Pull LoongArch updates from Huacai Chen: - Fix objtool about do_syscall() and Clang - Enable generic CPU vulnerabilites support - Enable ACPI BGRT handling - Rework CPU feature probe from CPUCFG/IOCSR - Add ARCH_HAS_SET_MEMORY support - Add ARCH_HAS_SET_DIRECT_MAP support - Improve hardware page table walker - Simplify _percpu_read() and _percpu_write() - Add advanced extended IRQ model documentions - Some bug fixes and other small changes * tag 'loongarch-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: Docs/LoongArch: Add advanced extended IRQ model description LoongArch: Remove posix_types.h include from sigcontext.h LoongArch: Fix memleak in pci_acpi_scan_root() LoongArch: Simplify _percpu_read() and _percpu_write() LoongArch: Improve hardware page table walker LoongArch: Add ARCH_HAS_SET_DIRECT_MAP support LoongArch: Add ARCH_HAS_SET_MEMORY support LoongArch: Rework CPU feature probe from CPUCFG/IOCSR LoongArch: Enable ACPI BGRT handling LoongArch: Enable generic CPU vulnerabilites support LoongArch: Remove STACK_FRAME_NON_STANDARD(do_syscall) LoongArch: Set AS_HAS_THIN_ADD_SUB as y if AS_IS_LLVM LoongArch: Enable objtool for Clang objtool: Handle frame pointer related instructions
After commit a0f7085f6a63 ("LoongArch: Add RANDOMIZE_KSTACK_OFFSET
support"), there are three new instructions "addi.d $fp, $sp, 32",
"sub.d $sp, $sp, $t0" and "addi.d $sp, $fp, -32" for the secondary
stack in do_syscall(), then there is a objtool warning "return with
modified stack frame" and no handle_syscall() which is the previous
frame of do_syscall() in the call trace when executing the command
"echo l > /proc/sysrq-trigger".
objdump shows something like this:
0000000000000000 <do_syscall>:
0: 02ff8063 addi.d $sp, $sp, -32
4: 29c04076 st.d $fp, $sp, 16
8: 29c02077 st.d $s0, $sp, 8
c: 29c06061 st.d $ra, $sp, 24
10: 02c08076 addi.d $fp, $sp, 32
...
74: 0011b063 sub.d $sp, $sp, $t0
...
a8: 4c000181 jirl $ra, $t0, 0
...
dc: 02ff82c3 addi.d $sp, $fp, -32
e0: 28c06061 ld.d $ra, $sp, 24
e4: 28c04076 ld.d $fp, $sp, 16
e8: 28c02077 ld.d $s0, $sp, 8
ec: 02c08063 addi.d $sp, $sp, 32
f0: 4c000020 jirl $zero, $ra, 0
The instruction "sub.d $sp, $sp, $t0" changes the stack bottom and the
new stack size is a random value, in order to find the return address of
do_syscall() which is stored in the original stack frame after executing
"jirl $ra, $t0, 0", it should use fp which points to the original stack
top.
At the beginning, the thought is tended to decode the secondary stack
instruction "sub.d $sp, $sp, $t0" and set it as a label, then check this
label for the two frame pointer instructions to change the cfa base and
cfa offset during the period of secondary stack in update_cfi_state().
This is valid for GCC but invalid for Clang due to there are different
secondary stack instructions for ClangBuiltLinux on LoongArch, something
like this:
0000000000000000 <do_syscall>:
...
88: 00119064 sub.d $a0, $sp, $a0
8c: 00150083 or $sp, $a0, $zero
...
Actually, it equals to a single instruction "sub.d $sp, $sp, $a0", but
there is no proper condition to check it as a label like GCC, and so the
beginning thought is not a good way.
Essentially, there are two special frame pointer instructions which are
"addi.d $fp, $sp, imm" and "addi.d $sp, $fp, imm", the first one points
fp to the original stack top and the second one restores the original
stack bottom from fp.
Based on the above analysis, in order to avoid adding an arch-specific
update_cfi_state(), we just add a member "frame_pointer" in the "struct
symbol" as a label to avoid affecting the current normal case, then set
it as true only if there is "addi.d $sp, $fp, imm". The last is to check
this label for the two frame pointer instructions to change the cfa base
and cfa offset in update_cfi_state().
Tested with the following two configs:
(1) CONFIG_RANDOMIZE_KSTACK_OFFSET=y &&
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=n
(2) CONFIG_RANDOMIZE_KSTACK_OFFSET=y &&
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y
By the way, there is no effect for x86 with this patch, tested on the
x86 machine with Fedora 40 system.
Cc: stable@vger.kernel.org # 6.9+
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Rust functions may be `noreturn` (i.e. diverging) by returning the
"never" type, `!`, e.g.
fn f() -> ! {
loop {}
}
Thus list the known `noreturn` functions to avoid such warnings.
