This implements the runtime constant infrastructure for x86, allowing
the dcache d_hash() function to be generated using as a constant for
hash table address followed by shift by a constant of the hash index.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 build updates from Ingo Molnar:

 - Use -fpic to build the kexec 'purgatory' (the self-contained
   code that runs between two kernels)

 - Clean up vmlinux.lds.S generation

 - Simplify the X86_EXTENDED_PLATFORM section of the x86 Kconfig

 - Misc cleanups & fixes

* tag 'x86-build-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/Kconfig: Merge the two CONFIG_X86_EXTENDED_PLATFORM entries
  x86/purgatory: Switch to the position-independent small code model
  x86/boot: Replace __PHYSICAL_START with LOAD_PHYSICAL_ADDR
  x86/vmlinux.lds.S: Take __START_KERNEL out conditional definition
  x86/vmlinux.lds.S: Remove conditional definition of LOAD_OFFSET
  vmlinux.lds.h: Fix a typo in comment

The stack of a task has been separated from the memory of a task_struct
struture for a long time on x86, as a result __{start,end}_init_task no
longer mark the start and end of the init_task structure, but its stack
only.

Rename __{start,end}_init_task to __{start,end}_init_stack.

Note other architectures are not affected because __{start,end}_init_task
are used on x86 only.

Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240322081616.3346181-1-xin@zytor.com

Define the symbol __top_init_kernel_stack instead of duplicating
the offset from __end_init_task in multiple places.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20240321180506.89030-1-brgerst@gmail.com

If CONFIG_X86_32=y, the section start address is defined to be
"LOAD_OFFSET + LOAD_PHYSICAL_ADDR", which is the same as
__START_KERNEL_map.

Unify it with the 64-bit definition to simplify the code.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240313075839.8321-5-richard.weiyang@gmail.com

In vmlinux.lds.S, we define LOAD_OFFSET conditionally to __PAGE_OFFSET
or __START_KERNEL_map. While __START_KERNEL_map is already defined to
the same value with the same condition.

So it is fine to define LOAD_OFFSET to __START_KERNEL_map directly.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240313075839.8321-4-richard.weiyang@gmail.com

Merge in pending alternatives patching infrastructure changes, before
applying more patches.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Conflicts:
	arch/x86/include/asm/percpu.h
	arch/x86/include/asm/text-patching.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Step 9/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-10-leitao@debian.org

Step 7/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-8-leitao@debian.org