arm64/pmap: Modify condition of valid_memattr that cannot be true

[timo.voelker_fh-muenster.de]

Summary

The function pmap_is_valid_memattr(pmap, mode) checks whether the given variable mode is between the two constant values VM_MEMATTR_DEVICE and VM_MEMATTR_WRITE_THROUGH. After the code for this function was written, the value of VM_MEMATTR_DEVICE changed from 0 to 4. Since VM_MEMATTR_WRITE_THROUGH is still 3, the condition is always false.

This patch changes the condition to check whether mode is equal to any of the VM_MEMATTR* constants.

[tuexen]

Does this patch solve any problem?

[timo.voelker_fh-muenster.de]

In D55534#1270843, @tuexen wrote:

Does this patch solve any problem?

Yes. I tried to dump the content of a PCI BAR with:

pciconf -D pci0:0:10:0 0x18 | hexdump

This command failed with EINVAL. It calls pci_bar_mmap(pcidev, pbm) in sys/dev/pci/pci_user.c, which returns EINVAL if pmap_is_valid_memattr(pmap, mode) returns false. With this patch, I was able to dump the content of the PCI BAR.

[tuexen]

In D55534#1271706, @timo.voelker_fh-muenster.de wrote:

In D55534#1270843, @tuexen wrote:

Does this patch solve any problem?

Yes. I tried to dump the content of a PCI BAR with:

pciconf -D pci0:0:10:0 0x18 | hexdump

This command failed with EINVAL. It calls pci_bar_mmap(pcidev, pbm) in sys/dev/pci/pci_user.c, which returns EINVAL if pmap_is_valid_memattr(pmap, mode) returns false. With this patch, I was able to dump the content of the PCI BAR.

Thanks for pointing that out. The patch looks good to me, but I will give the other reviewers a chance to look at it.