linux-kernel - [PATCH 1/3] paravirt,xen: remove xen

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170810125254.1347-2-jgross@suse.com>
Date:   Thu, 10 Aug 2017 14:52:52 +0200
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
        x86@...nel.org
Cc:     hpa@...or.com, mingo@...hat.com, tglx@...utronix.de,
        boris.ostrovsky@...cle.com, rusty@...tcorp.com.au,
        lguest@...ts.ozlabs.org, Juergen Gross <jgross@...e.com>
Subject: [PATCH 1/3] 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 patches inline, so the special case never applies.

As xen_patch() will call paravirt_patch_default() in all cases it can
be just dropped.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/xen/enlighten_pv.c | 59 +--------------------------------------------
 1 file changed, 1 insertion(+), 58 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 811e4ddb3f37..98491521bb43 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -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;
-- 
2.12.3