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Commit edcb5cf8 authored by Juergen Gross's avatar Juergen Gross Committed by Ingo Molnar
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x86/paravirt/xen: Remove xen_patch() 



Xen's paravirt patch function xen_patch() does some special casing for
irq_ops functions to apply relocations when those functions can be
patched inline instead of calls.

Unfortunately none of the special case function replacements is small
enough to be patched inline, so the special case never applies.

As xen_patch() will call paravirt_patch_default() in all cases it can
be just dropped. xen-asm.h doesn't seem necessary without xen_patch()
as the only thing left in it would be the definition of XEN_EFLAGS_NMI
used only once. So move that definition and remove xen-asm.h.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: rusty@rustcorp.com.au
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170816173157.8633-2-jgross@suse.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ee97638b

arch/x86/xen/enlighten_pv.c

+1 −58
Original line number Diff line number Diff line
@@ -981,59 +981,6 @@ void __ref xen_setup_vcpu_info_placement(void) 
	}

}



static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,

			  unsigned long addr, unsigned len)

{

	char *start, *end, *reloc;

	unsigned ret;



	start = end = reloc = NULL;



#define SITE(op, x)							\

	case PARAVIRT_PATCH(op.x):					\

	if (xen_have_vcpu_info_placement) {				\

		start = (char *)xen_##x##_direct;			\

		end = xen_##x##_direct_end;				\

		reloc = xen_##x##_direct_reloc;				\

	}								\

	goto patch_site



	switch (type) {

		SITE(pv_irq_ops, irq_enable);

		SITE(pv_irq_ops, irq_disable);

		SITE(pv_irq_ops, save_fl);

		SITE(pv_irq_ops, restore_fl);

#undef SITE



	patch_site:

		if (start == NULL || (end-start) > len)

			goto default_patch;



		ret = paravirt_patch_insns(insnbuf, len, start, end);



		/* Note: because reloc is assigned from something that

		   appears to be an array, gcc assumes it's non-null,

		   but doesn't know its relationship with start and

		   end. */

		if (reloc > start && reloc < end) {

			int reloc_off = reloc - start;

			long *relocp = (long *)(insnbuf + reloc_off);

			long delta = start - (char *)addr;



			*relocp += delta;

		}

		break;



	default_patch:

	default:

		ret = paravirt_patch_default(type, clobbers, insnbuf,

					     addr, len);

		break;

	}



	return ret;

}



static const struct pv_info xen_info __initconst = {

	.shared_kernel_pmd = 0,
@@ -1043,10 +990,6 @@ static const struct pv_info xen_info __initconst = { 
	.name = "Xen",

};



static const struct pv_init_ops xen_init_ops __initconst = {

	.patch = xen_patch,

};



static const struct pv_cpu_ops xen_cpu_ops __initconst = {

	.cpuid = xen_cpuid,
@@ -1244,7 +1187,7 @@ asmlinkage __visible void __init xen_start_kernel(void) 


	/* Install Xen paravirt ops */

	pv_info = xen_info;

	pv_init_ops = xen_init_ops;

	pv_init_ops.patch = paravirt_patch_default;

	pv_cpu_ops = xen_cpu_ops;



	x86_platform.get_nmi_reason = xen_get_nmi_reason;

arch/x86/xen/xen-asm.S

+6 −20
Original line number Diff line number Diff line 
/*

 * Asm versions of Xen pv-ops, suitable for either direct use or

 * inlining.  The inline versions are the same as the direct-use

 * versions, with the pre- and post-amble chopped off.

 *

 * This code is encoded for size rather than absolute efficiency, with

 * a view to being able to inline as much as possible.

 * Asm versions of Xen pv-ops, suitable for direct use.

 *

 * We only bother with direct forms (ie, vcpu in percpu data) of the

 * operations here; the indirect forms are better handled in C, since

 * they're generally too large to inline anyway.

 * operations here; the indirect forms are better handled in C.

