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[src/trunk]: src/sys/arch Mirror the changes to aarch64 and
details: https://anonhg.NetBSD.org/src/rev/c2c8ef86ef52
branches: trunk
changeset: 974866:c2c8ef86ef52
user: skrll <skrll%NetBSD.org@localhost>
date: Fri Aug 14 16:18:36 2020 +0000
description:
Mirror the changes to aarch64 and
- Switch to TPIDRPRW_IS_CURLWP, because curlwp is accessed much more often
by MI code. It also makes curlwp preemption safe,
- Make ASTs operate per-LWP rather than per-CPU, otherwise sometimes LWPs
can see spurious ASTs (which doesn't cause a problem, it just means some
time may be wasted).
- Make sure ASTs are always set on the same CPU as the target LWP, and
delivered via IPI if posted from a remote CPU so that they are resolved
quickly.
- Add some cache line padding to struct cpu_info.
- Add a memory barrier in a couple of places where ci_curlwp is set. This
is needed whenever an LWP that is resuming on the CPU could hold an
adaptive mutex. The barrier needs to drain the CPU's store buffer, so
that the update to ci_curlwp becomes globally visible before the LWP can
resume and call mutex_exit().
diffstat:
sys/arch/arm/arm/arm_machdep.c | 30 +++++++++++++++++++---
sys/arch/arm/arm32/cpuswitch.S | 6 +++-
sys/arch/arm/arm32/db_machdep.c | 6 +---
sys/arch/arm/arm32/genassym.cf | 4 +-
sys/arch/arm/include/arm32/frame.h | 47 +++++++++++++----------------------
sys/arch/arm/include/cpu.h | 50 +++++++++++++++++++-------------------
sys/arch/arm/include/locore.h | 7 ++++-
sys/arch/arm/include/proc.h | 3 +-
sys/arch/evbarm/conf/std.generic | 4 +-
9 files changed, 87 insertions(+), 70 deletions(-)
diffs (truncated from 406 to 300 lines):
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/arm/arm_machdep.c
--- a/sys/arch/arm/arm/arm_machdep.c Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/arm/arm_machdep.c Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: arm_machdep.c,v 1.63 2020/02/15 08:16:10 skrll Exp $ */
+/* $NetBSD: arm_machdep.c,v 1.64 2020/08/14 16:18:36 skrll Exp $ */
/*
* Copyright (c) 2001 Wasabi Systems, Inc.
@@ -80,7 +80,7 @@
#include <sys/param.h>
-__KERNEL_RCSID(0, "$NetBSD: arm_machdep.c,v 1.63 2020/02/15 08:16:10 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: arm_machdep.c,v 1.64 2020/08/14 16:18:36 skrll Exp $");
#include <sys/atomic.h>
#include <sys/cpu.h>
@@ -241,17 +241,39 @@
if (flags & RESCHED_REMOTE) {
intr_ipi_send(ci->ci_kcpuset, IPI_KPREEMPT);
} else {
- atomic_or_uint(&ci->ci_astpending, __BIT(1));
+ l->l_md.md_astpending |= __BIT(1);
}
#endif /* __HAVE_PREEMPTION */
return;
}
+
+ KASSERT((flags & RESCHED_UPREEMPT) != 0);
if (flags & RESCHED_REMOTE) {
#ifdef MULTIPROCESSOR
intr_ipi_send(ci->ci_kcpuset, IPI_AST);
#endif /* MULTIPROCESSOR */
} else {
- setsoftast(ci);
+ l->l_md.md_astpending |= __BIT(0);
+ }
+}
+
+
+/*
+ * Notify the current lwp (l) that it has a signal pending,
+ * process as soon as possible.
