There could be boards with DCN listed in IP discovery, but no
display hardware actually wired up. In this case the vbios
display table will not be populated. Detect this case and
skip loading DM when we detect it.
v2: Mark DCN as harvested as well so other display checks
elsewhere in the driver are handled properly.
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
These sysfs nodes are tested supported, so enable them.
Signed-off-by: Yiqing Yao <yiqing.yao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
A mistake has been made on some boards with NBIO 4.3.0 where some
NBIO registers aren't properly set by the hardware.
Ensure that they're set during initialization.
Cc: Natikar Basavaraj <Basavaraj.Natikar@amd.com>
Tested-by: Satyanarayana ReddyTVN <Satyanarayana.ReddyTVN@amd.com>
Tested-by: Rutvij Gajjar <Rutvij.Gajjar@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.1.x
Enable HDP clock gating control for gfx 11.0.3.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
PMFW will handle the features disablement properly for gpu reset case,
driver involvement may cause some unexpected issues.
Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Tim Huang <tim.huang@amd.com>
Reviewed-by: Yifan Zhang <yifan1.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Otherwise we can be out of sync with what's in the hardware, leading
to us rerunning every command that's presently in the ringbuffer.
[How]
Reset software state for the mailboxes in hw_reset callback.
This is already done as part of the mailbox init in hw_init, but we
do need to remember to reset the last cached wptr value as well here.
Reviewed-by: Hansen Dsouza <hansen.dsouza@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
The hwss function does_plane_fit_in_mall not applicable to dcn3.2 asics.
Using it with dcn3.2 can result in undefined behaviour.
[How]
Assign the function pointer to NULL.
Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Lower max_downscale_ratio and ARGB888 downscale factor
to prevent cases where underflow may occur on dcn314
[How]
Set max_downscale_ratio to 400 and ARGB downscale factor
to 250 for dcn314
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Daniel Miess <Daniel.Miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Why]
Brackets missing in the calculation for MIN_DST_Y_NEXT_START
[How]
Add missing brackets for this calculation
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Daniel Miess <Daniel.Miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
SQ_WAVE_INST_DW0 isn't present on gfx11 compared to gfx10, so update
wave data type to signify a difference.
Signed-off-by: Graham Sider <Graham.Sider@amd.com>
Reviewed-by: Mukul Joshi <Mukul.Joshi@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.1.x
Jisheng Zhang <jszhang@kernel.org> says:
Generally, riscv ISA extensions are fixed for any specific hardware
platform, so a hart's features won't change after booting, this
chacteristic makes it straightforward to use a static branch to check
a specific ISA extension is supported or not to optimize performance.
However, some ISA extensions such as SVPBMT and ZICBOM are handled
via. the alternative sequences.
Basically, for ease of maintenance, we prefer to use static branches
in C code, but recently, Samuel found that the static branch usage in
cpu_relax() breaks building with CONFIG_CC_OPTIMIZE_FOR_SIZE[1]. As
Samuel pointed out, "Having a static branch in cpu_relax() is
problematic because that function is widely inlined, including in some
quite complex functions like in the VDSO. A quick measurement shows
this static branch is responsible by itself for around 40% of the jump
table."
Samuel's findings pointed out one of a few downsides of static branches
usage in C code to handle ISA extensions detected at boot time:
static branch's metadata in the __jump_table section, which is not
discarded after ISA extensions are finalized, wastes some space.
I want to try to solve the issue for all possible dynamic handling of
ISA extensions at boot time. Inspired by Mark[2], this patch introduces
riscv_has_extension_*() helpers, which work like static branches but
are patched using alternatives, thus the metadata can be freed after
patching.
