linux-kernel - [patch 09/15] x86/tlb: Move flush_tlb

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Date:   Sun, 19 Apr 2020 22:31:46 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Kees Cook <keescook@...omium.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Lendacky <Thomas.Lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: [patch 09/15] x86/tlb: Move flush_tlb_others() out of line

cpu_tlbstate is exported because various TLB related functions need access
to it, but cpu_tlbstate is sensitive information which should only be
accessed by well contained kernel functions and not be directly exposed to
modules.

The various TLB flush functions need access to cpu_tlbstate. As last step
move __flush_tlb_others() out of line and hide the native function. The
latter can be static when CONFIG_PARAVIRT is disabled.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/include/asm/paravirt.h |    6 ++++--
 arch/x86/include/asm/tlbflush.h |   10 ++++------
 arch/x86/mm/tlb.c               |   11 +++++++++--
 3 files changed, 17 insertions(+), 10 deletions(-)


Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/include/asm/paravirt.h |    6 ++++--
 arch/x86/include/asm/tlbflush.h |   10 ++++------
 arch/x86/mm/tlb.c               |   11 +++++++++--
 3 files changed, 17 insertions(+), 10 deletions(-)

--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -50,6 +50,8 @@ static inline void slow_down_io(void)
 void native_flush_tlb_local(void);
 void native_flush_tlb_global(void);
 void native_flush_tlb_one_user(unsigned long addr);
+void native_flush_tlb_others(const struct cpumask *cpumask,
+			     const struct flush_tlb_info *info);
 
 static inline void __flush_tlb_local(void)
 {
@@ -66,8 +68,8 @@ static inline void __flush_tlb_one_user(
 	PVOP_VCALL1(mmu.flush_tlb_one_user, addr);
 }
 
-static inline void flush_tlb_others(const struct cpumask *cpumask,
-				    const struct flush_tlb_info *info)
+static inline void __flush_tlb_others(const struct cpumask *cpumask,
+				      const struct flush_tlb_info *info)
 {
 	PVOP_VCALL2(mmu.flush_tlb_others, cpumask, info);
 }
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -140,10 +140,14 @@ static inline unsigned long build_cr3_no
 	return __sme_pa(pgd) | kern_pcid(asid) | CR3_NOFLUSH;
 }
 
+struct flush_tlb_info;
+
 void flush_tlb_local(void);
 void flush_tlb_global(void);
 void flush_tlb_one_user(unsigned long addr);
 void flush_tlb_one_kernel(unsigned long addr);
+void flush_tlb_others(const struct cpumask *cpumask,
+		      const struct flush_tlb_info *info);
 
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
@@ -418,9 +422,6 @@ static inline void flush_tlb_page(struct
 	flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
 }
 
-void native_flush_tlb_others(const struct cpumask *cpumask,
-			     const struct flush_tlb_info *info);
-
 static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
 {
 	/*
@@ -442,9 +443,6 @@ static inline void arch_tlbbatch_add_mm(
 extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
 
 #ifndef CONFIG_PARAVIRT
-#define flush_tlb_others(mask, info)	\
-	native_flush_tlb_others(mask, info)
-
 #define paravirt_tlb_remove_table(tlb, page) \
 	tlb_remove_page(tlb, (void *)(page))
 #endif
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -25,6 +25,7 @@
 # define __flush_tlb_local		native_flush_tlb_local
 # define __flush_tlb_global		native_flush_tlb_global
 # define __flush_tlb_one_user(addr)	native_flush_tlb_one_user(addr)
+# define __flush_tlb_others(msk, info)	native_flush_tlb_others(msk, info)
 #endif
 
 /*
@@ -715,8 +716,8 @@ static bool tlb_is_not_lazy(int cpu, voi
 	return !per_cpu(cpu_tlbstate.is_lazy, cpu);
 }
 
-void native_flush_tlb_others(const struct cpumask *cpumask,
-			     const struct flush_tlb_info *info)
+STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
+					 const struct flush_tlb_info *info)
 {
 	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
 	if (info->end == TLB_FLUSH_ALL)
@@ -766,6 +767,12 @@ void native_flush_tlb_others(const struc
 				(void *)info, 1, cpumask);
 }
 
+void flush_tlb_others(const struct cpumask *cpumask,
+		      const struct flush_tlb_info *info)
+{
+	__flush_tlb_others(cpumask, info);
+}
+
 /*
  * See Documentation/x86/tlb.rst for details.  We choose 33
  * because it is large enough to cover the vast majority (at