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* [PATCH 2/3] Gdt_accessor
@ 2005-09-22  7:48 Zachary Amsden, Zachary Amsden
  2005-09-22  8:57 ` Ingo Molnar
  0 siblings, 1 reply; 2+ messages in thread
From: Zachary Amsden, Zachary Amsden @ 2005-09-22  7:48 UTC (permalink / raw)
  To: Linus Torvalds, Jeffrey Sheldon, Ole Agesen, Shai Fultheim,
	Andrew Morton, Jack Lo, Ingo Molnar, Linux Kernel Mailing List,
	Virtualization Mailing List, Chris Wright, Martin Bligh,
	Pratap Subrahmanyam, Christopher Li, H. Peter Anvin,
	Zwane Mwaikambo, Andi Kleen, Zachary Amsden

Add an accessor function for getting the per-CPU gdt.  Callee must already
have the CPU.

Signed-off-by: Zachary Amsden <zach@vmware.com>

Index: linux-2.6.14-rc1/include/asm-i386/desc.h
===================================================================
--- linux-2.6.14-rc1.orig/include/asm-i386/desc.h	2005-09-20 14:49:10.000000000 -0700
+++ linux-2.6.14-rc1/include/asm-i386/desc.h	2005-09-20 18:49:07.000000000 -0700
@@ -17,6 +17,8 @@
 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
 DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
 
+#define get_cpu_gdt_table(_cpu) (per_cpu(cpu_gdt_table,_cpu))
+
 DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
 
 struct Xgt_desc_struct {
@@ -60,7 +62,7 @@ __asm__ __volatile__ ("movw %w3,0(%2)\n\
 
 static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
 {
-	_set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[entry], (int)addr,
+	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[entry], (int)addr,
 		offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
 }
 
@@ -68,7 +70,7 @@ static inline void __set_tss_desc(unsign
 
 static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
 {
-	_set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
+	_set_tssldt_desc(&get_cpu_gdt_table(cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
 }
 
 #define LDT_entry_a(info) \
@@ -109,7 +111,7 @@ static inline void write_ldt_entry(void 
 
 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 {
-#define C(i) per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
+#define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
 	C(0); C(1); C(2);
 #undef C
 }
Index: linux-2.6.14-rc1/arch/i386/kernel/apm.c
===================================================================
--- linux-2.6.14-rc1.orig/arch/i386/kernel/apm.c	2005-09-20 14:49:10.000000000 -0700
+++ linux-2.6.14-rc1/arch/i386/kernel/apm.c	2005-09-20 14:53:14.000000000 -0700
@@ -597,12 +597,14 @@ static u8 apm_bios_call(u32 func, u32 eb
 	cpumask_t		cpus;
 	int			cpu;
 	struct desc_struct	save_desc_40;
+	struct desc_struct	*gdt;
 
 	cpus = apm_save_cpus();
 	
 	cpu = get_cpu();
-	save_desc_40 = per_cpu(cpu_gdt_table, cpu)[0x40 / 8];
-	per_cpu(cpu_gdt_table, cpu)[0x40 / 8] = bad_bios_desc;
+	gdt = get_cpu_gdt_table(cpu);
+	save_desc_40 = gdt[0x40 / 8];
+	gdt[0x40 / 8] = bad_bios_desc;
 
 	local_save_flags(flags);
 	APM_DO_CLI;
@@ -610,7 +612,7 @@ static u8 apm_bios_call(u32 func, u32 eb
 	apm_bios_call_asm(func, ebx_in, ecx_in, eax, ebx, ecx, edx, esi);
 	APM_DO_RESTORE_SEGS;
 	local_irq_restore(flags);
-	per_cpu(cpu_gdt_table, cpu)[0x40 / 8] = save_desc_40;
+	gdt[0x40 / 8] = save_desc_40;
 	put_cpu();
 	apm_restore_cpus(cpus);
 	
@@ -639,13 +641,14 @@ static u8 apm_bios_call_simple(u32 func,
 	cpumask_t		cpus;
 	int			cpu;
 	struct desc_struct	save_desc_40;
-
+	struct desc_struct	*gdt;
 
 	cpus = apm_save_cpus();
 	
 	cpu = get_cpu();
-	save_desc_40 = per_cpu(cpu_gdt_table, cpu)[0x40 / 8];
-	per_cpu(cpu_gdt_table, cpu)[0x40 / 8] = bad_bios_desc;
+	gdt = get_cpu_gdt_table(cpu);
+	save_desc_40 = gdt[0x40 / 8];
+	gdt[0x40 / 8] = bad_bios_desc;
 
 	local_save_flags(flags);
 	APM_DO_CLI;
@@ -653,7 +656,7 @@ static u8 apm_bios_call_simple(u32 func,
 	error = apm_bios_call_simple_asm(func, ebx_in, ecx_in, eax);
 	APM_DO_RESTORE_SEGS;
 	local_irq_restore(flags);
-	__get_cpu_var(cpu_gdt_table)[0x40 / 8] = save_desc_40;
+	gdt[0x40 / 8] = save_desc_40;
 	put_cpu();
 	apm_restore_cpus(cpus);
 	return error;
@@ -2295,35 +2298,36 @@ static int __init apm_init(void)
 	apm_bios_entry.segment = APM_CS;
 
