Commit-ID:  084c63d0cf9b2b2e9ee77984e570571f5df65dd5
Gitweb:     https://git.kernel.org/tip/084c63d0cf9b2b2e9ee77984e570571f5df65dd5
Author:     Andy Lutomirski <l...@kernel.org>
AuthorDate: Wed, 31 Jan 2018 08:03:10 -0800
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 13 Feb 2018 15:11:59 +0100

x86/mm: Rename flush_tlb_single() and flush_tlb_one() to 
__flush_tlb_one_[user|kernel]()

flush_tlb_single() and flush_tlb_one() sound almost identical, but
they really mean "flush one user translation" and "flush one kernel
translation".  Rename them to flush_tlb_one_user() and
flush_tlb_one_kernel() to make the semantics more obvious.

[ I was looking at some PTI-related code, and the flush-one-address code
  is unnecessarily hard to understand because the names of the helpers are
  uninformative.  This came up during PTI review, but no one got around to
  doing it. ]

Signed-off-by: Andy Lutomirski <l...@kernel.org>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Eduardo Valentin <edu...@amazon.com>
Cc: Hugh Dickins <hu...@google.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Kees Cook <keesc...@google.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Linux-MM <linux...@kvack.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Will Deacon <will.dea...@arm.com>
Link: 
http://lkml.kernel.org/r/3303b02e3c3d049dc5235d5651e0ae6d29a34354.1517414378.git.l...@kernel.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/include/asm/paravirt.h       |  4 ++--
 arch/x86/include/asm/paravirt_types.h |  2 +-
 arch/x86/include/asm/pgtable_32.h     |  2 +-
 arch/x86/include/asm/tlbflush.h       | 27 ++++++++++++++++++++-------
 arch/x86/kernel/paravirt.c            |  6 +++---
 arch/x86/mm/init_64.c                 |  2 +-
 arch/x86/mm/ioremap.c                 |  2 +-
 arch/x86/mm/kmmio.c                   |  2 +-
 arch/x86/mm/pgtable_32.c              |  2 +-
 arch/x86/mm/tlb.c                     |  6 +++---
 arch/x86/platform/uv/tlb_uv.c         |  2 +-
 arch/x86/xen/mmu_pv.c                 |  6 +++---
 include/trace/events/xen.h            |  2 +-
 13 files changed, 39 insertions(+), 26 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 892df37..554841f 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -297,9 +297,9 @@ static inline void __flush_tlb_global(void)
 {
        PVOP_VCALL0(pv_mmu_ops.flush_tlb_kernel);
 }
-static inline void __flush_tlb_single(unsigned long addr)
+static inline void __flush_tlb_one_user(unsigned long addr)
 {
-       PVOP_VCALL1(pv_mmu_ops.flush_tlb_single, addr);
+       PVOP_VCALL1(pv_mmu_ops.flush_tlb_one_user, addr);
 }
 
 static inline void flush_tlb_others(const struct cpumask *cpumask,
diff --git a/arch/x86/include/asm/paravirt_types.h 
b/arch/x86/include/asm/paravirt_types.h
index 6ec54d0..f624f1f 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -217,7 +217,7 @@ struct pv_mmu_ops {
        /* TLB operations */
        void (*flush_tlb_user)(void);
        void (*flush_tlb_kernel)(void);
-       void (*flush_tlb_single)(unsigned long addr);
+       void (*flush_tlb_one_user)(unsigned long addr);
        void (*flush_tlb_others)(const struct cpumask *cpus,
                                 const struct flush_tlb_info *info);
 
diff --git a/arch/x86/include/asm/pgtable_32.h 
b/arch/x86/include/asm/pgtable_32.h
index e67c062..e554667 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -61,7 +61,7 @@ void paging_init(void);
 #define kpte_clear_flush(ptep, vaddr)          \
 do {                                           \
        pte_clear(&init_mm, (vaddr), (ptep));   \
-       __flush_tlb_one((vaddr));               \
+       __flush_tlb_one_kernel((vaddr));                \
 } while (0)
 
 #endif /* !__ASSEMBLY__ */
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 2b8f18c..84137c2 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -140,7 +140,7 @@ static inline unsigned long build_cr3_noflush(pgd_t *pgd, 
u16 asid)
 #else
 #define __flush_tlb() __native_flush_tlb()
 #define __flush_tlb_global() __native_flush_tlb_global()
-#define __flush_tlb_single(addr) __native_flush_tlb_single(addr)
+#define __flush_tlb_one_user(addr) __native_flush_tlb_one_user(addr)
 #endif
 
 static inline bool tlb_defer_switch_to_init_mm(void)
@@ -400,7 +400,7 @@ static inline void __native_flush_tlb_global(void)
 /*
  * flush one page in the user mapping
  */
-static inline void __native_flush_tlb_single(unsigned long addr)
+static inline void __native_flush_tlb_one_user(unsigned long addr)
 {
        u32 loaded_mm_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid);
 
@@ -437,18 +437,31 @@ static inline void __flush_tlb_all(void)
 /*
  * flush one page in the kernel mapping
  */
-static inline void __flush_tlb_one(unsigned long addr)
+static inline void __flush_tlb_one_kernel(unsigned long addr)
 {
        count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
-       __flush_tlb_single(addr);
+
+       /*
+        * 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;
 