+ */
+void
+cpu_signotify(struct lwp *l)
+{
+
+ KASSERT(kpreempt_disabled());
+
+ if (l->l_cpu != curcpu()) {
+#ifdef MULTIPROCESSOR
+ intr_ipi_send(l->l_cpu->ci_kcpuset, IPI_AST);
+#endif
+ } else {
+ l->l_md.md_astpending |= __BIT(0);
}
}
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/arm32/cpuswitch.S
--- a/sys/arch/arm/arm32/cpuswitch.S Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/arm32/cpuswitch.S Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpuswitch.S,v 1.101 2020/07/10 12:25:09 skrll Exp $ */
+/* $NetBSD: cpuswitch.S,v 1.102 2020/08/14 16:18:36 skrll Exp $ */
/*
* Copyright 2003 Wasabi Systems, Inc.
@@ -87,7 +87,7 @@
#include <arm/asm.h>
#include <arm/locore.h>
- RCSID("$NetBSD: cpuswitch.S,v 1.101 2020/07/10 12:25:09 skrll Exp $")
+ RCSID("$NetBSD: cpuswitch.S,v 1.102 2020/08/14 16:18:36 skrll Exp $")
/* LINTSTUB: include <sys/param.h> */
@@ -191,6 +191,7 @@
/* We have a new curlwp now so make a note of it */
str r6, [r5, #(CI_CURLWP)]
+ dmb /* see comments in kern_mutex.c */
/* Get the new pcb */
ldr r7, [r6, #(L_PCB)]
@@ -388,6 +389,7 @@
mcr p15, 0, r5, c13, c0, 4 /* save new lwp */
#endif
str r5, [r7, #(CI_CURLWP)] /* save new lwp */
+ dmb /* see comments in kern_mutex.c */
#ifdef KASAN
mov r0, r5
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/arm32/db_machdep.c
--- a/sys/arch/arm/arm32/db_machdep.c Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/arm32/db_machdep.c Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: db_machdep.c,v 1.34 2020/07/03 10:19:18 jmcneill Exp $ */
+/* $NetBSD: db_machdep.c,v 1.35 2020/08/14 16:18:36 skrll Exp $ */
/*
* Copyright (c) 1996 Mark Brinicombe
@@ -34,7 +34,7 @@
#endif
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_machdep.c,v 1.34 2020/07/03 10:19:18 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_machdep.c,v 1.35 2020/08/14 16:18:36 skrll Exp $");
#include <sys/param.h>
@@ -521,8 +521,6 @@
&ci->ci_cpl, cpuid, ci->ci_cpl);
db_printf("%p cpu[%lu].ci_softints = 0x%08x\n",
&ci->ci_softints, cpuid, ci->ci_softints);
- db_printf("%p cpu[%lu].ci_astpending = 0x%08x\n",
- &ci->ci_astpending, cpuid, ci->ci_astpending);
db_printf("%p cpu[%lu].ci_intr_depth = %u\n",
&ci->ci_intr_depth, cpuid, ci->ci_intr_depth);
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/arm32/genassym.cf
--- a/sys/arch/arm/arm32/genassym.cf Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/arm32/genassym.cf Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: genassym.cf,v 1.93 2020/07/08 10:18:00 skrll Exp $
+# $NetBSD: genassym.cf,v 1.94 2020/08/14 16:18:36 skrll Exp $
# Copyright (c) 1982, 1990 The Regents of the University of California.
# All rights reserved.
@@ -166,6 +166,7 @@
define L_PROC offsetof(struct lwp, l_proc)
define L_PRIVATE offsetof(struct lwp, l_private)
define L_FLAG offsetof(struct lwp, l_flag)
+define L_MD_ASTPENDING offsetof(struct lwp, l_md.md_astpending)
define L_MD_FLAGS offsetof(struct lwp, l_md.md_flags)
define L_MD_TF offsetof(struct lwp, l_md.md_tf)
define MDLWP_NOALIGNFLT MDLWP_NOALIGNFLT
@@ -225,7 +226,6 @@
define CPU_INFO_SIZE sizeof(struct cpu_info)
define CI_ARM_CPUID offsetof(struct cpu_info, ci_arm_cpuid)
-define CI_ASTPENDING offsetof(struct cpu_info, ci_astpending)
define CI_CPL offsetof(struct cpu_info, ci_cpl)
define CI_CURLWP offsetof(struct cpu_info, ci_curlwp)
define CI_INTR_DEPTH offsetof(struct cpu_info, ci_intr_depth)
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/include/arm32/frame.h
--- a/sys/arch/arm/include/arm32/frame.h Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/include/arm32/frame.h Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: frame.h,v 1.47 2018/10/28 14:46:59 skrll Exp $ */
+/* $NetBSD: frame.h,v 1.48 2020/08/14 16:18:36 skrll Exp $ */
/*
* Copyright (c) 1994-1997 Mark Brinicombe.
