commit d45476d983 upstream.
The RETPOLINE_AMD name is unfortunate since it isn't necessarily
AMD only, in fact Hygon also uses it. Furthermore it will likely be
sufficient for some Intel processors. Therefore rename the thing to
RETPOLINE_LFENCE to better describe what it is.
Add the spectre_v2=retpoline,lfence option as an alias to
spectre_v2=retpoline,amd to preserve existing setups. However, the output
of /sys/devices/system/cpu/vulnerabilities/spectre_v2 will be changed.
[ bp: Fix typos, massage. ]
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
[fllinden@amazon.com: backported to 5.10]
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To pick the changes from:
ecac71816a ("x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT")
That don entail any changes in tooling, just addressing these perf tools
build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/required-features.h' differs from latest version at 'arch/x86/include/asm/required-features.h'
diff -u tools/arch/x86/include/asm/required-features.h arch/x86/include/asm/required-features.h
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: Juergen Gross <jgross@suse.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick the changes from:
5866e9205b ("x86/cpu: Add hardware-enforced cache coherency as a CPUID feature")
ff4f82816d ("x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions")
360e7c5c4c ("x86/cpufeatures: Add SEV-ES CPU feature")
18ec63faef ("x86/cpufeatures: Enumerate TSX suspend load address tracking instructions")
e48cb1a3fb ("x86/resctrl: Enumerate per-thread MBA controls")
Which don't cause any changes in tooling, just addresses these build
warnings:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/disabled-features.h' differs from latest version at 'arch/x86/include/asm/disabled-features.h'
diff -u tools/arch/x86/include/asm/disabled-features.h arch/x86/include/asm/disabled-features.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: Kyung Min Park <kyung.min.park@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull objtool updates from Ingo Molnar:
"Most of the changes are cleanups and reorganization to make the
objtool code more arch-agnostic. This is in preparation for non-x86
support.
Other changes:
- KASAN fixes
- Handle unreachable trap after call to noreturn functions better
- Ignore unreachable fake jumps
- Misc smaller fixes & cleanups"
* tag 'objtool-core-2020-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
perf build: Allow nested externs to enable BUILD_BUG() usage
objtool: Allow nested externs to enable BUILD_BUG()
objtool: Permit __kasan_check_{read,write} under UACCESS
objtool: Ignore unreachable trap after call to noreturn functions
objtool: Handle calling non-function symbols in other sections
objtool: Ignore unreachable fake jumps
objtool: Remove useless tests before save_reg()
objtool: Decode unwind hint register depending on architecture
objtool: Make unwind hint definitions available to other architectures
objtool: Only include valid definitions depending on source file type
objtool: Rename frame.h -> objtool.h
objtool: Refactor jump table code to support other architectures
objtool: Make relocation in alternative handling arch dependent
objtool: Abstract alternative special case handling
objtool: Move macros describing structures to arch-dependent code
objtool: Make sync-check consider the target architecture
objtool: Group headers to check in a single list
objtool: Define 'struct orc_entry' only when needed
objtool: Skip ORC entry creation for non-text sections
objtool: Move ORC logic out of check()
...
In reaction to a proposal to introduce a memcpy_mcsafe_fast()
implementation Linus points out that memcpy_mcsafe() is poorly named
relative to communicating the scope of the interface. Specifically what
addresses are valid to pass as source, destination, and what faults /
exceptions are handled.
Of particular concern is that even though x86 might be able to handle
the semantics of copy_mc_to_user() with its common copy_user_generic()
implementation other archs likely need / want an explicit path for this
case:
On Fri, May 1, 2020 at 11:28 AM Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> On Thu, Apr 30, 2020 at 6:21 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > However now I see that copy_user_generic() works for the wrong reason.
> > It works because the exception on the source address due to poison
> > looks no different than a write fault on the user address to the
> > caller, it's still just a short copy. So it makes copy_to_user() work
> > for the wrong reason relative to the name.
>
> Right.
>
> And it won't work that way on other architectures. On x86, we have a
> generic function that can take faults on either side, and we use it
> for both cases (and for the "in_user" case too), but that's an
> artifact of the architecture oddity.
>
> In fact, it's probably wrong even on x86 - because it can hide bugs -
> but writing those things is painful enough that everybody prefers
> having just one function.
Replace a single top-level memcpy_mcsafe() with either
copy_mc_to_user(), or copy_mc_to_kernel().
Introduce an x86 copy_mc_fragile() name as the rename for the
low-level x86 implementation formerly named memcpy_mcsafe(). It is used
as the slow / careful backend that is supplanted by a fast
copy_mc_generic() in a follow-on patch.
One side-effect of this reorganization is that separating copy_mc_64.S
to its own file means that perf no longer needs to track dependencies
for its memcpy_64.S benchmarks.
