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Commit f16b3da1 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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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: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d5b9a3da2b47c68325bd2bbe8f82d9554dee0d0f.1509609304.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3500130b

arch/x86/xen/smp_pv.c

+14 −3
Original line number Diff line number Diff line
@@ -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();