The Microsoft spec for SPCR says "The base address of the Serial Port
register set described using the ACPI Generic Address Structure, or
0 if console redirection is disabled". So, return early if redirection
is disabled (base address = 0). If this check is not done we may get
invalid ports on machines with redirection disabled and boot may hang
when reading the grub.cfg file.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Leo Sandoval <lsandova@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The calculation of the size of the table was incorrect (copy/pasta from
grub_acpi_rsdt_find_table() I assume...). The entries are 64-bit long.
This causes us to access beyond the end of the table which is causing
crashes during boot on some systems. Typically this is causing a crash
on VMWare when using UEFI and enabling serial autodetection, as
grub_acpi_find_table (GRUB_ACPI_SPCR_SIGNATURE);
will goes past the end of the table (the SPCR table doesn't exits).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Tested-by: Renata Ravanelli <rravanel@redhat.com>
The access_size is part of a union, so doesn't technically exist for
a PIO port (i.e., not MMIO), but we set it anyways.
This doesn't cause a bug today because the other leg of the union
doesn't have anything overlapping with it now, but it's bad, I will
punish myself for writing it that way :-) In the meantime, fix this
and actually name the struct inside the union for clarity of intent
and to avoid such issue in the future.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
We currently rely on some pretty fragile comparison by name to
identify whether a serial port being configured is identical
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The various functions to add a port used to return port->name, and
the callers would immediately iterate all registered ports to "find"
the one just created by comparing that return value with ... port->name.
This is a waste of cycles and code. Instead, have those functions
return "port" directly.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This adds the ability to explicitly add an MMIO based serial port
via the "serial" command. The syntax is:
serial --port=mmio,<hex_address>{.b,.w,.l,.q}
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
And while at it, unify it as clock frequency in Hz, to match the value in
grub_serial_config struct and do the division by 16 in one common place.
This will simplify adding SPCR support.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is useful on cloud instances with remote serial ports as it can be
difficult to connect "fast enough" to get the initial menu display
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Benjamin Herrenschmidt