From: Lai Jiangshan <jiangshan.ljs@antgroup.com>

Add some C equivalent functions of the ASM macros and implement the whole
error_entry() as C code.

The patches are picked from the huge patchset
https://lore.kernel.org/lkml/20211126101209.8613-1-jiangshanlai@gmail.com/
which converts a large chunk of ASM code to C code.

The C version generally has better readability and easier to be
updated/improved.

This smaller patchset converts error_entry() only.
The equivalent ASM macros are not removed because they are still used by
the IST exceptions.

Changed from the old huge patchset:
	squash some patches

Lai Jiangshan (7):
  x86/entry: Introduce __entry_text for entry code written in C
  x86/entry: Move PTI_USER_* to arch/x86/include/asm/processor-flags.h
  x86: Mark __native_read_cr3() & native_write_cr3() as __always_inline
  x86/entry: Add arch/x86/entry/entry64.c for C entry code
  x86/entry: Add the C verion of SWITCH_TO_KERNEL_CR3 as
    switch_to_kernel_cr3()
  x86/traps: Add fence_swapgs_{user,kernel}_entry() and
    user_entry_swapgs_and_fence()
  x86/entry: Implement the whole error_entry() as C code

 arch/x86/entry/Makefile                |   3 +-
 arch/x86/entry/calling.h               |  10 --
 arch/x86/entry/entry64.c               | 137 +++++++++++++++++++++++++
 arch/x86/entry/entry_64.S              |  85 +--------------
 arch/x86/include/asm/idtentry.h        |   3 +
 arch/x86/include/asm/pgtable.h         |  23 +----
 arch/x86/include/asm/processor-flags.h |  15 +++
 arch/x86/include/asm/proto.h           |   1 +
 arch/x86/include/asm/special_insns.h   |   4 +-
 arch/x86/include/asm/traps.h           |   1 +
 arch/x86/kernel/traps.c                |   2 -
 include/linux/compiler_types.h         |   8 +-
 12 files changed, 172 insertions(+), 120 deletions(-)
 create mode 100644 arch/x86/entry/entry64.c

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2.19.1.6.gb485710b