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Subject[tip:x86/pti] x86/mm: Rename flush_tlb_single() and flush_tlb_one() to __flush_tlb_one_[user|kernel]()
Commit-ID:  084c63d0cf9b2b2e9ee77984e570571f5df65dd5
Gitweb: https://git.kernel.org/tip/084c63d0cf9b2b2e9ee77984e570571f5df65dd5
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Wed, 31 Jan 2018 08:03:10 -0800
Committer: Ingo Molnar <mingo@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 <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/3303b02e3c3d049dc5235d5651e0ae6d29a34354.1517414378.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@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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