[PATCH 5/9] unify paravirt parts of system.h

Glauber de Oliveira Costa
2007-12-05T17:54:19Z

This patch moves the i386 control registers manipulation functions,
wbinvd, and clts functions to system.h. They are essentially the same
as in x86_64.

With this, system.h paravirt comes for free in x86_64.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
include/asm-x86/system.h | 110 +++++++++++++++++++++++++++++++++++++++++++
include/asm-x86/system_32.h | 94 ------------------------------------
include/asm-x86/system_64.h | 61 ------------------------
3 files changed, 110 insertions(+), 155 deletions(-)

diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h
index 1ac6088..518b7bd 100644
--- a/include/asm-x86/system.h
+++ b/include/asm-x86/system.h
@@ -3,6 +3,8 @@

#include <asm/asm.h>

+#include <linux/kernel.h>
+
#ifdef CONFIG_X86_32
# include "system_32.h"
#else
@@ -38,6 +40,8 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
#define set_base(ldt, base) _set_base(((char *)&(ldt)) , (base))
#define set_limit(ldt, limit) _set_limit(((char *)&(ldt)) , ((limit)-1))

+extern void load_gs_index(unsigned);
+
/*
* Load a segment. Fall back on loading the zero
* segment if something goes wrong..
@@ -72,6 +76,112 @@ static inline unsigned long get_limit(unsigned long segment)
:"=r" (__limit):"r" (segment));
return __limit+1;
}
+
+static inline void native_clts(void)
+{
+ asm volatile ("clts");
+}
+
+/*
+ * Volatile isn't enough to prevent the compiler from reordering the
+ * read/write functions for the control registers and messing everything up.
+ * A memory clobber would solve the problem, but would prevent reordering of
+ * all loads stores around it, which can hurt performance. Solution is to
+ * use a variable and mimic reads and writes to it to enforce serialization
+ */
+static unsigned long __force_order;
+
+static inline unsigned long native_read_cr0(void)
+{
+ unsigned long val;
+ asm volatile("mov %%cr0,%0\n\t" :"=r" (val), "=m" (__force_order));
+ return val;
+}
+
+static inline void native_write_cr0(unsigned long val)
+{
+ asm volatile("mov %0,%%cr0": :"r" (val), "m" (__force_order));
+}
+
+static inline unsigned long native_read_cr2(void)
+{
+ unsigned long val;
+ asm volatile("mov %%cr2,%0\n\t" :"=r" (val), "=m" (__force_order));
+ return val;
+}
+
+static inline void native_write_cr2(unsigned long val)
+{
+ asm volatile("mov %0,%%cr2": :"r" (val), "m" (__force_order));
+}
+
+static inline unsigned long native_read_cr3(void)
+{
+ unsigned long val;
+ asm volatile("mov %%cr3,%0\n\t" :"=r" (val), "=m" (__force_order));
+ return val;
+}
+
+static inline void native_write_cr3(unsigned long val)
+{
+ asm volatile("mov %0,%%cr3": :"r" (val), "m" (__force_order));
+}
+
+static inline unsigned long native_read_cr4(void)
+{
+ unsigned long val;
+ asm volatile("mov %%cr4,%0\n\t" :"=r" (val), "=m" (__force_order));
+ return val;
+}
+
+static inline unsigned long native_read_cr4_safe(void)
+{
+ unsigned long val;
+ /* This could fault if %cr4 does not exist. In x86_64, a cr4 always
+ * exists, so it will never fail. */
+#ifdef CONFIG_X86_32
+ asm volatile("1: mov %%cr4, %0 \n"
+ "2: \n"
+ ".section __ex_table,\"a\" \n"
+ ".long 1b,2b \n"
+ ".previous \n"
+ : "=r" (val), "=m" (__force_order) : "0" (0));
+#else
+ val = native_read_cr4();
+#endif
+ return val;
+}
+
+static inline void native_write_cr4(unsigned long val)
+{
+ asm volatile("mov %0,%%cr4": :"r" (val), "m" (__force_order));
+}
+
+static inline void native_wbinvd(void)
+{
+ asm volatile("wbinvd": : :"memory");
+}
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#else
+#define read_cr0() (native_read_cr0())
+#define write_cr0(x) (native_write_cr0(x))
+#define read_cr2() (native_read_cr2())
+#define write_cr2(x) (native_write_cr2(x))
+#define read_cr3() (native_read_cr3())
+#define write_cr3(x) (native_write_cr3(x))
+#define read_cr4() (native_read_cr4())
+#define read_cr4_safe() (native_read_cr4_safe())
+#define write_cr4(x) (native_write_cr4(x))
+#define wbinvd() (native_wbinvd())
+
+/* Clear the 'TS' bit */
+#define clts() (native_clts())
+
+#endif/* CONFIG_PARAVIRT */
+
+#define stts() write_cr0(8 | read_cr0())
+
#endif /* __KERNEL__ */

static inline void clflush(void *__p)
diff --git a/include/asm-x86/system_32.h b/include/asm-x86/system_32.h
index a0641a3..6c69567 100644
--- a/include/asm-x86/system_32.h
+++ b/include/asm-x86/system_32.h
@@ -1,7 +1,6 @@
#ifndef __ASM_SYSTEM_H
#define __ASM_SYSTEM_H

