Jeremy Fitzhardinge
2009-Jan-31 01:42 UTC
[Xen-devel] [PATCH 1/3] xen: setup percpu data pointers
We need to access percpu data fairly early, so set up the percpu registers as soon as possible. We only need to load the appropriate segment register. We already have a GDT, but its hard to change it early because we need to manipulate the pagetable to do so, and that hasn''t been set up yet. Also, set the kernel stack when bringing up secondary CPUs. If we don''t they all end up sharing the same stack... [This depends on the two other percpu patches that Tejun has in his tree. ] Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/xen/enlighten.c | 16 ++++++++++++++++ arch/x86/xen/smp.c | 4 +++- arch/x86/xen/xen-ops.h | 2 ++ 3 files changed, 21 insertions(+), 1 deletion(-) diff -r 9f052779cc5d arch/x86/xen/enlighten.c --- a/arch/x86/xen/enlighten.c Fri Jan 30 17:20:43 2009 -0800 +++ b/arch/x86/xen/enlighten.c Fri Jan 30 17:37:05 2009 -0800 @@ -61,6 +61,8 @@ enum xen_domain_type xen_domain_type = XEN_NATIVE; EXPORT_SYMBOL_GPL(xen_domain_type); +void *xen_initial_gdt; + /* * Identity map, in addition to plain kernel map. This needs to be * large enough to allocate page table pages to allocate the rest. @@ -1646,6 +1648,20 @@ have_vcpu_info_placement = 0; #endif +#ifdef CONFIG_X86_64 + /* + * Setup percpu state. We only need to do this for 64-bit + * because 32-bit already has %fs set properly. + */ + load_percpu_segment(0); +#endif + /* + * The only reliable way to retain the initial address of the + * percpu gdt_page is to remember it here, so we can go and + * mark it RW later, when the initial percpu area is freed. + */ + xen_initial_gdt = &per_cpu(gdt_page, 0); + xen_smp_init(); /* Get mfn list */ diff -r 9f052779cc5d arch/x86/xen/smp.c --- a/arch/x86/xen/smp.c Fri Jan 30 17:20:43 2009 -0800 +++ b/arch/x86/xen/smp.c Fri Jan 30 17:37:05 2009 -0800 @@ -170,7 +170,7 @@ /* We''ve switched to the "real" per-cpu gdt, so make sure the old memory can be recycled */ - make_lowmem_page_readwrite(&per_cpu_var(gdt_page)); + make_lowmem_page_readwrite(xen_initial_gdt); xen_setup_vcpu_info_placement(); } @@ -235,6 +235,8 @@ ctxt->user_regs.ss = __KERNEL_DS; #ifdef CONFIG_X86_32 ctxt->user_regs.fs = __KERNEL_PERCPU; +#else + ctxt->gs_base_kernel = per_cpu_offset(cpu); #endif ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ @@ -284,6 +286,9 @@ irq_ctx_init(cpu); #else clear_tsk_thread_flag(idle, TIF_FORK); + per_cpu(kernel_stack, cpu) + (unsigned long)task_stack_page(idle) - + KERNEL_STACK_OFFSET + THREAD_SIZE; #endif xen_setup_timer(cpu); xen_init_lock_cpu(cpu); diff -r 9f052779cc5d arch/x86/xen/xen-ops.h --- a/arch/x86/xen/xen-ops.h Fri Jan 30 17:20:43 2009 -0800 +++ b/arch/x86/xen/xen-ops.h Fri Jan 30 17:37:05 2009 -0800 @@ -10,6 +10,8 @@ extern const char xen_hypervisor_callback[]; extern const char xen_failsafe_callback[]; +extern void *xen_initial_gdt; + struct trap_info; void xen_copy_trap_info(struct trap_info *traps); _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2009-Feb-02 21:55 UTC
[Xen-devel] [PATCH 1/3] xen: setup percpu data pointers
We need to access percpu data fairly early, so set up the percpu registers as soon as possible. We only need to load the appropriate segment register. We already have a GDT, but its hard to change it early because we need to manipulate the pagetable to do so, and that hasn''t been set up yet. Also, set the kernel stack when bringing up secondary CPUs. If we don''t they all end up sharing the same stack... Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/xen/enlighten.c | 16 ++++++++++++++++ arch/x86/xen/smp.c | 7 ++++++- arch/x86/xen/xen-ops.h | 2 ++ 3 files changed, 24 insertions(+), 1 deletion(-) diff -r 42a1fb2574f0 arch/x86/xen/enlighten.c --- a/arch/x86/xen/enlighten.c Mon Feb 02 12:44:32 2009 -0800 +++ b/arch/x86/xen/enlighten.c Mon Feb 02 13:24:32 2009 -0800 @@ -66,6 +66,8 @@ struct shared_info xen_dummy_shared_info; +void *xen_initial_gdt; + /* * Point at some empty memory to start with. We map the real shared_info * page as soon as fixmap is up and running. @@ -917,8 +919,19 @@ have_vcpu_info_placement = 0; #endif - /* setup percpu state */ +#ifdef CONFIG_X86_64 + /* + * Setup percpu state. We only need to do this for 64-bit + * because 32-bit already has %fs set properly. + */ load_percpu_segment(0); +#endif + /* + * The only reliable way to retain the initial address of the + * percpu gdt_page is to remember it here, so we can go and + * mark it RW later, when the initial percpu area is freed. + */ + xen_initial_gdt = &per_cpu(gdt_page, 0); xen_smp_init(); diff -r 42a1fb2574f0 arch/x86/xen/smp.c --- a/arch/x86/xen/smp.c Mon Feb 02 12:44:32 2009 -0800 +++ b/arch/x86/xen/smp.c Mon Feb 02 13:24:32 2009 -0800 @@ -170,8 +170,7 @@ /* We''ve switched to the "real" per-cpu gdt, so make sure the old memory can be recycled */ - make_lowmem_page_readwrite(__per_cpu_load + - (unsigned long)&per_cpu_var(gdt_page)); + make_lowmem_page_readwrite(xen_initial_gdt); xen_setup_vcpu_info_placement(); } @@ -287,6 +286,9 @@ irq_ctx_init(cpu); #else clear_tsk_thread_flag(idle, TIF_FORK); + per_cpu(kernel_stack, cpu) + (unsigned long)task_stack_page(idle) - + KERNEL_STACK_OFFSET + THREAD_SIZE; #endif xen_setup_timer(cpu); xen_init_lock_cpu(cpu); diff -r 42a1fb2574f0 arch/x86/xen/xen-ops.h --- a/arch/x86/xen/xen-ops.h Mon Feb 02 12:44:32 2009 -0800 +++ b/arch/x86/xen/xen-ops.h Mon Feb 02 13:24:32 2009 -0800 @@ -10,6 +10,8 @@ extern const char xen_hypervisor_callback[]; extern const char xen_failsafe_callback[]; +extern void *xen_initial_gdt; + struct trap_info; void xen_copy_trap_info(struct trap_info *traps); _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2009-Feb-05 07:17 UTC
[Xen-devel] Re: [PATCH 1/3] xen: setup percpu data pointers
Tejun Heo wrote:> Tejun Heo wrote: > >> Applied 1-3 to #tj-percpu with trivial modification on #2 (will reply >> to the message). >> > > Oh... hpa already merged them into x86/paravirt. I''ll just pull > x86/paravirt into core/percpu because the first patch needs to be in > core/percpu to keep xen working. > > hpa, can you please take the other xen patch[1] into x86/paravirt too? > So that I can receive it via you?Looks like its already there. J _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ingo Molnar
2009-Feb-05 14:57 UTC
[Xen-devel] Re: [PATCH 1/3] xen: setup percpu data pointers
* Tejun Heo <tj@kernel.org> wrote:> Jeremy Fitzhardinge wrote: > > Tejun Heo wrote: > >> Tejun Heo wrote: > >> > >>> Applied 1-3 to #tj-percpu with trivial modification on #2 (will reply > >>> to the message). > >>> > >> > >> Oh... hpa already merged them into x86/paravirt. I''ll just pull > >> x86/paravirt into core/percpu because the first patch needs to be in > >> core/percpu to keep xen working. > >> > >> hpa, can you please take the other xen patch[1] into x86/paravirt too? > >> So that I can receive it via you? > > > > Looks like its already there. > > Yes, right, which means tj-percpu == x86/paravirt for the time being. > Ingo, please pull from the following to fast forward core/percpu to > x86/paravirt (or you can just do it yourself :-) > > git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git tj-percpudone, thanks Tejun. Testing results look good so far. Ingo _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel