From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: [PATCH 09/28] Fix UP gdt bugs Date: Sat, 14 Apr 2007 13:42:03 -0700 Message-ID: <20070414204924.051019372@goop.org> References: <20070414204154.871250608@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline; filename=fix-uniproc-gdt-bugs.patch List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Andi Kleen Cc: Chris Wright , virtualization@lists.osdl.org, Andrew Morton , lkml List-Id: virtualization@lists.linuxfoundation.org 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 Signed-off-by: Jeremy Fitzhardinge Cc: Rusty Russell --- arch/i386/kernel/cpu/common.c | 13 +++++++++++++ arch/i386/kernel/smpboot.c | 12 ------------ include/asm-i386/processor.h | 1 + include/asm-i386/segment.h | 4 ++++ 4 files changed, 18 insertions(+), 12 deletions(-) =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -644,6 +644,18 @@ struct pt_regs * __devinit idle_regs(str 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 =3D (long)get_cpu_gdt_table(smp_processor_id()); + gdt_descr.size =3D 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 @@ -674,6 +688,7 @@ void __cpuinit cpu_init(void) } = load_idt(&idt_descr); + switch_to_new_gdt(); = /* * Set up and load the per-CPU TSS and LDT =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -1176,18 +1176,6 @@ void __init native_smp_prepare_cpus(unsi 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 =3D (long)get_cpu_gdt_table(smp_processor_id()); - gdt_descr.size =3D 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 =3D smp_processor_id(); =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -777,6 +777,7 @@ extern int sysenter_setup(void); extern int sysenter_setup(void); = extern void cpu_set_gdt(int); +extern void switch_to_new_gdt(void); extern void cpu_init(void); = #endif /* __ASM_I386_PROCESSOR_H */ =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- 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 = -- =