[1]https://lore.kernel.org/linux-riscv/20220922060958.44203-1-samuel@sholland.org/
[2]https://lore.kernel.org/linux-arm-kernel/20220912162210.3626215-8-mark.rutland@arm.com/
[3]https://lore.kernel.org/linux-riscv/20221130225614.1594256-1-heiko@sntech.de/
* b4-shazam-merge:
riscv: remove riscv_isa_ext_keys[] array and related usage
riscv: KVM: Switch has_svinval() to riscv_has_extension_unlikely()
riscv: cpu_relax: switch to riscv_has_extension_likely()
riscv: alternative: patch alternatives in the vDSO
riscv: switch to relative alternative entries
riscv: module: Add ADD16 and SUB16 rela types
riscv: module: move find_section to module.h
riscv: fpu: switch has_fpu() to riscv_has_extension_likely()
riscv: introduce riscv_has_extension_[un]likely()
riscv: cpufeature: extend riscv_cpufeature_patch_func to all ISA extensions
riscv: hwcap: make ISA extension ids can be used in asm
riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier
riscv: move riscv_noncoherent_supported() out of ZICBOM probe
Link: https://lore.kernel.org/r/20230128172856.3814-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Modified the bnxt_en code to create and pre-configure RDMA devices
with the right MSI-X vector count for the ROCE driver to use.
This is to align the ROCE driver to the auxiliary device model which
will simply bind the driver without getting into PCI-related handling.
All PCI-related logic will now be in the bnxt_en driver.
Suggested-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Remove the SRIOV config callback which the bnxt_en was calling
to reconfigure the chip resources for a PF device when VFs are
created. The code is now modified to provision the VF resources
based on the total VF count instead of the actual VF count.
This allows the SRIOV config callback to be removed from the
list of ulp_ops.
Suggested-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Decouple RoCE driver from directly accessing L2's private bnxt
structure. Move the fields needed by RoCE driver into bnxt_en_dev.
They'll be passed to RoCE driver by bnxt_rdma_aux_device_add()
function.
Signed-off-by: Hongguang Gao <hongguang.gao@broadcom.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Wherever possible use the function ops provided by auxiliary bus
instead of using proprietary ops.
Defined bnxt_re_suspend and bnxt_re_resume calls which can be
invoked by the bnxt_en driver instead of the ULP stop/start calls.
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
For a single ULP user there is no need for complicating function
indirection calls. Remove all this complexity in favour of direct
function calls exported by the bnxt_en driver. This allows to
simplify the code greatly. Also remove unused ulp_async_notifier.
Suggested-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Since the driver continues to use the single ULP model,
the extra complexity and indirection is unnecessary.
Remove the usage of ulp_id from the code.
Suggested-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Use auxiliary driver interface for driver load, unload ROCE driver.
The driver does not need to register the interface using the netdev
notifier anymore. Removed the bnxt_re_dev_list which is not needed.
Currently probe, remove and shutdown ops have been implemented for
the auxiliary device.
Also remove exccessve validation checks for rdev.
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Add auxiliary driver support.
An auxiliary device will be created if the hardware indicates
support for RDMA.
The bnxt_ulp_probe() function has been removed and a new
bnxt_rdma_aux_device_add() function has been added.
The bnxt_free_msix_vecs() and bnxt_req_msix_vecs() will now hold
the RTNL lock when they call the bnxt_close_nic()and bnxt_open_nic()
since the device close and open need to be protected under RTNL lock.
The operations between the bnxt_en and bnxt_re will be protected
using the en_ops_lock.
This will be used by the bnxt_re driver in a follow-on patch
to create ROCE interfaces.
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
We source root cgroup stats from the system-wide stats, see blkcg_print_stat
and blkcg_rstat_flush, so don't update io state for root cgroup.
Fixes blkg leak issue introduced in commit 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
which starts to grab blkg's reference when adding iostat_cpu into percpu
blkcg list, but this state won't be consumed by blkcg_rstat_flush() where
the blkg reference is dropped.
Tested-by: Bart van Assche <bvanassche@acm.org>
Reported-by: Bart van Assche <bvanassche@acm.org>
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230202021804.278582-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit baf1ed24b2 ("powerpc/mm: Remove empty hash__ functions")
removed some empty hash MMU flushing routines, but got a bit overeager
and also removed the call to hash__tlb_flush() from tlb_flush().
In regular use this doesn't lead to any noticable breakage, which is a
little concerning. Presumably there are flushes happening via other
paths such as arch_leave_lazy_mmu_mode(), and/or a bit of luck.
Fix it by reinstating the call to hash__tlb_flush().
Fixes: baf1ed24b2 ("powerpc/mm: Remove empty hash__ functions")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230131111407.806770-1-mpe@ellerman.id.au
A statically linked executable can have a .plt due to IFUNCs, in which
case .symtab is used not .dynsym. Check the section header link to see
if that is the case, and then use symtab instead.
