[upstream commit 4b3da77b72ad6b3c48c6fe4a395ace7db39a12c5]
Add BPF_MOD_{NOP_TO_JUMP,JUMP_TO_JUMP,JUMP_TO_NOP} patching for x86
JIT in order to be able to patch direct jumps or nop them out. We need
this facility in order to patch tail call jumps and in later work also
BPF static keys.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/aa4784196a8e5e985af4b30a4fe5336bce6e9643.1574452833.git.daniel@iogearbox.net
[upstream commit 85d33df357b634649ddbe0a20fd2d0fc5732c3cb]
The patch introduces BPF_MAP_TYPE_STRUCT_OPS. The map value
is a kernel struct with its func ptr implemented in bpf prog.
This new map is the interface to register/unregister/introspect
a bpf implemented kernel struct.
The kernel struct is actually embedded inside another new struct
(or called the "value" struct in the code). For example,
"struct tcp_congestion_ops" is embbeded in:
struct bpf_struct_ops_tcp_congestion_ops {
refcount_t refcnt;
enum bpf_struct_ops_state state;
struct tcp_congestion_ops data; /* <-- kernel subsystem struct here */
}
The map value is "struct bpf_struct_ops_tcp_congestion_ops".
The "bpftool map dump" will then be able to show the
state ("inuse"/"tobefree") and the number of subsystem's refcnt (e.g.
number of tcp_sock in the tcp_congestion_ops case). This "value" struct
is created automatically by a macro. Having a separate "value" struct
will also make extending "struct bpf_struct_ops_XYZ" easier (e.g. adding
"void (*init)(void)" to "struct bpf_struct_ops_XYZ" to do some
initialization works before registering the struct_ops to the kernel
subsystem). The libbpf will take care of finding and populating the
"struct bpf_struct_ops_XYZ" from "struct XYZ".
Register a struct_ops to a kernel subsystem:
1. Load all needed BPF_PROG_TYPE_STRUCT_OPS prog(s)
2. Create a BPF_MAP_TYPE_STRUCT_OPS with attr->btf_vmlinux_value_type_id
set to the btf id "struct bpf_struct_ops_tcp_congestion_ops" of the
running kernel.
Instead of reusing the attr->btf_value_type_id,
btf_vmlinux_value_type_id s added such that attr->btf_fd can still be
used as the "user" btf which could store other useful sysadmin/debug
info that may be introduced in the furture,
e.g. creation-date/compiler-details/map-creator...etc.
3. Create a "struct bpf_struct_ops_tcp_congestion_ops" object as described
in the running kernel btf. Populate the value of this object.
The function ptr should be populated with the prog fds.
4. Call BPF_MAP_UPDATE with the object created in (3) as
the map value. The key is always "0".
During BPF_MAP_UPDATE, the code that saves the kernel-func-ptr's
args as an array of u64 is generated. BPF_MAP_UPDATE also allows
the specific struct_ops to do some final checks in "st_ops->init_member()"
(e.g. ensure all mandatory func ptrs are implemented).
If everything looks good, it will register this kernel struct
to the kernel subsystem. The map will not allow further update
from this point.
Unregister a struct_ops from the kernel subsystem:
BPF_MAP_DELETE with key "0".
Introspect a struct_ops:
BPF_MAP_LOOKUP_ELEM with key "0". The map value returned will
have the prog _id_ populated as the func ptr.
The map value state (enum bpf_struct_ops_state) will transit from:
INIT (map created) =>
INUSE (map updated, i.e. reg) =>
TOBEFREE (map value deleted, i.e. unreg)
The kernel subsystem needs to call bpf_struct_ops_get() and
bpf_struct_ops_put() to manage the "refcnt" in the
"struct bpf_struct_ops_XYZ". This patch uses a separate refcnt
for the purose of tracking the subsystem usage. Another approach
is to reuse the map->refcnt and then "show" (i.e. during map_lookup)
the subsystem's usage by doing map->refcnt - map->usercnt to filter out
the map-fd/pinned-map usage. However, that will also tie down the
future semantics of map->refcnt and map->usercnt.
The very first subsystem's refcnt (during reg()) holds one
count to map->refcnt. When the very last subsystem's refcnt
is gone, it will also release the map->refcnt. All bpf_prog will be
freed when the map->refcnt reaches 0 (i.e. during map_free()).
Here is how the bpftool map command will look like:
[root@arch-fb-vm1 bpf]# bpftool map show
6: struct_ops name dctcp flags 0x0
key 4B value 256B max_entries 1 memlock 4096B
btf_id 6
[root@arch-fb-vm1 bpf]# bpftool map dump id 6
[{
"value": {
"refcnt": {
"refs": {
"counter": 1
}
},
"state": 1,
"data": {
"list": {
"next": 0,
"prev": 0
},
"key": 0,
"flags": 2,
"init": 24,
"release": 0,
"ssthresh": 25,
"cong_avoid": 30,
"set_state": 27,
"cwnd_event": 28,
"in_ack_event": 26,
"undo_cwnd": 29,
"pkts_acked": 0,
"min_tso_segs": 0,
"sndbuf_expand": 0,
"cong_control": 0,
"get_info": 0,
"name": [98,112,102,95,100,99,116,99,112,0,0,0,0,0,0,0
],
"owner": 0
}
}
}
]
Misc Notes:
* bpf_struct_ops_map_sys_lookup_elem() is added for syscall lookup.