[ bp: Massage a bit. ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>
Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com
Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com
Unwind hints are useful to provide objtool with information about stack
states in non-standard functions/code.
While the type of information being provided might be very arch
specific, the mechanism to provide the information can be useful for
other architectures.
Move the relevant unwint hint definitions for all architectures to
see.
[ jpoimboe: REGS_IRET -> REGS_PARTIAL ]
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
To pick up the changes from:
85b23fbc7d ("x86/cpufeatures: Add enumeration for SERIALIZE instruction")
bd657aa3dd ("x86/cpufeatures: Add Architectural LBRs feature bit")
fbd5969d1f ("x86/cpufeatures: Mark two free bits in word 3")
These should't cause any changes in tooling, it just gets rebuilt by
including those headers:
CC /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
CC /tmp/build/perf/bench/mem-memset-x86-64-asm.o
LD /tmp/build/perf/bench/perf-in.o
LD /tmp/build/perf/perf-in.o
LINK /tmp/build/perf/perf
And silences this perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
d6a162a41b x86/msr-index: Add bunch of MSRs for Arch LBR
ed7bde7a6d cpufreq: intel_pstate: Allow enable/disable energy efficiency
99e40204e0 (tip/x86/cleanups) x86/msr: Move the F15h MSRs where they belong
1068ed4547 x86/msr: Lift AMD family 0x15 power-specific MSRs
5cde265384 (tag: perf-core-2020-06-01) perf/x86/rapl: Add AMD Fam17h RAPL support
Addressing these tools/perf build warnings:
That makes the beautification scripts to pick some new entries:
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
$ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
$ diff -u before after
--- before 2020-08-07 08:45:18.801298854 -0300
+++ after 2020-08-07 08:45:28.654456422 -0300
@@ -271,6 +271,8 @@
[0xc0010062 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PERF_CTL",
[0xc0010063 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PERF_STATUS",
[0xc0010064 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PSTATE_DEF_BASE",
+ [0xc001007a - x86_AMD_V_KVM_MSRs_offset] = "F15H_CU_PWR_ACCUMULATOR",
+ [0xc001007b - x86_AMD_V_KVM_MSRs_offset] = "F15H_CU_MAX_PWR_ACCUMULATOR",
[0xc0010112 - x86_AMD_V_KVM_MSRs_offset] = "K8_TSEG_ADDR",
[0xc0010113 - x86_AMD_V_KVM_MSRs_offset] = "K8_TSEG_MASK",
[0xc0010114 - x86_AMD_V_KVM_MSRs_offset] = "VM_CR",
$
And this gets rebuilt:
CC /tmp/build/perf/trace/beauty/tracepoints/x86_msr.o
INSTALL trace_plugins
LD /tmp/build/perf/trace/beauty/tracepoints/perf-in.o
LD /tmp/build/perf/trace/beauty/perf-in.o
LD /tmp/build/perf/perf-in.o
LINK /tmp/build/perf/perf
Now one can trace systemwide asking to see backtraces to where those
MSRs are being read/written with:
# perf trace -e msr:*_msr/max-stack=32/ --filter="msr==F15H_CU_PWR_ACCUMULATOR || msr==F15H_CU_MAX_PWR_ACCUMULATOR"
^C#
#
If we use -v (verbose mode) we can see what it does behind the scenes:
# perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr==F15H_CU_PWR_ACCUMULATOR || msr==F15H_CU_MAX_PWR_ACCUMULATOR"
Using CPUID GenuineIntel-6-8E-A
0xc001007a
0xc001007b
New filter for msr:read_msr: (msr==0xc001007a || msr==0xc001007b) && (common_pid != 2448054 && common_pid != 2782)
0xc001007a
0xc001007b
New filter for msr:write_msr: (msr==0xc001007a || msr==0xc001007b) && (common_pid != 2448054 && common_pid != 2782)
mmap size 528384B
^C#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
7e5b3c267d ("x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation")
Addressing these tools/perf build warnings:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'
diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
With this one will be able to use these new AMD MSRs in filters, by
name, e.g.:
# perf trace -e msr:* --filter "msr==IA32_MCU_OPT_CTRL"
^C#
Using -v we can see how it sets up the tracepoint filters, converting
from the string in the filter to the numeric value:
# perf trace -v -e msr:* --filter "msr==IA32_MCU_OPT_CTRL"
Using CPUID GenuineIntel-6-8E-A
0x123
New filter for msr:read_msr: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
0x123
New filter for msr:write_msr: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
0x123
New filter for msr:rdpmc: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
mmap size 528384B
^C#
The updating process shows how this affects tooling in more detail:
$ diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
--- tools/arch/x86/include/asm/msr-index.h 2020-06-03 10:36:09.959910238 -0300
+++ arch/x86/include/asm/msr-index.h 2020-06-17 10:04:20.235052901 -0300
@@ -128,6 +128,10 @@
#define TSX_CTRL_RTM_DISABLE BIT(0) /* Disable RTM feature */
#define TSX_CTRL_CPUID_CLEAR BIT(1) /* Disable TSX enumeration */
+/* SRBDS support */
+#define MSR_IA32_MCU_OPT_CTRL 0x00000123
+#define RNGDS_MITG_DIS BIT(0)
+
#define MSR_IA32_SYSENTER_CS 0x00000174
#define MSR_IA32_SYSENTER_ESP 0x00000175
#define MSR_IA32_SYSENTER_EIP 0x00000176
$ set -o vi
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
$ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
$ diff -u before after
--- before 2020-06-17 10:05:49.653114752 -0300
+++ after 2020-06-17 10:06:01.777258731 -0300
@@ -51,6 +51,7 @@
[0x0000011e] = "IA32_BBL_CR_CTL3",
[0x00000120] = "IDT_MCR_CTRL",
[0x00000122] = "IA32_TSX_CTRL",
+ [0x00000123] = "IA32_MCU_OPT_CTRL",
[0x00000140] = "MISC_FEATURES_ENABLES",
[0x00000174] = "IA32_SYSENTER_CS",
[0x00000175] = "IA32_SYSENTER_ESP",
$
The related change to cpu-features.h affects this:
CC /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
CC /tmp/build/perf/bench/mem-memset-x86-64-asm.o
This shouldn't be affecting that 'perf bench' entry:
$ find tools/perf/ -type f | xargs grep SRBDS
$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Gross <mgross@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf tooling updates from Arnaldo Carvalho de Melo:
"These are additional changes to the perf tools, on top of what Ingo
already submitted.
- Further Intel PT call-trace fixes
- Improve SELinux docs and tool warnings
- Fix race at exit in 'perf record' using eventfd.
- Add missing build tests to the default set of 'make -C tools/perf
build-test'
- Sync msr-index.h getting new AMD MSRs to decode and filter in 'perf
trace'.
- Fix fallback to libaudit in 'perf trace' for arches not using
per-arch *.tbl files.
- Fixes for 'perf ftrace'.
- Fixes and improvements for the 'perf stat' metrics.
- Use dummy event to get PERF_RECORD_{FORK,MMAP,etc} while
synthesizing those metadata events for pre-existing threads.
- Fix leaks detected using clang tooling.
- Improvements to PMU event metric testing.
- Report summary for 'perf stat' interval mode at the end, summing up
all the intervals.
- Improve pipe mode, i.e. this now works as expected, continuously
dumping samples:
# perf record -g -e raw_syscalls:sys_enter | perf --no-pager script
- Fixes for event grouping, detecting incompatible groups such as:
# perf stat -e '{cycles,power/energy-cores/}' -v
WARNING: group events cpu maps do not match, disabling group:
anon group { power/energy-cores/, cycles }
power/energy-cores/: 0
cycles: 0-7
- Fixes for 'perf probe': blacklist address checking, number of
kretprobe instances, etc.
- JIT processing improvements and fixes plus the addition of a 'perf
test' entry for the java demangler.
- Add support for synthesizing first/last level cache, TLB and remove
access events from HW tracing in the auxtrace code, first to use is
ARM SPE.
- Vendor events updates and fixes, including for POWER9 and Intel.
- Allow using ~/.perfconfig for removing the ',' separators in 'perf
stat' output.
- Opt-in support for libpfm4"
* tag 'perf-tools-2020-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (120 commits)
perf tools: Remove some duplicated includes
perf symbols: Fix kernel maps for kcore and eBPF
tools arch x86: Sync the msr-index.h copy with the kernel sources
perf stat: Ensure group is defined on top of the same cpu mask
perf libdw: Fix off-by 1 relative directory includes
perf arm-spe: Support synthetic events
perf auxtrace: Add four itrace options
perf tools: Move arm-spe-pkt-decoder.h/c to the new dir
perf test: Initialize memory in dwarf-unwind
perf tests: Don't tail call optimize in unwind test
tools compiler.h: Add attribute to disable tail calls
perf build: Add a LIBPFM4=1 build test entry
perf tools: Add optional support for libpfm4
perf tools: Correct license on jsmn JSON parser
perf jit: Fix inaccurate DWARF line table
perf jvmti: Remove redundant jitdump line table entries
perf build: Add NO_SDT=1 to the default set of build tests
perf build: Add NO_LIBCRYPTO=1 to the default set of build tests
perf build: Add NO_SYSCALL_TABLE=1 to the build tests
perf build: Remove libaudit from the default feature checks
...
