When creating an annotation section, allocate the reloc section data at
the beginning. This simplifies the data model a bit and also saves
memory due to the removal of malloc() in elf_rebuild_reloc_section().
With allyesconfig + CONFIG_DEBUG_INFO:
- Before: peak heap memory consumption: 53.49G
- After: peak heap memory consumption: 49.02G
Link: https://lore.kernel.org/r/048e908f3ede9b66c15e44672b6dda992b1dae3e.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
The GElf_Rel[a] structs have more similarities than differences. It's
safe to hard-code the assumptions about their shared fields as they will
never change. Consolidate their handling where possible, getting rid of
duplicated code.
Also, at least for now we only ever create rela sections, so simplify
the relocation creation code to be rela-only.
Link: https://lore.kernel.org/r/dcabf6df400ca500ea929f1e4284f5e5ec0b27c8.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
- The term "reloc" is overloaded to mean both "an instance of struct
reloc" and "a reloc section". Change the latter to "rsec".
- For variable names, use "sec" for regular sections and "rsec" for rela
sections to prevent them getting mixed up.
- For struct reloc variables, use "reloc" instead of "rel" everywhere
for consistency.
Link: https://lore.kernel.org/r/8b790e403df46f445c21003e7893b8f53b99a6f3.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
There are several places where warnings variables are not needed,
remove them and directly return 0.
Signed-off-by: Lu Hongfei <luhongfei@vivo.com>
Link: https://lore.kernel.org/r/20230530075649.21661-1-luhongfei@vivo.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
This is a hack, but it works for now.
Problem is, exc_double_fault() may or may not return, depending on
whether CONFIG_X86_ESPFIX64 is set. But objtool has no visibility to
the kernel config.
"Fix" it by silencing the exc_double_fault() __noreturn warning.
This removes the following warning:
vmlinux.o: warning: objtool: xenpv_exc_double_fault+0xd: exc_double_fault() is missing a __noreturn annotation
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/a45b085071d3a7d049a20f9e78754452336ecbe8.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Unreachable instruction warnings are limited to once per object file.
That no longer makes sense for vmlinux validation, which might have
more unreachable instructions lurking in other places. Change it to
once per function.
Note this affects some other (much rarer) non-fatal warnings as well.
In general I think one-warning-per-function makes sense, as related
warnings can accumulate quickly and we want to eventually get back to
failing the build with -Werror anyway.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/9d38f881bfc34e031c74e4e90064ccb3e49f599a.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
- 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/panic functions.
- Misc improvements & fixes.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=NwEV
-----END PGP SIGNATURE-----
Merge tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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
...
-----BEGIN PGP SIGNATURE-----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=Jt7p
-----END PGP SIGNATURE-----
Merge tag 'for-6.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
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
...
still a fair amount going on, including:
- Reorganizing 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.
-----BEGIN PGP SIGNATURE-----
iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAmRGze0PHGNvcmJldEBs
d24ubmV0AAoJEBdDWhNsDH5Y/VsH/RyWqinorRVFZmHqRJMRhR0j7hE2pAgK5prE
dGXYVtHHNQ+25thNaqhZTOLYFbSX6ii2NG7sLRXmyOTGIZrhUCFFXCHkuq4ZUypR
gJpMUiKQVT4dhln3gIZ0k09NSr60gz8UTcq895N9UFpUdY1SCDhbCcLc4uXTRajq
NrdgFaHWRkPb+gBRbXOExYm75DmCC6Ny5AyGo2rXfItV//ETjWIJVQpJhlxKrpMZ
3LgpdYSLhEFFnFGnXJ+EAPJ7gXDi2Tg5DuPbkvJyFOTouF3j4h8lSS9l+refMljN
xNRessv+boge/JAQidS6u8F2m2ESSqSxisv/0irgtKIMJwXaoX4=
=1//8
-----END PGP SIGNATURE-----
Merge tag 'docs-6.4' of git://git.lwn.net/linux
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/
...
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 <torvalds@linux-foundation.org>
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 <torvalds@linux-foundation.org>
This does the same thing for the user copies as commit 0db7058e8e
("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 <torvalds@linux-foundation.org>
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 <torvalds@linux-foundation.org>
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 <torvalds@linux-foundation.org>
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 <hv_ghcb_terminate>
1b6f: jmpq ffffffff82f217ec <hyperv_init+0x9c> # unreachable
1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip)
[...]
Now, after adding the __noreturn to the function prototype:
[...]
17df: callq ffffffff8102f6d0 <hv_ghcb_negotiate_protocol>
17e4: test %al,%al
17e6: je ffffffff82f21bb9 <hyperv_init+0x469>
[...] <many insns>
1bb9: mov $0x1,%esi
1bbe: xor %edi,%edi
1bc0: callq ffffffff8102f680 <hv_ghcb_terminate>
1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/32453a703dfcf0d007b473c9acbf70718222b74b.1681342859.git.jpoimboe@kernel.org
If a global function doesn't return, and its prototype has the
__noreturn attribute, its weak counterpart must also not return so that
it matches the prototype and meets call site expectations.
To properly follow the compiled control flow at the call sites, change
the global_noreturns check to include both global and weak functions.
On the other hand, if a weak function isn't in global_noreturns, assume
the prototype doesn't have __noreturn. Even if the weak function
doesn't return, call sites treat it like a returnable function.