        /*
-        * __flush_tlb_single() will have cleared the TLB entry for this ASID,
-        * but since kernel space is replicated across all, we must also
-        * invalidate all others.
+        * 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();
 }
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 041096b..99dc79e 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -200,9 +200,9 @@ static void native_flush_tlb_global(void)
        __native_flush_tlb_global();
 }
 
-static void native_flush_tlb_single(unsigned long addr)
+static void native_flush_tlb_one_user(unsigned long addr)
 {
-       __native_flush_tlb_single(addr);
+       __native_flush_tlb_one_user(addr);
 }
 
 struct static_key paravirt_steal_enabled;
@@ -401,7 +401,7 @@ struct pv_mmu_ops pv_mmu_ops __ro_after_init = {
 
        .flush_tlb_user = native_flush_tlb,
        .flush_tlb_kernel = native_flush_tlb_global,
-       .flush_tlb_single = native_flush_tlb_single,
+       .flush_tlb_one_user = native_flush_tlb_one_user,
        .flush_tlb_others = native_flush_tlb_others,
 
        .pgd_alloc = __paravirt_pgd_alloc,
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 4a83728..60ae1fe 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -256,7 +256,7 @@ 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(vaddr);
+       __flush_tlb_one_kernel(vaddr);
 }
 
 void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index c45b6ec..e2db83b 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -820,5 +820,5 @@ 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(addr);
+       __flush_tlb_one_kernel(addr);
 }
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 58477ec..7c86867 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -168,7 +168,7 @@ static int clear_page_presence(struct kmmio_fault_page *f, 
bool clear)
                return -1;
        }
 
-       __flush_tlb_one(f->addr);
+       __flush_tlb_one_kernel(f->addr);
        return 0;
 }
 
diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
index c3c5274..9bb7f0a 100644
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -63,7 +63,7 @@ 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(vaddr);
+       __flush_tlb_one_kernel(vaddr);
 }
 
 unsigned long __FIXADDR_TOP = 0xfffff000;
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 012d026..0c93643 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -492,7 +492,7 @@ static void flush_tlb_func_common(const struct 
flush_tlb_info *f,
         *    flush that changes context.tlb_gen from 2 to 3.  If they get
         *    processed on this CPU in reverse order, we'll see
         *     local_tlb_gen == 1, mm_tlb_gen == 3, and end != TLB_FLUSH_ALL.
-        *    If we were to use __flush_tlb_single() and set local_tlb_gen to
+        *    If we were to use __flush_tlb_one_user() and set local_tlb_gen to
         *    3, we'd be break the invariant: we'd update local_tlb_gen above
         *    1 without the full flush that's needed for tlb_gen 2.
         *
@@ -513,7 +513,7 @@ static void flush_tlb_func_common(const struct 
flush_tlb_info *f,
 
                addr = f->start;
                while (addr < f->end) {
-                       __flush_tlb_single(addr);
+                       __flush_tlb_one_user(addr);
                        addr += PAGE_SIZE;
                }
                if (local)
@@ -660,7 +660,7 @@ 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(addr);
+               __flush_tlb_one_kernel(addr);
 }
 
 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 8538a67..7d5d53f 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -299,7 +299,7 @@ static void bau_process_message(struct msg_desc *mdp, 
struct bau_control *bcp,
                local_flush_tlb();
                stat->d_alltlb++;
        } else {
-               __flush_tlb_single(msg->address);
+               __flush_tlb_one_user(msg->address);
                stat->d_onetlb++;
        }
        stat->d_requestee++;
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index d850762..aae88fe 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1300,12 +1300,12 @@ static void xen_flush_tlb(void)
        preempt_enable();
 }
 
-static void xen_flush_tlb_single(unsigned long addr)
+static void xen_flush_tlb_one_user(unsigned long addr)
 {
        struct mmuext_op *op;
        struct multicall_space mcs;
 
-       trace_xen_mmu_flush_tlb_single(addr);
+       trace_xen_mmu_flush_tlb_one_user(addr);
 
        preempt_disable();
 
@@ -2370,7 +2370,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
 
        .flush_tlb_user = xen_flush_tlb,
        .flush_tlb_kernel = xen_flush_tlb,
-       .flush_tlb_single = xen_flush_tlb_single,
+       .flush_tlb_one_user = xen_flush_tlb_one_user,
        .flush_tlb_others = xen_flush_tlb_others,
 
        .pgd_alloc = xen_pgd_alloc,
diff --git a/include/trace/events/xen.h b/include/trace/events/xen.h
index b8adf05..7dd8f34 100644
--- a/include/trace/events/xen.h
+++ b/include/trace/events/xen.h
@@ -368,7 +368,7 @@ TRACE_EVENT(xen_mmu_flush_tlb,
            TP_printk("%s", "")
        );
 
-TRACE_EVENT(xen_mmu_flush_tlb_single,
+TRACE_EVENT(xen_mmu_flush_tlb_one_user,
            TP_PROTO(unsigned long addr),
            TP_ARGS(addr),
            TP_STRUCT__entry(

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