It does an inplace update on "*value" instead returning a pointer
to syscall.c. Otherwise, it needs a separate copy of "zero" value
for the BPF_STRUCT_OPS_STATE_INIT to avoid races.
* The bpf_struct_ops_map_delete_elem() is also called without
preempt_disable() from map_delete_elem(). It is because
the "->unreg()" may requires sleepable context, e.g.
the "tcp_unregister_congestion_control()".
* "const" is added to some of the existing "struct btf_func_model *"
function arg to avoid a compiler warning caused by this patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200109003505.3855919-1-kafai@fb.com
[upstream commit 5b92a28aae4dd0f88778d540ecfdcdaec5a41723]
Allow FENTRY/FEXIT BPF programs to attach to other BPF programs of any type
including their subprograms. This feature allows snooping on input and output
packets in XDP, TC programs including their return values. In order to do that
the verifier needs to track types not only of vmlinux, but types of other BPF
programs as well. The verifier also needs to translate uapi/linux/bpf.h types
used by networking programs into kernel internal BTF types used by FENTRY/FEXIT
BPF programs. In some cases LLVM optimizations can remove arguments from BPF
subprograms without adjusting BTF info that LLVM backend knows. When BTF info
disagrees with actual types that the verifiers sees the BPF trampoline has to
fallback to conservative and treat all arguments as u64. The FENTRY/FEXIT
program can still attach to such subprograms, but it won't be able to recognize
pointer types like 'struct sk_buff *' and it won't be able to pass them to
bpf_skb_output() for dumping packets to user space. The FENTRY/FEXIT program
would need to use bpf_probe_read_kernel() instead.
The BPF_PROG_LOAD command is extended with attach_prog_fd field. When it's set
to zero the attach_btf_id is one vmlinux BTF type ids. When attach_prog_fd
points to previously loaded BPF program the attach_btf_id is BTF type id of
main function or one of its subprograms.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-18-ast@kernel.org
[upstream commit 9fd4a39dc7fe734d26eb89ea97e8c91331c6378c]
BPF trampoline can be made to work with existing 5 bytes of BPF program
prologue, but let's add 5 bytes of NOPs to the beginning of every JITed BPF
program to make BPF trampoline job easier. They can be removed in the future.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-14-ast@kernel.org
[upstream commit 75a1a607bb7e6d918be3aca11ec2214a275392f4]
Add two new probe_kernel_read_strict() and strncpy_from_unsafe_strict()
helpers which by default alias to the __probe_kernel_read() and the
__strncpy_from_unsafe(), respectively, but can be overridden by archs
which have non-overlapping address ranges for kernel space and user
space in order to bail out with -EFAULT when attempting to probe user
memory including non-canonical user access addresses [0]:
4-level page tables:
user-space mem: 0x0000000000000000 - 0x00007fffffffffff
non-canonical: 0x0000800000000000 - 0xffff7fffffffffff
5-level page tables:
user-space mem: 0x0000000000000000 - 0x00ffffffffffffff
non-canonical: 0x0100000000000000 - 0xfeffffffffffffff
The idea is that these helpers are complementary to the probe_user_read()
and strncpy_from_unsafe_user() which probe user-only memory. Both added
helpers here do the same, but for kernel-only addresses.
Both set of helpers are going to be used for BPF tracing. They also
explicitly avoid throwing the splat for non-canonical user addresses from
00c42373d397 ("x86-64: add warning for non-canonical user access address
dereferences").
For compat, the current probe_kernel_read() and strncpy_from_unsafe() are
left as-is.
[0] Documentation/x86/x86_64/mm.txt
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: x86@kernel.org
Link: https://lore.kernel.org/bpf/eefeefd769aa5a013531f491a71f0936779e916b.1572649915.git.daniel@iogearbox.net
[upstream commit 5964b2000f283ff5df366f718e0f083ebbaae977]
Add bpf_arch_text_poke() helper that is used by BPF trampoline logic to patch
nops/calls in kernel text into calls into BPF trampoline and to patch
calls/nops inside BPF programs too.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-4-ast@kernel.org
[upstream commit 3b2744e665206ea82ce7673cb3ec889b2898a267]
Refactor x86 JITing of LDX, STX, CALL instructions into separate helper
functions. No functional changes in LDX and STX helpers. There is a minor
change in CALL helper. It will populate target address correctly on the first
pass of JIT instead of second pass. That won't reduce total number of JIT
passes though.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-3-ast@kernel.org
[upstream commit fec56f5890d93fc2ed74166c397dc186b1c25951]
Introduce BPF trampoline concept to allow kernel code to call into BPF programs
with practically zero overhead. The trampoline generation logic is
architecture dependent. It's converting native calling convention into BPF
calling convention. BPF ISA is 64-bit (even on 32-bit architectures). The
registers R1 to R5 are used to pass arguments into BPF functions. The main BPF
program accepts only single argument "ctx" in R1. Whereas CPU native calling
convention is different. x86-64 is passing first 6 arguments in registers
and the rest on the stack. x86-32 is passing first 3 arguments in registers.
sparc64 is passing first 6 in registers. And so on.
