptr__] "+&a" (ptr__), "+m" (*ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
: [val__] "d" (val__), \
- [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
old__ + val__; \
@@ -217,13 +210,10 @@ do { \
#define arch_this_cpu_to_op(pcp, val, op) \
do { \
- unsigned long lc_pcpr, lc_pcpo; \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
\
- lc_pcpr = offsetof(struct lowcore, percpu_register); \
- lc_pcpo = offsetof(struct lowcore, percpu_offset); \
ptr__ = PERCPU_PTR(&(pcp)); \
asm_inline volatile( \
MVIY_PERCPU("%[disppcpr]","%[ptr__]") \
@@ -234,8 +224,8 @@ do { \
[ptr__] "+&a" (ptr__), "+m" (*ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
: [val__] "d" (val__), \
- [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
} while (0)
@@ -249,12 +239,10 @@ do { \
#define arch_this_cpu_read(pcp, op) \
({ \
- unsigned long lc_pcpr, lc_pcpo, res__; \
typedef typeof(pcp) pcp_op_T__; \
+ unsigned long res__; \
pcp_op_T__ *ptr__; \
\
- lc_pcpr = offsetof(struct lowcore, percpu_register); \
- lc_pcpo = offsetof(struct lowcore, percpu_offset); \
ptr__ = PERCPU_PTR(&(pcp)); \
asm_inline volatile( \
MVIY_PERCPU("%[disppcpr]","%[ptr__]") \
@@ -263,8 +251,8 @@ do { \
MVIY_ALT("%[disppcpr]") \
: [res__] "=&d" (res__), [ptr__] "+&a" (ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
- : [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ : [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (*ptr__), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
@@ -278,12 +266,9 @@ do { \
#define arch_this_cpu_write(pcp, val, op) \
do { \
- unsigned long lc_pcpr, lc_pcpo; \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ *ptr__, val__ = (val); \
\
- lc_pcpr = offsetof(struct lowcore, percpu_register); \
- lc_pcpo = offsetof(struct lowcore, percpu_offset); \
ptr__ = PERCPU_PTR(&(pcp)); \
asm_inline volatile( \
MVIY_PERCPU("%[disppcpr]","%[ptr__]") \
@@ -293,8 +278,8 @@ do { \
: [ptr__] "+&a" (ptr__), "=m" (*ptr__), \
"=m" (((struct lowcore *)0)->percpu_register) \
: [val__] "d" (val__), \
- [disppcpr] "i" (lc_pcpr), \
- [disppcpo] "i" (lc_pcpo), \
+ [disppcpr] "i" (LC_PERCPU_REGISTER), \
+ [disppcpo] "i" (LC_PERCPU_OFFSET), \
"m" (((struct lowcore *)0)->percpu_offset) \
: "cc"); \
} while (0)
--
2.53.0
next prev parent reply other threads:[~2026-09-21 8:40 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-21 8:39 [PATCH v3 00/11] s390: More this_cpu_*() changes Heiko Carstens
2026-09-21 8:39 ` [PATCH v3 01/11] s390/percpu: Fix comment typo Heiko Carstens
2026-09-21 8:41 ` sashiko-bot
2026-09-21 8:39 ` [PATCH v3 02/11] s390/percpu: Add sanity check to GEN_MVIY macro Heiko Carstens
2026-09-21 8:44 ` sashiko-bot
2026-09-21 8:39 ` [PATCH v3 03/11] s390/lowcore: Remove _AC() from LOWCORE_ALT_ADDRESS Heiko Carstens
2026-09-21 8:45 ` sashiko-bot
2026-09-21 8:39 ` [PATCH v3 04/11] s390/percpu: Let MVIY_PERCPU() calculate alternative displacement Heiko Carstens
2026-09-21 8:45 ` sashiko-bot
2026-09-21 8:39 ` Heiko Carstens [this message]
2026-09-21 8:45 ` [PATCH v3 05/11] s390/percpu/lowcore: Add and use LC_PERCPU lowcore offset defines sashiko-bot
2026-09-21 8:40 ` [PATCH v3 06/11] s390/percpu: Rename inline assembly symbolic names Heiko Carstens
2026-09-21 8:44 ` sashiko-bot
2026-09-21 8:40 ` [PATCH v3 07/11] s390/percpu: Use __PCPU_BEGIN() and __PCPU_END() for inline assemblies Heiko Carstens
2026-09-21 8:45 ` sashiko-bot
2026-09-21 8:40 ` [PATCH v3 08/11] s390/percpu: Use percpu code section for this_cpu_cmpxchg128() Heiko Carstens
2026-09-21 8:46 ` sashiko-bot
2026-09-21 8:40 ` [PATCH v3 09/11] s390/percpu: Use percpu code section for this_cpu_xchg() Heiko Carstens
2026-09-21 8:45 ` sashiko-bot
2026-09-21 8:40 ` [PATCH v3 10/11] s390/percpu: Use percpu code section for this_cpu_cmpxchg() Heiko Carstens
2026-09-21 8:52 ` sashiko-bot
2026-09-21 8:40 ` [PATCH v3 11/11] s390/percpu: Rework to simplify percpu_entry() and percpu_exit() Heiko Carstens
2026-09-21 8:52 ` sashiko-bot
2026-09-21 9:55 ` David Laight
2026-09-21 10:07 ` Mark Rutland
2026-09-21 10:17 ` Heiko Carstens
2026-09-21 9:15 ` [PATCH v3 00/11] s390: More this_cpu_*() changes Heiko Carstens
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