- alignment fix

[packages/xen.git] / gcc9.patch

From 3fd3b266d4198c06e8e421ca515d9ba09ccd5155 Mon Sep 17 00:00:00 2001
From: Jan Beulich <jbeulich@suse.com>
Date: Mon, 13 May 2019 09:51:23 +0200
Subject: [PATCH] trace: fix build with gcc9
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

While I've not observed this myself, gcc 9 (imo validly) reportedly may
complain

trace.c: In function '__trace_hypercall':
trace.c:826:19: error: taking address of packed member of 'struct <anonymous>' may result in an unaligned pointer value [-Werror=address-of-packed-member]
  826 |     uint32_t *a = d.args;

and the fix is rather simple - remove the __packed attribute. Introduce
a BUILD_BUG_ON() as replacement, for the unlikely case that Xen might
get ported to an architecture where array alignment higher that that of
its elements.

Reported-by: Martin Liška <martin.liska@suse.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
---
 xen/common/trace.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/xen/common/trace.c b/xen/common/trace.c
index cc294fc38473..d1ef81407b71 100644
--- a/xen/common/trace.c
+++ b/xen/common/trace.c
@@ -819,12 +819,18 @@ void __trace_var(u32 event, bool_t cycles, unsigned int extra,
 void __trace_hypercall(uint32_t event, unsigned long op,
                        const xen_ulong_t *args)
 {
-    struct __packed {
+    struct {
         uint32_t op;
         uint32_t args[6];
     } d;
     uint32_t *a = d.args;
 
+    /*
+     * In lieu of using __packed above, which gcc9 legitimately doesn't
+     * like in combination with the address of d.args[] taken.
+     */
+    BUILD_BUG_ON(offsetof(typeof(d), args) != sizeof(d.op));
+
 #define APPEND_ARG32(i)                         \
     do {                                        \
         unsigned i_ = (i);                      \
--- xen-4.11.1/xen/drivers/passthrough/vtd/vtd.h.orig	2018-11-29 14:04:11.000000000 +0000
+++ xen-4.11.1/xen/drivers/passthrough/vtd/vtd.h	2019-02-05 21:32:50.056774501 +0000
@@ -28,7 +28,7 @@
 /* Allow for both IOAPIC and IOSAPIC. */
 #define IO_xAPIC_route_entry IO_APIC_route_entry
 
-struct IO_APIC_route_remap_entry {
+struct __packed IO_APIC_route_remap_entry {
     union {
         u64 val;
         struct {
--- xen-4.11.1/xen/arch/x86/cpu/mtrr/generic.c.orig	2018-11-29 14:04:11.000000000 +0000
+++ xen-4.11.1/xen/arch/x86/cpu/mtrr/generic.c	2019-02-10 19:24:09.378805103 +0000
@@ -171,6 +171,9 @@
 	printk("%sMTRR variable ranges %sabled:\n", level,
 	       mtrr_state.enabled ? "en" : "dis");
 	width = (paddr_bits - PAGE_SHIFT + 3) / 4;
+	if (  width > 64 ) {
+		width=64;
+	}
 
 	for (i = 0; i < num_var_ranges; ++i) {
 		if (mtrr_state.var_ranges[i].mask & MTRR_PHYSMASK_VALID)
--- xen-4.6.6/xen/arch/x86/mm.c~	2017-07-06 09:04:28.000000000 +0200
+++ xen-4.6.6/xen/arch/x86/mm.c	2019-10-27 14:02:41.582770616 +0100
@@ -517,7 +517,7 @@
     make_cr3(v, cr3_mfn);
 }
 
-static const char __section(".bss.page_aligned") zero_page[PAGE_SIZE];
+static const char __section(".bss.page_aligned.const") zero_page[PAGE_SIZE];
 
 static void invalidate_shadow_ldt(struct vcpu *v, int flush)
 {