+ i386-pda-basic-definitions-for-i386-pda.patch added to -mm tree

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The patch titled

     i386-pda: Basic definitions for i386-pda

has been added to the -mm tree.  Its filename is

     i386-pda-basic-definitions-for-i386-pda.patch

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: i386-pda: Basic definitions for i386-pda
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>

This patch has the basic definitions of struct i386_pda, and the segment
selector in the GDT.

asm-i386/pda.h is more or less a direct copy of asm-x86_64/pda.h.  The most
interesting difference is the use of _proxy_pda, which is used to give gcc a
model for the actual memory operations on the real pda structure.  No actual
reference is ever made to _proxy_pda, so it is never defined.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx>
Cc: Zachary Amsden <zach@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 arch/i386/kernel/head.S    |    2 
 include/asm-i386/pda.h     |   95 +++++++++++++++++++++++++++++++++++
 include/asm-i386/segment.h |    5 +
 3 files changed, 100 insertions(+), 2 deletions(-)

diff -puN arch/i386/kernel/head.S~i386-pda-basic-definitions-for-i386-pda arch/i386/kernel/head.S
--- a/arch/i386/kernel/head.S~i386-pda-basic-definitions-for-i386-pda
+++ a/arch/i386/kernel/head.S
@@ -585,7 +585,7 @@ ENTRY(cpu_gdt_table)
 	.quad 0x004092000000ffff	/* 0xc8 APM DS    data */
 
 	.quad 0x00c0920000000000	/* 0xd0 - ESPFIX SS */
-	.quad 0x0000000000000000	/* 0xd8 - unused */
+	.quad 0x0000000000000000	/* 0xd8 - PDA */
 	.quad 0x0000000000000000	/* 0xe0 - unused */
 	.quad 0x0000000000000000	/* 0xe8 - unused */
 	.quad 0x0000000000000000	/* 0xf0 - unused */
diff -puN /dev/null include/asm-i386/pda.h
--- /dev/null
+++ a/include/asm-i386/pda.h
@@ -0,0 +1,95 @@
+/*
+   Per-processor Data Areas
+   Jeremy Fitzhardinge <jeremy@xxxxxxxx> 2006
+   Based on asm-x86_64/pda.h by Andi Kleen.
+ */
+#ifndef _I386_PDA_H
+#define _I386_PDA_H
+
+#include <linux/stddef.h>
+
+struct i386_pda
+{
+	struct i386_pda *_pda;		/* pointer to self */
+};
+
+extern struct i386_pda *_cpu_pda[];
+
+#define cpu_pda(i)	(_cpu_pda[i])
+
+#define pda_offset(field) offsetof(struct i386_pda, field)
+
+extern void __bad_pda_field(void);
+
+/* This variable is never instantiated.  It is only used as a stand-in
+   for the real per-cpu PDA memory, so that gcc can understand what
+   memory operations the inline asms() below are performing.  This
+   eliminates the need to make the asms volatile or have memory
+   clobbers, so gcc can readily analyse them. */
+extern struct i386_pda _proxy_pda;
+
+#define pda_to_op(op,field,val)						\
+	do {								\
+		typedef typeof(_proxy_pda.field) T__;			\
+		if (0) { T__ tmp__; tmp__ = (val); }			\
+		switch (sizeof(_proxy_pda.field)) {			\
+		case 1:							\
+			asm(op "b %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		case 2:							\
+			asm(op "w %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		case 4:							\
+			asm(op "l %1,%%gs:%c2"				\
+			    : "+m" (_proxy_pda.field)			\
+			    :"ri" ((T__)val),				\
+			     "i"(pda_offset(field)));			\
+			break;						\
+		default: __bad_pda_field();				\
+		}							\
+	} while (0)
+
+#define pda_from_op(op,field)						\
+	({								\
+		typeof(_proxy_pda.field) ret__;				\
+		switch (sizeof(_proxy_pda.field)) {			\
+		case 1:							\
+			asm(op "b %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		case 2:							\
+			asm(op "w %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		case 4:							\
+			asm(op "l %%gs:%c1,%0"				\
+			    : "=r" (ret__)				\
+			    : "i" (pda_offset(field)),			\
+			      "m" (_proxy_pda.field));			\
+			break;						\
+		default: __bad_pda_field();				\
+		}							\
+		ret__; })
+
+/* Return a pointer to a pda field */
+#define pda_addr(field)							\
+	((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
+				      pda_offset(field)))
+
+#define read_pda(field) pda_from_op("mov",field)
+#define write_pda(field,val) pda_to_op("mov",field,val)
+#define add_pda(field,val) pda_to_op("add",field,val)
+#define sub_pda(field,val) pda_to_op("sub",field,val)
+#define or_pda(field,val) pda_to_op("or",field,val)
+
+#endif	/* _I386_PDA_H */
diff -puN include/asm-i386/segment.h~i386-pda-basic-definitions-for-i386-pda include/asm-i386/segment.h
--- a/include/asm-i386/segment.h~i386-pda-basic-definitions-for-i386-pda
+++ a/include/asm-i386/segment.h
@@ -39,7 +39,7 @@
  *  25 - APM BIOS support 
  *
  *  26 - ESPFIX small SS
- *  27 - unused
+ *  27 - PDA				[ per-cpu private data area ]
  *  28 - unused
  *  29 - unused
  *  30 - unused
@@ -74,6 +74,9 @@
 #define GDT_ENTRY_ESPFIX_SS		(GDT_ENTRY_KERNEL_BASE + 14)
 #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
 
+#define GDT_ENTRY_PDA			(GDT_ENTRY_KERNEL_BASE + 15)
+#define __KERNEL_PDA (GDT_ENTRY_PDA * 8)
+
 #define GDT_ENTRY_DOUBLEFAULT_TSS	31
 
 /*
_

Patches currently in -mm which might be from jeremy@xxxxxxxx are

x86-remove-default_ldt-and-simplify-ldt-setting.patch
i386-use-asm-offsets-for-the-offsets-of-registers-into-the-pt_regs-struct-rather-than-having-hard-coded-constants.patch
i386-pda-basic-definitions-for-i386-pda.patch
i386-pda-initialize-the-per-cpu-data-area.patch
i386-pda-use-%gs-as-the-pda-base-segment-in-the-kernel.patch
i386-pda-fix-places-where-using-%gs-changes-the-usermode-abi.patch
i386-pda-update-sys_vm86-to-cope-with-changed-pt_regs-and-%gs-usage.patch
i386-pda-implement-smp_processor_id-with-the-pda.patch
i386-pda-implement-current-with-the-pda.patch
i386-pda-store-the-interrupt-regs-pointer-in-the-pda.patch
generic-bug-implementation.patch
generic-bug-for-i386.patch
generic-bug-for-x86-64.patch
generic-bug-for-powerpc.patch
uml-add-generic-bug-support.patch
use-generic-bug-for-ppc.patch
bug-test-1.patch

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