The trampolines between BPF and kernel already exist. BPF_CALL_x macros in
include/linux/filter.h statically compile trampolines from BPF into kernel
helpers. They convert up to five u64 arguments into kernel C pointers and
integers. On 64-bit architectures this BPF_to_kernel trampolines are nops. On
32-bit architecture they're meaningful.
The opposite job kernel_to_BPF trampolines is done by CAST_TO_U64 macros and
__bpf_trace_##call() shim functions in include/trace/bpf_probe.h. They convert
kernel function arguments into array of u64s that BPF program consumes via
R1=ctx pointer.
This patch set is doing the same job as __bpf_trace_##call() static
trampolines, but dynamically for any kernel function. There are ~22k global
kernel functions that are attachable via nop at function entry. The function
arguments and types are described in BTF. The job of btf_distill_func_proto()
function is to extract useful information from BTF into "function model" that
architecture dependent trampoline generators will use to generate assembly code
to cast kernel function arguments into array of u64s. For example the kernel
function eth_type_trans has two pointers. They will be casted to u64 and stored
into stack of generated trampoline. The pointer to that stack space will be
passed into BPF program in R1. On x86-64 such generated trampoline will consume
16 bytes of stack and two stores of %rdi and %rsi into stack. The verifier will
make sure that only two u64 are accessed read-only by BPF program. The verifier
will also recognize the precise type of the pointers being accessed and will
not allow typecasting of the pointer to a different type within BPF program.
The tracing use case in the datacenter demonstrated that certain key kernel
functions have (like tcp_retransmit_skb) have 2 or more kprobes that are always
active. Other functions have both kprobe and kretprobe. So it is essential to
keep both kernel code and BPF programs executing at maximum speed. Hence
generated BPF trampoline is re-generated every time new program is attached or
detached to maintain maximum performance.
To avoid the high cost of retpoline the attached BPF programs are called
directly. __bpf_prog_enter/exit() are used to support per-program execution
stats. In the future this logic will be optimized further by adding support
for bpf_stats_enabled_key inside generated assembly code. Introduction of
preemptible and sleepable BPF programs will completely remove the need to call
to __bpf_prog_enter/exit().
Detach of a BPF program from the trampoline should not fail. To avoid memory
allocation in detach path the half of the page is used as a reserve and flipped
after each attach/detach. 2k bytes is enough to call 40+ BPF programs directly
which is enough for BPF tracing use cases. This limit can be increased in the
future.
BPF_TRACE_FENTRY programs have access to raw kernel function arguments while
BPF_TRACE_FEXIT programs have access to kernel return value as well. Often
kprobe BPF program remembers function arguments in a map while kretprobe
fetches arguments from a map and analyzes them together with return value.
BPF_TRACE_FEXIT accelerates this typical use case.
Recursion prevention for kprobe BPF programs is done via per-cpu
bpf_prog_active counter. In practice that turned out to be a mistake. It
caused programs to randomly skip execution. The tracing tools missed results
they were looking for. Hence BPF trampoline doesn't provide builtin recursion
prevention. It's a job of BPF program itself and will be addressed in the
follow up patches.
BPF trampoline is intended to be used beyond tracing and fentry/fexit use cases
in the future. For example to remove retpoline cost from XDP programs.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191114185720.1641606-5-ast@kernel.org
[upstream commit 3dec541b2e632d630fe7142ed44f0b3702ef1f8c]
Pointer to BTF object is a pointer to kernel object or NULL.
Such pointers can only be used by BPF_LDX instructions.
The verifier changed their opcode from LDX|MEM|size
to LDX|PROBE_MEM|size to make JITing easier.
The number of entries in extable is the number of BPF_LDX insns
that access kernel memory via "pointer to BTF type".
Only these load instructions can fault.
Since x86 extable is relative it has to be allocated in the same
memory region as JITed code.
Allocate it prior to last pass of JITing and let the last pass populate it.
Pointer to extable in bpf_prog_aux is necessary to make page fault
handling fast.
Page fault handling is done in two steps:
1. bpf_prog_kallsyms_find() finds BPF program that page faulted.
It's done by walking rb tree.
2. then extable for given bpf program is binary searched.