Example:
Before:
$ cat tstifunc.c
#include <stdio.h>
void thing1(void)
{
printf("thing1\n");
}
void thing2(void)
{
printf("thing2\n");
}
typedef void (*thing_fn_t)(void);
thing_fn_t thing_ifunc(void)
{
int x;
if (x & 1)
return thing2;
return thing1;
}
void thing(void) __attribute__ ((ifunc ("thing_ifunc")));
int main()
{
thing();
return 0;
}
$ gcc --version
gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ gcc -static -Wall -Wextra -Wno-uninitialized -o tstifuncstatic tstifunc.c
$ readelf -SW tstifuncstatic | grep 'Name\|plt\|dyn'
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 4] .rela.plt RELA 00000000004002e8 0002e8 000258 18 AI 29 20 8
[ 6] .plt PROGBITS 0000000000401020 001020 000190 00 AX 0 0 16
[20] .got.plt PROGBITS 00000000004c5000 0c4000 0000e0 08 WA 0 0 8
$ perf record -e intel_pt//u --filter 'filter main @ ./tstifuncstatic' ./tstifuncstatic
thing1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.008 MB perf.data ]
$ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso
15786.690189535: tr strt 0 [unknown] => 4017cd main+0x0
15786.690189535: tr end call 4017d5 main+0x8 => 401170 [unknown]
15786.690197660: tr strt 0 [unknown] => 4017da main+0xd
15786.690197660: tr end return 4017e0 main+0x13 => 401c1a __libc_start_call_main+0x6a
After:
$ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso
15786.690189535: tr strt 0 [unknown] => 4017cd main+0x0
15786.690189535: tr end call 4017d5 main+0x8 => 401170 thing_ifunc@plt+0x0
15786.690197660: tr strt 0 [unknown] => 4017da main+0xd
15786.690197660: tr end return 4017e0 main+0x13 => 401c1a __libc_start_call_main+0x6a
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230131131625.6964-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
A static executable can have a .plt due to the presence of IFUNCs. In
that case the .plt does not have a header. Check for whether there is a
header by comparing the number of entries to the number of relocation
entries.
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230131131625.6964-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To assist with synthesizing plt symbols for IFUNCs, record whether a
symbol is an alias of an IFUNC symbol.
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230131131625.6964-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The section .plt.sec was originally added for MPX and was first called
.plt.bnd. While MPX has been deprecated, .plt.sec is now also used for
IBT. On x86_64, IBT may be enabled by default, but can be switched off
using gcc option -fcf-protection=none, or switched on by -z ibt or -z
ibtplt. On 32-bit, option -z ibt or -z ibtplt will enable IBT.
With .plt.sec, calls are made into .plt.sec instead of .plt, so it makes
more sense to put the symbols there instead of .plt. A notable
difference is that .plt.sec does not have a header entry.
For x86, when synthesizing symbols for plt, use offset and entry size of
.plt.sec instead of .plt when there is a .plt.sec section.
Example on Ubuntu 22.04 gcc 11.3:
Before:
$ cat tstpltlib.c
void fn1(void) {}
void fn2(void) {}
void fn3(void) {}
void fn4(void) {}
$ cat tstplt.c
void fn1(void);
void fn2(void);
void fn3(void);
void fn4(void);
int main()
{
fn4();
fn1();
fn2();
fn3();
return 0;
}
$ gcc --version
gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ gcc -Wall -Wextra -shared -o libtstpltlib.so tstpltlib.c
$ gcc -Wall -Wextra -z ibt -o tstplt tstplt.c -L . -ltstpltlib -Wl,-rpath=$(pwd)
$ readelf -SW tstplt | grep 'plt\|Name'
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[11] .rela.plt RELA 0000000000000698 000698 000060 18 AI 6 24 8
[13] .plt PROGBITS 0000000000001020 001020 000050 10 AX 0 0 16
[14] .plt.got PROGBITS 0000000000001070 001070 000010 10 AX 0 0 16
[15] .plt.sec PROGBITS 0000000000001080 001080 000040 10 AX 0 0 16
$ perf record -e intel_pt//u --filter 'filter main @ ./tstplt' ./tstplt
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.015 MB perf.data ]
$ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso
38970.522546686: tr strt 0 [unknown] => 55fc222a81a9 main+0x0
38970.522546686: tr end call 55fc222a81b1 main+0x8 => 55fc222a80a0 [unknown]
