kernel_optimize_test/tools
Linus Torvalds 4da9f33026 Support for FSGSBASE. Almost 5 years after the first RFC to support it,
this has been brought into a shape which is maintainable and actually
 works.
 
 This final version was done by Sasha Levin who took it up after Intel
 dropped the ball. Sasha discovered that the SGX (sic!) offerings out there
 ship rogue kernel modules enabling FSGSBASE behind the kernels back which
 opens an instantanious unpriviledged root hole.
 
 The FSGSBASE instructions provide a considerable speedup of the context
 switch path and enable user space to write GSBASE without kernel
 interaction. This enablement requires careful handling of the exception
 entries which go through the paranoid entry path as they cannot longer rely
 on the assumption that user GSBASE is positive (as enforced via prctl() on
 non FSGSBASE enabled systemn). All other entries (syscalls, interrupts and
 exceptions) can still just utilize SWAPGS unconditionally when the entry
 comes from user space. Converting these entries to use FSGSBASE has no
 benefit as SWAPGS is only marginally slower than WRGSBASE and locating and
 retrieving the kernel GSBASE value is not a free operation either. The real
 benefit of RD/WRGSBASE is the avoidance of the MSR reads and writes.
 
 The changes come with appropriate selftests and have held up in field
 testing against the (sanitized) Graphene-SGX driver.
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Merge tag 'x86-fsgsbase-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fsgsbase from Thomas Gleixner:
 "Support for FSGSBASE. Almost 5 years after the first RFC to support
  it, this has been brought into a shape which is maintainable and
  actually works.

  This final version was done by Sasha Levin who took it up after Intel
  dropped the ball. Sasha discovered that the SGX (sic!) offerings out
  there ship rogue kernel modules enabling FSGSBASE behind the kernels
  back which opens an instantanious unpriviledged root hole.

  The FSGSBASE instructions provide a considerable speedup of the
  context switch path and enable user space to write GSBASE without
  kernel interaction. This enablement requires careful handling of the
  exception entries which go through the paranoid entry path as they
  can no longer rely on the assumption that user GSBASE is positive (as
  enforced via prctl() on non FSGSBASE enabled systemn).

  All other entries (syscalls, interrupts and exceptions) can still just
  utilize SWAPGS unconditionally when the entry comes from user space.
  Converting these entries to use FSGSBASE has no benefit as SWAPGS is
  only marginally slower than WRGSBASE and locating and retrieving the
  kernel GSBASE value is not a free operation either. The real benefit
  of RD/WRGSBASE is the avoidance of the MSR reads and writes.

  The changes come with appropriate selftests and have held up in field
  testing against the (sanitized) Graphene-SGX driver"

* tag 'x86-fsgsbase-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/fsgsbase: Fix Xen PV support
  x86/ptrace: Fix 32-bit PTRACE_SETREGS vs fsbase and gsbase
  selftests/x86/fsgsbase: Add a missing memory constraint
  selftests/x86/fsgsbase: Fix a comment in the ptrace_write_gsbase test
  selftests/x86: Add a syscall_arg_fault_64 test for negative GSBASE
  selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE
  selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write
  Documentation/x86/64: Add documentation for GS/FS addressing mode
  x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2
  x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit
  x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit
  x86/entry/64: Introduce the FIND_PERCPU_BASE macro
  x86/entry/64: Switch CR3 before SWAPGS in paranoid entry
  x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation
  x86/process/64: Use FSGSBASE instructions on thread copy and ptrace
  x86/process/64: Use FSBSBASE in switch_to() if available
  x86/process/64: Make save_fsgs_for_kvm() ready for FSGSBASE
  x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions
  x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions
  x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE
  ...
2020-08-04 21:16:22 -07:00
..
accounting SPDX patches for 5.7-rc1. 2020-04-03 13:12:26 -07:00
arch tools arch kvm: Sync kvm headers with the kernel sources 2020-07-17 09:39:16 -03:00
bootconfig tools/bootconfig: Add testcase for show-command and quotes test 2020-06-16 21:21:03 -04:00
bpf tools: bpf: Use local copy of headers including uapi/linux/filter.h 2020-07-21 10:50:35 +01:00
build perf build: Remove libaudit from the default feature checks 2020-05-29 16:51:13 -03:00
cgroup iocost_monitor: start from the oldest usage index 2020-07-30 11:45:29 -06:00
debugging
edid tools/edid: Move EDID data sets from Documentation/ 2020-02-19 04:10:32 -07:00
firewire
firmware
gpio tools: gpio: add bias flags to lsgpio 2020-05-05 18:27:09 +02:00
hv
iio .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
include Remove uninitialized_var() macro for v5.9-rc1 2020-08-04 13:49:43 -07:00
io_uring io_uring: change the poll type to be 32-bits 2020-06-21 20:44:00 -06:00
kvm/kvm_stat tools/kvm_stat: add sample systemd unit file 2020-04-21 09:13:12 -04:00
laptop change email address for Pali Rohár 2020-04-10 15:36:22 -07:00
leds .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
lib libtraceevent: Fix build with binutils 2.35 2020-07-31 09:31:55 -03:00
memory-model These were the main changes in this cycle: 2020-08-03 14:39:35 -07:00
nfsd
objtool Misc updates: 2020-08-03 14:45:33 -07:00
pci tools: PCI: Add 'e' to clear IRQ 2020-04-02 17:57:10 +01:00
pcmcia .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
perf perf tools: Fix record failure when mixed with ARM SPE event 2020-07-31 09:29:01 -03:00
power ACPI updates for 5.9-rc1 2020-08-03 20:37:22 -07:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-25 18:58:11 -07:00
spi spi: tools: Make default_tx/rx and input_tx static 2020-06-11 16:27:24 +01:00
testing Support for FSGSBASE. Almost 5 years after the first RFC to support it, 2020-08-04 21:16:22 -07:00
thermal/tmon - Convert tsens configuration DT binding to yaml (Rajeshwari) 2020-04-07 20:00:16 -07:00
time
usb .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
virtio compiler: Remove uninitialized_var() macro 2020-07-16 12:35:31 -07:00
vm tools/vm/page_owner_sort.c: filter out unneeded line 2020-06-03 20:09:49 -07:00
wmi
Makefile