Normally objtool ensures a function keeps the stack layout invariant.
But there is a useful exception, it is possible to stuff the return
stack in order to 'inject' a 'call':
push $fun
ret
In this case the invariant mentioned above is violated.
Add an objtool HINT to annotate this and allow a function exit with a
modified stack frame.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200416115118.690601403@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
To pick up the changes from:
077168e241 ("x86/mce/amd: Add PPIN support for AMD MCE")
753039ef8b ("x86/cpu/amd: Call init_amd_zn() om Family 19h processors too")
6650cdd9a8 ("x86/split_lock: Enable split lock detection by kernel")
These don't cause any changes in tooling, just silences this perf build
warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull kvm updates from Paolo Bonzini:
"ARM:
- GICv4.1 support
- 32bit host removal
PPC:
- secure (encrypted) using under the Protected Execution Framework
ultravisor
s390:
- allow disabling GISA (hardware interrupt injection) and protected
VMs/ultravisor support.
x86:
- New dirty bitmap flag that sets all bits in the bitmap when dirty
page logging is enabled; this is faster because it doesn't require
bulk modification of the page tables.
- Initial work on making nested SVM event injection more similar to
VMX, and less buggy.
- Various cleanups to MMU code (though the big ones and related
optimizations were delayed to 5.8). Instead of using cr3 in
function names which occasionally means eptp, KVM too has
standardized on "pgd".
- A large refactoring of CPUID features, which now use an array that
parallels the core x86_features.
- Some removal of pointer chasing from kvm_x86_ops, which will also
be switched to static calls as soon as they are available.
- New Tigerlake CPUID features.
- More bugfixes, optimizations and cleanups.
Generic:
- selftests: cleanups, new MMU notifier stress test, steal-time test
- CSV output for kvm_stat"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (277 commits)
x86/kvm: fix a missing-prototypes "vmread_error"
KVM: x86: Fix BUILD_BUG() in __cpuid_entry_get_reg() w/ CONFIG_UBSAN=y
KVM: VMX: Add a trampoline to fix VMREAD error handling
KVM: SVM: Annotate svm_x86_ops as __initdata
KVM: VMX: Annotate vmx_x86_ops as __initdata
KVM: x86: Drop __exit from kvm_x86_ops' hardware_unsetup()
KVM: x86: Copy kvm_x86_ops by value to eliminate layer of indirection
KVM: x86: Set kvm_x86_ops only after ->hardware_setup() completes
KVM: VMX: Configure runtime hooks using vmx_x86_ops
KVM: VMX: Move hardware_setup() definition below vmx_x86_ops
KVM: x86: Move init-only kvm_x86_ops to separate struct
KVM: Pass kvm_init()'s opaque param to additional arch funcs
s390/gmap: return proper error code on ksm unsharing
KVM: selftests: Fix cosmetic copy-paste error in vm_mem_region_move()
KVM: Fix out of range accesses to memslots
KVM: X86: Micro-optimize IPI fastpath delay
KVM: X86: Delay read msr data iff writes ICR MSR
KVM: PPC: Book3S HV: Add a capability for enabling secure guests
KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs
KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs
...
KVM: s390: Features and Enhancements for 5.7 part1
1. Allow to disable gisa
2. protected virtual machines
Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's
state like guest memory and guest registers anymore. Instead the
PVMs are mostly managed by a new entity called Ultravisor (UV),
which provides an API, so KVM and the PV can request management
actions.
PVMs are encrypted at rest and protected from hypervisor access
while running. They switch from a normal operation into protected
mode, so we can still use the standard boot process to load a
encrypted blob and then move it into protected mode.
Rebooting is only possible by passing through the unprotected/normal
mode and switching to protected again.
One mm related patch will go via Andrews mm tree ( mm/gup/writeback:
add callbacks for inaccessible pages)
The demand paging test is currently a simple page access test which, while
potentially useful, doesn't add much versus the existing dirty logging
test. To improve the demand paging test, add a basic userfaultfd demand
paging implementation.
Signed-off-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
To pick up the changes from these csets:
21b5ee59ef ("x86/cpu/amd: Enable the fixed Instructions Retired counter IRPERF")
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
$ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
$ git diff
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index ebe1685e92dd..d5e517d1c3dd 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -512,6 +512,8 @@
#define MSR_K7_HWCR 0xc0010015
#define MSR_K7_HWCR_SMMLOCK_BIT 0
#define MSR_K7_HWCR_SMMLOCK BIT_ULL(MSR_K7_HWCR_SMMLOCK_BIT)
+#define MSR_K7_HWCR_IRPERF_EN_BIT 30
+#define MSR_K7_HWCR_IRPERF_EN BIT_ULL(MSR_K7_HWCR_IRPERF_EN_BIT)
#define MSR_K7_FID_VID_CTL 0xc0010041
#define MSR_K7_FID_VID_STATUS 0xc0010042
$
That don't result in any change in tooling:
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
$ diff -u before after
$
To silence this perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'
diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes from:
85c17291e2 ("x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured")
f444a5ff95 ("x86/cpufeatures: Add support for fast short REP; MOVSB")
These don't cause any changes in tooling, just silences this perf build
warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To silence the following tools/perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/disabled-features.h' differs from latest version at 'arch/x86/include/asm/disabled-features.h'
diff -u tools/arch/x86/include/asm/disabled-features.h arch/x86/include/asm/disabled-features.h
Picking up the changes in:
45fc24e89b ("x86/mpx: remove MPX from arch/x86")
that didn't entail any functionality change in the tooling side.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull x86 cpu-features updates from Ingo Molnar:
"The biggest change in this cycle was a large series from Sean
Christopherson to clean up the handling of VMX features. This both
fixes bugs/inconsistencies and makes the code more coherent and
future-proof.
There are also two cleanups and a minor TSX syslog messages
enhancement"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/cpu: Remove redundant cpu_detect_cache_sizes() call
x86/cpu: Print "VMX disabled" error message iff KVM is enabled
KVM: VMX: Allow KVM_INTEL when building for Centaur and/or Zhaoxin CPUs
perf/x86: Provide stubs of KVM helpers for non-Intel CPUs
KVM: VMX: Use VMX_FEATURE_* flags to define VMCS control bits
KVM: VMX: Check for full VMX support when verifying CPU compatibility
KVM: VMX: Use VMX feature flag to query BIOS enabling
KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR
x86/cpufeatures: Add flag to track whether MSR IA32_FEAT_CTL is configured
x86/cpu: Set synthetic VMX cpufeatures during init_ia32_feat_ctl()
x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_*
x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs
x86/vmx: Introduce VMX_FEATURES_*
x86/cpu: Clear VMX feature flag if VMX is not fully enabled
x86/zhaoxin: Use common IA32_FEAT_CTL MSR initialization
x86/centaur: Use common IA32_FEAT_CTL MSR initialization
x86/mce: WARN once if IA32_FEAT_CTL MSR is left unlocked
x86/intel: Initialize IA32_FEAT_CTL MSR at boot
tools/x86: Sync msr-index.h from kernel sources
selftests, kvm: Replace manual MSR defs with common msr-index.h
...
Sync msr-index.h to pull in recent renames of the IA32_FEATURE_CONTROL
MSR definitions. Update KVM's VMX selftest and turbostat accordingly.
Keep the full name in turbostat's output to avoid breaking someone's
workflow, e.g. if a script is looking for the full name.
While using the renamed defines is by no means necessary, do the sync
now to avoid leaving a landmine that will get stepped on the next time
msr-index.h needs to be refreshed for some other reason.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-4-sean.j.christopherson@intel.com
Pull perf updates from Ingo Molnar:
"The main kernel side changes in this cycle were:
- Various Intel-PT updates and optimizations (Alexander Shishkin)
- Prohibit kprobes on Xen/KVM emulate prefixes (Masami Hiramatsu)
- Add support for LSM and SELinux checks to control access to the
perf syscall (Joel Fernandes)
- Misc other changes, optimizations, fixes and cleanups - see the
shortlog for details.
There were numerous tooling changes as well - 254 non-merge commits.
Here are the main changes - too many to list in detail:
- Enhancements to core tooling infrastructure, perf.data, libperf,
libtraceevent, event parsing, vendor events, Intel PT, callchains,
BPF support and instruction decoding.
- There were updates to the following tools:
perf annotate
perf diff
perf inject
perf kvm
perf list
perf maps
perf parse
perf probe
perf record
perf report
perf script
perf stat
perf test
perf trace
- And a lot of other changes: please see the shortlog and Git log for
more details"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (279 commits)
perf parse: Fix potential memory leak when handling tracepoint errors
perf probe: Fix spelling mistake "addrees" -> "address"
libtraceevent: Fix memory leakage in copy_filter_type
libtraceevent: Fix header installation
perf intel-bts: Does not support AUX area sampling
perf intel-pt: Add support for decoding AUX area samples
perf intel-pt: Add support for recording AUX area samples
perf pmu: When using default config, record which bits of config were changed by the user
perf auxtrace: Add support for queuing AUX area samples
perf session: Add facility to peek at all events
perf auxtrace: Add support for dumping AUX area samples
perf inject: Cut AUX area samples
perf record: Add aux-sample-size config term
perf record: Add support for AUX area sampling
perf auxtrace: Add support for AUX area sample recording
perf auxtrace: Move perf_evsel__find_pmu()
perf record: Add a function to test for kernel support for AUX area sampling
perf tools: Add kernel AUX area sampling definitions
perf/core: Make the mlock accounting simple again
perf report: Jump to symbol source view from total cycles view
...
To pick up the changes from:
b4dd4f6e36 ("x86/vmware: Add a header file for hypercall definitions")
f36cf386e3 ("x86/speculation/swapgs: Exclude ATOMs from speculation through SWAPGS")
be261ffce6 ("x86: Remove X86_FEATURE_MFENCE_RDTSC")
018ebca8bd ("x86/cpufeatures: Enable a new AVX512 CPU feature")
These don't cause any changes in tooling, just silences this perf build
warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
To clarify, updating those files cause these bits of tools/perf to rebuild:
CC /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
CC /tmp/build/perf/bench/mem-memset-x86-64-asm.o
INSTALL GTK UI
LD /tmp/build/perf/bench/perf-in.o
Those use just:
$ grep FEATURE tools/arch/x86/lib/mem*.S
tools/arch/x86/lib/memcpy_64.S: ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
tools/arch/x86/lib/memcpy_64.S: "jmp memcpy_erms", X86_FEATURE_ERMS
tools/arch/x86/lib/memset_64.S: ALTERNATIVE_2 "jmp memset_orig", "", X86_FEATURE_REP_GOOD, \
tools/arch/x86/lib/memset_64.S: "jmp memset_erms", X86_FEATURE_ERMS
$
I.e. none of the feature defines added/removed by the patches above.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Gayatri Kammela <gayatri.kammela@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Link: https://lkml.kernel.org/n/tip-pq63abgknsaeov23p80d8gjv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull x86 cpu-feature updates from Ingo Molnar:
- Rework the Intel model names symbols/macros, which were decades of
ad-hoc extensions and added random noise. It's now a coherent, easy
to follow nomenclature.
- Add new Intel CPU model IDs:
- "Tiger Lake" desktop and mobile models
- "Elkhart Lake" model ID
- and the "Lightning Mountain" variant of Airmont, plus support code
- Add the new AVX512_VP2INTERSECT instruction to cpufeatures
- Remove Intel MPX user-visible APIs and the self-tests, because the
toolchain (gcc) is not supporting it going forward. This is the
first, lowest-risk phase of MPX removal.
- Remove X86_FEATURE_MFENCE_RDTSC
- Various smaller cleanups and fixes
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
x86/cpu: Update init data for new Airmont CPU model
x86/cpu: Add new Airmont variant to Intel family
x86/cpu: Add Elkhart Lake to Intel family
x86/cpu: Add Tiger Lake to Intel family
x86: Correct misc typos
x86/intel: Add common OPTDIFFs
x86/intel: Aggregate microserver naming
x86/intel: Aggregate big core graphics naming
x86/intel: Aggregate big core mobile naming
x86/intel: Aggregate big core client naming
x86/cpufeature: Explain the macro duplication
x86/ftrace: Remove mcount() declaration
x86/PCI: Remove superfluous returns from void functions
x86/msr-index: Move AMD MSRs where they belong
x86/cpu: Use constant definitions for CPU models
lib: Remove redundant ftrace flag removal
x86/crash: Remove unnecessary comparison
x86/bitops: Use __builtin_constant_p() directly instead of IS_IMMEDIATE()
x86: Remove X86_FEATURE_MFENCE_RDTSC
x86/mpx: Remove MPX APIs
...
Now that there's a common version of the decoder for all tools, use it
instead of the local copy.
Also use perf's check-headers.sh script to diff the decoder files to
make sure they remain in sync with the kernel version. Objtool has a
similar check.
Committer notes:
Had to keep this all pointing explicitely to x86 headers/files, i.e.
instead of asm/isnn.h we had to use ../include/asm/insn.h when the files
were in differemt dirs, or just replace "<asm/foo.h>" with "foo.h".
This way we continue to be able to process perf.data files with Intel PT
traces in distros other than x86.
Also fixed up the awk script paths to use $(srcdir)/tools/arch instead
or relative directories so that we keep detached tarballs (make help |
grep perf) working.
For now the include lines in these headers are being ignored so as not
to flag false reports of kernel/tools out of sync.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/8a37e615d2880f039505d693d1e068a009358a2b.1567118001.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
f36cf386e3 ("x86/speculation/swapgs: Exclude ATOMs from speculation through SWAPGS")
18ec54fdd6 ("x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations")
That don't affect anything in tools/.