Fixes the following warning:
kernel/sched/build_policy.o: warning: objtool: do_idle() falls through to next function play_idle_precise()
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/ede3460d63f4a65d282c86f1175bd2662c2286ba.1681342859.git.jpoimboe@kernel.org
In preparation for improving objtool's handling of weak noreturn
functions, mark start_kernel(), arch_call_rest_init(), and rest_init()
__noreturn.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/7194ed8a989a85b98d92e62df660f4a90435a723.1681342859.git.jpoimboe@kernel.org
Allow unwinding from prefix code by copying the CFI from the starting
instruction of the corresponding function. Even when the NOPs are
replaced, they're still stack-invariant instructions so the same ORC
entry can be reused everywhere.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/bc3344e51f3e87102f1301a0be0f72a7689ea4a4.1681331135.git.jpoimboe@kernel.org
It's easier to use and also gives easy access to the instruction's
containing function, which is useful for printing that function's
symbol. It will also be useful in the future for rate-limiting and
disassembly of warned functions.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/2eaa3155c90fba683d8723599f279c46025b75f3.1681325924.git.jpoimboe@kernel.org
If a function has a large stack frame, the stackleak plugin adds a call
to stackleak_track_stack() after the prologue.
This function may be called in uaccess-enabled code. Add it to the
uaccess safe list.
Fixes the following warning:
vmlinux.o: warning: objtool: kasan_report+0x12: call to stackleak_track_stack() with UACCESS enabled
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/42e9b487ef89e9b237fd5220ad1c7cf1a2ad7eb8.1681320562.git.jpoimboe@kernel.org
Commit 468af56a7b ("objtool: Support addition to set CFA base") was
added as a preparatory patch for arm64 support, but that support never
came. It triggers a false positive warning on x86, so just revert it
for now.
Fixes the following warning:
vmlinux.o: warning: objtool: cdce925_regmap_i2c_write+0xdb: stack state mismatch: cfa1=4+120 cfa2=5+40
Fixes: 468af56a7b ("objtool: Support addition to set CFA base")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/oe-kbuild-all/202304080538.j5G6h1AB-lkp@intel.com/
Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.
All in-kernel references to the old paths have been updated.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Mark reported that the ORC unwinder incorrectly marks an unwind as
reliable when the unwind terminates prematurely in the dark corners of
return_to_handler() due to lack of information about the next frame.
The problem is UNWIND_HINT_EMPTY is used in two different situations:
1) The end of the kernel stack unwind before hitting user entry, boot
code, or fork entry
2) A blind spot in ORC coverage where the unwinder has to bail due to
lack of information about the next frame
The ORC unwinder has no way to tell the difference between the two.
When it encounters an undefined stack state with 'end=1', it blindly
marks the stack reliable, which can break the livepatch consistency
model.
Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and
UNWIND_HINT_END_OF_STACK.
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org
The ENTRY unwind hint type is serving double duty as both an empty
unwind hint and an unret validation annotation.
Unret validation is unrelated to unwinding. Separate it out into its own
annotation.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/ff7448d492ea21b86d8a90264b105fbd0d751077.1677683419.git.jpoimboe@kernel.org
Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), in Xen, when a previously offlined CPU was brought back
online, it unexpectedly resumed execution where it left off in the
middle of the idle loop.
There were some hacks to make that work, but the behavior was surprising
as do_idle() doesn't expect an offlined CPU to return from the dead (in
arch_cpu_idle_dead()).
Now that Xen has been fixed, and the arch-specific implementations of
arch_cpu_idle_dead() also don't return, give it a __noreturn attribute.
This will cause the compiler to complain if an arch-specific
implementation might return. It also improves code generation for both
caller and callee.
Also fixes the following warning:
vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
- Shrink 'struct instruction', to improve objtool performance & memory
footprint.
- Other maximum memory usage reductions - this makes the build both faster,
and fixes kernel build OOM failures on allyesconfig and similar configs
when they try to build the final (large) vmlinux.o.
- Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying
single-byte instruction (PUSH/POP or LEAVE). This requires the
extension of the ORC metadata structure with a 'signal' field.
- Misc fixes & cleanups.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=bpPY
-----END PGP SIGNATURE-----
Merge tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool updates from Ingo Molnar:
- Shrink 'struct instruction', to improve objtool performance & memory
footprint
- Other maximum memory usage reductions - this makes the build both
faster, and fixes kernel build OOM failures on allyesconfig and
similar configs when they try to build the final (large) vmlinux.o
- Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying
single-byte instruction (PUSH/POP or LEAVE). This requires the
extension of the ORC metadata structure with a 'signal' field
- Misc fixes & cleanups
* tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
objtool: Fix ORC 'signal' propagation
objtool: Remove instruction::list
x86: Fix FILL_RETURN_BUFFER
objtool: Fix overlapping alternatives
objtool: Union instruction::{call_dest,jump_table}
objtool: Remove instruction::reloc
objtool: Shrink instruction::{type,visited}
objtool: Make instruction::alts a single-linked list
objtool: Make instruction::stack_ops a single-linked list
objtool: Change arch_decode_instruction() signature
x86/entry: Fix unwinding from kprobe on PUSH/POP instruction
x86/unwind/orc: Add 'signal' field to ORC metadata
objtool: Optimize layout of struct special_alt
objtool: Optimize layout of struct symbol
objtool: Allocate multiple structures with calloc()
objtool: Make struct check_options static
objtool: Make struct entries[] static and const
objtool: Fix HOSTCC flag usage
objtool: Properly support make V=1
objtool: Install libsubcmd in build
...
Josh Poimboeuf