This process is similar to how page faulting is done for kernel modules.
The exception handler skips over faulting x86 instruction and
initializes destination register with zero. This mimics exact
behavior of bpf_probe_read (when probe_kernel_read faults dest is zeroed).
JITs for other architectures can add support in similar way.
Until then they will reject unknown opcode and fallback to interpreter.
Since extable should be aligned and placed near JITed code
make bpf_jit_binary_alloc() return 4 byte aligned image offset,
so that extable aligning formula in bpf_int_jit_compile() doesn't need
to rely on internal implementation of bpf_jit_binary_alloc().
On x86 gcc defaults to 16-byte alignment for regular kernel functions
due to better performance. JITed code may be aligned to 16 in the future,
but it will use 4 in the meantime.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191016032505.2089704-10-ast@kernel.org
commit f5e81d1117501546b7be050c5fbafa6efd2c722c upstream.
In case of JITs, each of the JIT backends compiles the BPF nospec instruction
/either/ to a machine instruction which emits a speculation barrier /or/ to
/no/ machine instruction in case the underlying architecture is not affected
by Speculative Store Bypass or has different mitigations in place already.
This covers both x86 and (implicitly) arm64: In case of x86, we use 'lfence'
instruction for mitigation. In case of arm64, we rely on the firmware mitigation
as controlled via the ssbd kernel parameter. Whenever the mitigation is enabled,
it works for all of the kernel code with no need to provide any additional
instructions here (hence only comment in arm64 JIT). Other archs can follow
as needed. The BPF nospec instruction is specifically targeting Spectre v4
since i) we don't use a serialization barrier for the Spectre v1 case, and
ii) mitigation instructions for v1 and v4 might be different on some archs.
The BPF nospec is required for a future commit, where the BPF verifier does
annotate intermediate BPF programs with speculation barriers.
Co-developed-by: Piotr Krysiuk <piotras@gmail.com>
Co-developed-by: Benedict Schlueter <benedict.schlueter@rub.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[OP: - adjusted context for 5.4
- apply riscv changes to /arch/riscv/net/bpf_jit_comp.c]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's getting more common to run nested container environments for
testing cloud software. One of such examples is Kind [1] which runs a
Kubernetes cluster in Docker containers on a single host. Each container
acts as a Kubernetes node, and thus can run any Pod (aka container)
inside the former. This approach simplifies testing a lot, as it
eliminates complicated VM setups.
Unfortunately, such a setup breaks some functionality when cgroupv2 BPF
programs are used for load-balancing. The load-balancer BPF program
needs to detect whether a request originates from the host netns or a
container netns in order to allow some access, e.g. to a service via a
loopback IP address. Typically, the programs detect this by comparing
netns cookies with the one of the init ns via a call to
bpf_get_netns_cookie(NULL). However, in nested environments the latter
cannot be used given the Kubernetes node's netns is outside the init ns.
To fix this, we need to pass the Kubernetes node netns cookie to the
program in a different way: by extending getsockopt() with a
SO_NETNS_COOKIE option, the orchestrator which runs in the Kubernetes
node netns can retrieve the cookie and pass it to the program instead.
Thus, this is following up on Eric's commit 3d368ab87cf6 ("net:
initialize net->net_cookie at netns setup") to allow retrieval via
SO_NETNS_COOKIE. This is also in line in how we retrieve socket cookie
via SO_COOKIE.
[1] https://kind.sigs.k8s.io/
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Cc: Eric Dumazet <edumazet@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cross-LLC is the same as cross-numa, which will cause longer
cache synchronization. This patch changes numa aware to LLC
aware and disables llc spinlock by default.
Signed-off-by: Mungerjiang <mungerjiang@tencent.com>
In CNA, spinning threads are organized in two queues, a primary queue for
threads running on the same node as the current lock holder, and a
secondary queue for threads running on other nodes. After acquiring the
MCS lock and before acquiring the spinlock, the MCS lock
holder checks whether the next waiter in the primary queue (if exists) is
running on the same NUMA node. If it is not, that waiter is detached from
the main queue and moved into the tail of the secondary queue. This way,
we gradually filter the primary queue, leaving only waiters running on
the same preferred NUMA node. For more details, see
https://arxiv.org/abs/1810.05600.
Note that this variant of CNA may introduce starvation by continuously
passing the lock between waiters in the main queue. This issue will be
addressed later in the series.
Enabling CNA is controlled via a new configuration option
(NUMA_AWARE_SPINLOCKS). By default, the CNA variant is patched in at the
boot time only if we run on a multi-node machine in native environment and
the new config is enabled. (For the time being, the patching requires
CONFIG_PARAVIRT_SPINLOCKS to be enabled as well. However, this should be
resolved once static_call() is available.) This default behavior can be
overridden with the new kernel boot command-line option
"numa_spinlock=on/off" (default is "auto").
