[PATCH 00/41] Simplify, reorganize and clean up the x86 INT3 based batch-patching code (alternative.c)

[Ingo Molnar]

This series has 3 main parts:

(1)

The first part of this series performs a thorough text-patching API namespace
cleanup discussed with Peter Zijlstra:

	https://lore.kernel.org/r/20250325123119.GL36322@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Non-SMP APIs retain their existing text_poke*() namespace:

	text_poke()
	text_poke_sync_each_cpu()
	text_poke_kgdb()
	text_poke_copy()
	text_poke_copy
	text_poke_copy_locked()
	text_poke_set()

The SMP text-patching APIs had 3 separate prefixes:

	text_poke_
	text_poke_bp_
	poke_int3_

These get standardized to the single text_poke_int3*() namespace:

	text_poke_addr()	=> text_poke_int3_addr()
	poke_int3_handler()	=> text_poke_int3_handler()
	text_poke_bp_batch()	=> text_poke_int3_batch_process()
	text_poke_loc_init()	=> text_poke_int3_loc_add()
	text_poke_flush()	=> text_poke_int3_finish()
	text_poke_finish()	=> text_poke_int3_flush()
	text_poke_queue()	=> text_poke_int3_queue()
	text_poke_bp()		=> text_poke_int3_now()

(2)

The second part of the series simplifies and standardizes the SMP batch-patching
data & types namespace, around the new tp_array* namespace:

	int3_patching_desc	=> [removed]
	temp_mm_state_t		=> [removed]
	try_get_desc()		=> [removed]
	put_desc()		=> [removed]

	tp_vec,tp_vec_nr	=> tp_array
	int3_refs		=> tp_array_refs

(3)

The third part of the series contains additional patches, that
together with the data-namespace simplification changes remove
about 3 layers of unnecessary indirections and simplify/streamline
various aspects of the code:

	[PATCH] x86/alternatives: Remove the confusing, inaccurate & unnecessary 'temp_mm_state_t' abstraction
	[PATCH] x86/alternatives: Use non-inverted logic instead of 'tp_order_fail()'
	[PATCH] x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from text_poke_int3_finish()/text_poke_int3_flush()/tp_addr_ordered()
	[PATCH] x86/alternatives: Simplify text_poke_int3() by using tp_vec and existing APIs
	[PATCH] x86/alternatives: Introduce 'struct text_poke_int3_array' and move tp_vec and tp_vec_nr to it
	[PATCH] x86/alternatives: Remove the tp_vec indirection
	[PATCH] x86/alternatives: Simplify try_get_tp_array()
	[PATCH] x86/alternatives: Simplify text_poke_int3_handler()
	[PATCH] x86/alternatives: Simplify text_poke_int3_batch()
	[PATCH] x86/alternatives: Move the tp_array manipulation into text_poke_int3_loc_init() and rename it to text_poke_int3_loc_add()
	[PATCH] x86/alternatives: Move tp_array completion from text_poke_int3_finish() and text_poke_int3_flush() to text_poke_int3_batch_process()
	[PATCH] x86/alternatives: Simplify tp_addr_ordered()

Various APIs also had their names clarified, as part of the renames.
I also added comments where justified.

There's almost no functional changes in the end, other than
mixed text_poke_int3_now() & text_poke_int3_queue() calls
are now probably working better than before - although I'm not
aware of such in-tree usage at the moment.

After these changes there's a reduction of about ~20 lines of
code if we exclude comments, and some reduction in text size:

   text       data        bss        dec        hex    filename
  13637       1009       4112      18758       4946    arch/x86/kernel/alternative.o.before
  13549       1009       4156      18714       491a    arch/x86/kernel/alternative.o.after

But the main goal was to perform a thorough round of source code TLC,
to make the code easier to read & maintain, and to remove a chunk
of technical debt accumulated incrementally over 20 years, which
improvements are only partly reflected in line count and code size decreases.

Lightly tested only.

