x86/tlb: Move __flush_tlb_one_kernel() 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.

As a fourth step, move __flush_tlb_one_kernel() out of line and hide
the native function. The latter can be static when CONFIG_PARAVIRT is
disabled.

Consolidate the name space while at it and remove the pointless extra
wrapper in the paravirt code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421092559.535159540@linutronix.de

arch/x86/include/asm/pgtable_32.h

@@ -60,7 +60,7 @@ void sync_initial_page_table(void);
 #define kpte_clear_flush(ptep, vaddr)		\
 do {						\
 	pte_clear(&init_mm, (vaddr), (ptep));	\
-	__flush_tlb_one_kernel((vaddr));		\
+	flush_tlb_one_kernel((vaddr));		\
 } while (0)
 
 #endif /* !__ASSEMBLY__ */

arch/x86/include/asm/tlbflush.h

@@ -143,6 +143,7 @@ static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
 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);
 
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
@@ -317,14 +318,6 @@ static inline void cr4_clear_bits(unsigned long mask)
 	local_irq_restore(flags);
 }
 
-/*
- * Mark all other ASIDs as invalid, preserves the current.
- */
-static inline void invalidate_other_asid(void)
-{
-	this_cpu_write(cpu_tlbstate.invalidate_other, true);
-}
-
 /*
  * Save some of cr4 feature set we're using (e.g.  Pentium 4MB
  * enable and PPro Global page enable), so that any CPU's that boot
@@ -365,38 +358,6 @@ static inline void __flush_tlb_all(void)
 	}
 }
 
-/*
- * flush one page in the kernel mapping
- */
-static inline void __flush_tlb_one_kernel(unsigned long addr)
-{
-	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
-
-	/*
-	 * If PTI is off, then __flush_tlb_one_user() is just INVLPG or its
-	 * paravirt equivalent.  Even with PCID, this is sufficient: we only
-	 * use PCID if we also use global PTEs for the kernel mapping, and
-	 * INVLPG flushes global translations across all address spaces.
-	 *
-	 * If PTI is on, then the kernel is mapped with non-global PTEs, and
-	 * __flush_tlb_one_user() will flush the given address for the current
-	 * kernel address space and for its usermode counterpart, but it does
-	 * not flush it for other address spaces.
-	 */
-	flush_tlb_one_user(addr);
-
-	if (!static_cpu_has(X86_FEATURE_PTI))
-		return;
-
-	/*
-	 * See above.  We need to propagate the flush to all other address
-	 * spaces.  In principle, we only need to propagate it to kernelmode
-	 * address spaces, but the extra bookkeeping we would need is not
-	 * worth it.
-	 */
-	invalidate_other_asid();
-}
-
 #define TLB_FLUSH_ALL	-1UL
 
 /*

arch/x86/mm/init_64.c

@@ -298,7 +298,7 @@ static void __set_pte_vaddr(pud_t *pud, unsigned long vaddr, pte_t new_pte)
 	 * It's enough to flush this one mapping.
 	 * (PGE mappings get flushed as well)
 	 */
-	__flush_tlb_one_kernel(vaddr);
+	flush_tlb_one_kernel(vaddr);
 }
 
 void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte)

arch/x86/mm/ioremap.c

@@ -885,5 +885,5 @@ void __init __early_set_fixmap(enum fixed_addresses idx,
 		set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 	else
 		pte_clear(&init_mm, addr, pte);
-	__flush_tlb_one_kernel(addr);
+	flush_tlb_one_kernel(addr);
 }

arch/x86/mm/kmmio.c

@@ -173,7 +173,7 @@ static int clear_page_presence(struct kmmio_fault_page *f, bool clear)
 		return -1;
 	}
 
-	__flush_tlb_one_kernel(f->addr);
+	flush_tlb_one_kernel(f->addr);
 	return 0;
 }
 

arch/x86/mm/pat/set_memory.c

@@ -345,7 +345,7 @@ static void __cpa_flush_tlb(void *data)
 	unsigned int i;
 
 	for (i = 0; i < cpa->numpages; i++)
-		__flush_tlb_one_kernel(fix_addr(__cpa_addr(cpa, i)));
+		flush_tlb_one_kernel(fix_addr(__cpa_addr(cpa, i)));
 }
 
 static void cpa_flush(struct cpa_data *data, int cache)

arch/x86/mm/pgtable_32.c

@@ -64,7 +64,7 @@ void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
 	 * It's enough to flush this one mapping.
 	 * (PGE mappings get flushed as well)
 	 */
-	__flush_tlb_one_kernel(vaddr);
+	flush_tlb_one_kernel(vaddr);
 }
 
 unsigned long __FIXADDR_TOP = 0xfffff000;

arch/x86/mm/tlb.c

@@ -876,7 +876,7 @@ static void do_kernel_range_flush(void *info)
 
 	/* flush range by one by one 'invlpg' */
 	for (addr = f->start; addr < f->end; addr += PAGE_SIZE)
-		__flush_tlb_one_kernel(addr);
+		flush_tlb_one_kernel(addr);
 }
 
 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
@@ -918,6 +918,38 @@ unsigned long __get_current_cr3_fast(void)
 }
 EXPORT_SYMBOL_GPL(__get_current_cr3_fast);
 
+/*
+ * Flush one page in the kernel mapping
+ */
+void flush_tlb_one_kernel(unsigned long addr)
+{
+	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
+
+	/*
+	 * If PTI is off, then __flush_tlb_one_user() is just INVLPG or its
+	 * paravirt equivalent.  Even with PCID, this is sufficient: we only
+	 * use PCID if we also use global PTEs for the kernel mapping, and
+	 * INVLPG flushes global translations across all address spaces.
+	 *
+	 * If PTI is on, then the kernel is mapped with non-global PTEs, and
+	 * __flush_tlb_one_user() will flush the given address for the current
+	 * kernel address space and for its usermode counterpart, but it does
+	 * not flush it for other address spaces.
+	 */
+	flush_tlb_one_user(addr);
+
+	if (!static_cpu_has(X86_FEATURE_PTI))
+		return;
+
+	/*
+	 * See above.  We need to propagate the flush to all other address
+	 * spaces.  In principle, we only need to propagate it to kernelmode
+	 * address spaces, but the extra bookkeeping we would need is not
+	 * worth it.
+	 */
+	this_cpu_write(cpu_tlbstate.invalidate_other, true);
+}
+
 /*
  * Flush one page in the user mapping
  */