@@ -151,26 +151,16 @@
msr cpsr_c, ra /* Restore interrupts */
#endif
-#ifdef __HAVE_PREEMPTION
-#define DO_CLEAR_ASTPENDING \
- mvn r1, #1 /* complement of 1 */ ;\
- add r0, r4, #CI_ASTPENDING /* address of astpending */ ;\
- bl _C_LABEL(atomic_and_uint) /* clear AST */
-#else
-#define DO_CLEAR_ASTPENDING \
- mov r0, #0 ;\
- str r0, [r4, #CI_ASTPENDING] /* clear AST */
-#endif
-
#define DO_PENDING_AST(lbl) ;\
-1: ldr r1, [r4, #CI_ASTPENDING] /* Pending AST? */ ;\
- tst r1, #0x00000001 ;\
+1: ldr r1, [r5, #L_MD_ASTPENDING] /* Pending AST? */ ;\
+ tst r1, #1 ;\
beq lbl /* Nope. Just bail */ ;\
- DO_CLEAR_ASTPENDING ;\
- CPSIE_I(r5, r5) /* Restore interrupts */ ;\
+ bic r0, r1, #1 /* clear AST */ ;\
+ str r0, [r5, #L_MD_ASTPENDING] ;\
+ CPSIE_I(r6, r6) /* Restore interrupts */ ;\
mov r0, sp ;\
bl _C_LABEL(ast) /* ast(frame) */ ;\
- CPSID_I(r0, r5) /* Disable interrupts */ ;\
+ CPSID_I(r0, r6) /* Disable interrupts */ ;\
b 1b /* test again */
/*
@@ -179,8 +169,8 @@
* alignment faults when executing old a.out ARM binaries.
*
* Note that when ENABLE_ALIGNMENTS_FAULTS finishes r4 will contain
- * pointer to the cpu's cpu_info. DO_AST_AND_RESTORE_ALIGNMENT_FAULTS
- * relies on r4 being preserved.
+ * curcpu() and r5 containing curlwp. DO_AST_AND_RESTORE_ALIGNMENT_FAULTS
+ * relies on r4 and r5 being preserved.
*/
#ifdef EXEC_AOUT
#define AST_ALIGNMENT_FAULT_LOCALS \
@@ -198,10 +188,9 @@
#define ENABLE_ALIGNMENT_FAULTS \
and r7, r0, #(PSR_MODE) /* Test for USR32 mode */ ;\
cmp r7, #(PSR_USR32_MODE) ;\
- GET_CURCPU(r4) /* r4 = cpuinfo */ ;\
+ GET_CURX(r4, r5) /* r4 = curcpu, r5 = curlwp */ ;\
bne 1f /* Not USR mode skip AFLT */ ;\
- ldr r1, [r4, #CI_CURLWP] /* get curlwp from cpu_info */ ;\
- ldr r1, [r1, #L_MD_FLAGS] /* Fetch l_md.md_flags */ ;\
+ ldr r1, [r5, #L_MD_FLAGS] /* Fetch l_md.md_flags */ ;\
tst r1, #MDLWP_NOALIGNFLT ;\
beq 1f /* AFLTs already enabled */ ;\
ldr r2, .Laflt_cpufuncs ;\
@@ -213,13 +202,13 @@
/*
* This macro must be invoked just before PULLFRAMEFROMSVCANDEXIT or
* PULLFRAME at the end of interrupt/exception handlers. We know that
- * r4 points to cpu_info since that is what ENABLE_ALIGNMENT_FAULTS did
- * for use.