Without this, `objtool` would complain if enabled for Rust, e.g.:
rust/core.o: warning: objtool:
_R...9panic_fmt() falls through to next function _R...18panic_nounwind_fmt()
rust/alloc.o: warning: objtool:
.text: unexpected end of section
In order to do so, we cannot match symbols' names exactly, for two
reasons:
- Rust mangling scheme [1] contains disambiguators [2] which we
cannot predict (e.g. they may vary depending on the compiler version).
One possibility to solve this would be to parse v0 and ignore/zero
those before comparison.
- Some of the diverging functions come from `core`, i.e. the Rust
standard library, which may change with each compiler version
since they are implementation details (e.g. `panic_internals`).
Thus, to workaround both issues, only part of the symbols are matched,
instead of using the `NORETURN` macro in `noreturns.h`.
Ideally, just like for the C side, we should have a better solution. For
instance, the compiler could give us the list via something like:
$ rustc --emit=noreturns ...
[ Kees agrees this should be automated and Peter says:
So it would be fairly simple to make objtool consume a magic section
emitted by the compiler.. I think we've asked the compiler folks
for that at some point even, but I don't have clear recollections.
We will ask upstream Rust about it. And if they agree, then perhaps
we can get Clang/GCC to implement something similar too -- for this
sort of thing we can take advantage of the shorter cycles of `rustc`
as well as their unstable features concept to experiment.
Gary proposed using DWARF (though it would need to be available), and
wrote a proof of concept script using the `object` and `gimli` crates:
https://gist.github.com/nbdd0121/449692570622c2f46a29ad9f47c3379a
- Miguel ]
Link: https://rust-lang.github.io/rfcs/2603-rust-symbol-name-mangling-v0.html [1]
Link: https://doc.rust-lang.org/rustc/symbol-mangling/v0.html#disambiguator [2]
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240725183325.122827-6-ojeda@kernel.org
[ Added `len_mismatch_fail` symbol for new `kernel` crate code merged
since then as well as 3 more `core::panicking` symbols that appear
in `RUST_DEBUG_ASSERTIONS=y` builds. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Like for KASAN, it's useful to temporarily disable KMSAN checks around, e.g., redzone accesses. Introduce kmsan_disable_current() and kmsan_enable_current(), which are similar to their KASAN counterparts. Make them reentrant in order to handle memory allocations in interrupt context. Repurpose the allow_reporting field for this. Link: https://lkml.kernel.org/r/20240621113706.315500-12-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When compiling the v6.9-rc1 kernel with the x32 compiler, the following
errors are reported. The reason is that we take an "unsigned long"
variable and print it using "PRIx64" format string.
In file included from check.c:16:
check.c: In function ‘add_dead_ends’:
/usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:46:17: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 5 has type ‘long unsigned int’ [-Werror=format=]
46 | "%s: warning: objtool: " format "\n", \
| ^~~~~~~~~~~~~~~~~~~~~~~~
check.c:613:33: note: in expansion of macro ‘WARN’
613 | WARN("can't find unreachable insn at %s+0x%" PRIx64,
| ^~~~
...
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org
Pull LoongArch updates from Huacai Chen:
- Add objtool support for LoongArch
- Add ORC stack unwinder support for LoongArch
- Add kernel livepatching support for LoongArch
- Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig
- Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig
- Some bug fixes and other small changes
* tag 'loongarch-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch/crypto: Clean up useless assignment operations
LoongArch: Define the __io_aw() hook as mmiowb()
LoongArch: Remove superfluous flush_dcache_page() definition
LoongArch: Move {dmw,tlb}_virt_to_page() definition to page.h
LoongArch: Change __my_cpu_offset definition to avoid mis-optimization
LoongArch: Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig
LoongArch: Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig
LoongArch: Add kernel livepatching support
LoongArch: Add ORC stack unwinder support
objtool: Check local label in read_unwind_hints()
objtool: Check local label in add_dead_ends()
objtool/LoongArch: Enable orc to be built
objtool/x86: Separate arch-specific and generic parts
objtool/LoongArch: Implement instruction decoder
objtool/LoongArch: Enable objtool to be built
Pull hardening updates from Kees Cook:
"As is pretty normal for this tree, there are changes all over the
place, especially for small fixes, selftest improvements, and improved
macro usability.
Some header changes ended up landing via this tree as they depended on
the string header cleanups. Also, a notable set of changes is the work
for the reintroduction of the UBSAN signed integer overflow sanitizer
so that we can continue to make improvements on the compiler side to
make this sanitizer a more viable future security hardening option.
