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Subject[tip: x86/mm] x86/tlb: Move __flush_tlb() out of line
The following commit has been merged into the x86/mm branch of tip:

Commit-ID: 2faf153bb7346b7dfc895f916edf93a86297ec0a
Gitweb: https://git.kernel.org/tip/2faf153bb7346b7dfc895f916edf93a86297ec0a
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 21 Apr 2020 11:20:32 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Sun, 26 Apr 2020 11:00:05 +02:00

x86/tlb: Move __flush_tlb() 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 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 namespace 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/20200421092559.246130908@linutronix.de
---
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(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 694d8da..f412450 100644
--- 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);
}
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d804030..fe1fd02 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -140,12 +140,13 @@ static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
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(u16 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)

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 51b9190..23ad8e9 100644
--- 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(set_atomicity_lock)

/* 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(set_atomicity_lock)
{
/* 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);
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index c131ba4..4cb3d82 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -160,11 +160,6 @@ unsigned paravirt_patch_insns(void *insn_buff, unsigned len,
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,
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index a03614b..4a781cf 100644
--- 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_mem(void *vaddr, unsigned long size,
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)
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 3d9d819..0611648 100644
--- 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 struct flush_tlb_info *f,
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(void)
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
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 1fd321f..6af766c 100644
--- 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 msg_desc *mdp, struct bau_control *bcp,
* 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);
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