38970.522546687: tr strt 0 [unknown] => 55fc222a81b6 main+0xd
38970.522546687: tr end call 55fc222a81b6 main+0xd => 55fc222a8080 [unknown]
38970.522546688: tr strt 0 [unknown] => 55fc222a81bb main+0x12
38970.522546688: tr end call 55fc222a81bb main+0x12 => 55fc222a80b0 [unknown]
38970.522546688: tr strt 0 [unknown] => 55fc222a81c0 main+0x17
38970.522546688: tr end call 55fc222a81c0 main+0x17 => 55fc222a8090 [unknown]
38970.522546689: tr strt 0 [unknown] => 55fc222a81c5 main+0x1c
38970.522546894: tr end return 55fc222a81cb main+0x22 => 7f3a4dc29d90 __libc_start_call_main+0x80
After:
$ perf script --itrace=be --ns -F+flags,-event,+addr,-period,-comm,-tid,-cpu,-dso
38970.522546686: tr strt 0 [unknown] => 55fc222a81a9 main+0x0
38970.522546686: tr end call 55fc222a81b1 main+0x8 => 55fc222a80a0 fn4@plt+0x0
38970.522546687: tr strt 0 [unknown] => 55fc222a81b6 main+0xd
38970.522546687: tr end call 55fc222a81b6 main+0xd => 55fc222a8080 fn1@plt+0x0
38970.522546688: tr strt 0 [unknown] => 55fc222a81bb main+0x12
38970.522546688: tr end call 55fc222a81bb main+0x12 => 55fc222a80b0 fn2@plt+0x0
38970.522546688: tr strt 0 [unknown] => 55fc222a81c0 main+0x17
38970.522546688: tr end call 55fc222a81c0 main+0x17 => 55fc222a8090 fn3@plt+0x0
38970.522546689: tr strt 0 [unknown] => 55fc222a81c5 main+0x1c
38970.522546894: tr end return 55fc222a81cb main+0x22 => 7f3a4dc29d90 __libc_start_call_main+0x80
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230131131625.6964-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Test “Use vfs_getname probe to get syscall args filenames” fails in
environment with missing libtraceevent support as below:
82: Use vfs_getname probe to get syscall args filenames :
--- start ---
test child forked, pid 304726
Recording open file:
event syntax error: 'probe:vfs_getname*'
\___ unsupported tracepoint
libtraceevent is necessary for tracepoint support
Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
test child finished with -1
---- end ----
Use vfs_getname probe to get syscall args filenames: FAILED!
The environment has debuginfo but is missing the libtraceevent devel.
Hence perf is compiled without libtraceevent support. The test tries to
add probe “probe:vfs_getname” and then uses it with “perf record”. This
fails at function “parse_events_add_tracepoint" due to missing
libtraceevent.
Similarly "probe libc's inet_pton & backtrace it with ping" test slso
fails with same reason.
Add a function in 'perf test shell' library to check if perf record with
—dry-run reports any error on missing support for libtraceevent. Update
both the tests to use this new function “skip_no_probe_record_support”
before proceeding With using probe point via perf builtin record.
With the change,
82: Use vfs_getname probe to get syscall args filenames :
--- start ---
test child forked, pid 305014
Recording open file:
libtraceevent is necessary for tracepoint support
test child finished with -2
---- end ----
Use vfs_getname probe to get syscall args filenames: Skip
81: probe libc's inet_pton & backtrace it with ping :
--- start ---
test child forked, pid 305036
libtraceevent is necessary for tracepoint support
test child finished with -2
---- end ----
probe libc's inet_pton & backtrace it with ping: Skip
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Disha Goel <disgoel@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: kjain@linux.ibm.com,
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lore.kernel.org/r/20230201180421.59640-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The "probe libc's inet_pton & backtrace it with ping" test installs a
uprobe and uses perf record/script to check the backtrace. Currently
even if the "perf record" fails, the test reports success. Logs below:
# ./perf test -v "probe libc's inet_pton & backtrace it with ping"
81: probe libc's inet_pton & backtrace it with ping :
--- start ---
test child forked, pid 304211
failed to open /tmp/perf.data.Btf: No such file or directory
test child finished with 0
---- end ----
probe libc's inet_pton & backtrace it with ping: Ok
Fix this by adding check for presence of perf.data file
before proceeding with "perf script".
