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x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux) 

In the expression "word1 << 16", word1 starts as u16, but is promoted to a
signed int, then sign-extended to resource_size_t, which is probably not
what was intended.  Cast to resource_size_t to avoid the sign extension.

This fixes an identical issue as fixed by commit 0b2d70764b ("x86/PCI:
Fix Broadcom CNB20LE unintended sign extension") back in 2014.

Detected by CoverityScan, CID#138749, 138750 ("Unintended sign extension")

Fixes: 3f6ea84a30 ("PCI: read memory ranges out of Broadcom CNB20LE host bridge")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
hifive-unleashed-5.1
Colin Ian King 2018-10-25 14:52:31 +01:00 committed by Bjorn Helgaas
parent 651022382c
commit 53bb565fc5
1 changed files with 2 additions and 2 deletions
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4
arch/x86/pci/broadcom_bus.c
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@ -50,8 +50,8 @@ static void __init cnb20le_res(u8 bus, u8 slot, u8 func)
word1 = read_pci_config_16(bus, slot, func, 0xc0);
word2 = read_pci_config_16(bus, slot, func, 0xc2);
if (word1 != word2) {
res.start = (word1 << 16) | 0x0000;
res.end = (word2 << 16) | 0xffff;
res.start = ((resource_size_t) word1 << 16) | 0x0000;
res.end = ((resource_size_t) word2 << 16) | 0xffff;
res.flags = IORESOURCE_MEM;
update_res(info, res.start, res.end, res.flags, 0);
}