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Message-ID: <20250328132704.1901674-1-mingo@kernel.org>
Date: Fri, 28 Mar 2025 14:26:15 +0100
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Juergen Gross <jgross@...e.com>,
"H . Peter Anvin" <hpa@...or.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>
Subject: [PATCH -v2 00/49] Simplify, reorganize and clean up the x86 text-patching code (alternative.c)
This series has 3 main parts:
(1)
The first part of this series performs a thorough text-patching API namespace
cleanup discussed with Linus for the -v1 series:
# boot/UP APIs & single-thread helpers:
text_poke()
text_poke_kgdb()
[ unchanged APIs: ] text_poke_copy()
text_poke_copy_locked()
text_poke_set()
text_poke_addr()
# SMP API & helpers namespace:
text_poke_bp() => smp_text_poke_single()
text_poke_loc_init() => __smp_text_poke_batch_add()
text_poke_queue() => smp_text_poke_batch_add()
text_poke_finish() => smp_text_poke_batch_finish()
text_poke_flush() => [removed]
text_poke_bp_batch() => smp_text_poke_batch_process()
poke_int3_handler() => smp_text_poke_int3_trap_handler()
text_poke_sync() => smp_text_poke_sync_each_cpu()
(2)
The second part of the series simplifies and standardizes the SMP batch-patching
data & types & accessors namespace, around the new text_poke_array* namespace:
int3_patching_desc = [removed]
temp_mm_state_t => [removed]
try_get_desc() => try_get_text_poke_array()
put_desc() => put_text_poke_array()
tp_vec,tp_vec_nr => text_poke_array
int3_refs => text_poke_array_refs
- All constants got moved into the TEXT_POKE_* namespace
- All local variables and function parameters got standardized around
the 'tpl' naming scheme. No more toilet paper references. ;-)
(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:
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: Add text_mutex) assert to smp_text_poke_batch_flush()
x86/alternatives: Use non-inverted logic instead of 'tp_order_fail()'
x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from smp_text_poke_batch_finish()/smp_text_poke_batch_flush()/text_poke_addr_ordered()
x86/alternatives: Simplify smp_text_poke_single() by using tp_vec and existing APIs
x86/alternatives: Introduce 'struct smp_text_poke_array' and move tp_vec and tp_vec_nr to it
x86/alternatives: Remove the tp_vec indirection
x86/alternatives: Simplify try_get_text_poke_array()
x86/alternatives: Simplify smp_text_poke_int3_trap_handler()
x86/alternatives: Simplify smp_text_poke_batch_process()
x86/alternatives: Move the text_poke_array manipulation into text_poke_int3_loc_init() and rename it to __smp_text_poke_batch_add()
x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()
x86/alternatives: Document 'smp_text_poke_single()'
x86/alternatives: Add documentation for smp_text_poke_batch_add()
x86/alternatives: Move text_poke_array completion from smp_text_poke_batch_finish() and smp_text_poke_batch_flush() to smp_text_poke_batch_process()
x86/alternatives: Simplify text_poke_addr_ordered()
x86/alternatives: Constify text_poke_addr()
x86/alternatives: Simplify and clean up patch_cmp()
x86/alternatives: Standardize on 'tpl' local variable names for 'struct smp_text_poke_loc *'
x86/alternatives: Simplify the #include section
x86/alternatives: Move declarations of vmlinux.lds.S defined section symbols to <asm/alternative.h>
x86/alternatives: Remove 'smp_text_poke_batch_flush()'
x86/alternatives: Update the comments in smp_text_poke_batch_process()
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 smp_text_poke_single() & smp_text_poke_batch_add() 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 (49):
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 'smp_text_poke_batch_process()'
x86/alternatives: Rename 'text_poke_bp()' to 'smp_text_poke_single()'
x86/alternatives: Rename 'poke_int3_handler()' to 'smp_text_poke_int3_trap_handler()'
x86/alternatives: Rename 'poking_mm' to 'text_poke_mm'
x86/alternatives: Rename 'poking_addr' to 'text_poke_mm_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 'smp_text_poke_batch_flush()'
x86/alternatives: Rename 'text_poke_finish()' to 'smp_text_poke_batch_finish()'
x86/alternatives: Rename 'text_poke_queue()' to 'smp_text_poke_batch_add()'
x86/alternatives: Rename 'text_poke_loc_init()' to 'text_poke_int3_loc_init()'
x86/alternatives: Rename 'struct text_poke_loc' to 'struct smp_text_poke_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 smp_text_poke_batch_flush()
x86/alternatives: Assert that smp_text_poke_int3_trap_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 smp_text_poke_batch_finish()/smp_text_poke_batch_flush()/text_poke_addr_ordered()
x86/alternatives: Simplify smp_text_poke_single() by using tp_vec and existing APIs
x86/alternatives: Assert input parameters in smp_text_poke_batch_process()
x86/alternatives: Introduce 'struct smp_text_poke_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_text_poke_array()'
x86/alternatives: Rename 'put_desc()' to 'put_text_poke_array()'
x86/alternatives: Simplify try_get_text_poke_array()
x86/alternatives: Simplify smp_text_poke_int3_trap_handler()
x86/alternatives: Simplify smp_text_poke_batch_process()
x86/alternatives: Rename 'int3_refs' to 'text_poke_array_refs'
x86/alternatives: Move the text_poke_array manipulation into text_poke_int3_loc_init() and rename it to __smp_text_poke_batch_add()
x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()
x86/alternatives: Document 'smp_text_poke_single()'
x86/alternatives: Add documentation for smp_text_poke_batch_add()
x86/alternatives: Move text_poke_array completion from smp_text_poke_batch_finish() and smp_text_poke_batch_flush() to smp_text_poke_batch_process()
x86/alternatives: Rename 'text_poke_sync()' to 'smp_text_poke_sync_each_cpu()'
x86/alternatives: Simplify text_poke_addr_ordered()
x86/alternatives: Constify text_poke_addr()
x86/alternatives: Simplify and clean up patch_cmp()
x86/alternatives: Standardize on 'tpl' local variable names for 'struct smp_text_poke_loc *'
x86/alternatives: Rename 'TP_ARRAY_NR_ENTRIES_MAX' to 'TEXT_POKE_ARRAY_MAX'
x86/alternatives: Rename 'POKE_MAX_OPCODE_SIZE' to 'TEXT_POKE_MAX_OPCODE_SIZE'
x86/alternatives: Simplify the #include section
x86/alternatives: Move declarations of vmlinux.lds.S defined section symbols to <asm/alternative.h>
x86/alternatives: Remove 'smp_text_poke_batch_flush()'
x86/alternatives: Update the comments in smp_text_poke_batch_process()
x86/alternatives: Rename 'apply_relocation()' to 'text_poke_apply_relocation()'
arch/x86/include/asm/alternative.h | 6 +
arch/x86/include/asm/text-patching.h | 29 ++---
arch/x86/kernel/alternative.c | 364 +++++++++++++++++++++++++------------------------------
arch/x86/kernel/callthunks.c | 6 +-
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 +-
13 files changed, 219 insertions(+), 248 deletions(-)
--
2.45.2
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