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Message-Id: <20200419203336.134117165@linutronix.de>
User-Agent: quilt/0.65
Date:   Sun, 19 Apr 2020 22:31:42 +0200
From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     x86@kernel.org, Kees Cook <keescook@chromium.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Lendacky <Thomas.Lendacky@amd.com>,
        Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: [patch 05/15] x86/tlb: Move __flush_tlb() out of line
References: <20200419203137.214111265@linutronix.de>
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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.

The various TLB flush functions need access to cpu_tlbstate. As a first
step move __flush_tlb() 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>
Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>
Cc: Juergen Gross <jgross@suse.com>
---
 arch/x86/include/asm/paravirt.h    |    4 +++-
 arch/x86/include/asm/tlbflush.h    |   29 +++++------------------------
 arch/x86/kernel/cpu/mtrr/generic.c |    4 ++--
 arch/x86/kernel/paravirt.c         |    7 +------
 arch/x86/mm/mem_encrypt.c          |    2 +-
 arch/x86/mm/tlb.c                  |   33 ++++++++++++++++++++++++++++++++-
 arch/x86/platform/uv/tlb_uv.c      |    2 +-
 7 files changed, 45 insertions(+), 36 deletions(-)

--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -47,7 +47,9 @@ static inline void slow_down_io(void)
 #endif
 }
 
-static inline void __flush_tlb(void)
+void native_flush_tlb_local(void);
+
+static inline void __flush_tlb_local(void)
 {
 	PVOP_VCALL0(mmu.flush_tlb_user);
 }
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -140,12 +140,13 @@ static inline unsigned long build_cr3_no
 	return __sme_pa(pgd) | kern_pcid(asid) | CR3_NOFLUSH;
 }
 
+void flush_tlb_local(void);
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else
-#define __flush_tlb() __native_flush_tlb()
-#define __flush_tlb_global() __native_flush_tlb_global()
-#define __flush_tlb_one_user(addr) __native_flush_tlb_one_user(addr)
+#define __flush_tlb_global()		__native_flush_tlb_global()
+#define __flush_tlb_one_user(addr)	__native_flush_tlb_one_user(addr)
 #endif
 
 struct tlb_context {
@@ -371,24 +372,6 @@ static inline void invalidate_user_asid(
 }
 
 /*
- * flush the entire current user mapping
- */
-static inline void __native_flush_tlb(void)
-{
-	/*
-	 * Preemption or interrupts must be disabled to protect the access
-	 * to the per CPU variable and to prevent being preempted between
-	 * read_cr3() and write_cr3().
-	 */
-	WARN_ON_ONCE(preemptible());
-
-	invalidate_user_asid(this_cpu_read(cpu_tlbstate.loaded_mm_asid));
-
-	/* If current->mm == NULL then the read_cr3() "borrows" an mm */
-	native_write_cr3(__native_read_cr3());
-}
-
-/*
  * flush everything
  */
 static inline void __native_flush_tlb_global(void)
@@ -461,7 +444,7 @@ static inline void __flush_tlb_all(void)
 		/*
 		 * !PGE -> !PCID (setup_pcid()), thus every flush is total.
 		 */
-		__flush_tlb();
+		flush_tlb_local();
 	}
 }
 
@@ -537,8 +520,6 @@ struct flush_tlb_info {
 	bool			freed_tables;
 };
 
-#define local_flush_tlb() __flush_tlb()
-
 #define flush_tlb_mm(mm)						\
 		flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true)
 
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -761,7 +761,7 @@ static void prepare_set(void) __acquires
 
 	/* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
 	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
-	__flush_tlb();
+	flush_tlb_local();
 
 	/* Save MTRR state */
 	rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
@@ -778,7 +778,7 @@ static void post_set(void) __releases(se
 {
 	/* Flush TLBs (no need to flush caches - they are disabled) */
 	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
-	__flush_tlb();
+	flush_tlb_local();
 
 	/* Intel (P6) standard MTRRs */
 	mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -160,11 +160,6 @@ unsigned paravirt_patch_insns(void *insn
 	return insn_len;
 }
 
-static void native_flush_tlb(void)
-{
-	__native_flush_tlb();
-}
-
 /*
  * Global pages have to be flushed a bit differently. Not a real
  * performance problem because this does not happen often.
@@ -359,7 +354,7 @@ struct paravirt_patch_template pv_ops =
 #endif /* CONFIG_PARAVIRT_XXL */
 
 	/* Mmu ops. */
-	.mmu.flush_tlb_user	= native_flush_tlb,
+	.mmu.flush_tlb_user	= native_flush_tlb_local,
 	.mmu.flush_tlb_kernel	= native_flush_tlb_global,
 	.mmu.flush_tlb_one_user	= native_flush_tlb_one_user,
 	.mmu.flush_tlb_others	= native_flush_tlb_others,
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -134,7 +134,7 @@ static void __init __sme_early_map_unmap
 		size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
 	} while (size);
 
-	__native_flush_tlb();
+	flush_tlb_local();
 }
 
 void __init sme_unmap_bootdata(char *real_mode_data)
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -18,6 +18,13 @@
 
 #include "mm_internal.h"
 
+#ifdef CONFIG_PARAVIRT
+# define STATIC_NOPV
+#else
+# define STATIC_NOPV			static
+# define __flush_tlb_local		native_flush_tlb_local
+#endif
+
 /*
  *	TLB flushing, formerly SMP-only
  *		c/o Linus Torvalds.
@@ -645,7 +652,7 @@ static void flush_tlb_func_common(const
 		trace_tlb_flush(reason, nr_invalidate);
 	} else {
 		/* Full flush. */
-		local_flush_tlb();
+		flush_tlb_local();
 		if (local)
 			count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
 		trace_tlb_flush(reason, TLB_FLUSH_ALL);
@@ -884,6 +891,30 @@ unsigned long __get_current_cr3_fast(voi
 EXPORT_SYMBOL_GPL(__get_current_cr3_fast);
 
 /*
+ * Flush the entire current user mapping
+ */
+STATIC_NOPV void native_flush_tlb_local(void)
+{
+	/*
+	 * Preemption or interrupts must be disabled to protect the access
+	 * to the per CPU variable and to prevent being preempted between
+	 * read_cr3() and write_cr3().
+	 */
+	WARN_ON_ONCE(preemptible());
+
+	invalidate_user_asid(this_cpu_read(cpu_tlbstate.loaded_mm_asid));
+
+	/* If current->mm == NULL then the read_cr3() "borrows" an mm */
+	native_write_cr3(__native_read_cr3());
+}
+
+void flush_tlb_local(void)
+{
+	__flush_tlb_local();
+}
+EXPORT_SYMBOL_GPL(flush_tlb_local);
+
+/*
  * 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
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -293,7 +293,7 @@ static void bau_process_message(struct m
 	 * This must be a normal message, or retry of a normal message
 	 */
 	if (msg->address == TLB_FLUSH_ALL) {
-		local_flush_tlb();
+		flush_tlb_local();
 		stat->d_alltlb++;
 	} else {
 		__flush_tlb_one_user(msg->address);