 	for (i = 0; i < NR_CPUS; i++) {
-		set_base(per_cpu(cpu_gdt_table, i)[APM_CS >> 3],
+		struct desc_struct *gdt = get_cpu_gdt_table(i);
+		set_base(gdt[APM_CS >> 3],
 			 __va((unsigned long)apm_info.bios.cseg << 4));
-		set_base(per_cpu(cpu_gdt_table, i)[APM_CS_16 >> 3],
+		set_base(gdt[APM_CS_16 >> 3],
 			 __va((unsigned long)apm_info.bios.cseg_16 << 4));
-		set_base(per_cpu(cpu_gdt_table, i)[APM_DS >> 3],
+		set_base(gdt[APM_DS >> 3],
 			 __va((unsigned long)apm_info.bios.dseg << 4));
 #ifndef APM_RELAX_SEGMENTS
 		if (apm_info.bios.version == 0x100) {
 #endif
 			/* For ASUS motherboard, Award BIOS rev 110 (and others?) */
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS >> 3], 64 * 1024 - 1);
+			_set_limit((char *)&gdt[APM_CS >> 3], 64 * 1024 - 1);
 			/* For some unknown machine. */
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS_16 >> 3], 64 * 1024 - 1);
+			_set_limit((char *)&gdt[APM_CS_16 >> 3], 64 * 1024 - 1);
 			/* For the DEC Hinote Ultra CT475 (and others?) */
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_DS >> 3], 64 * 1024 - 1);
+			_set_limit((char *)&gdt[APM_DS >> 3], 64 * 1024 - 1);
 #ifndef APM_RELAX_SEGMENTS
 		} else {
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS >> 3],
+			_set_limit((char *)&gdt[APM_CS >> 3],
 				(apm_info.bios.cseg_len - 1) & 0xffff);
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS_16 >> 3],
+			_set_limit((char *)&gdt[APM_CS_16 >> 3],
 				(apm_info.bios.cseg_16_len - 1) & 0xffff);
-			_set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_DS >> 3],
+			_set_limit((char *)&gdt[APM_DS >> 3],
 				(apm_info.bios.dseg_len - 1) & 0xffff);
 		      /* workaround for broken BIOSes */
 	                if (apm_info.bios.cseg_len <= apm_info.bios.offset)
-        	                _set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS >> 3], 64 * 1024 -1);
+        	                _set_limit((char *)&gdt[APM_CS >> 3], 64 * 1024 -1);
                        if (apm_info.bios.dseg_len <= 0x40) { /* 0x40 * 4kB == 64kB */
                         	/* for the BIOS that assumes granularity = 1 */
-                        	per_cpu(cpu_gdt_table, i)[APM_DS >> 3].b |= 0x800000;
+                        	gdt[APM_DS >> 3].b |= 0x800000;
                         	printk(KERN_NOTICE "apm: we set the granularity of dseg.\n");
         	        }
 		}
Index: linux-2.6.14-rc1/arch/i386/kernel/cpu/common.c
===================================================================
--- linux-2.6.14-rc1.orig/arch/i386/kernel/cpu/common.c	2005-09-20 14:49:41.000000000 -0700
+++ linux-2.6.14-rc1/arch/i386/kernel/cpu/common.c	2005-09-20 14:49:50.000000000 -0700
@@ -573,6 +573,7 @@ void __devinit cpu_init(void)
 	int cpu = smp_processor_id();
 	struct tss_struct * t = &per_cpu(init_tss, cpu);
 	struct thread_struct *thread = &current->thread;
+	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 	__u32 stk16_off = (__u32)&per_cpu(cpu_16bit_stack, cpu);
 
 	if (cpu_test_and_set(cpu, cpu_initialized)) {
@@ -594,18 +595,16 @@ void __devinit cpu_init(void)
 	 * Initialize the per-CPU GDT with the boot GDT,
 	 * and set up the GDT descriptor:
 	 */
-	memcpy(&per_cpu(cpu_gdt_table, cpu), cpu_gdt_table,
-	       GDT_SIZE);
+ 	memcpy(gdt, cpu_gdt_table, GDT_SIZE);
 
 	/* Set up GDT entry for 16bit stack */
-	*(__u64 *)&(per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_ESPFIX_SS]) |=
+ 	*(__u64 *)(&gdt[GDT_ENTRY_ESPFIX_SS]) |=
 		((((__u64)stk16_off) << 16) & 0x000000ffffff0000ULL) |
 		((((__u64)stk16_off) << 32) & 0xff00000000000000ULL) |
 		(CPU_16BIT_STACK_SIZE - 1);
 
 	cpu_gdt_descr[cpu].size = GDT_SIZE - 1;
-	cpu_gdt_descr[cpu].address =
-	    (unsigned long)&per_cpu(cpu_gdt_table, cpu);
+ 	cpu_gdt_descr[cpu].address = (unsigned long)gdt;
 
 	load_gdt(&cpu_gdt_descr[cpu]);
 	load_idt(&idt_descr);
Index: linux-2.6.14-rc1/arch/i386/mm/fault.c
===================================================================
--- linux-2.6.14-rc1.orig/arch/i386/mm/fault.c	2005-09-20 14:49:10.000000000 -0700
+++ linux-2.6.14-rc1/arch/i386/mm/fault.c	2005-09-20 14:49:50.000000000 -0700
@@ -108,7 +108,7 @@ static inline unsigned long get_segment_
 		desc = (void *)desc + (seg & ~7);
 	} else {
 		/* Must disable preemption while reading the GDT. */
-		desc = (u32 *)&per_cpu(cpu_gdt_table, get_cpu());
+ 		desc = (u32 *)get_cpu_gdt_table(get_cpu());
 		desc = (void *)desc + (seg & ~7);
 	}
 

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2005-09-22  7:48 [PATCH 2/3] Gdt_accessor Zachary Amsden, Zachary Amsden
2005-09-22  8:57 ` Ingo Molnar

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