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kernel_samsung_a53x/arch/x86/kernel
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Juergen Gross 37c9b25886 x86/xen: Drop USERGS_SYSRET64 paravirt call 
commit afd30525a659ac0ae0904f0cb4a2ca75522c3123 upstream.

USERGS_SYSRET64 is used to return from a syscall via SYSRET, but
a Xen PV guest will nevertheless use the IRET hypercall, as there
is no sysret PV hypercall defined.

So instead of testing all the prerequisites for doing a sysret and
then mangling the stack for Xen PV again for doing an iret just use
the iret exit from the beginning.

This can easily be done via an ALTERNATIVE like it is done for the
sysenter compat case already.

It should be noted that this drops the optimization in Xen for not
restoring a few registers when returning to user mode, but it seems
as if the saved instructions in the kernel more than compensate for
this drop (a kernel build in a Xen PV guest was slightly faster with
this patch applied).

While at it remove the stale sysret32 remnants.

  [ pawan: Brad Spengler and Salvatore Bonaccorso <carnil@debian.org>
	   reported a problem with the 5.10 backport commit edc702b4a820
	   ("x86/entry_64: Add VERW just before userspace transition").

	   When CONFIG_PARAVIRT_XXL=y, CLEAR_CPU_BUFFERS is not executed in
	   syscall_return_via_sysret path as USERGS_SYSRET64 is runtime
	   patched to:

	.cpu_usergs_sysret64    = { 0x0f, 0x01, 0xf8,
				    0x48, 0x0f, 0x07 }, // swapgs; sysretq

	   which is missing CLEAR_CPU_BUFFERS. It turns out dropping
	   USERGS_SYSRET64 simplifies the code, allowing CLEAR_CPU_BUFFERS
	   to be explicitly added to syscall_return_via_sysret path. Below
	   is with CONFIG_PARAVIRT_XXL=y and this patch applied:

	   syscall_return_via_sysret:
	   ...
	   <+342>:   swapgs
	   <+345>:   xchg   %ax,%ax
	   <+347>:   verw   -0x1a2(%rip)  <------
	   <+354>:   sysretq
  ]

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Link: https://lkml.kernel.org/r/20210120135555.32594-6-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-19 12:26:38 +01:00
..
acpi x86/i8259: Skip probing when ACPI/MADT advertises PCAT compatibility 2024-11-18 10:58:32 +01:00
apic Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
cpu x86/cpufeatures: Fix dependencies for GFNI, VAES, and VPCLMULQDQ 2024-11-19 11:32:22 +01:00
fpu Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kprobes x86/kprobes: fix incorrect return address calculation in kprobe_emulate_call_indirect 2024-11-18 12:12:08 +01:00
alternative.c x86/alternative: Make custom return thunk unconditional 2024-11-18 22:25:38 +01:00
amd_gart_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
amd_nb.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
apb_timer.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
aperture_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
apm_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
asm-offsets.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
asm-offsets_32.c x86/stackprotector/32: Make the canary into a regular percpu variable 2024-11-19 09:22:37 +01:00
asm-offsets_64.c x86/xen: Drop USERGS_SYSRET64 paravirt call 2024-11-19 12:26:38 +01:00
audit_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
bootflag.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
cc_platform.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
check.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
cpuid.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
crash.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
crash_core_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
crash_core_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
crash_dump_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
crash_dump_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
devicetree.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
doublefault_32.c x86/stackprotector/32: Make the canary into a regular percpu variable 2024-11-19 09:22:37 +01:00
dumpstack.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dumpstack_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
dumpstack_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
e820.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
early-quirks.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
early_printk.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ebda.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
eisa.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
espfix_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ftrace.c x86/returnthunk: Allow different return thunks 2024-11-18 22:25:38 +01:00
ftrace_32.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ftrace_64.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
head32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
head64.c x86/head/64: Re-enable stack protection 2024-11-19 09:23:16 +01:00
head_32.S x86/stackprotector/32: Make the canary into a regular percpu variable 2024-11-19 09:22:37 +01:00
head_64.S x86/head/64: Re-enable stack protection 2024-11-19 09:23:16 +01:00
hpet.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
hw_breakpoint.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
i8237.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
i8253.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
i8259.c x86/i8259: Skip probing when ACPI/MADT advertises PCAT compatibility 2024-11-18 10:58:32 +01:00
idt.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ima_arch.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
io_delay.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ioport.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irq.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irq_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irq_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irq_work.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irqflags.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
irqinit.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
itmt.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
jailhouse.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
jump_label.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kdebugfs.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kexec-bzimage64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kgdb.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ksysfs.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kvm.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
kvmclock.c x86/kvm: Do not try to disable kvmclock if it was not enabled 2024-11-18 12:12:48 +01:00
ldt.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
machine_kexec_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
machine_kexec_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
Makefile x86/head/64: Re-enable stack protection 2024-11-19 09:23:16 +01:00
mmconf-fam10h_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
module.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
mpparse.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
msr.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
nmi.c x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key 2024-11-19 09:22:40 +01:00
nmi_selftest.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
paravirt-spinlocks.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
paravirt.c x86/xen: Drop USERGS_SYSRET64 paravirt call 2024-11-19 12:26:38 +01:00
paravirt_patch.c x86/xen: Drop USERGS_SYSRET64 paravirt call 2024-11-19 12:26:38 +01:00
pci-dma.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
pci-iommu_table.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
pci-swiotlb.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
pcspeaker.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
perf_regs.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
platform-quirks.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
pmem.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
probe_roms.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
process.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
process.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
process_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
process_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
ptrace.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
pvclock.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
quirks.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
reboot.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
reboot_fixups_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
relocate_kernel_32.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
relocate_kernel_64.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
resource.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
rtc.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
setup.c x86/mm: Fix RESERVE_BRK() for older binutils 2024-11-18 10:58:45 +01:00
setup_percpu.c x86/stackprotector/32: Make the canary into a regular percpu variable 2024-11-19 09:22:37 +01:00
sev-es-shared.c x86/sev: Check for user-space IOIO pointing to kernel space 2024-11-08 11:26:09 +01:00
sev-es.c x86/sev: Check IOBM for IOIO exceptions from user-space 2024-11-08 11:26:09 +01:00
sev_verify_cbit.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
signal.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
signal_compat.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
smp.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
smpboot.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
stacktrace.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
static_call.c x86/returnthunk: Allow different return thunks 2024-11-18 22:25:38 +01:00
step.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
sys_ia32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
sys_x86_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
sysfb.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
sysfb_efi.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
sysfb_simplefb.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tboot.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
time.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tls.c x86/stackprotector/32: Make the canary into a regular percpu variable 2024-11-19 09:22:37 +01:00
tls.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
topology.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
trace_clock.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tracepoint.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
traps.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tsc.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tsc_msr.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
tsc_sync.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
umip.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
unwind_frame.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
unwind_guess.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
unwind_orc.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
uprobes.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
verify_cpu.S Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
vm86_32.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
vmlinux.lds.S x86: Fix .brk attribute in linker script 2024-11-18 10:58:46 +01:00
vsmp_64.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
x86_init.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00