linux/tools/objtool, branch v6.4

Merge tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-04-28T21:02:54Z

Pull objtool updates from Ingo Molnar: - Mark arch_cpu_idle_dead() __noreturn, make all architectures & drivers that did this inconsistently follow this new, common convention, and fix all the fallout that objtool can now detect statically - Fix/improve the ORC unwinder becoming unreliable due to UNWIND_HINT_EMPTY ambiguity, split it into UNWIND_HINT_END_OF_STACK and UNWIND_HINT_UNDEFINED to resolve it - Fix noinstr violations in the KCSAN code and the lkdtm/stackleak code - Generate ORC data for __pfx code - Add more __noreturn annotations to various kernel startup/shutdown and panic functions - Misc improvements & fixes * tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) x86/hyperv: Mark hv_ghcb_terminate() as noreturn scsi: message: fusion: Mark mpt_halt_firmware() __noreturn x86/cpu: Mark {hlt,resume}_play_dead() __noreturn btrfs: Mark btrfs_assertfail() __noreturn objtool: Include weak functions in global_noreturns check cpu: Mark nmi_panic_self_stop() __noreturn cpu: Mark panic_smp_self_stop() __noreturn arm64/cpu: Mark cpu_park_loop() and friends __noreturn x86/head: Mark *_start_kernel() __noreturn init: Mark start_kernel() __noreturn init: Mark [arch_call_]rest_init() __noreturn objtool: Generate ORC data for __pfx code x86/linkage: Fix padding for typed functions objtool: Separate prefix code from stack validation code objtool: Remove superfluous dead_end_function() check objtool: Add symbol iteration helpers objtool: Add WARN_INSN() scripts/objdump-func: Support multiple functions context_tracking: Fix KCSAN noinstr violation objtool: Add stackleak instrumentation to uaccess safe list ...

Merge tag 'for-6.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2023-04-26T16:13:44Z

Pull btrfs updates from David Sterba: "Mostly core changes and cleanups, some notable fixes and two performance improvements in directory logging. The IO path cleanups are removing or refactoring old code, scrub main loop has been completely rewritten also refactoring old code. There are some changes to non-btrfs code, mostly trivial, the cgroup punt bio logic is only moved from generic code. Performance improvements: - improve logging changes in a directory during one transaction, avoid iterating over items and reduce lock contention (fsync time 4x lower) - when logging directory entries during one transaction, reduce locking of subvolume trees by checking tree-log instead (improvement in throughput and latency for concurrent access to a subvolume) Notable fixes: - dev-replace: - properly honor read mode when requested to avoid reading from source device - target device won't be used for eventual read repair, this is unreliable for NODATASUM files - when there are unpaired (and unrepairable) metadata during replace, exit early with error and don't try to finish whole operation - scrub ioctl properly rejects unknown flags - fix global block reserve calculations - fix partial direct io write when there's a page fault in the middle, iomap will try to continue with partial request but the btrfs part did not match that, this can lead to zeros written instead of data Core changes: - io path: - continued cleanups and refactoring around bio handling - extent io submit path simplifications and cleanups - flush write path simplifications and cleanups - rework logic of passing sync mode of bio, with further cleanups - rewrite scrub code flow, restructure how the stripes are enumerated and verified in a more unified way - allow to set lower threshold for block group reclaim in debug mode to aid zoned mode testing - remove obsolete time-based delayed ref throttling logic when truncating items - DREW locks are not using percpu variables anymore - more warning fixes (-Wmaybe-uninitialized) - u64 division simplifications - error handling improvements Non-btrfs code changes: - push cgroup punt bio logic to btrfs code (there was no other user of that), the functionality can be now selected separately by BLK_CGROUP_PUNT_BIO - crc32c_impl removed after removing last uses in btrfs code - add btrfs_assertfail() to objtool table" * tag 'for-6.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (147 commits) btrfs: mark btrfs_assertfail() __noreturn btrfs: fix uninitialized variable warnings btrfs: use log root when iterating over index keys when logging directory btrfs: avoid iterating over all indexes when logging directory btrfs: dev-replace: error out if we have unrepaired metadata error during btrfs: remove pointless loop at btrfs_get_next_valid_item() btrfs: scrub: reject unsupported scrub flags btrfs: reinterpret async discard iops_limit=0 as no delay btrfs: set default discard iops_limit to 1000 btrfs: remove unused raid56 functions which were dedicated for scrub btrfs: scrub: remove scrub_bio structure btrfs: scrub: remove scrub_block and scrub_sector structures btrfs: scrub: remove the old scrub recheck code btrfs: scrub: remove the old writeback infrastructure btrfs: scrub: remove scrub_parity structure btrfs: scrub: use scrub_stripe to implement RAID56 P/Q scrub btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure btrfs: scrub: introduce helper to queue a stripe for scrub btrfs: scrub: introduce error reporting functionality for scrub_stripe btrfs: scrub: introduce a writeback helper for scrub_stripe ...

