[PATCH] x86: add an accessor function for getting the per-CPU gdt

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

Signed-off-by: Zachary Amsden <zach@vmware.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 32 insertions, 27 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index d7811c4e8b50..d2ef0c2aa93e 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -597,12 +597,14 @@ static u8 apm_bios_call(u32 func, u32 ebx_in, u32 ecx_in,
         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 ebx_in, u32 ecx_in,
         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, u32 ebx_in, u32 ecx_in, u32 *eax)
         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, u32 ebx_in, u32 ecx_in, u32 *eax)
         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");
                         }
                 }
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index a162c0326b4a..74145a33cb0f 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -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);
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index 9edd4485b91e..cf572d9a3b6e 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -108,7 +108,7 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
                 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);
         }
 
diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index 6df1a53c190e..29b851a18c6e 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -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\t" \
 
 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(unsigned int cpu, unsigned int entry, void *ad
 
 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 *ldt, int entry, __u32 entry_a, __u32 en
 
 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
 }