With the patch changes, test reports fail correctly.
# ./perf test -v "probe libc's inet_pton & backtrace it with ping"
81: probe libc's inet_pton & backtrace it with ping :
--- start ---
test child forked, pid 304358
FAIL: perf record failed to create "/tmp/perf.data.Uoi"
test child finished with -1
---- end ----
probe libc's inet_pton & backtrace it with ping: FAILED!
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Disha Goel <disgoel@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lore.kernel.org/r/20230201180421.59640-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
According to Intel SDM, the EPT-friendly PEBS is supported by all the
platforms after ICX, ADL and the future platforms with PEBS format 5.
Currently the only in-kernel user of this capability is KVM, which has
very limited support for hybrid core pmu, so ADL and its successors do
not currently expose this capability. When both hybrid core and PEBS
format 5 are present, KVM will decide on its own merits.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-perf-users@vger.kernel.org
Suggested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221109082802.27543-4-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
The pebs capability on the SPR is basically the same as Ice Lake Server
with the exception of two special facilities that have been enhanced and
require special handling.
Upon triggering a PEBS assist, there will be a finite delay between the
time the counter overflows and when the microcode starts to carry out
its data collection obligations. Even if the delay is constant in core
clock space, it invariably manifest as variable "skids" in instruction
address space.
On the Ice Lake Server, the Precise Distribution of Instructions Retire
(PDIR) facility mitigates the "skid" problem by providing an early
indication of when the counter is about to overflow. On SPR, the PDIR
counter available (Fixed 0) is unchanged, but the capability is enhanced
to Instruction-Accurate PDIR (PDIR++), where PEBS is taken on the
next instruction after the one that caused the overflow.
SPR also introduces a new Precise Distribution (PDist) facility only on
general programmable counter 0. Per Intel SDM, PDist eliminates any
skid or shadowing effects from PEBS. With PDist, the PEBS record will
be generated precisely upon completion of the instruction or operation
that causes the counter to overflow (there is no "wait for next occurrence"
by default).
In terms of KVM handling, when guest accesses those special counters,
the KVM needs to request the same index counters via the perf_event
kernel subsystem to ensure that the guest uses the correct pebs hardware
counter (PRIR++ or PDist). This is mainly achieved by adjusting the
event precise level to the maximum, where the semantics of this magic
number is mainly defined by the internal software context of perf_event
and it's also backwards compatible as part of the user space interface.
Opportunistically, refine confusing comments on TNT+, as the only
ones that currently support pebs_ept are Ice Lake server and SPR (GLC+).
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20221109082802.27543-3-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
The test_pipe() function will check perf report and perf inject with
pipe input.
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20230131023350.1903992-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We should not call lseek(2) for pipes as it won't work. And we already
in the proper place to read the data for AUXTRACE. Add the comment like
in the PERF_RECORD_HEADER_TRACING_DATA.
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20230131023350.1903992-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When it processes AUXTRACE_INFO, it calls to auxtrace_queue_data() to
collect AUXTRACE data first. That won't work with pipe since it needs
lseek() to read the scattered aux data.
$ perf record -o- -e intel_pt// true | perf report -i- --itrace=i100
# To display the perf.data header info, please use --header/--header-only options.
#
0x4118 [0xa0]: failed to process type: 70
Error:
failed to process sample
For the pipe mode, it can handle the aux data as it gets. But there's
no guarantee it can get the aux data in time. So the following warning
will be shown at the beginning:
WARNING: Intel PT with pipe mode is not recommended.
The output cannot relied upon. In particular,
time stamps and the order of events may be incorrect.
Fixes: dbd134322e ("perf intel-pt: Add support for decoding AUX area samples")
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20230131023350.1903992-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a sub-test to verify that KVM stuffs the APIC_ID when userspace forces
a transition from x2APIC to xAPIC without first disabling the APIC. Such
a transition is architecturally disallowed (WRMSR will #GP), but needs to
be handled by KVM to allow userspace to emulate RESET (ignoring that
userspace should also stuff local APIC state on RESET).