This silences this perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/n/tip-860dq1qie2cpnfghlpcnxrzr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
AMD and Intel both have serializing lfence (X86_FEATURE_LFENCE_RDTSC).
They've both had it for a long time, and AMD has had it enabled in Linux
since Spectre v1 was announced.
Back then, there was a proposal to remove the serializing mfence feature
bit (X86_FEATURE_MFENCE_RDTSC), since both AMD and Intel have
serializing lfence. At the time, it was (ahem) speculated that some
hypervisors might not yet support its removal, so it remained for the
time being.
Now a year-and-a-half later, it should be safe to remove.
I asked Andrew Cooper about whether it's still needed:
So if you're virtualised, you've got no choice in the matter. lfence
is either dispatch-serialising or not on AMD, and you won't be able to
change it.
Furthermore, you can't accurately tell what state the bit is in, because
the MSR might not be virtualised at all, or may not reflect the true
state in hardware. Worse still, attempting to set the bit may not be
successful even if there isn't a fault for doing so.
Xen sets the DE_CFG bit unconditionally, as does Linux by the looks of
things (see MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT). ISTR other hypervisor
vendors saying the same, but I don't have any information to hand.
If you are running under a hypervisor which has been updated, then
lfence will almost certainly be dispatch-serialising in practice, and
you'll almost certainly see the bit already set in DE_CFG. If you're
running under a hypervisor which hasn't been patched since Spectre,
you've already lost in many more ways.
I'd argue that X86_FEATURE_MFENCE_RDTSC is not worth keeping.
So remove it. This will reduce some code rot, and also make it easier
to hook barrier_nospec() up to a cmdline disable for performance
raisins, without having to need an alternative_3() macro.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/d990aa51e40063acb9888e8c1b688e41355a9588.1562255067.git.jpoimboe@redhat.com
To pick up the changes in:
6dbbf5ec9e ("x86/cpufeatures: Enumerate user wait instructions")
b302e4b176 ("x86/cpufeatures: Enumerate the new AVX512 BFLOAT16 instructions")
acec0ce081 ("x86/cpufeatures: Combine word 11 and 12 into a new scattered features word")
cbb99c0f58 ("x86/cpufeatures: Add FDP_EXCPTN_ONLY and ZERO_FCS_FDS")
That don't affect anything in tools/.
This silences this perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
Cc: Aaron Lewis <aaronlewis@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/n/tip-y60wnyg2fuxi0hx7icruo9po@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Daniel Borkmann says:
====================
pull-request: bpf-next 2019-04-12
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Improve BPF verifier scalability for large programs through two
optimizations: i) remove verifier states that are not useful in pruning,
ii) stop walking parentage chain once first LIVE_READ is seen. Combined
gives approx 20x speedup. Increase limits for accepting large programs
under root, and add various stress tests, from Alexei.
2) Implement global data support in BPF. This enables static global variables
for .data, .rodata and .bss sections to be properly handled which allows
for more natural program development. This also opens up the possibility
to optimize program workflow by compiling ELFs only once and later only
rewriting section data before reload, from Daniel and with test cases and
libbpf refactoring from Joe.
3) Add config option to generate BTF type info for vmlinux as part of the
kernel build process. DWARF debug info is converted via pahole to BTF.
Latter relies on libbpf and makes use of BTF deduplication algorithm which
results in 100x savings compared to DWARF data. Resulting .BTF section is
typically about 2MB in size, from Andrii.
4) Add BPF verifier support for stack access with variable offset from
helpers and add various test cases along with it, from Andrey.
5) Extend bpf_skb_adjust_room() growth BPF helper to mark inner MAC header
so that L2 encapsulation can be used for tc tunnels, from Alan.
6) Add support for input __sk_buff context in BPF_PROG_TEST_RUN so that
users can define a subset of allowed __sk_buff fields that get fed into
the test program, from Stanislav.
7) Add bpf fs multi-dimensional array tests for BTF test suite and fix up
various UBSAN warnings in bpftool, from Yonghong.
8) Generate a pkg-config file for libbpf, from Luca.
9) Dump program's BTF id in bpftool, from Prashant.
10) libbpf fix to use smaller BPF log buffer size for AF_XDP's XDP
program, from Magnus.
11) kallsyms related fixes for the case when symbols are not present in
BPF selftests and samples, from Daniel
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the definition for smp_rmb(), smp_wmb(), and smp_mb() to the
tools include infrastructure: this patch adds the implementation
for x86-64 and arm64, and have it fall back as currently is for
other archs which do not have it implemented at this point. The
x86-64 one uses lock + add combination for smp_mb() with address
below red zone.