This tree can also be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip WIP.x86/alternatives

Thanks,

    Ingo

================>

Ingo Molnar (41):
  x86/alternatives: Rename 'struct bp_patching_desc' to 'struct int3_patching_desc'
  x86/alternatives: Rename 'bp_refs' to 'int3_refs'
  x86/alternatives: Rename 'text_poke_bp_batch()' to 'text_poke_int3_batch()'
  x86/alternatives: Rename 'text_poke_bp()' to 'text_poke_int3()'
  x86/alternatives: Rename 'poke_int3_handler()' to 'text_poke_int3_handler()'
  x86/alternatives: Rename 'poking_mm' to 'text_poke_mm'
  x86/alternatives: Rename 'text_poke_addr' to 'text_poke_int3_addr'
  x86/alternatives: Rename 'poking_addr' to 'text_poke_addr'
  x86/alternatives: Rename 'bp_desc' to 'int3_desc'
  x86/alternatives: Remove duplicate 'text_poke_early()' prototype
  x86/alternatives: Update comments in int3_emulate_push()
  x86/alternatives: Remove the confusing, inaccurate & unnecessary 'temp_mm_state_t' abstraction
  x86/alternatives: Rename 'text_poke_flush()' to 'text_poke_int3_flush()'
  x86/alternatives: Rename 'text_poke_finish()' to 'text_poke_int3_finish()'
  x86/alternatives: Rename 'text_poke_queue()' to 'text_poke_int3_queue()'
  x86/alternatives: Rename 'text_poke_loc_init()' to 'text_poke_int3_loc_init()'
  x86/alternatives: Rename 'struct text_poke_loc' to 'struct text_poke_int3_loc'
  x86/alternatives: Rename 'struct int3_patching_desc' to 'struct text_poke_int3_vec'
  x86/alternatives: Rename 'int3_desc' to 'int3_vec'
  x86/alternatives: Add text_mutex) assert to text_poke_int3_flush()
  x86/alternatives: Assert that text_poke_int3_handler() can only ever handle 'tp_vec[]' based requests
  x86/alternatives: Use non-inverted logic instead of 'tp_order_fail()'
  x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from text_poke_int3_finish()/text_poke_int3_flush()/tp_addr_ordered()
  x86/alternatives: Simplify text_poke_int3() by using tp_vec and existing APIs
  x86/alternatives: Assert input parameters in text_poke_int3_batch()
  x86/alternatives: Introduce 'struct text_poke_int3_array' and move tp_vec and tp_vec_nr to it
  x86/alternatives: Remove the tp_vec indirection
  x86/alternatives: Rename 'try_get_desc()' to 'try_get_tp_array()'
  x86/alternatives: Rename 'put_desc()' to 'put_tp_array()'
  x86/alternatives: Simplify try_get_tp_array()
  x86/alternatives: Simplify text_poke_int3_handler()
  x86/alternatives: Simplify text_poke_int3_batch()
  x86/alternatives: Rename 'text_poke_int3_batch()' to 'text_poke_int3_batch_process()'
  x86/alternatives: Rename 'int3_refs' to 'tp_array_refs'
  x86/alternatives: Move the tp_array manipulation into text_poke_int3_loc_init() and rename it to text_poke_int3_loc_add()
  x86/alternatives: Remove the mixed-patching restriction on text_poke_int3()
  x86/alternatives: Rename 'text_poke_int3()' to 'text_poke_int3_now()'
  x86/alternatives: Add documentation for text_poke_int3_queue()
  x86/alternatives: Move tp_array completion from text_poke_int3_finish() and text_poke_int3_flush() to text_poke_int3_batch_process()
  x86/alternatives: Rename 'text_poke_sync()' to 'text_poke_sync_each_cpu()'
  x86/alternatives: Simplify tp_addr_ordered()

 arch/x86/include/asm/text-patching.h |  23 ++---
 arch/x86/kernel/alternative.c        | 255 ++++++++++++++++++++++++++++---------------------------
 arch/x86/kernel/ftrace.c             |  18 ++--
 arch/x86/kernel/jump_label.c         |   6 +-
 arch/x86/kernel/kprobes/core.c       |   4 +-
 arch/x86/kernel/kprobes/opt.c        |   6 +-
 arch/x86/kernel/module.c             |   2 +-
 arch/x86/kernel/static_call.c        |   2 +-
 arch/x86/kernel/traps.c              |   6 +-
 arch/x86/mm/init.c                   |  16 ++--
 arch/x86/net/bpf_jit_comp.c          |   2 +-
 11 files changed, 172 insertions(+), 168 deletions(-)

-- 
2.45.2