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Link: https://lore.kernel.org/r/20230109130605.2013555-3-eesposit@redhat.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
The ifname char pointer is taken directly from the command line
as input and the string is copied directly into struct ifreq
via strcpy. This makes it easy to corrupt other members of ifreq
and generally do stack overflows.
Most often the ioctl will fail with:
./xdp_hw_metadata: ioctl(SIOCETHTOOL): Bad address
As people will likely copy-paste code for getting NIC queue
channels (rxq_num) and enabling HW timestamping (hwtstamp_ioctl)
lets make this code a bit more secure by using strncpy.
Fixes: 297a3f1241 ("selftests/bpf: Simple program to dump XDP RX metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/167527272543.937063.16993147790832546209.stgit@firesoul
The glibc error reporting function error():
void error(int status, int errnum, const char *format, ...);
The status argument should be a positive value between 0-255 as it
is passed over to the exit(3) function as the value as the shell exit
status. The least significant byte of status (i.e., status & 0xFF) is
returned to the shell parent.
Fix this by using 1 instead of -1. As 1 corresponds to C standard
constant EXIT_FAILURE.
Fixes: 297a3f1241 ("selftests/bpf: Simple program to dump XDP RX metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/167527272038.937063.9137108142012298120.stgit@firesoul
Using xdp_hw_metadata I experince Segmentation fault after seeing
"detaching bpf program....".
On my system the segfault happened when accessing bpf_obj->skeleton
in xdp_hw_metadata__destroy(bpf_obj) call. That doesn't make any sense
as this memory have not been freed by program at this point in time.
Prior to calling xdp_hw_metadata__destroy(bpf_obj) the function
close_xsk() is called for each RX-queue xsk. The real bug lays
in close_xsk() that unmap via munmap() the wrong memory pointer.
The call xsk_umem__delete(xsk->umem) will free xsk->umem, thus
the call to munmap(xsk->umem, UMEM_SIZE) will have unpredictable
behavior. And man page explain subsequent references to these
pages will generate SIGSEGV.
Unmapping xsk->umem_area instead removes the segfault.
Fixes: 297a3f1241 ("selftests/bpf: Simple program to dump XDP RX metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/167527271533.937063.5717065138099679142.stgit@firesoul
The AF_XDP userspace part of xdp_hw_metadata see non-zero as a signal of
the availability of rx_timestamp and rx_hash in data_meta area. The
kernel-side BPF-prog code doesn't initialize these members when kernel
returns an error e.g. -EOPNOTSUPP. This memory area is not guaranteed to
be zeroed, and can contain garbage/previous values, which will be read
and interpreted by AF_XDP userspace side.
Tested this on different drivers. The experiences are that for most
packets they will have zeroed this data_meta area, but occasionally it
will contain garbage data.
Example of failure tested on ixgbe:
poll: 1 (0)
xsk_ring_cons__peek: 1
0x18ec788: rx_desc[0]->addr=100000000008000 addr=8100 comp_addr=8000
rx_hash: 3697961069
rx_timestamp: 9024981991734834796 (sec:9024981991.7348)
0x18ec788: complete idx=8 addr=8000
Converting to date:
date -d @9024981991
2255-12-28T20:26:31 CET
I choose a simple fix in this patch. When kfunc fails or isn't supported
assign zero to the corresponding struct meta value.
It's up to the individual BPF-programmer to do something smarter e.g.
that fits their use-case, like getting a software timestamp and marking
a flag that gives the type of timestamp.
Fixes: 297a3f1241 ("selftests/bpf: Simple program to dump XDP RX metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/167527271027.937063.5177725618616476592.stgit@firesoul
The function close_xsk() unmap via munmap() the wrong memory pointer.
The call xsk_umem__delete(xsk->umem) have already freed xsk->umem.
Thus the call to munmap(xsk->umem, UMEM_SIZE) will have unpredictable
behavior that can lead to Segmentation fault elsewhere, as man page
explain subsequent references to these pages will generate SIGSEGV.
Fixes: e2a46d54d7 ("selftests/bpf: Verify xdp_metadata xdp->af_xdp path")
Reported-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/167527517464.938135.13750760520577765269.stgit@firesoul
Reinitialize the xAPIC ID to the vCPU ID when userspace forces the APIC
to transition directly from x2APIC to xAPIC mode, e.g. to emulate RESET.