Merge tag 'docs-6.4' of git://git.lwn.net/linux

2023-04-24T19:35:49Z

Pull documentation updates from Jonathan Corbet: "Commit volume in documentation is relatively low this time, but there is still a fair amount going on, including: - Reorganize the architecture-specific documentation under Documentation/arch This makes the structure match the source directory and helps to clean up the mess that is the top-level Documentation directory a bit. This work creates the new directory and moves x86 and most of the less-active architectures there. The current plan is to move the rest of the architectures in 6.5, with the patches going through the appropriate subsystem trees. - Some more Spanish translations and maintenance of the Italian translation - A new "Kernel contribution maturity model" document from Ted - A new tutorial on quickly building a trimmed kernel from Thorsten Plus the usual set of updates and fixes" * tag 'docs-6.4' of git://git.lwn.net/linux: (47 commits) media: Adjust column width for pdfdocs media: Fix building pdfdocs docs: clk: add documentation to log which clocks have been disabled docs: trace: Fix typo in ftrace.rst Documentation/process: always CC responsible lists docs: kmemleak: adjust to config renaming ELF: document some de-facto PT_* ABI quirks Documentation: arm: remove stih415/stih416 related entries docs: turn off "smart quotes" in the HTML build Documentation: firmware: Clarify firmware path usage docs/mm: Physical Memory: Fix grammar Documentation: Add document for false sharing dma-api-howto: typo fix docs: move m68k architecture documentation under Documentation/arch/ docs: move parisc documentation under Documentation/arch/ docs: move ia64 architecture docs under Documentation/arch/ docs: Move arc architecture docs under Documentation/arch/ docs: move nios2 documentation under Documentation/arch/ docs: move openrisc documentation under Documentation/arch/ docs: move superh documentation under Documentation/arch/ ...

x86: improve on the non-rep 'copy_user' function

2023-04-19T00:05:28Z

The old 'copy_user_generic_unrolled' function was oddly implemented for largely historical reasons: it had been largely based on the uncached copy case, which has some other concerns. For example, the __copy_user_nocache() function uses 'movnti' for the destination stores, and those want the destination to be aligned. In contrast, the regular copy function doesn't really care, and trying to align things only complicates matters. Also, like the clear_user function, the copy function had some odd handling of the repeat counts, complicating the exception handling for no really good reason. So as with clear_user, just write it to keep all the byte counts in the %rcx register, exactly like the 'rep movs' functionality that this replaces. Unlike a real 'rep movs', we do allow for this to trash a few temporary registers to not have to unnecessarily save/restore registers on the stack. And like the clearing case, rename this to what it now clearly is: 'rep_movs_alternative', and make it one coherent function, so that it shows up as such in profiles (instead of the odd split between "copy_user_generic_unrolled" and "copy_user_short_string", the latter of which was not about strings at all, and which was shared with the uncached case). Signed-off-by: Linus Torvalds

x86: improve on the non-rep 'clear_user' function

2023-04-19T00:05:28Z

The old version was oddly written to have the repeat count in multiple registers. So instead of taking advantage of %rax being zero, it had some sub-counts in it. All just for a "single word clearing" loop, which isn't even efficient to begin with. So get rid of those games, and just keep all the state in the same registers we got it in (and that we should return things in). That not only makes this act much more like 'rep stos' (which this function is replacing), but makes it much easier to actually do the obvious loop unrolling. Also rename the function from the now nonsensical 'clear_user_original' to what it now clearly is: 'rep_stos_alternative'. End result: if we don't have a fast 'rep stosb', at least we can have a fast fallback for it. Signed-off-by: Linus Torvalds

