kernel.git/arch/x86/kernel/alternative.c, branch linux-6.10.y

x86/alternatives: Use the correct length when optimizing NOPs

2024-05-17T07:27:06Z

Commit in Fixes moved the optimize_nops() call inside apply_relocation() and made it a second optimization pass after the relocations have been done. Since optimize_nops() works only on NOPs, that is fine and it'll simply jump over instructions which are not NOPs. However, it made that call with repl_len as the buffer length to optimize. However, it can happen that there are alternatives calls like this one: alternative("mfence; lfence", "", ALT_NOT(X86_FEATURE_APIC_MSRS_FENCE)); where the replacement length is 0. And using repl_len is wrong because apply_alternatives() expands the buffer size to the length of the source insn that is being patched, by padding it with one-byte NOPs: for (; insn_buff_sz < a->instrlen; insn_buff_sz++) insn_buff[insn_buff_sz] = 0x90; Long story short: pass the length of the original instruction(s) as the length of the temporary buffer which to optimize. Result: SMP alternatives: feat: 11*32+27, old: (lapic_next_deadline+0x9/0x50 (ffffffff81061829) len: 6), repl: (ffffffff89b1cc60, len: 0) flags: 0x1 SMP alternatives: ffffffff81061829: old_insn: 0f ae f0 0f ae e8 SMP alternatives: ffffffff81061829: final_insn: 90 90 90 90 90 90 => SMP alternatives: feat: 11*32+27, old: (lapic_next_deadline+0x9/0x50 (ffffffff81061839) len: 6), repl: (ffffffff89b1cc60, len: 0) flags: 0x1 SMP alternatives: ffffffff81061839: [0:6) optimized NOPs: 66 0f 1f 44 00 00 SMP alternatives: ffffffff81061839: old_insn: 0f ae f0 0f ae e8 SMP alternatives: ffffffff81061839: final_insn: 66 0f 1f 44 00 00 Fixes: da8f9cf7e721 ("x86/alternatives: Get rid of __optimize_nops()") Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240515104804.32004-1-bp@kernel.org

x86/alternatives: Sort local vars in apply_alternatives()

2024-04-09T16:16:57Z

In a reverse x-mas tree. No functional changes. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240130105941.19707-5-bp@alien8.de

x86/alternatives: Optimize optimize_nops()

2024-04-09T16:15:03Z

Return early if NOPs have already been optimized. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240130105941.19707-4-bp@alien8.de

x86/alternatives: Get rid of __optimize_nops()

2024-04-09T16:12:53Z

There's no need to carve out bits of the NOP optimization functionality and look at JMP opcodes - simply do one more NOPs optimization pass at the end of patching. A lot simpler code. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240130105941.19707-3-bp@alien8.de

x86/alternatives: Use a temporary buffer when optimizing NOPs

2024-04-09T16:08:11Z

Instead of optimizing NOPs in-place, use a temporary buffer like the usual alternatives patching flow does. This obviates the need to grab locks when patching, see 6778977590da ("x86/alternatives: Disable interrupts and sync when optimizing NOPs in place") While at it, add nomenclature definitions clarifying and simplifying the naming of function-local variables in the alternatives code. Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240130105941.19707-2-bp@alien8.de

Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-03-15T00:43:30Z

Pull MM updates from Andrew Morton: - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames from hotplugged memory rather than only from main memory. Series "implement "memmap on memory" feature on s390". - More folio conversions from Matthew Wilcox in the series "Convert memcontrol charge moving to use folios" "mm: convert mm counter to take a folio" - Chengming Zhou has optimized zswap's rbtree locking, providing significant reductions in system time and modest but measurable reductions in overall runtimes. The series is "mm/zswap: optimize the scalability of zswap rb-tree". - Chengming Zhou has also provided the series "mm/zswap: optimize zswap lru list" which provides measurable runtime benefits in some swap-intensive situations. - And Chengming Zhou further optimizes zswap in the series "mm/zswap: optimize for dynamic zswap_pools". Measured improvements are modest. - zswap cleanups and simplifications from Yosry Ahmed in the series "mm: zswap: simplify zswap_swapoff()". - In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has contributed several DAX cleanups as well as adding a sysfs tunable to control the memmap_on_memory setting when the dax device is hotplugged as system memory. - Johannes Weiner has added the large series "mm: zswap: cleanups", which does that. - More DAMON work from SeongJae Park in the series "mm/damon: make DAMON debugfs interface deprecation unignorable" "selftests/damon: add more tests for core functionalities and corner cases" "Docs/mm/damon: misc readability improvements" "mm/damon: let DAMOS feeds and tame/auto-tune itself" - In the series "mm/mempolicy: weighted interleave mempolicy and sysfs extension" Rakie Kim has developed a new mempolicy interleaving policy wherein we allocate memory across nodes in a weighted fashion rather than uniformly. This is beneficial in heterogeneous memory environments appearing with CXL. - Christophe Leroy has contributed some cleanup and consolidation work against the ARM pagetable dumping code in the series "mm: ptdump: Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute". - Luis Chamberlain has added some additional xarray selftesting in the series "test_xarray: advanced API multi-index tests". - Muhammad Usama Anjum has reworked the selftest code to make its human-readable output conform to the TAP ("Test Anything Protocol") format. Amongst other things, this opens up the use of third-party tools to parse and process out selftesting results. - Ryan Roberts has added fork()-time PTE batching of THP ptes in the series "mm/memory: optimize fork() with PTE-mapped THP". Mainly targeted at arm64, this significantly speeds up fork() when the process has a large number of pte-mapped folios. - David Hildenbrand also gets in on the THP pte batching game in his series "mm/memory: optimize unmap/zap with PTE-mapped THP". It implements batching during munmap() and other pte teardown situations. The microbenchmark improvements are nice. - And in the series "Transparent Contiguous PTEs for User Mappings" Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte mappings"). Kernel build times on arm64 improved nicely. Ryan's series "Address some contpte nits" provides some followup work. - In the series "mm/hugetlb: Restore the reservation" Breno Leitao has fixed an obscure hugetlb race which was causing unnecessary page faults. He has also added a reproducer under the selftest code. - In the series "selftests/mm: Output cleanups for the compaction test", Mark Brown did what the title claims. - Kinsey Ho has added the series "mm/mglru: code cleanup and refactoring". - Even more zswap material from Nhat Pham. The series "fix and extend zswap kselftests" does as claimed. - In the series "Introduce cpu_dcache_is_aliasing() to fix DAX regression" Mathieu Desnoyers has cleaned up and fixed rather a mess in our handling of DAX on archiecctures which have virtually aliasing data caches. The arm architecture is the main beneficiary. - Lokesh Gidra's series "per-vma locks in userfaultfd" provides dramatic improvements in worst-case mmap_lock hold times during certain userfaultfd operations. - Some page_owner enhancements and maintenance work from Oscar Salvador in his series "page_owner: print stacks and their outstanding allocations" "page_owner: Fixup and cleanup" - Uladzislau Rezki has contributed some vmalloc scalability improvements in his series "Mitigate a vmap lock contention". It realizes a 12x improvement for a certain microbenchmark. - Some kexec/crash cleanup work from Baoquan He in the series "Split crash out from kexec and clean up related config items". - Some zsmalloc maintenance work from Chengming Zhou in the series "mm/zsmalloc: fix and optimize objects/page migration" "mm/zsmalloc: some cleanup for get/set_zspage_mapping()" - Zi Yan has taught the MM to perform compaction on folios larger than order=0. This a step along the path to implementaton of the merging of large anonymous folios. The series is named "Enable >0 order folio memory compaction". - Christoph Hellwig has done quite a lot of cleanup work in the pagecache writeback code in his series "convert write_cache_pages() to an iterator". - Some modest hugetlb cleanups and speedups in Vishal Moola's series "Handle hugetlb faults under the VMA lock". - Zi Yan has changed the page splitting code so we can split huge pages into sizes other than order-0 to better utilize large folios. The series is named "Split a folio to any lower order folios". - David Hildenbrand has contributed the series "mm: remove total_mapcount()", a cleanup. - Matthew Wilcox has sought to improve the performance of bulk memory freeing in his series "Rearrange batched folio freeing". - Gang Li's series "hugetlb: parallelize hugetlb page init on boot" provides large improvements in bootup times on large machines which are configured to use large numbers of hugetlb pages. - Matthew Wilcox's series "PageFlags cleanups" does that. - Qi Zheng's series "minor fixes and supplement for ptdesc" does that also. S390 is affected. - Cleanups to our pagemap utility functions from Peter Xu in his series "mm/treewide: Replace pXd_large() with pXd_leaf()". - Nico Pache has fixed a few things with our hugepage selftests in his series "selftests/mm: Improve Hugepage Test Handling in MM Selftests". - Also, of course, many singleton patches to many things. Please see the individual changelogs for details. * tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits) mm/zswap: remove the memcpy if acomp is not sleepable crypto: introduce: acomp_is_async to expose if comp drivers might sleep memtest: use {READ,WRITE}_ONCE in memory scanning mm: prohibit the last subpage from reusing the entire large folio mm: recover pud_leaf() definitions in nopmd case selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements selftests/mm: skip uffd hugetlb tests with insufficient hugepages selftests/mm: dont fail testsuite due to a lack of hugepages mm/huge_memory: skip invalid debugfs new_order input for folio split mm/huge_memory: check new folio order when split a folio mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure mm: add an explicit smp_wmb() to UFFDIO_CONTINUE mm: fix list corruption in put_pages_list mm: remove folio from deferred split list before uncharging it filemap: avoid unnecessary major faults in filemap_fault() mm,page_owner: drop unnecessary check mm,page_owner: check for null stack_record before bumping its refcount mm: swap: fix race between free_swap_and_cache() and swapoff() mm/treewide: align up pXd_leaf() retval across archs mm/treewide: drop pXd_large() ...

x86/mm: delete unused cpu argument to leave_mm()

2024-02-22T18:24:41Z

The argument is unused since commit 3d28ebceaffa ("x86/mm: Rework lazy TLB to track the actual loaded mm"), delete it. Link: https://lkml.kernel.org/r/20240126080644.1714297-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed Cc: Andy Lutomirski Cc: Borislav Petkov (AMD) Cc: Dave Hansen Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton

Merge branch 'x86/bugs' into x86/core, to pick up pending changes before dependent patches

2024-02-14T09:49:37Z

Merge in pending alternatives patching infrastructure changes, before applying more patches. Signed-off-by: Ingo Molnar

Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch

2024-02-14T09:45:07Z

Conflicts: arch/x86/include/asm/percpu.h arch/x86/include/asm/text-patching.h Signed-off-by: Ingo Molnar

x86/paravirt: Make BUG_func() usable by non-GPL modules

2024-01-22T14:51:07Z

Several inlined functions subject to paravirt patching are referencing BUG_func() after the recent switch to the alternative patching mechanism. As those functions can legally be used by non-GPL modules, BUG_func() must be usable by those modules, too. So use EXPORT_SYMBOL() when exporting BUG_func(). Fixes: 9824b00c2b58 ("x86/paravirt: Move some functions and defines to alternative.c") Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240109082232.22657-1-jgross@suse.com