sparc: kernel/pcic: silence gcc 7.x warning in pcibios_fixup_bus()

commit 2dc77533f1e495788d73ffa4bee4323b2646d2bb upstream.

When building the kernel for Sparc using gcc 7.x, the build fails
with:

arch/sparc/kernel/pcic.c: In function ‘pcibios_fixup_bus’:
arch/sparc/kernel/pcic.c:647:8: error: ‘cmd’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
    cmd |= PCI_COMMAND_IO;
        ^~

The simplified code looks like this:

unsigned int cmd;
[...]
pcic_read_config(dev->bus, dev->devfn, PCI_COMMAND, 2, &cmd);
[...]
cmd |= PCI_COMMAND_IO;

I.e, the code assumes that pcic_read_config() will always initialize
cmd. But it's not the case. Looking at pcic_read_config(), if
bus->number is != 0 or if the size is not one of 1, 2 or 4, *val will
not be initialized.

As a simple fix, we initialize cmd to zero at the beginning of
pcibios_fixup_bus.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
index 24384e1dc33d30bd22a8bc819f7b87daf0d3612b..a7aeb036b070538f57158f4a1410243bfcc0c28e 100644 (file)
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -602,7 +602,7 @@ void pcibios_fixup_bus(struct pci_bus *bus)
 {
        struct pci_dev *dev;
        int i, has_io, has_mem;
-       unsigned int cmd;
+       unsigned int cmd = 0;
        struct linux_pcic *pcic;
        /* struct linux_pbm_info* pbm = &pcic->pbm; */
        int node;