Signed-off-by: Alex Kogan <alex.kogan@oracle.com>
Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Waiman Long <longman@redhat.com>
The mcs unlock macro (arch_mcs_lock_handoff) should accept the value to be
stored into the lock argument as another argument. This allows using the
same macro in cases where the value to be stored when passing the lock is
different from 1.
Signed-off-by: Alex Kogan <alex.kogan@oracle.com>
Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Waiman Long <longman@redhat.com>
upstream:05eee619ed61c8cd89633954d38c4e5653086845
x86/kvm: Add "nopvspin" parameter to disable PV spinlocks
There are cases where a guest tries to switch spinlocks to bare metal
behavior (e.g. by setting "xen_nopvspin" on XEN platform and
"hv_nopvspin" on HYPER_V).
That feature is missed on KVM, add a new parameter "nopvspin" to disable
PV spinlocks for KVM guest.
The new 'nopvspin' parameter will also replace Xen and Hyper-V specific
parameters in future patches.
Define variable nopvsin as global because it will be used in future
patches as above.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
commit: f444a5ff95dce07cf4353cbb85fc3e785019d430
>From the Intel Optimization Reference Manual:
3.7.6.1 Fast Short REP MOVSB
Beginning with processors based on Ice Lake Client microarchitecture,
REP MOVSB performance of short operations is enhanced. The enhancement
applies to string lengths between 1 and 128 bytes long. Support for
fast-short REP MOVSB is enumerated by the CPUID feature flag: CPUID
[EAX=7H, ECX=0H).EDX.FAST_SHORT_REP_MOVSB[bit 4] = 1. There is no change
in the REP STOS performance.
Add an X86_FEATURE_FSRM flag for this.
memmove() avoids REP MOVSB for short (< 32 byte) copies. Check FSRM and
use REP MOVSB for short copies on systems that support it.
[ bp: Massage and add comment. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191216214254.26492-1-tony.luck@intel.com
For AMD EPYC 7K83 64-Core Processor, enable erms/fsrm features to
improve memory copy performance. This is just for specific cpu and
when the features are not transmitted to guest by the host.
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
When a process is running in the system space, it cann't be preempted until
it return to userspace, even if the process should be reschedule and other
process was ready to run(because the server system close the kernel preempt
by default). This schedule delay may impact the performance of waiting process,
therefor we introduce the longsys check to collect the schedule delay information
of process. The longsys indication could help us spot the possible performance
jitter in the system.
Signed-off-by: Munger jiang <mungerjiang@tencent.com>
Signed-off-by: Bin Lai <robinlai@tencent.com>
Reviewed-by: benbjiang<benbjiang@tencent.com>
Reviewed-by: Bauerchen <bauerchen@tencent.com>
Family 19h introduces change in slice, core and thread specification in
its L3 Performance Event Select (ChL3PmcCfg) h/w register. The change is
incompatible with Family 17h's version of the register.
Introduce a new path in l3_thread_slice_mask() to do things differently
for Family 19h vs. Family 17h, otherwise the new hardware doesn't get
programmed correctly.
Instead of a linear core--thread bitmask, Family 19h takes an encoded
core number, and a separate thread mask. There are new bits that are set
for all cores and all slices, of which only the latter is used, since
the driver counts events for all slices on behalf of the specified CPU.
Also update amd_uncore_init() to base its L2/NB vs. L3/Data Fabric mode
decision based on Family 17h or above, not just 17h and 18h: the Family
19h Data Fabric PMC is compatible with the Family 17h DF PMC.
[ bp: Touchups. ]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200313231024.17601-3-kim.phillips@amd.com
Convert the l3_thread_slice_mask() function to use the more readable
topology_* helper functions, more intuitive variable names like shift
and thread_mask, and BIT_ULL().
No functional changes.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200313231024.17601-2-kim.phillips@amd.com
In order to better accommodate the upcoming Family 19h, given
the 80-char line limit, move the existing code into a new
l3_thread_slice_mask() function.
No functional changes.
[ bp: Touchups. ]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200313231024.17601-1-kim.phillips@amd.com
Add support for a new version of the Load Store unit bank type as
indicated by its McaType value, which will be present in future SMCA
systems.
Add the new (HWID, MCATYPE) tuple. Reuse the same name, since this is
logically the same to the user.
Also, add the new error descriptions to edac_mce_amd.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200110015651.14887-2-Yazen.Ghannam@amd.com
commit c75890700455113c366f795f3d22ee03623835e8 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
When native_load_gs_index() fails on .Lgs_change, CR3 must be kernel
CR3. No need to switch it.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200419144049.1906-2-laijs@linux.alibaba.com
(cherry picked from commit c75890700455113c366f795f3d22ee03623835e8)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 978e1342c3c4d7b20808fd5875d9ac0d57db22ee upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Before enabling FSGSBASE the kernel could safely assume that the content
of GS base was a user address. Thus any speculative access as the result
of a mispredicted branch controlling the execution of SWAPGS would be to
a user address. So systems with speculation-proof SMAP did not need to
add additional LFENCE instructions to mitigate.