Summary:
- string.h and related header cleanups (Tanzir Hasan, Andy
Shevchenko)
- VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev,
Harshit Mogalapalli)
- selftests/powerpc: Fix load_unaligned_zeropad build failure
(Michael Ellerman)
- hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)
- Handle tail call optimization better in LKDTM (Douglas Anderson)
- Use long form types in overflow.h (Andy Shevchenko)
- Add flags param to string_get_size() (Andy Shevchenko)
- Add Coccinelle script for potential struct_size() use (Jacob
Keller)
- Fix objtool corner case under KCFI (Josh Poimboeuf)
- Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)
- Add str_plural() helper (Michal Wajdeczko, Kees Cook)
- Ignore relocations in .notes section
- Add comments to explain how __is_constexpr() works
- Fix m68k stack alignment expectations in stackinit Kunit test
- Convert string selftests to KUnit
- Add KUnit tests for fortified string functions
- Improve reporting during fortified string warnings
- Allow non-type arg to type_max() and type_min()
- Allow strscpy() to be called with only 2 arguments
- Add binary mode to leaking_addresses scanner
- Various small cleanups to leaking_addresses scanner
- Adding wrapping_*() arithmetic helper
- Annotate initial signed integer wrap-around in refcount_t
- Add explicit UBSAN section to MAINTAINERS
- Fix UBSAN self-test warnings
- Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL
- Reintroduce UBSAN's signed overflow sanitizer"
* tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits)
selftests/powerpc: Fix load_unaligned_zeropad build failure
string: Convert helpers selftest to KUnit
string: Convert selftest to KUnit
sh: Fix build with CONFIG_UBSAN=y
compiler.h: Explain how __is_constexpr() works
overflow: Allow non-type arg to type_max() and type_min()
VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler()
lib/string_helpers: Add flags param to string_get_size()
x86, relocs: Ignore relocations in .notes section
objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
overflow: Use POD in check_shl_overflow()
lib: stackinit: Adjust target string to 8 bytes for m68k
sparc: vdso: Disable UBSAN instrumentation
kernel.h: Move lib/cmdline.c prototypes to string.h
leaking_addresses: Provide mechanism to scan binary files
leaking_addresses: Ignore input device status lines
leaking_addresses: Use File::Temp for /tmp files
MAINTAINERS: Update LEAKING_ADDRESSES details
fortify: Improve buffer overflow reporting
fortify: Add KUnit tests for runtime overflows
...
When update the latest upstream gcc and binutils, it generates some objtool warnings on LoongArch, like this: arch/loongarch/kernel/entry.o: warning: objtool: ret_from_fork+0x0: unreachable instruction We can see that the reloc sym name is local label instead of section in relocation section '.rela.discard.unwind_hints', in this case, the reloc sym type is STT_NOTYPE instead of STT_SECTION. Let us check it to not return -1, then use reloc->sym->offset instead of reloc addend which is 0 to find the corresponding instruction. Here are some detailed info: [fedora@linux 6.8.test]$ gcc --version gcc (GCC) 14.0.1 20240129 (experimental) [fedora@linux 6.8.test]$ as --version GNU assembler (GNU Binutils) 2.42.50.20240129 [fedora@linux 6.8.test]$ readelf -r arch/loongarch/kernel/entry.o | grep -A 3 "rela.discard.unwind_hints" Relocation section '.rela.discard.unwind_hints' at offset 0x3a8 contains 7 entries: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 000a00000063 R_LARCH_32_PCREL 0000000000000000 .Lhere_1 + 0 00000000000c 000b00000063 R_LARCH_32_PCREL 00000000000000a8 .Lhere_50 + 0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
When update the latest upstream gcc and binutils, it generates more objtool warnings on LoongArch, like this: init/main.o: warning: objtool: unexpected relocation symbol type in .rela.discard.unreachable We can see that the reloc sym name is local label instead of section in relocation section '.rela.discard.unreachable', in this case, the reloc sym type is STT_NOTYPE instead of STT_SECTION. As suggested by Peter Zijlstra, we add a "local_label" member in struct symbol, then set it as true if symbol type is STT_NOTYPE and symbol name starts with ".L" string in classify_symbols(). Let's check reloc->sym->local_label to not return -1 in add_dead_ends(), and also use reloc->sym->offset instead of reloc addend which is 0 to find the corresponding instruction. At the same time, let's replace the variable "addend" with "offset" to reflect the reality. Here are some detailed info: [fedora@linux 6.8.test]$ gcc --version gcc (GCC) 14.0.1 20240129 (experimental) [fedora@linux 6.8.test]$ as --version GNU assembler (GNU Binutils) 2.42.50.20240129 [fedora@linux 6.8.test]$ readelf -r init/main.o | grep -A 2 "rela.discard.unreachable" Relocation section '.rela.discard.unreachable' at offset 0x6028 contains 1 entry: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 00d900000063 R_LARCH_32_PCREL 00000000000002c4 .L500^B1 + 0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
If SAVE and RESTORE unwind hints are in different basic blocks, and
objtool sees the RESTORE before the SAVE, it errors out with:
vmlinux.o: warning: objtool: vmw_port_hb_in+0x242: objtool isn't smart enough to handle this CFI save/restore combo
In such a case, defer following the RESTORE block until the
straight-line path gets followed later.
Fixes: 8faea26e6111 ("objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402240702.zJFNmahW-lkp@intel.com/
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240227073527.avcm5naavbv3cj5s@treble
Signed-off-by: Kees Cook <keescook@chromium.org>