linux-kernel - [PATCH 4.19 17/35] asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE

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Date:   Mon,  4 Jan 2021 16:57:20 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Santosh Sivaraj <santosh@...six.org>
Subject: [PATCH 4.19 17/35] asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATE

From: Peter Zijlstra <peterz@...radead.org>

commit 96bc9567cbe112e9320250f01b9c060c882e8619 upstream.

Make issuing a TLB invalidate for page-table pages the normal case.

The reason is twofold:

 - too many invalidates is safer than too few,
 - most architectures use the linux page-tables natively
   and would thus require this.

Make it an opt-out, instead of an opt-in.

No change in behavior intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: <stable@...r.kernel.org> # 4.19
Signed-off-by: Santosh Sivaraj <santosh@...six.org>
[santosh: prerequisite for upcoming tlbflush backports]
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/Kconfig         |    2 +-
 arch/powerpc/Kconfig |    1 +
 arch/sparc/Kconfig   |    1 +
 arch/x86/Kconfig     |    1 -
 mm/memory.c          |    2 +-
 5 files changed, 4 insertions(+), 3 deletions(-)

--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -363,7 +363,7 @@ config HAVE_ARCH_JUMP_LABEL
 config HAVE_RCU_TABLE_FREE
 	bool
 
-config HAVE_RCU_TABLE_INVALIDATE
+config HAVE_RCU_TABLE_NO_INVALIDATE
 	bool
 
 config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -217,6 +217,7 @@ config PPC
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_RCU_TABLE_FREE		if SMP
+	select HAVE_RCU_TABLE_NO_INVALIDATE	if HAVE_RCU_TABLE_FREE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SYSCALL_TRACEPOINTS
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -64,6 +64,7 @@ config SPARC64
 	select HAVE_KRETPROBES
 	select HAVE_KPROBES
 	select HAVE_RCU_TABLE_FREE if SMP
+	select HAVE_RCU_TABLE_NO_INVALIDATE if HAVE_RCU_TABLE_FREE
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_DYNAMIC_FTRACE
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -181,7 +181,6 @@ config X86
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_RCU_TABLE_FREE		if PARAVIRT
-	select HAVE_RCU_TABLE_INVALIDATE	if HAVE_RCU_TABLE_FREE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
 	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -339,7 +339,7 @@ bool __tlb_remove_page_size(struct mmu_g
  */
 static inline void tlb_table_invalidate(struct mmu_gather *tlb)
 {
-#ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE
+#ifndef CONFIG_HAVE_RCU_TABLE_NO_INVALIDATE
 	/*
 	 * Invalidate page-table caches used by hardware walkers. Then we still
 	 * need to RCU-sched wait while freeing the pages because software