KVM already stuffs the xAPIC ID when the APIC is transitioned from
DISABLED to xAPIC (commit 49bd29ba1d ("KVM: x86: reset APIC ID when
enabling LAPIC")), i.e. userspace is conditioned to expect KVM to update
the xAPIC ID, but KVM doesn't handle the architecturally-impossible case
where userspace forces x2APIC=>xAPIC via KVM_SET_MSRS.
On its own, the "bug" is benign, as userspace emulation of RESET will also
stuff APIC registers via KVM_SET_LAPIC, i.e. will manually set the xAPIC
ID. However, commit 3743c2f025 ("KVM: x86: inhibit APICv/AVIC on
changes to APIC ID or APIC base") introduced a bug, fixed by commit
commit ef40757743 ("KVM: x86: fix APICv/x2AVIC disabled when vm reboot
by itself"), that caused KVM to fail to properly update the xAPIC ID when
handling KVM_SET_LAPIC. Refresh the xAPIC ID even though it's not
strictly necessary so that KVM provides consistent behavior.
Note, KVM follows Intel architecture with regard to handling the xAPIC ID
and x2APIC IDs across mode transitions. For the APIC DISABLED case
(commit 49bd29ba1d), Intel's SDM says the xAPIC ID _may_ be
reinitialized
10.4.3 Enabling or Disabling the Local APIC
When IA32_APIC_BASE[11] is set to 0, prior initialization to the APIC
may be lost and the APIC may return to the state described in Section
10.4.7.1, “Local APIC State After Power-Up or Reset.”
10.4.7.1 Local APIC State After Power-Up or Reset
... The local APIC ID register is set to a unique APIC ID. ...
i.e. KVM's behavior is legal as per Intel's architecture. In practice,
Intel's behavior is N/A as modern Intel CPUs (since at least Haswell) make
the xAPIC ID fully read-only.
And for xAPIC => x2APIC transitions (commit 257b9a5faa ("KVM: x86: use
correct APIC ID on x2APIC transition")), Intel's SDM says:
Any APIC ID value written to the memory-mapped local APIC ID register
is not preserved.
AMD's APM says nothing (that I could find) about the xAPIC ID when the
APIC is DISABLED, but testing on bare metal (Rome) shows that the xAPIC ID
is preserved when the APIC is DISABLED and re-enabled in xAPIC mode. AMD
also preserves the xAPIC ID when the APIC is transitioned from xAPIC to
x2APIC, i.e. allows a backdoor write of the x2APIC ID, which is again not
emulated by KVM.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Link: https://lore.kernel.org/all/20230109130605.2013555-2-eesposit@redhat.com
[sean: rewrite changelog, set xAPIC ID iff APIC is enabled]
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Vernet says:
====================
This is v3 of the patchset [0]. v2 can be found at [1].
[0]: https://lore.kernel.org/bpf/Y7kCsjBZ%2FFrsWW%2Fe@maniforge.lan/T/
[1]: https://lore.kernel.org/lkml/20230123171506.71995-1-void@manifault.com/
Changelog:
----------
v2 -> v3:
- Go back to the __bpf_kfunc approach from v1. The BPF_KFUNC macro
received pushback as it didn't match the more typical EXPORT_SYMBOL*
APIs used elsewhere in the kernel. It's the longer term plan, but for
now we're proposing something less controversial to fix kfuncs and BTF
encoding.
- Add __bpf_kfunc macro to newly added cpumask kfuncs.
- Add __bpf_kfunc macro to newly added XDP metadata kfuncs, which were
failing to be BTF encoded in the thread in [2].
- Update patch description(s) to reference the discussions in [2].
- Add a selftest that validates that a static kfunc with unused args is
properly BTF encoded and can be invoked.
[2]: https://lore.kernel.org/all/fe5d42d1-faad-d05e-99ad-1c2c04776950@oracle.com/
v1 -> v2:
- Wrap entire function signature in BPF_KFUNC macro instead of using
__bpf_kfunc tag (Kumar)
- Update all kfunc definitions to use this macro.
- Update kfuncs.rst documentation to describe and illustrate the macro.
