linux.git/arch/powerpc/kernel/prom_init.c, branch v3.12.65

powerpc/prom: Fix sub-processor option passed to ibm, client-architecture-support

2016-10-07T08:06:55+00:00

commit 66443efa83dc73775100b7442962ce2cb0d4472e upstream.

When booting from an OpenFirmware which supports it, we use the
"ibm,client-architecture-support" firmware call to communicate
our capabilities to firmware.

The format of the structure we pass to firmware is specified in
PAPR (Power Architecture Platform Requirements), or the public version
LoPAPR (Linux on Power Architecture Platform Reference).

Referring to table 244 in LoPAPR v1.1, option vector 5 contains a 4 byte
field at bytes 17-20 for the "Platform Facilities Enable". This is
followed by a 1 byte field at byte 21 for "Sub-Processor Represenation
Level".

Comparing to the code, there we have the Platform Facilities
options (OV5_PFO_*) at byte 17, but we fail to pad that field out to its
full width of 4 bytes. This means the OV5_SUB_PROCESSORS option is
incorrectly placed at byte 18.

Fix it by adding zero bytes for bytes 18, 19, 20, and comment the bytes
to hopefully make it clearer in future.

As far as I'm aware nothing actually consumes this value at this time,
so the effect of this bug is nil in practice.

It does mean we've been incorrectly setting bit 15 of the "Platform
Facilities Enable" option for the past ~3 1/2 years, so we should avoid
allocating that bit to anything else in future.

Fixes: df77c7992029 ("powerpc/pseries: Update ibm,architecture.vec for PAPR 2.7/POWER8")
Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Jiri Slaby

powerpc: Add macros for the ibm_architecture_vec[] lengths

2016-10-07T07:42:32+00:00

commit e8a4fd0afe05d5213d809fa686d3b8319464acfd upstream.

The encoding of the lengths in the ibm_architecture_vec array is
"interesting" to say the least. It's non-obvious how the number of bytes
we provide relates to the length value.

In fact we already got it wrong once, see 11e9ed43ca8a "Fix up
ibm_architecture_vec definition".

So add some macros to make it (hopefully) clearer. These at least have
the property that the integer present in the code is equal to the number
of bytes that follows it.

Signed-off-by: Michael Ellerman 
Reviewed-by: Stewart Smith 
Signed-off-by: Jiri Slaby

powerpc/pseries: Do not start secondaries in Open Firmware

2013-09-25T04:19:00+00:00

Starting secondary CPUs early on from Open Firmware and placing them
in a holding spin loop slows down the boot process significantly under
some hypervisors such as KVM.

This is also unnecessary when RTAS supports querying the CPU state

So let's not do it.

Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix section mismatch warning for prom_rtas_call

2013-09-11T01:39:38+00:00

While cross-building for PPC64 I've got

WARNING: vmlinux.o(.text.unlikely+0x1ba): Section mismatch in
reference from the function .prom_rtas_call() to the variable
.init.data:dt_string_start The function .prom_rtas_call() references
the variable __initdata dt_string_start.  This is often because
.prom_rtas_call lacks a __initdata annotation or the annotation of
dt_string_start is wrong.

WARNING: vmlinux.o(.meminit.text+0xeb0): Section mismatch in reference
from the function .free_area_init_core.isra.47() to the function
.init.text:.set_pageblock_order() The function __meminit
.free_area_init_core.isra.47() references a function __init
.set_pageblock_order().  If .set_pageblock_order is only used by
.free_area_init_core.isra.47 then annotate .set_pageblock_order with a
matching annotation.

Fix it by proper annotation of prom_rtas_call.

Signed-off-by: Vladimir Murzin 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Make prom_init.c endian safe

2013-08-14T05:33:28+00:00

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc/pmac: Early debug output on screen on 64-bit macs

2013-08-14T04:57:40+00:00

We have a bunch of CONFIG_PPC_EARLY_DEBUG_* options that are intended
for bringup/debug only. They hard wire a machine specific udbg backend
very early on (before we even probe the platform), and use whatever
tricks are available on each machine/cpu to be able to get some kind
of output out there early on.

So far, on powermac with no serial ports, we have CONFIG_PPC_EARLY_DEBUG_BOOTX
to use the low-level btext engine on the screen, but it doesn't do much, at
least on 64-bit. It only really gets enabled after the platform has been
probed and the MMU enabled.

This adds a way to enable it much earlier. From prom_init.c (while still
running with Open Firmware), we grab the screen details and set things up
using the physical address of the frame buffer.

Then btext itself uses the "rm_ci" feature of the 970 processor (Real
Mode Cache Inhibited) to access it while in real mode.

We need to do a little bit of reorg of the btext code to inline things
better, in order to limit how much we touch memory while in this mode as
the consequences might be ... interesting.

This successfully allowed me to debug problems early on with the G5
(related to gold being broken vs. ppc64 kernels).

Signed-off-by: Benjamin Herrenschmidt

powerpc: Add second POWER8 PVR entry

2013-07-24T04:18:43+00:00

POWER8 comes with two different PVRs.  This patch enables the additional
PVR in the cputable.

The existing entry (PVR=0x4b) is renamed to POWER8E and the new entry
(PVR=0x4d) is given POWER8.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Enable PRRN handling

2013-04-26T06:08:26+00:00

The Linux kernel and platform firmware negotiate their mutual support
of the PRRN option via the ibm,client-architecture-support interface.
This patch simply sets the appropriate fields in the client architecture
vector to indicate Linux support for PRRN and will allow the firmware to
report PRRN events via the RTAS event-scan mechanism.

Signed-off-by: Nathan Fontenot 
Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Update firmware_has_feature() to check architecture vector 5 bits

2013-04-26T06:08:22+00:00

The firmware_has_feature() function makes it easy to check for supported
features of the hypervisor. This patch extends the capability of
firmware_has_feature() to include checking for specified bits
in vector 5 of the architecture vector as reported in the device tree.

As part of this the #defines used for the architecture vector are re-defined
such that each option has the index into vector 5 and the feature bit encoded
into it. This makes checking for architecture bits when initiating data
for firmware_has_feature much easier.

Signed-off-by: Nathan Fontenot 
Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Move architecture vector definitions to prom.h

2013-04-26T06:08:21+00:00

As part of handling of PRRN events we need to check vector 5 of the
architecture vector bits reported in the device tree to ensure PRRN event
handling is enabled. To do this firmware_has_feature() is updated (in a
subsequent patch) to make this check vector 5 bits. To avoid having to
re-define bits in the architecture vector the bit definitions are moved
to prom.h.

Signed-off-by: Nathan Fontenot 
Signed-off-by: Benjamin Herrenschmidt