This is on top of 09d62154f6 ("tools, perf: add and use optimized
ring_buffer_{read_head, write_tail} helpers"), which didn't touch
smp_* barrier implementations. Magnus recently rightfully reported
however that the latter on x86-64 still wrongly falls back to sfence,
lfence and mfence respectively, thus fix that for applications under
tools making use of these to avoid such ugly surprises. The main
header under tools (include/asm/barrier.h) will in that case not
select the fallback implementation.
Reported-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
perf annotate:
Ivan Krylov:
- Pass filename to objdump via execl, fixing usage with filenames
with special characters.
perf report:
Jin Yao:
Fix wrong iteration count in --branch-history
perf stat:
Jin Yao:
- Fix endless wait for child process
perf test:
Arnaldo Carvalho de Melo:
- Use a fallback to get the pathname in vfs_getname in
tools build:
Jiri Olsa:
- Allow overriding CFLAGS assignments.
Misc:
Arnaldo Carvalho de Melo:
- Syncronize UAPI headers
Mattias Jacobsson:
- Remove redundant va_end() in strbuf_addv()
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
To silence the following tools/perf build warning:
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/disabled-features.h' differs from latest version at 'arch/x86/include/asm/disabled-features.h'
diff -u tools/arch/x86/include/asm/disabled-features.h arch/x86/include/asm/disabled-features.h
Picking up the changes in dae0a10593 ("x86/cpufeatures, x86/fault:
Mark SMAP as disabled when configured out") that didn't entail any
functionality change in the tooling side.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-vvge5xh6ii12oszexqknbgwp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently, on x86-64, perf uses LFENCE and MFENCE (rmb() and mb(),
respectively) when processing events from the perf ring buffer which
is unnecessarily expensive as we can do more lightweight in particular
given this is critical fast-path in perf.
According to Peter rmb()/mb() were added back then via a94d342b9c
("tools/perf: Add required memory barriers") at a time where kernel
still supported chips that needed it, but nowadays support for these
has been ditched completely, therefore we can fix them up as well.
While for x86-64, replacing rmb() and mb() with smp_*() variants would
result in just a compiler barrier for the former and LOCK + ADD for
the latter (__sync_synchronize() uses slower MFENCE by the way), Peter
suggested we can use smp_{load_acquire,store_release}() instead for
architectures where its implementation doesn't resolve in slower smp_mb().
Thus, e.g. in x86-64 we would be able to avoid CPU barrier entirely due
to TSO. For architectures where the latter needs to use smp_mb() e.g.
on arm, we stick to cheaper smp_rmb() variant for fetching the head.
This work adds helpers ring_buffer_read_head() and ring_buffer_write_tail()
for tools infrastructure that either switches to smp_load_acquire() for
architectures where it is cheaper or uses READ_ONCE() + smp_rmb() barrier
for those where it's not in order to fetch the data_head from the perf
control page, and it uses smp_store_release() to write the data_tail.
Latter is smp_mb() + WRITE_ONCE() combination or a cheaper variant if
architecture allows for it. Those that rely on smp_rmb() and smp_mb() can
further improve performance in a follow up step by implementing the two
under tools/arch/*/include/asm/barrier.h such that they don't have to
fallback to rmb() and mb() in tools/include/asm/barrier.h.
Switch perf to use ring_buffer_read_head() and ring_buffer_write_tail()
so it can make use of the optimizations. Later, we convert libbpf as
well to use the same helpers.
Side note [0]: the topic has been raised of whether one could simply use
the C11 gcc builtins [1] for the smp_load_acquire() and smp_store_release()
instead:
__atomic_load_n(ptr, __ATOMIC_ACQUIRE);
__atomic_store_n(ptr, val, __ATOMIC_RELEASE);
Kernel and (presumably) tooling shipped along with the kernel has a
minimum requirement of being able to build with gcc-4.6 and the latter
does not have C11 builtins. While generally the C11 memory models don't
align with the kernel's, the C11 load-acquire and store-release alone
/could/ suffice, however. Issue is that this is implementation dependent
on how the load-acquire and store-release is done by the compiler and
the mapping of supported compilers must align to be compatible with the
kernel's implementation, and thus needs to be verified/tracked on a
case by case basis whether they match (unless an architecture uses them
also from kernel side). The implementations for smp_load_acquire() and
smp_store_release() in this patch have been adapted from the kernel side
ones to have a concrete and compatible mapping in place.
[0] http://patchwork.ozlabs.org/patch/985422/
[1] https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Peter Zijlstra (Intel)
Masami Hiramatsu
Arnaldo Carvalho de Melo
Linus Torvalds
Dan Williams
Julien Thierry
Paolo Bonzini
Ben Gardon
Sean Christopherson
Ingo Molnar
Babu Moger
Josh Poimboeuf
David S. Miller
Daniel Borkmann
Masahiro Yamada