[Xen-devel] [PATCH] x86/mmcfg: Fix initalisation of variables in pci_mmcfg_nvidia_mcp55()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Shifting into the sign bit of an integer is undefined behaviour.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>

I was experimenting with -fsanitise=undefined and this bit failed to compile,
as the initialisation became a non-constant expression.
---
 xen/arch/x86/x86_64/mmconfig-shared.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/x86_64/mmconfig-shared.c 
b/xen/arch/x86/x86_64/mmconfig-shared.c
index 742bc18..a7592c6 100644
--- a/xen/arch/x86/x86_64/mmconfig-shared.c
+++ b/xen/arch/x86/x86_64/mmconfig-shared.c
@@ -182,10 +182,10 @@ static const char __init *pci_mmcfg_nvidia_mcp55(void)
     int bus, i;
 
     static const u32 extcfg_regnum      = 0x90;
-    static const u32 extcfg_enable_mask = 1<<31;
-    static const u32 extcfg_start_mask  = 0xff<<16;
+    static const u32 extcfg_enable_mask = 1u << 31;
+    static const u32 extcfg_start_mask  = 0xffu << 16;
     static const int extcfg_start_shift = 16;
-    static const u32 extcfg_size_mask   = 0x3<<28;
+    static const u32 extcfg_size_mask   = 3u << 28;
     static const int extcfg_size_shift  = 28;
     static const int extcfg_sizebus[]   = {0xff, 0x7f, 0x3f, 0x1f};
     static const u32 extcfg_base_mask[] = {0x7ff8, 0x7ffc, 0x7ffe, 0x7fff};
-- 
2.1.4


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