x86: inline the 'rep movs' in user copies for the FSRM case

2023-04-19T00:05:28Z

This does the same thing for the user copies as commit 0db7058e8e23 ("x86/clear_user: Make it faster") did for clear_user(). In other words, it inlines the "rep movs" case when X86_FEATURE_FSRM is set, avoiding the function call entirely. In order to do that, it makes the calling convention for the out-of-line case ("copy_user_generic_unrolled") match the 'rep movs' calling convention, although it does also end up clobbering a number of additional registers. Also, to simplify code sharing in the low-level assembly with the __copy_user_nocache() function (that uses the normal C calling convention), we end up with a kind of mixed return value for the low-level asm code: it will return the result in both %rcx (to work as an alternative for the 'rep movs' case), _and_ in %rax (for the nocache case). We could avoid this by wrapping __copy_user_nocache() callers in an inline asm, but since the cost is just an extra register copy, it's probably not worth it. Signed-off-by: Linus Torvalds

x86: move stac/clac from user copy routines into callers

2023-04-19T00:05:28Z

This is preparatory work for inlining the 'rep movs' case, but also a cleanup. The __copy_user_nocache() function was mis-used by the rdma code to do uncached kernel copies that don't actually want user copies at all, and as a result doesn't want the stac/clac either. Signed-off-by: Linus Torvalds

x86: don't use REP_GOOD or ERMS for user memory clearing

2023-04-19T00:05:28Z

The modern target to use is FSRS (Fast Short REP STOS), and the other cases should only be used for bigger areas (ie mainly things like page clearing). Note! This changes the conditional for the inlining from FSRM ("fast short rep movs") to FSRS ("fast short rep stos"). We'll have a separate fixup for AMD microarchitectures that have a good 'rep stosb' yet do not set the new Intel-specific FSRS bit (because FSRM was there first). Signed-off-by: Linus Torvalds

btrfs: mark btrfs_assertfail() __noreturn

2023-04-17T17:52:19Z

Fixes a bunch of warnings including: vmlinux.o: warning: objtool: select_reloc_root+0x314: unreachable instruction vmlinux.o: warning: objtool: finish_inode_if_needed+0x15b1: unreachable instruction vmlinux.o: warning: objtool: get_bio_sector_nr+0x259: unreachable instruction vmlinux.o: warning: objtool: raid_wait_read_end_io+0xc26: unreachable instruction vmlinux.o: warning: objtool: raid56_parity_alloc_scrub_rbio+0x37b: unreachable instruction ... Reported-by: kernel test robot Link: https://lore.kernel.org/oe-kbuild-all/202302210709.IlXfgMpX-lkp@intel.com/ Signed-off-by: Josh Poimboeuf Reviewed-by: David Sterba Signed-off-by: David Sterba

x86/hyperv: Mark hv_ghcb_terminate() as noreturn

2023-04-14T15:31:28Z

Annotate the function prototype and definition as noreturn to prevent objtool warnings like: vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction Also, as per Josh's suggestion, add it to the global_noreturns list. As a comparison, an objdump output without the annotation: [...] 1b63: mov $0x1,%esi 1b68: xor %edi,%edi 1b6a: callq ffffffff8102f680 1b6f: jmpq ffffffff82f217ec # unreachable 1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip) [...] Now, after adding the __noreturn to the function prototype: [...] 17df: callq ffffffff8102f6d0 17e4: test %al,%al 17e6: je ffffffff82f21bb9 [...] 1bb9: mov $0x1,%esi 1bbe: xor %edi,%edi 1bc0: callq ffffffff8102f680 1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function Reported-by: Arnd Bergmann Signed-off-by: Guilherme G. Piccoli Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/32453a703dfcf0d007b473c9acbf70718222b74b.1681342859.git.jpoimboe@kernel.org