[PATCH 8/14] i386 / Add a per cpu gdt accessor

From: zach
Date: Wed Aug 10 2005 - 23:57:07 EST

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

Patch-base: 2.6.13-rc5-mm1
Patch-keys: i386 desc xen
Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Index: linux-2.6.13/include/asm-i386/desc.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-09 20:17:21.000000000 -0700
+++ linux-2.6.13/include/asm-i386/desc.h 2005-08-10 20:41:03.000000000 -0700
@@ -39,6 +39,8 @@
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 {
Index: linux-2.6.13/include/asm-i386/mach-default/mach_desc.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/mach-default/mach_desc.h 2005-08-09 20:17:21.000000000 -0700
+++ linux-2.6.13/include/asm-i386/mach-default/mach_desc.h 2005-08-10 16:37:36.000000000 -0700
@@ -53,13 +53,13 @@

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);
}

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);
}

static inline int write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b)
@@ -72,7 +72,7 @@

static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
{
- memcpy(&per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN], t->tls_array, TLS_SIZE);
+ memcpy(&get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN], t->tls_array, TLS_SIZE);
}

#endif
Index: linux-2.6.13/arch/i386/kernel/apm.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/apm.c 2005-08-09 20:17:21.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/apm.c 2005-08-10 20:41:52.000000000 -0700
@@ -597,12 +597,14 @@
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[segment_index(0x40)];
+ gdt[segment_index(0x40)] = bad_bios_desc;

local_save_flags(flags);
APM_DO_CLI;
@@ -610,7 +612,7 @@
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[segment_index(0x40)] = save_desc_40;
put_cpu();
apm_restore_cpus(cpus);

@@ -639,13 +641,14 @@
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[segment_index(0x40)];
+ gdt[segment_index(0x40)] = bad_bios_desc;

local_save_flags(flags);
APM_DO_CLI;
@@ -653,7 +656,7 @@
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[segment_index(0x40)] = save_desc_40;
put_cpu();
apm_restore_cpus(cpus);
return error;
@@ -2295,35 +2298,36 @@
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[segment_index(APM_CS)],
__va((unsigned long)apm_info.bios.cseg << 4));
- set_base(per_cpu(cpu_gdt_table, i)[APM_CS_16 >> 3],
+ set_base(gdt[segment_index(APM_CS_16)],
__va((unsigned long)apm_info.bios.cseg_16 << 4));
- set_base(per_cpu(cpu_gdt_table, i)[APM_DS >> 3],
+ set_base(gdt[segment_index(APM_DS)],
__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[segment_index(APM_CS)], 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[segment_index(APM_CS_16)], 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[segment_index(APM_DS)], 64 * 1024 - 1);
#ifndef APM_RELAX_SEGMENTS
} else {
- _set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS >> 3],
+ _set_limit((char *)&gdt[segment_index(APM_CS)],
(apm_info.bios.cseg_len - 1) & 0xffff);
- _set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_CS_16 >> 3],
+ _set_limit((char *)&gdt[segment_index(APM_CS_16)],
(apm_info.bios.cseg_16_len - 1) & 0xffff);
- _set_limit((char *)&per_cpu(cpu_gdt_table, i)[APM_DS >> 3],
+ _set_limit((char *)&gdt[segment_index(APM_DS)],
(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[segment_index(APM_CS)], 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[segment_index(APM_DS)].b |= 0x800000;
printk(KERN_NOTICE "apm: we set the granularity of dseg.\n");
}
}
Index: linux-2.6.13/arch/i386/kernel/kprobes.c
===================================================================
Index: linux-2.6.13/arch/i386/kernel/cpu/common.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/cpu/common.c 2005-08-09 20:17:21.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/cpu/common.c 2005-08-09 20:17:26.000000000 -0700
@@ -573,6 +573,7 @@
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 @@
* 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-2.6.13/arch/i386/mm/fault.c
===================================================================
--- linux-2.6.13.orig/arch/i386/mm/fault.c 2005-08-09 20:17:21.000000000 -0700
+++ linux-2.6.13/arch/i386/mm/fault.c 2005-08-09 20:17:26.000000000 -0700
@@ -109,7 +109,7 @@
desc = (void *)desc + (seg & ~7);
} else {
/* Must disable preemption while reading the GDT. */
- desc = per_cpu(cpu_gdt_table, get_cpu());
+ desc = get_cpu_gdt_table(get_cpu());
desc = (void *)desc + (seg & ~7);
}

Index: linux-2.6.13/arch/i386/math-emu/fpu_system.h
===================================================================
-
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Next message: zach: "[PATCH 9/14] i386 / Typecheck and optimize base and limit accessors"
Previous message: zach: "[PATCH 7/14] i386 / Add some descriptor convenience functions"
Next in thread: Zwane Mwaikambo: "Re: [PATCH 8/14] i386 / Add a per cpu gdt accessor"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]