+ * r4 points to curcpu() and r5 points to curlwp since that is what
+ * ENABLE_ALIGNMENT_FAULTS did for us.
*/
#define DO_AST_AND_RESTORE_ALIGNMENT_FAULTS \
DO_PENDING_SOFTINTS ;\
- GET_CPSR(r5) /* save CPSR */ ;\
- CPSID_I(r1, r5) /* Disable interrupts */ ;\
+ GET_CPSR(r6) /* save CPSR */ ;\
+ CPSID_I(r1, r6) /* Disable interrupts */ ;\
cmp r7, #(PSR_USR32_MODE) /* Returning to USR mode? */ ;\
bne 3f /* Nope, get out now */ ;\
DO_PENDING_AST(2f) /* Pending AST? */ ;\
@@ -240,13 +229,13 @@
#define ENABLE_ALIGNMENT_FAULTS \
and r7, r0, #(PSR_MODE) /* Test for USR32 mode */ ;\
- GET_CURCPU(r4) /* r4 = cpuinfo */
+ GET_CURX(r4, r5) /* r4 = curcpu, r5 = curlwp */
#define DO_AST_AND_RESTORE_ALIGNMENT_FAULTS \
DO_PENDING_SOFTINTS ;\
- GET_CPSR(r5) /* save CPSR */ ;\
- CPSID_I(r1, r5) /* Disable interrupts */ ;\
+ GET_CPSR(r6) /* save CPSR */ ;\
+ CPSID_I(r1, r6) /* Disable interrupts */ ;\
cmp r7, #(PSR_USR32_MODE) ;\
bne 2f /* Nope, get out now */ ;\
DO_PENDING_AST(2f) /* Pending AST? */ ;\
diff -r 05d012f96435 -r c2c8ef86ef52 sys/arch/arm/include/cpu.h
--- a/sys/arch/arm/include/cpu.h Fri Aug 14 14:42:44 2020 +0000
+++ b/sys/arch/arm/include/cpu.h Fri Aug 14 16:18:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.h,v 1.111 2020/06/29 23:54:06 riastradh Exp $ */
+/* $NetBSD: cpu.h,v 1.112 2020/08/14 16:18:36 skrll Exp $ */
/*
* Copyright (c) 1994-1996 Mark Brinicombe.
@@ -154,6 +154,7 @@
#include <sys/cpu_data.h>
#include <sys/device_if.h>
#include <sys/evcnt.h>
+#include <sys/param.h>
struct cpu_info {
struct cpu_data ci_data; /* MI per-cpu data */
@@ -163,22 +164,32 @@
uint32_t ci_arm_cputype; /* CPU type */
uint32_t ci_arm_cpurev; /* CPU revision */
uint32_t ci_ctrl; /* The CPU control register */
- int ci_cpl; /* current processor level (spl) */
- volatile int ci_astpending; /* */
- int ci_want_resched;/* resched() was called */
- int ci_intr_depth; /* */
- int ci_kfpu_spl;
+ /*
+ * the following are in their own cache line, as they are stored to
+ * regularly by remote CPUs; when they were mixed with other fields
+ * we observed frequent cache misses.
+ */
+ int ci_want_resched __aligned(COHERENCY_UNIT);
+ /* resched() was called */
+ lwp_t * ci_curlwp __aligned(COHERENCY_UNIT);
+ /* current lwp */
+ lwp_t * ci_onproc; /* current user LWP / kthread */
+
+ /*
+ * largely CPU-private.
+ */
+ lwp_t * ci_softlwps[SOFTINT_COUNT] __aligned(COHERENCY_UNIT);
struct cpu_softc *
ci_softc; /* platform softc */
- lwp_t * ci_softlwps[SOFTINT_COUNT];
- volatile uint32_t
- ci_softints;
+ int ci_cpl; /* current processor level (spl) */
+ int ci_kfpu_spl;
- lwp_t * ci_curlwp; /* current lwp */
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