[PATCH] paravirt: Patch inline replacements for paravirt intercepts

It turns out that the most called ops, by several orders of magnitude,
are the interrupt manipulation ops.  These are obvious candidates for
patching, so mark them up and create infrastructure for it.

The method used is that the ops structure has a patch function, which
is called for each place which needs to be patched: this returns a
number of instructions (the rest are NOP-padded).

Usually we can spare a register (%eax) for the binary patched code to
use, but in a couple of critical places in entry.S we can't: we make
the clobbers explicit at the call site, and manually clobber the
allowed registers in debug mode as an extra check.

And:

Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT.

And:

AK:  Fix warnings in x86-64 alternative.c build

And:

AK: Fix compilation with defconfig

And:

^From: Andrew Morton <akpm@osdl.org>

Some binutlises still like to emit references to __stop_parainstructions and
__start_parainstructions.

And:

AK: Fix warnings about unused variables when PARAVIRT is disabled.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>

1 files changed, 21 insertions, 20 deletions

diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index f19820f0834f..f398cc456448 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -81,31 +81,15 @@ static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 #undef C
 }
 
-static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
-{
-        __u32 *lp = (__u32 *)((char *)dt + entry*8);
-        *lp = entry_a;
-        *(lp+1) = entry_b;
-}
-
 #define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 #define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 #define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 
-static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
-{
-        __u32 a, b;
-        pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
-        write_idt_entry(idt_table, gate, a, b);
-}
-
-static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
+static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
 {
-        __u32 a, b;
-        pack_descriptor(&a, &b, (unsigned long)addr,
-                        offsetof(struct tss_struct, __cacheline_filler) - 1,
-                        DESCTYPE_TSS, 0);
-        write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
+        __u32 *lp = (__u32 *)((char *)dt + entry*8);
+        *lp = entry_a;
+        *(lp+1) = entry_b;
 }
 
 #define set_ldt native_set_ldt
@@ -128,6 +112,23 @@ static inline fastcall void native_set_ldt(const void *addr,
         }
 }
 
+static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
+{
+        __u32 a, b;
+        pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
+        write_idt_entry(idt_table, gate, a, b);
+}
+
+static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
+{
+        __u32 a, b;
+        pack_descriptor(&a, &b, (unsigned long)addr,
+                        offsetof(struct tss_struct, __cacheline_filler) - 1,
+                        DESCTYPE_TSS, 0);
+        write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
+}
+
+
 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 
 #define LDT_entry_a(info) \