Commit-ID: f16b3da1dc936c0f8121741d0a1731bf242f2f56 Gitweb: https://git.kernel.org/tip/f16b3da1dc936c0f8121741d0a1731bf242f2f56 Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Thu, 2 Nov 2017 00:59:12 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 2 Nov 2017 11:04:45 +0100 x86/xen/64, x86/entry/64: Clean up SP code in cpu_initialize_context() I'm removing thread_struct::sp0, and Xen's usage of it is slightly dubious and unnecessary. Use appropriate helpers instead. While we're at at, reorder the code slightly to make it more obvious what's going on. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: Borislav Petkov <bpetkov@xxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/d5b9a3da2b47c68325bd2bbe8f82d9554dee0d0f.1509609304.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/xen/smp_pv.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c index 5147140..8c0e047 100644 --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -13,6 +13,7 @@ * single-threaded. */ #include <linux/sched.h> +#include <linux/sched/task_stack.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/smp.h> @@ -293,12 +294,19 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) #endif memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt)); + /* + * Bring up the CPU in cpu_bringup_and_idle() with the stack + * pointing just below where pt_regs would be if it were a normal + * kernel entry. + */ ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; ctxt->flags = VGCF_IN_KERNEL; ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ ctxt->user_regs.ds = __USER_DS; ctxt->user_regs.es = __USER_DS; ctxt->user_regs.ss = __KERNEL_DS; + ctxt->user_regs.cs = __KERNEL_CS; + ctxt->user_regs.esp = (unsigned long)task_pt_regs(idle); xen_copy_trap_info(ctxt->trap_ctxt); @@ -313,8 +321,13 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) ctxt->gdt_frames[0] = gdt_mfn; ctxt->gdt_ents = GDT_ENTRIES; + /* + * Set SS:SP that Xen will use when entering guest kernel mode + * from guest user mode. Subsequent calls to load_sp0() can + * change this value. + */ ctxt->kernel_ss = __KERNEL_DS; - ctxt->kernel_sp = idle->thread.sp0; + ctxt->kernel_sp = task_top_of_stack(idle); #ifdef CONFIG_X86_32 ctxt->event_callback_cs = __KERNEL_CS; @@ -326,10 +339,8 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) (unsigned long)xen_hypervisor_callback; ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback; - ctxt->user_regs.cs = __KERNEL_CS; per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir); - ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs); ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir)); if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt)) BUG(); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|