lkml.org 
[lkml]   [2020]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/mm] x86/tlb: Move __flush_tlb_global() out of line
The following commit has been merged into the x86/mm branch of tip:

Commit-ID: cd30d26cf307b45159cd629d60b989e582372afe
Gitweb: https://git.kernel.org/tip/cd30d26cf307b45159cd629d60b989e582372afe
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 21 Apr 2020 11:20:33 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Sun, 26 Apr 2020 11:00:27 +02:00

x86/tlb: Move __flush_tlb_global() 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 second step, move __flush_tlb_global() 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/20200421092559.336916818@linutronix.de
---
arch/x86/include/asm/paravirt.h | 1 +-
arch/x86/include/asm/tlbflush.h | 38 +-----------------------------
arch/x86/kernel/paravirt.c | 9 +-------
arch/x86/mm/tlb.c | 41 ++++++++++++++++++++++++++++++++-
4 files changed, 44 insertions(+), 45 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f412450..712e059 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -48,6 +48,7 @@ static inline void slow_down_io(void)
}

void native_flush_tlb_local(void);
+void native_flush_tlb_global(void);

static inline void __flush_tlb_local(void)
{
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index fe1fd02..d66d16e 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -141,11 +141,11 @@ static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
}

void flush_tlb_local(void);
+void flush_tlb_global(void);

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
-#define __flush_tlb_global() __native_flush_tlb_global()
#define __flush_tlb_one_user(addr) __native_flush_tlb_one_user(addr)
#endif

@@ -372,40 +372,6 @@ static inline void invalidate_user_asid(u16 asid)
}

/*
- * flush everything
- */
-static inline void __native_flush_tlb_global(void)
-{
- unsigned long cr4, flags;
-
- if (static_cpu_has(X86_FEATURE_INVPCID)) {
- /*
- * Using INVPCID is considerably faster than a pair of writes
- * to CR4 sandwiched inside an IRQ flag save/restore.
- *
- * Note, this works with CR4.PCIDE=0 or 1.
- */
- invpcid_flush_all();
- return;
- }
-
- /*
- * Read-modify-write to CR4 - protect it from preemption and
- * from interrupts. (Use the raw variant because this code can
- * be called from deep inside debugging code.)
- */
- raw_local_irq_save(flags);
-
- cr4 = this_cpu_read(cpu_tlbstate.cr4);
- /* toggle PGE */
- native_write_cr4(cr4 ^ X86_CR4_PGE);
- /* write old PGE again and flush TLBs */
- native_write_cr4(cr4);
-
- raw_local_irq_restore(flags);
-}
-
-/*
* flush one page in the user mapping
*/
static inline void __native_flush_tlb_one_user(unsigned long addr)
@@ -439,7 +405,7 @@ static inline void __flush_tlb_all(void)
VM_WARN_ON_ONCE(preemptible());

if (boot_cpu_has(X86_FEATURE_PGE)) {
- __flush_tlb_global();
+ flush_tlb_global();
} else {
/*
* !PGE -> !PCID (setup_pcid()), thus every flush is total.
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 4cb3d82..6094b00 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -160,15 +160,6 @@ unsigned paravirt_patch_insns(void *insn_buff, unsigned len,
return insn_len;
}

-/*
- * Global pages have to be flushed a bit differently. Not a real
- * performance problem because this does not happen often.
- */
-static void native_flush_tlb_global(void)
-{
- __native_flush_tlb_global();
-}
-
static void native_flush_tlb_one_user(unsigned long addr)
{
__native_flush_tlb_one_user(addr);
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 0611648..d548b98 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -23,6 +23,7 @@
#else
# define STATIC_NOPV static
# define __flush_tlb_local native_flush_tlb_local
+# define __flush_tlb_global native_flush_tlb_global
#endif

/*
@@ -891,6 +892,46 @@ unsigned long __get_current_cr3_fast(void)
EXPORT_SYMBOL_GPL(__get_current_cr3_fast);

/*
+ * Flush everything
+ */
+STATIC_NOPV void native_flush_tlb_global(void)
+{
+ unsigned long cr4, flags;
+
+ if (static_cpu_has(X86_FEATURE_INVPCID)) {
+ /*
+ * Using INVPCID is considerably faster than a pair of writes
+ * to CR4 sandwiched inside an IRQ flag save/restore.
+ *
+ * Note, this works with CR4.PCIDE=0 or 1.
+ */
+ invpcid_flush_all();
+ return;
+ }
+
+ /*
+ * Read-modify-write to CR4 - protect it from preemption and
+ * from interrupts. (Use the raw variant because this code can
+ * be called from deep inside debugging code.)
+ */
+ raw_local_irq_save(flags);
+
+ cr4 = this_cpu_read(cpu_tlbstate.cr4);
+ /* toggle PGE */
+ native_write_cr4(cr4 ^ X86_CR4_PGE);
+ /* write old PGE again and flush TLBs */
+ native_write_cr4(cr4);
+
+ raw_local_irq_restore(flags);
+}
+
+void flush_tlb_global(void)
+{
+ __flush_tlb_global();
+}
+EXPORT_SYMBOL_GPL(flush_tlb_global);
+
+/*
* Flush the entire current user mapping
*/
STATIC_NOPV void native_flush_tlb_local(void)
\
 
 \ /
  Last update: 2020-04-26 20:44    [W:0.114 / U:31.816 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site