diff options
| author |   Jeremy Fitzhardinge <jeremy@goop.org> | 2007-05-02 19:27:16 +0200 |
|---|---|---|
| committer |   Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:16 +0200 |
| commit | c5413fbe894924ddb8aa474a4d4da52e7a6c7e0b (patch) | |
| tree | 8f317bf2494b6b4bceb5e6d1ee35fabc0eeb9971 | |
| parent | [PATCH] i386: Define per_cpu_offset (diff) | |
| download | linux-dev-c5413fbe894924ddb8aa474a4d4da52e7a6c7e0b.tar.xz linux-dev-c5413fbe894924ddb8aa474a4d4da52e7a6c7e0b.zip | |
[PATCH] i386: Fix UP gdt bugs
Fixes two problems with the GDT when compiling for uniprocessor:
- There's no percpu segment, so trying to load its selector into %fs fails.
Use a null selector instead.
- The real gdt needs to be loaded at some point. Do it in cpu_init().
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | arch/i386/kernel/cpu/common.c | 13 | ||||
| -rw-r--r-- | arch/i386/kernel/smpboot.c | 12 | ||||
| -rw-r--r-- | include/asm-i386/processor.h | 1 | ||||
| -rw-r--r-- | include/asm-i386/segment.h | 4 |
4 files changed, 18 insertions, 12 deletions
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 27e00565f5e4..794d593c47eb 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -638,6 +638,18 @@ struct pt_regs * __devinit idle_regs(struct pt_regs *regs) return regs; } +/* Current gdt points %fs at the "master" per-cpu area: after this, + * it's on the real one. */ +void switch_to_new_gdt(void) +{ + struct Xgt_desc_struct gdt_descr; + + gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id()); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); + asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory"); +} + /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT @@ -668,6 +680,7 @@ void __cpuinit cpu_init(void) } load_idt(&idt_descr); + switch_to_new_gdt(); /* * Set up and load the per-CPU TSS and LDT diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index f79b6233db78..7c1dbef399cd 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -1177,18 +1177,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) smp_boot_cpus(max_cpus); } -/* Current gdt points %fs at the "master" per-cpu area: after this, - * it's on the real one. */ -static inline void switch_to_new_gdt(void) -{ - struct Xgt_desc_struct gdt_descr; - - gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id()); - gdt_descr.size = GDT_SIZE - 1; - load_gdt(&gdt_descr); - asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory"); -} - void __init native_smp_prepare_boot_cpu(void) { unsigned int cpu = smp_processor_id(); diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index ced2da8a0d65..70f3515c3db0 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -750,6 +750,7 @@ extern void enable_sep_cpu(void); extern int sysenter_setup(void); extern void cpu_set_gdt(int); +extern void switch_to_new_gdt(void); extern void cpu_init(void); extern int force_mwait; diff --git a/include/asm-i386/segment.h b/include/asm-i386/segment.h index 07e70624d87c..597a47c2515f 100644 --- a/include/asm-i386/segment.h +++ b/include/asm-i386/segment.h @@ -75,7 +75,11 @@ #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8) #define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE + 15) +#ifdef CONFIG_SMP #define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8) +#else +#define __KERNEL_PERCPU 0 +#endif #define GDT_ENTRY_DOUBLEFAULT_TSS 31 |