 */



#include <asm/asm-offsets.h>
@@ -16,7 +10,7 @@ 
#include <asm/processor-flags.h>

#include <asm/frame.h>



#include "xen-asm.h"

#include <linux/linkage.h>



/*

 * Enable events.  This clears the event mask and tests the pending
@@ -38,13 +32,11 @@ ENTRY(xen_irq_enable_direct) 
	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending

	jz 1f



2:	call check_events

	call check_events

1:

ENDPATCH(xen_irq_enable_direct)

	FRAME_END

	ret

	ENDPROC(xen_irq_enable_direct)

	RELOC(xen_irq_enable_direct, 2b+1)





/*
@@ -53,10 +45,8 @@ ENDPATCH(xen_irq_enable_direct) 
 */

ENTRY(xen_irq_disable_direct)

	movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask

ENDPATCH(xen_irq_disable_direct)

	ret

ENDPROC(xen_irq_disable_direct)

	RELOC(xen_irq_disable_direct, 0)



/*

 * (xen_)save_fl is used to get the current interrupt enable status.
@@ -71,10 +61,8 @@ ENTRY(xen_save_fl_direct) 
	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask

	setz %ah

	addb %ah, %ah

ENDPATCH(xen_save_fl_direct)

	ret

	ENDPROC(xen_save_fl_direct)

	RELOC(xen_save_fl_direct, 0)





/*
@@ -101,13 +89,11 @@ ENTRY(xen_restore_fl_direct) 
	/* check for unmasked and pending */

	cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending

	jnz 1f

2:	call check_events

	call check_events

1:

ENDPATCH(xen_restore_fl_direct)

	FRAME_END

	ret

	ENDPROC(xen_restore_fl_direct)

	RELOC(xen_restore_fl_direct, 2b+1)





/*

arch/x86/xen/xen-asm.h

deleted100644 → 0
+0 −12
Original line number Diff line number Diff line 
#ifndef _XEN_XEN_ASM_H

#define _XEN_XEN_ASM_H



#include <linux/linkage.h>



#define RELOC(x, v)	.globl x##_reloc; x##_reloc=v

#define ENDPATCH(x)	.globl x##_end; x##_end=.



/* Pseudo-flag used for virtual NMI, which we don't implement yet */

#define XEN_EFLAGS_NMI	0x80000000



#endif

arch/x86/xen/xen-asm_32.S

+5 −22
Original line number Diff line number Diff line 
/*

 * Asm versions of Xen pv-ops, suitable for either direct use or

 * inlining.  The inline versions are the same as the direct-use

 * versions, with the pre- and post-amble chopped off.

 *

 * This code is encoded for size rather than absolute efficiency, with

 * a view to being able to inline as much as possible.

 * Asm versions of Xen pv-ops, suitable for direct use.

 *

 * We only bother with direct forms (ie, vcpu in pda) of the

 * operations here; the indirect forms are better handled in C, since

 * they're generally too large to inline anyway.

 * operations here; the indirect forms are better handled in C.

 */



#include <asm/thread_info.h>
@@ -18,21 +12,10 @@ 


#include <xen/interface/xen.h>



#include "xen-asm.h"

#include <linux/linkage.h>



/*

 * Force an event check by making a hypercall, but preserve regs

 * before making the call.

 */

check_events:

	push %eax

	push %ecx

	push %edx

	call xen_force_evtchn_callback

	pop %edx

	pop %ecx

	pop %eax

	ret

/* Pseudo-flag used for virtual NMI, which we don't implement yet */

#define XEN_EFLAGS_NMI  0x80000000



/*

 * This is run where a normal iret would be run, with the same stack setup:

arch/x86/xen/xen-asm_64.S

+5 −15
Original line number Diff line number Diff line 
/*

 * Asm versions of Xen pv-ops, suitable for either direct use or

 * inlining.  The inline versions are the same as the direct-use

 * versions, with the pre- and post-amble chopped off.

 *

 * This code is encoded for size rather than absolute efficiency, with

 * a view to being able to inline as much as possible.

 * Asm versions of Xen pv-ops, suitable for direct use.

 *

 * We only bother with direct forms (ie, vcpu in pda) of the

 * operations here; the indirect forms are better handled in C, since

 * they're generally too large to inline anyway.

 * operations here; the indirect forms are better handled in C.

 */



#include <asm/errno.h>
@@ -20,7 +14,7 @@ 


#include <xen/interface/xen.h>



#include "xen-asm.h"

#include <linux/linkage.h>



ENTRY(xen_adjust_exception_frame)

	mov 8+0(%rsp), %rcx
@@ -46,9 +40,7 @@ hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 
 */

ENTRY(xen_iret)

	pushq $0

1:	jmp hypercall_iret

ENDPATCH(xen_iret)

RELOC(xen_iret, 1b+1)

	jmp hypercall_iret



ENTRY(xen_sysret64)

	/*
@@ -65,9 +57,7 @@ ENTRY(xen_sysret64) 
	pushq %rcx



	pushq $VGCF_in_syscall

1:	jmp hypercall_iret

ENDPATCH(xen_sysret64)

RELOC(xen_sysret64, 1b+1)

	jmp hypercall_iret



/*

 * Xen handles syscall callbacks much like ordinary exceptions, which