- Also clean up a few small parts of kfuncs.rst, e.g. some grammar, and
in general making it a bit tighter.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
kfuncs are allowed to be static, or not use one or more of their
arguments. For example, bpf_xdp_metadata_rx_hash() in net/core/xdp.c is
meant to be implemented by drivers, with the default implementation just
returning -EOPNOTSUPP. As described in [0], such kfuncs can have their
arguments elided, which can cause BTF encoding to be skipped. The new
__bpf_kfunc macro should address this, and this patch adds a selftest
which verifies that a static kfunc with at least one unused argument can
still be encoded and invoked by a BPF program.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230201173016.342758-5-void@manifault.com
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
Now that the __bpf_kfunc macro has been added to linux/btf.h, include a
blurb about it in the kfuncs.rst file. In order for the macro to
successfully render with .. kernel-doc, we'll also need to add it to the
c_id_attributes array.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-3-void@manifault.com
kfuncs are functions defined in the kernel, which may be invoked by BPF
programs. They may or may not also be used as regular kernel functions,
implying that they may be static (in which case the compiler could e.g.
inline it away, or elide one or more arguments), or it could have
external linkage, but potentially be elided in an LTO build if a
function is observed to never be used, and is stripped from the final
kernel binary.
This has already resulted in some issues, such as those discussed in [0]
wherein changes in DWARF that identify when a parameter has been
optimized out can break BTF encodings (and in general break the kfunc).
[0]: https://lore.kernel.org/all/1675088985-20300-2-git-send-email-alan.maguire@oracle.com/
We therefore require some convenience macro that kfunc developers can
use just add to their kfuncs, and which will prevent all of the above
issues from happening. This is in contrast with what we have today,
where some kfunc definitions have "noinline", some have "__used", and
others are static and have neither.
Note that longer term, this mechanism may be replaced by a macro that
more closely resembles EXPORT_SYMBOL_GPL(), as described in [1]. For
now, we're going with this shorter-term approach to fix existing issues
in kfuncs.
[1]: https://lore.kernel.org/lkml/Y9AFT4pTydKh+PD3@maniforge.lan/
Note as well that checkpatch complains about this patch with the
following:
ERROR: Macros with complex values should be enclosed in parentheses
+#define __bpf_kfunc __used noinline
There seems to be a precedent for using this pattern in other places
such as compiler_types.h (see e.g. __randomize_layout and noinstr), so
it seems appropriate.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-2-void@manifault.com
Add support for Lemans TLMM configuration and control via the pinctrl
framework.
Signed-off-by: Yadu MG <quic_ymg@quicinc.com>
Signed-off-by: Prasad Sodagudi <quic_psodagud@quicinc.com>
[Bartosz: made the driver ready for upstream]
Co-developed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230201150011.200613-3-brgl@bgdev.pl
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Maciej Fijalkowski says:
====================
Although this work started as an effort to add multi-buffer XDP support
to ice driver, as usual it turned out that some other side stuff needed
to be addressed, so let me give you an overview.
First patch adjusts legacy-rx in a way that it will be possible to refer
to skb_shared_info being at the end of the buffer when gathering up
frame fragments within xdp_buff.
Then, patches 2-9 prepare ice driver in a way that actual multi-buffer
patches will be easier to swallow.
10 and 11 are the meat. What is worth mentioning is that this set
actually *fixes* things as patch 11 removes the logic based on
next_dd/rs and we previously stepped away from this for ice_xmit_zc().
Currently, AF_XDP ZC XDP_TX workload is off as there are two cleaning
sides that can be triggered and two of them work on different internal
logic. This set unifies that and allows us to improve the performance by
2x with a trick on the last (13) patch.
12th is a simple cleanup of no longer fields from Tx ring.
I might be wrong but I have not seen anyone reporting performance impact
among patches that add XDP multi-buffer support to a particular driver.
Numbers below were gathered via xdp_rxq_info and xdp_redirect_map on
1500 MTU:
XDP_DROP +1%
XDP_PASS -1,2%
XDP_TX -0,5%
XDP_REDIRECT -3,3%
Cherry on top, which is not directly related to mbuf support (last
patch):
XDP_TX ZC +126%
Target the we agreed on was to not degrade performance for any action by
anything that would be over 5%, so our goal was met. Basically this set
keeps the performance where it was. Redirect is slower due to more
frequent tail bumps.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Alex Deucher