With FSGSBASE enabled a hostile user can set GS base to a kernel address.
So they can make the kernel speculatively access data they wish to leak
via a side channel. This means that SMAP provides no protection.
Add FSGSBASE as an additional condition to enable the fence-based SWAPGS
mitigation.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528201402.1708239-9-sashal@kernel.org
(cherry picked from commit 978e1342c3c4d7b20808fd5875d9ac0d57db22ee)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 673903495c85137791d5820d690229efe09c8f7b upstream.
Backport summary: for 5.4 kernel fsgsbase support.
With the new FSGSBASE instructions, FS and GSABSE can be efficiently read
and writen in __switch_to(). Use that capability to preserve the full
state.
This will enable user code to do whatever it wants with the new
instructions without any kernel-induced gotchas. (There can still be
architectural gotchas: movl %gs,%eax; movl %eax,%gs may change GSBASE if
WRGSBASE was used, but users are expected to read the CPU manual before
doing things like that.)
This is a considerable speedup. It seems to save about 100 cycles
per context switch compared to the baseline 4.6-rc1 behavior on a
Skylake laptop. This is mostly due to avoiding the WRMSR operation.
[ chang: 5~10% performance improvements were seen with a context switch
benchmark that ran threads with different FS/GSBASE values (to the
baseline 4.16). Minor edit on the changelog. ]
[ tglx: Masaage changelog ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/1557309753-24073-8-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-6-sashal@kernel.org
(cherry picked from commit 673903495c85137791d5820d690229efe09c8f7b)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 40c45904f818c1f6555294ca27afc5fda4f09e68 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Debuggers expect that doing PTRACE_GETREGS, then poking at a tracee
and maybe letting it run for a while, then doing PTRACE_SETREGS will
put the tracee back where it was. In the specific case of a 32-bit
tracer and tracee, the PTRACE_GETREGS/SETREGS data structure doesn't
have fs_base or gs_base fields, so FSBASE and GSBASE fields are
never stored anywhere. Everything used to still work because
nonzero FS or GS would result full reloads of the segment registers
when the tracee resumes, and the bases associated with FS==0 or
GS==0 are irrelevant to 32-bit code.
Adding FSGSBASE support broke this: when FSGSBASE is enabled, FSBASE
and GSBASE are now restored independently of FS and GS for all tasks
when context-switched in. This means that, if a 32-bit tracer
restores a previous state using PTRACE_SETREGS but the tracee's
pre-restore and post-restore bases don't match, then the tracee is
resumed with the wrong base.
Fix it by explicitly loading the base when a 32-bit tracer pokes FS
or GS on a 64-bit kernel.
Also add a test case.
Fixes: 673903495c85 ("x86/process/64: Use FSBSBASE in switch_to() if available")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/229cc6a50ecbb701abd50fe4ddaf0eda888898cd.1593192140.git.luto@kernel.org
(cherry picked from commit 40c45904f818c1f6555294ca27afc5fda4f09e68)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 6a3ea3e68b8a8a26c4aaac03432ed92269c9a14e upstream.
Backport summary: for 5.4 kernel fsgsbase support.
KVM has an optmization to avoid expensive MRS read/writes on
VMENTER/EXIT. It caches the MSR values and restores them either when
leaving the run loop, on preemption or when going out to user space.
The affected MSRs are not required for kernel context operations. This
changed with the recently introduced mechanism to handle FSGSBASE in the
paranoid entry code which has to retrieve the kernel GSBASE value by
accessing per CPU memory. The mechanism needs to retrieve the CPU number
and uses either LSL or RDPID if the processor supports it.
Unfortunately RDPID uses MSR_TSC_AUX which is in the list of cached and
lazily restored MSRs, which means between the point where the guest value
is written and the point of restore, MSR_TSC_AUX contains a random number.
If an NMI or any other exception which uses the paranoid entry path happens
in such a context, then RDPID returns the random guest MSR_TSC_AUX value.
As a consequence this reads from the wrong memory location to retrieve the
kernel GSBASE value. Kernel GS is used to for all regular this_cpu_*()
operations. If the GSBASE in the exception handler points to the per CPU
memory of a different CPU then this has the obvious consequences of data
corruption and crashes.
As the paranoid entry path is the only place which accesses MSR_TSX_AUX
(via RDPID) and the fallback via LSL is not significantly slower, remove
the RDPID alternative from the entry path and always use LSL.
The alternative would be to write MSR_TSC_AUX on every VMENTER and VMEXIT
which would be inflicting massive overhead on that code path.
