Messages in this thread Patch in this message | | | Date | Sun, 19 Apr 2020 22:31:38 +0200 | From | Thomas Gleixner <> | Subject | [patch 01/15] x86/tlb: Uninline __get_current_cr3_fast() |
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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.
In preparation of unexporting cpu_tlbstate move __get_current_cr3_fast() into the x86 TLB management code.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/include/asm/mmu_context.h | 19 +------------------ arch/x86/mm/tlb.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+), 18 deletions(-)
--- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -225,24 +225,7 @@ static inline bool arch_vma_access_permi return __pkru_allows_pkey(vma_pkey(vma), write); } -/* - * This can be used from process context to figure out what the value of - * CR3 is without needing to do a (slow) __read_cr3(). - * - * It's intended to be used for code like KVM that sneakily changes CR3 - * and needs to restore it. It needs to be used very carefully. - */ -static inline unsigned long __get_current_cr3_fast(void) -{ - unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd, - this_cpu_read(cpu_tlbstate.loaded_mm_asid)); - - /* For now, be very restrictive about when this can be called. */ - VM_WARN_ON(in_nmi() || preemptible()); - - VM_BUG_ON(cr3 != __read_cr3()); - return cr3; -} +unsigned long __get_current_cr3_fast(void); typedef struct { struct mm_struct *mm; --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -844,6 +844,26 @@ void flush_tlb_kernel_range(unsigned lon } /* + * This can be used from process context to figure out what the value of + * CR3 is without needing to do a (slow) __read_cr3(). + * + * It's intended to be used for code like KVM that sneakily changes CR3 + * and needs to restore it. It needs to be used very carefully. + */ +unsigned long __get_current_cr3_fast(void) +{ + unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd, + this_cpu_read(cpu_tlbstate.loaded_mm_asid)); + + /* For now, be very restrictive about when this can be called. */ + VM_WARN_ON(in_nmi() || preemptible()); + + VM_BUG_ON(cr3 != __read_cr3()); + return cr3; +} +EXPORT_SYMBOL_GPL(__get_current_cr3_fast); + +/* * arch_tlbbatch_flush() performs a full TLB flush regardless of the active mm. * This means that the 'struct flush_tlb_info' that describes which mappings to * flush is actually fixed. We therefore set a single fixed struct and use it in
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