Some developers really like to have -Werror enabled for their code, as
it helps to ensure warning free code. Others don't want -Werror, as it
(for example) can cause problems when newer (or older) compilers have
different sets of warnings, or new warnings can appear just when turning
up the warning level (e.g., make W=1 or W=2). Thus, it seems prudent to
have the use of -Werror be configurable.
It so happens that cxl is only built on PowerPC, and PowerPC already
has a nice set of Kconfig options for this, under CONFIG_PPC_WERROR. So
let's use that, and the world is a happy place again! (Note that
PPC_WERROR defaults to =y, so the common case compile should still be
enforcing -Werror.)
Fixes: d3d73f4b38 ("cxl: Compile with -Werror")
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
GCC 4.6.3 does not support -Wno-unused-const-variable. Instead, use the
kbuild infrastructure that checks if this options exists.
Fixes: 2cd55c68c0 ("cxl: Fix build failure due to -Wunused-variable behaviour change")
Suggested-by: Michal Marek <mmarek@suse.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A recent change in gcc caused this build failure:
/var/lib/jenkins/workspace/gcc_kernel_build/linux/drivers/misc/cxl/cxl.h:72:27:
error: ‘CXL_PSL_DLCNTL’ defined but not used [-Werror=unused-const-variable]
static const cxl_p1_reg_t CXL_PSL_DLCNTL = {0x0060};
Because of this gcc commit:
Commit 1bca8cbd0c68366f07277f98ce6963e10c2aa617 by mark
PR28901 -Wunused-variable ignores unused const initialised variables in C
12 years ago it was decided that -Wunused-variable shouldn't warn about
static const variables because some code used const static char rcsid[]
strings which were never used but wanted in the code anyway. But as the
bug points out this hides some real bugs. These days the usage of
rcsids is not very popular anymore. So this patch changes the default
to warn about unused static const variables in C with
-Wunused-variable. And it adds a new option -Wno-unused-const-variable
to turn this warning off. For C++ this new warning is off by default,
since const variables can be used as #defines in C++. New testcases for
the new defaults in C and C++ are included testing the new warning and
suppressing it with an unused attribute or using
-Wno-unused-const-variable. gcc/ChangeLog
The cxl driver uses static consts in place of #defines in some cases
for type safety, so this change causes the driver to fail to build on
new copilers as these constants are not all used in every file that
imports the header. Suppress the warning for this driver to return to
the old behaviour of -Wunused-variable.
Reported-by: Anton Blanchard <anton@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
It's a good idea, and it brings us in line with the rest of arch/powerpc.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch does two things.
Firstly it presents the Accelerator Function Unit (AFUs) behind the POWER
Service Layer (PSL) as PCI devices on a virtual PCI Host Bridge (vPHB). This
in in addition to the PSL being a PCI device itself.
As part of the Coherent Accelerator Interface Architecture (CAIA) AFUs can
provide an AFU configuration. This AFU configuration recored is architected to
be the same as a PCI config space.
This patch sets discovers the AFU configuration records, provides AFU config
space read/write functions to these configuration records. It then enumerates
the PCI bus. It also hooks in PCI ops where appropriate. It also destroys the
vPHB when the physical card is removed.
Secondly, it add an in kernel API for AFU to use CXL. AFUs must present a
driver that firstly binds as a PCI device. This PCI device can then be using
to do CXL specific operations (that can't sit in the PCI ops) using this API.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cleanup Makefile by fixing line wrapping.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch adds tracepoints throughout the cxl driver, which can provide
insight into:
- Context lifetimes
- Commands sent to the PSL and AFU and their completion status
- Segment and page table misses and their resolution
- PSL and AFU interrupts
- slbia calls from the powerpc copro_fault code
These tracepoints are mostly intended to aid in debugging (particularly
for new AFU designs), and may be useful standalone or in conjunction
with hardware traces collected by the PSL (read out via the trace
interface in debugfs) and AFUs.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds the base cxl support that cannot be built as a module. Specifically
it adds the cxl callbacks that are called from the core powerpc mm code which
must always exist irrespective of if the cxl module is loaded or not. This is
similar to how cell works with CONFIG_SPU_BASE.
This adds a cxl_slbia() call (similar to spu_flush_all_slbs()) which checks if
the cxl module is loaded and in use, returning immediately if it is not. If it
is in use it calls into the cxl SLB invalidation code.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Brian Norris