[ tglx: Rewrote changelog ]
Fixes: eaad981291ee3 ("x86/entry/64: Introduce the FIND_PERCPU_BASE macro")
Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Debugged-by: Tom Lendacky <thomas.lendacky@amd.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200821105229.18938-1-pbonzini@redhat.com
(cherry picked from commit 6a3ea3e68b8a8a26c4aaac03432ed92269c9a14e)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit d029bff60aa6c7eab281d52602b6a7a971615324 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
On Xen PV, SWAPGS doesn't work. Teach __rdfsbase_inactive() and
__wrgsbase_inactive() to use rdmsrl()/wrmsrl() on Xen PV. The Xen
pvop code will understand this and issue the correct hypercalls.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/f07c08f178fe9711915862b656722a207cd52c28.1593192140.git.luto@kernel.org
(cherry picked from commit d029bff60aa6c7eab281d52602b6a7a971615324)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit d19e789f068b3d633cbac430764962f404198022 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Linus pointed out that compiler.h - which is a key header that gets included in every
single one of the 28,000+ kernel files during a kernel build - was bloated in:
655389666643: ("vmlinux.lds.h: Create section for protection against instrumentation")
Linus noted:
> I have pulled this, but do we really want to add this to a header file
> that is _so_ core that it gets included for basically every single
> file built?
>
> I don't even see those instrumentation_begin/end() things used
> anywhere right now.
>
> It seems excessive. That 53 lines is maybe not a lot, but it pushed
> that header file to over 12kB, and while it's mostly comments, it's
> extra IO and parsing basically for _every_ single file compiled in the
> kernel.
>
> For what appears to be absolutely zero upside right now, and I really
> don't see why this should be in such a core header file!
Move these primitives into a new header: <linux/instrumentation.h>, and include that
header in the headers that make use of it.
Unfortunately one of these headers is asm-generic/bug.h, which does get included
in a lot of places, similarly to compiler.h. So the de-bloating effect isn't as
good as we'd like it to be - but at least the interfaces are defined separately.
No change to functionality intended.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200604071921.GA1361070@gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
(cherry picked from commit d19e789f068b3d633cbac430764962f404198022)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 5f1dd4dda5c8796c405e856aaa11e187f6885924 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
ptrace and prctl() are not really fast paths to warrant the use of
static_cpu_has() and cause alternatives patching for no good reason.
Replace with boot_cpu_has() which is simple and fast enough.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200818103715.32736-1-bp@alien8.de
(cherry picked from commit 5f1dd4dda5c8796c405e856aaa11e187f6885924)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit fddf8ba1e48860211c9639d00883833b42fcc1e0 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
When a ptracer writes a ptracee's FS/GSBASE with a different value, the
selector is also cleared. This behavior is not correct as the selector
should be preserved.
Update only the base value and leave the selector intact. To simplify the
code further remove the conditional checking for the same value as this
code is not performance critical.
The only recognizable downside of this change is when the selector is
already nonzero on write. The base will be reloaded according to the
selector. But the case is highly unexpected in real usages.
[ tglx: Massage changelog ]
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/9040CFCD-74BD-4C17-9A01-B9B713CF6B10@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-2-sashal@kernel.org
(cherry picked from commit fddf8ba1e48860211c9639d00883833b42fcc1e0)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 742c45c3ecc9255e15eddbbcee44fd8de401cf1c upstream.
Backport summary: for 5.4 kernel fsgsbase support.
The kernel needs to explicitly enable FSGSBASE. So, the application needs
to know if it can safely use these instructions. Just looking at the CPUID
bit is not enough because it may be running in a kernel that does not
enable the instructions.
One way for the application would be to just try and catch the SIGILL.
But that is difficult to do in libraries which may not want to overwrite
the signal handlers of the main application.
Enumerate the enabled FSGSBASE capability in bit 1 of AT_HWCAP2 in the ELF
aux vector. AT_HWCAP2 is already used by PPC for similar purposes.
The application can access it open coded or by using the getauxval()
function in newer versions of glibc.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-18-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-14-sashal@kernel.org
(cherry picked from commit 742c45c3ecc9255e15eddbbcee44fd8de401cf1c)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit c82965f9e53005c1c62632c468968293262056cb upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Without FSGSBASE, user space cannot change GSBASE other than through a
PRCTL. The kernel enforces that the user space GSBASE value is postive as
negative values are used for detecting the kernel space GSBASE value in the
paranoid entry code.
If FSGSBASE is enabled, user space can set arbitrary GSBASE values without
kernel intervention, including negative ones, which breaks the paranoid
entry assumptions.
To avoid this, paranoid entry needs to unconditionally save the current
GSBASE value independent of the interrupted context, retrieve and write the
kernel GSBASE and unconditionally restore the saved value on exit. The
restore happens either in paranoid_exit or in the special exit path of the
NMI low level code.
All other entry code pathes which use unconditional SWAPGS are not affected
as they do not depend on the actual content.
