[patch 09/15] x86/tlb: Move flush_tlb_others() out of line

From: Thomas Gleixner
Date: Sun Apr 19 2020 - 16:36:51 EST


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@xxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx>
---
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