-#include <linux/kernel.h>
#include <asm/segment.h>
#include <asm/cpufeature.h>
#include <asm/cmpxchg.h>
@@ -34,99 +33,6 @@ extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struc
"2" (prev), "d" (next)); \
} while (0)

-static inline void native_clts(void)
-{
- asm volatile ("clts");
-}
-
-static inline unsigned long native_read_cr0(void)
-{
- unsigned long val;
- asm volatile("movl %%cr0,%0\n\t" :"=r" (val));
- return val;
-}
-
-static inline void native_write_cr0(unsigned long val)
-{
- asm volatile("movl %0,%%cr0": :"r" (val));
-}
-
-static inline unsigned long native_read_cr2(void)
-{
- unsigned long val;
- asm volatile("movl %%cr2,%0\n\t" :"=r" (val));
- return val;
-}
-
-static inline void native_write_cr2(unsigned long val)
-{
- asm volatile("movl %0,%%cr2": :"r" (val));
-}
-
-static inline unsigned long native_read_cr3(void)
-{
- unsigned long val;
- asm volatile("movl %%cr3,%0\n\t" :"=r" (val));
- return val;
-}
-
-static inline void native_write_cr3(unsigned long val)
-{
- asm volatile("movl %0,%%cr3": :"r" (val));
-}
-
-static inline unsigned long native_read_cr4(void)
-{
- unsigned long val;
- asm volatile("movl %%cr4,%0\n\t" :"=r" (val));
- return val;
-}
-
-static inline unsigned long native_read_cr4_safe(void)
-{
- unsigned long val;
- /* This could fault if %cr4 does not exist */
- asm volatile("1: movl %%cr4, %0 \n"
- "2: \n"
- ".section __ex_table,\"a\" \n"
- ".long 1b,2b \n"
- ".previous \n"
- : "=r" (val): "0" (0));
- return val;
-}
-
-static inline void native_write_cr4(unsigned long val)
-{
- asm volatile("movl %0,%%cr4": :"r" (val));
-}
-
-static inline void native_wbinvd(void)
-{
- asm volatile("wbinvd": : :"memory");
-}
-
-#ifdef CONFIG_PARAVIRT
-#include <asm/paravirt.h>
-#else
-#define read_cr0() (native_read_cr0())
-#define write_cr0(x) (native_write_cr0(x))
-#define read_cr2() (native_read_cr2())
-#define write_cr2(x) (native_write_cr2(x))
-#define read_cr3() (native_read_cr3())
-#define write_cr3(x) (native_write_cr3(x))
-#define read_cr4() (native_read_cr4())
-#define read_cr4_safe() (native_read_cr4_safe())
-#define write_cr4(x) (native_write_cr4(x))
-#define wbinvd() (native_wbinvd())
-
-/* Clear the 'TS' bit */
-#define clts() (native_clts())
-
-#endif/* CONFIG_PARAVIRT */
-
-/* Set the 'TS' bit */
-#define stts() write_cr0(8 | read_cr0())
-
#endif /* __KERNEL__ */

diff --git a/include/asm-x86/system_64.h b/include/asm-x86/system_64.h
index d7f0776..2757258 100644
--- a/include/asm-x86/system_64.h
+++ b/include/asm-x86/system_64.h
@@ -1,7 +1,6 @@
#ifndef __ASM_SYSTEM_H
#define __ASM_SYSTEM_H

-#include <linux/kernel.h>
#include <asm/segment.h>
#include <asm/cmpxchg.h>

@@ -40,66 +39,6 @@
[pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
: "memory", "cc" __EXTRA_CLOBBER)

-extern void load_gs_index(unsigned);
-
-/*
- * Clear and set 'TS' bit respectively
- */
-#define clts() __asm__ __volatile__ ("clts")
-
-static inline unsigned long read_cr0(void)
-{
- unsigned long cr0;
- asm volatile("movq %%cr0,%0" : "=r" (cr0));
- return cr0;
-}
-
-static inline void write_cr0(unsigned long val)
-{
- asm volatile("movq %0,%%cr0" :: "r" (val));
-}
-
-static inline unsigned long read_cr2(void)
-{
- unsigned long cr2;
- asm volatile("movq %%cr2,%0" : "=r" (cr2));
- return cr2;
-}
-
-static inline void write_cr2(unsigned long val)
-{
- asm volatile("movq %0,%%cr2" :: "r" (val));
-}
-
-static inline unsigned long read_cr3(void)
-{
- unsigned long cr3;
- asm volatile("movq %%cr3,%0" : "=r" (cr3));
- return cr3;
-}
-
-static inline void write_cr3(unsigned long val)
-{
- asm volatile("movq %0,%%cr3" :: "r" (val) : "memory");
-}
-
-static inline unsigned long read_cr4(void)
-{
- unsigned long cr4;
- asm volatile("movq %%cr4,%0" : "=r" (cr4));
- return cr4;
-}
-
-static inline void write_cr4(unsigned long val)
-{
- asm volatile("movq %0,%%cr4" :: "r" (val) : "memory");
-}
-
-#define stts() write_cr0(8 | read_cr0())
-
-#define wbinvd() \
- __asm__ __volatile__ ("wbinvd": : :"memory")
-
#endif /* __KERNEL__ */

#ifdef CONFIG_SMP
--
1.4.4.2