[ tglx: Massaged changelogs and comments ]
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-13-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-12-sashal@kernel.org
(cherry picked from commit c82965f9e53005c1c62632c468968293262056cb)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit eaad981291ee36efee15a5e515d4598ae94ace07 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
GSBASE is used to find per-CPU data in the kernel. But when GSBASE is
unknown, the per-CPU base can be found from the per_cpu_offset table with a
CPU NR. The CPU NR is extracted from the limit field of the CPUNODE entry
in GDT, or by the RDPID instruction. This is a prerequisite for using
FSGSBASE in the low level entry code.
Also, add the GAS-compatible RDPID macro as binutils 2.23 do not support
it. Support is added in version 2.27.
[ tglx: Massaged changelog ]
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-12-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-11-sashal@kernel.org
(cherry picked from commit eaad981291ee36efee15a5e515d4598ae94ace07)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 96b2371413e8f636a5f25c42a933af21c35a2a41 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
When FSGSBASE is enabled, the GSBASE handling in paranoid entry will need
to retrieve the kernel GSBASE which requires that the kernel page table is
active.
As the CR3 switch to the kernel page tables (PTI is active) does not depend
on kernel GSBASE, move the CR3 switch in front of the GSBASE handling.
Comment the EBX content while at it.
No functional change.
[ tglx: Rewrote changelog and comments ]
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-11-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-10-sashal@kernel.org
(cherry picked from commit 96b2371413e8f636a5f25c42a933af21c35a2a41)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 005f141e5d5e05d3986539567d0bc5aa2f4dc640 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
When FSGSBASE is enabled, copying threads and reading fsbase and gsbase
using ptrace must read the actual values.
When copying a thread, use save_fsgs() and copy the saved values. For
ptrace, the bases must be read from memory regardless of the selector if
FSGSBASE is enabled.
[ tglx: Invoke __rdgsbase_inactive() with interrupts disabled ]
[ luto: Massage changelog ]
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-9-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-8-sashal@kernel.org
(cherry picked from commit 005f141e5d5e05d3986539567d0bc5aa2f4dc640)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 6758034e4d6a7f0e26b748789ab1f83f3116d1b9 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
save_fsgs_for_kvm() is invoked via
vcpu_enter_guest()
kvm_x86_ops.prepare_guest_switch(vcpu)
vmx_prepare_switch_to_guest()
save_fsgs_for_kvm()
with preemption disabled, but interrupts enabled.
The upcoming FSGSBASE based GS safe needs interrupts to be disabled. This
could be done in the helper function, but that function is also called from
switch_to() which has interrupts disabled already.
Disable interrupts inside save_fsgs_for_kvm() and rename the function to
current_save_fsgs() so it can be invoked from other places.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200528201402.1708239-7-sashal@kernel.org
(cherry picked from commit 6758034e4d6a7f0e26b748789ab1f83f3116d1b9)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 2fff071d28b54f050f62654dad4ec111b8416d8e upstream.
Backport summary: for 5.4 kernel fsgsbase support.
While looking at the TSS io bitmap it turned out that any change in that
area would require identical changes to copy_thread_tls(). The 32 and 64
bit variants share sufficient code to consolidate them into a common
function to avoid duplication of upcoming modifications.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
(cherry picked from commit 2fff071d28b54f050f62654dad4ec111b8416d8e)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 58edfd2e0a93c9adc2f29902a0335af0584041a0 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Add cpu feature conditional FSGSBASE access to the relevant helper
functions. That allows to accelerate certain FS/GS base operations in
subsequent changes.
Note, that while possible, the user space entry/exit GSBASE operations are
not going to use the new FSGSBASE instructions. The reason is that it would
require additional storage for the user space value which adds more
complexity to the low level code and experiments have shown marginal
benefit. This may be revisited later but for now the SWAPGS based handling
in the entry code is preserved except for the paranoid entry/exit code.
To preserve the SWAPGS entry mechanism introduce __[rd|wr]gsbase_inactive()
helpers. Note, for Xen PV, paravirt hooks can be added later as they might
allow a very efficient but different implementation.
[ tglx: Massaged changelog, convert it to noinstr and force inline
native_swapgs() ]
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-7-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-5-sashal@kernel.org
(cherry picked from commit 58edfd2e0a93c9adc2f29902a0335af0584041a0)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit b15378ca50810c1350086cafad3fe19979262a83 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
[ luto: Rename the variables from FS and GS to FSBASE and GSBASE and
make <asm/fsgsbase.h> safe to include on 32-bit kernels. ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/1557309753-24073-6-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-4-sashal@kernel.org
(cherry picked from commit b15378ca50810c1350086cafad3fe19979262a83)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit dd649bd0b3aa012740059b1ba31ecad28a408f7f upstream.
Backport summary: for 5.4 kernel fsgsbase support.
This is temporary. It will allow the next few patches to be tested
incrementally.
Setting unsafe_fsgsbase is a root hole. Don't do it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/1557309753-24073-4-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-3-sashal@kernel.org
(cherry picked from commit dd649bd0b3aa012740059b1ba31ecad28a408f7f)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
Daniel Borkmann