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[PATCH] i386: Implement smp_processor_id() with the PDA

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Use the cpu_number in the PDA to implement raw_smp_processor_id.  This is a
little simpler than using thread_info, though the cpu field in thread_info
cannot be removed since it is used for things other than getting the current
CPU in common code.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
This commit is contained in:
Jeremy Fitzhardinge 2006-12-07 02:14:03 +01:00 committed by Andi Kleen
parent 49d26b6eaa
commit b2938f8808
5 changed files with 10 additions and 4 deletions
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4
arch/i386/kernel/asm-offsets.c
View File

@ -51,7 +51,6 @@ void foo(void)
OFFSET(TI_exec_domain, thread_info, exec_domain);
OFFSET(TI_flags, thread_info, flags);
OFFSET(TI_status, thread_info, status);
OFFSET(TI_cpu, thread_info, cpu);
OFFSET(TI_preempt_count, thread_info, preempt_count);
OFFSET(TI_addr_limit, thread_info, addr_limit);
OFFSET(TI_restart_block, thread_info, restart_block);
@ -97,4 +96,7 @@ void foo(void)
DEFINE(VDSO_PRELINK, VDSO_PRELINK);
OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx);
BLANK();
OFFSET(PDA_cpu, i386_pda, cpu_number);
}

2
arch/i386/kernel/cpu/common.c
View File

@ -650,6 +650,7 @@ __cpuinit int alloc_gdt(int cpu)
/* Initial PDA used by boot CPU */
struct i386_pda boot_pda = {
._pda = &boot_pda,
.cpu_number = 0,
};
static inline void set_kernel_gs(void)
@ -694,6 +695,7 @@ __cpuinit int init_gdt(int cpu, struct task_struct *idle)
memset(pda, 0, sizeof(*pda));
pda->_pda = pda;
pda->cpu_number = cpu;
return 1;
}

3
arch/i386/kernel/entry.S
View File

@ -524,8 +524,7 @@ syscall_badsys:
#define FIXUP_ESPFIX_STACK \
/* since we are on a wrong stack, we cant make it a C code :( */ \
GET_THREAD_INFO(%ebp); \
movl TI_cpu(%ebp), %ebx; \
movl %gs:PDA_cpu, %ebx; \
PER_CPU(cpu_gdt_descr, %ebx); \
movl GDS_address(%ebx), %ebx; \
GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \

2
include/asm-i386/pda.h
View File

@ -11,6 +11,8 @@
struct i386_pda
{
struct i386_pda *_pda; /* pointer to self */
int cpu_number;
};
extern struct i386_pda *_cpu_pda[];

3
include/asm-i386/smp.h
View File

@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <asm/pda.h>
#endif
#ifdef CONFIG_X86_LOCAL_APIC
@ -56,7 +57,7 @@ extern void cpu_uninit(void);
* from the initial startup. We map APIC_BASE very early in page_setup(),
* so this is correct in the x86 case.
*/
#define raw_smp_processor_id() (current_thread_info()->cpu)
#define raw_smp_processor_id() (read_pda(cpu_number))
extern cpumask_t cpu_callout_map;
extern cpumask_t cpu_callin_map;