linux-stable/arch/x86
Andy Lutomirski 33344368cb x86/fpu: Clean up the fpu__clear() variants
fpu__clear() currently resets both register state and kernel XSAVE buffer
state.  It has two modes: one for all state (supervisor and user) and
another for user state only.  fpu__clear_all() uses the "all state"
(user_only=0) mode, while a number of signal paths use the user_only=1
mode.

Make fpu__clear() work only for user state (user_only=1) and remove the
"all state" (user_only=0) code.  Rename it to match so it can be used by
the signal paths.

Replace the "all state" (user_only=0) fpu__clear() functionality.  Use the
TIF_NEED_FPU_LOAD functionality instead of making any actual hardware
registers changes in this path.

Instead of invoking fpu__initialize() just memcpy() init_fpstate into the
task's FPU state because that has already the correct format and in case of
PKRU also contains the default PKRU value. Move the actual PKRU write out
into flush_thread() where it belongs and where it will end up anyway when
PKRU and XSTATE have been untangled.

For bisectability a workaround is required which stores the PKRU value in
the xstate memory until PKRU is untangled from XSTATE for context
switching and return to user.

[ Dave Hansen: Polished changelog ]
[ tglx: Fixed the PKRU fallout ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.922729522@linutronix.de
2021-06-23 19:23:07 +02:00
..
boot x86/boot/compressed: Enable -Wundef 2021-05-12 21:39:56 +02:00
configs module: remove EXPORT_UNUSED_SYMBOL* 2021-02-08 12:28:07 +01:00
crypto Objtool updates in this cycle were: 2021-04-28 12:53:24 -07:00
entry quota: Disable quotactl_path syscall 2021-05-17 14:39:56 +02:00
events x86/fpu/xstate: Sanitize handling of independent features 2021-06-23 18:46:20 +02:00
hyperv The x86 MM changes in this cycle were: 2021-04-29 11:41:43 -07:00
ia32
include x86/fpu: Rename fpu__clear_all() to fpu_flush_thread() 2021-06-23 19:20:10 +02:00
kernel x86/fpu: Clean up the fpu__clear() variants 2021-06-23 19:23:07 +02:00
kvm x86/pkeys: Move read_pkru() and write_pkru() 2021-06-23 18:52:57 +02:00
lib - turn the stack canary into a normal __percpu variable on 32-bit which 2021-04-27 17:45:09 -07:00
math-emu x86/math-emu: Rename frstor() 2021-06-23 18:16:33 +02:00
mm x86/fpu: Use pkru_write_default() in copy_init_fpstate_to_fpregs() 2021-06-23 19:15:16 +02:00
net Networking changes for 5.13. 2021-04-29 11:57:23 -07:00
pci pci-v5.13-fixes-2 2021-06-18 13:54:11 -07:00
platform x86/setup: Always reserve the first 1M of RAM 2021-06-03 19:57:55 +02:00
power - turn the stack canary into a normal __percpu variable on 32-bit which 2021-04-27 17:45:09 -07:00
purgatory
ras
realmode x86/setup: Always reserve the first 1M of RAM 2021-06-03 19:57:55 +02:00
tools x86/tools/insn_sanity: Convert to insn_decode() 2021-03-15 12:21:11 +01:00
um um: elf.h: Fix W=1 warning for empty body in 'do' statement 2021-04-15 23:10:50 +02:00
video
xen x86/Xen: swap NX determination and GDT setup on BSP 2021-05-21 09:53:52 +02:00
.gitignore
Kbuild
Kconfig x86/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE 2021-05-05 11:27:27 -07:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug
Makefile x86, lto: Pass -stack-alignment only on LLD < 13.0.0 2021-06-11 10:33:45 -07:00
Makefile.um
Makefile_32.cpu