After commit 88fd2b70120d ("LoongArch: Fix sleeping in atomic context for
PREEMPT_RT"), it should guard percpu handler under !CONFIG_PREEMPT_RT to
avoid redundant operations.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Currently, use %p to prevent leaking information about the kernel memory
layout when printing the PC address, but the kernel log messages are not
useful to debug problem if bt_address() returns 0. Given that the type of
"pc" variable is unsigned long, it should use %px to print the unmodified
unwinding address.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with LLVM and CONFIG_LTO_CLANG is set, there exist many
objtool warnings "sibling call from callable instruction with modified
stack frame".
For this special case, the related object file shows that there is no
generated relocation section '.rela.discard.tablejump_annotate' for the
table jump instruction jirl, thus objtool can not know that what is the
actual destination address.
It needs to do something on the LLVM side to make sure that there is the
relocation section '.rela.discard.tablejump_annotate' if LTO is enabled,
but in order to maintain compatibility for the current LLVM compiler,
this can be done in the kernel Makefile for now. Ensure it is aware of
linker with LTO, '--loongarch-annotate-tablejump' needs to be passed via
'-mllvm' to ld.lld.
Note that it should also pass the compiler option -mannotate-tablejump
rather than only pass '-mllvm --loongarch-annotate-tablejump' to ld.lld
if LTO is enabled, otherwise there are no jump info for some table jump
instructions.
Fixes: e20ab7d454ee ("LoongArch: Enable jump table for objtool")
Closes: https://lore.kernel.org/loongarch/20250731175655.GA1455142@ax162/
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Co-developed-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
If the MAC controller does not connect to any PHY interface, there is a
missing clock, then the DMA reset fails.
For this case, the DMA_BUS_MODE_SFT_RESET bit is 1 before software reset,
just print an error message which gives a hint the PHY clock is missing,
and then return -EINVAL immediately to avoid waiting for the timeout when
the DMA reset fails in loongson_dwmac_fix_reset().
With this patch, for the normal end user, the computer start faster with
reducing boot time for 2 seconds on the specified mainboard.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://patch.msgid.link/20250811073506.27513-4-yangtiezhu@loongson.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
It is better to use unsigned long rather than long for _end and _text to
calculate the kernel length.
Cc: stable@vger.kernel.org # v6.3+
Fixes: e5f02b51fa0c ("LoongArch: Add support for kernel address space layout randomization (KASLR)")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The atomic instructions sc.q, llacq.{w/d}, screl.{w/d} were newly added
in the LoongArch Reference Manual v1.10, it is necessary to handle them
in insns_not_supported() to avoid putting a breakpoint in the middle of
a ll/sc atomic sequence, otherwise it will loop forever for kprobes and
uprobes.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When testing the kernel live patching with "modprobe livepatch-sample",
there is a timeout over 15 seconds from "starting patching transition"
to "patching complete". The dmesg command shows "unreliable stack" for
user tasks in debug mode, here is one of the messages:
livepatch: klp_try_switch_task: bash:1193 has an unreliable stack
The "unreliable stack" is because it can not unwind from do_syscall()
to its previous frame handle_syscall(). It should use fp to find the
original stack top due to secondary stack in do_syscall(), but fp is
not used for some other functions, then fp can not be restored by the
next frame of do_syscall(), so it is necessary to save fp if task is
not current, in order to get the stack top of do_syscall().
Here are the call chains:
klp_enable_patch()
klp_try_complete_transition()
klp_try_switch_task()
klp_check_and_switch_task()
klp_check_stack()
stack_trace_save_tsk_reliable()
arch_stack_walk_reliable()
When executing "rmmod livepatch-sample", there exists a similar issue.
With this patch, it takes a short time for patching and unpatching.
Before:
# modprobe livepatch-sample
# dmesg -T | tail -3
[Sat Sep 6 11:00:20 2025] livepatch: 'livepatch_sample': starting patching transition
[Sat Sep 6 11:00:35 2025] livepatch: signaling remaining tasks
[Sat Sep 6 11:00:36 2025] livepatch: 'livepatch_sample': patching complete
# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
# rmmod livepatch_sample
rmmod: ERROR: Module livepatch_sample is in use
# rmmod livepatch_sample
# dmesg -T | tail -3
[Sat Sep 6 11:06:05 2025] livepatch: 'livepatch_sample': starting unpatching transition
[Sat Sep 6 11:06:20 2025] livepatch: signaling remaining tasks
[Sat Sep 6 11:06:21 2025] livepatch: 'livepatch_sample': unpatching complete
After:
# modprobe livepatch-sample
# dmesg -T | tail -2
[Tue Sep 16 16:19:30 2025] livepatch: 'livepatch_sample': starting patching transition
[Tue Sep 16 16:19:31 2025] livepatch: 'livepatch_sample': patching complete
# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
# rmmod livepatch_sample
# dmesg -T | tail -2
[Tue Sep 16 16:19:36 2025] livepatch: 'livepatch_sample': starting unpatching transition
[Tue Sep 16 16:19:37 2025] livepatch: 'livepatch_sample': unpatching complete
Cc: stable@vger.kernel.org # v6.9+
Fixes: 199cc14cb4f1 ("LoongArch: Add kernel livepatching support")
Reported-by: Xi Zhang <zhangxi@kylinos.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Loongson-3A6000 and 3C6000 CPUs also support unaligned memory access, so
the current description is out of date to some extent.
Actually, all of Loongson-3 series processors based on LoongArch support
unaligned memory access, this hardware capability is indicated by the bit
20 (UAL) of CPUCFG1 register, update the help info to reflect the reality.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with LLVM and CONFIG_RUST is set, there exists the
following objtool warning:
rust/compiler_builtins.o: warning: objtool: __rust__unordsf2(): unexpected end of section .text.unlikely.
objdump shows that the end of section .text.unlikely is an atomic
instruction:
amswap.w $zero, $ra, $zero
According to the LoongArch Reference Manual, if the amswap.w atomic
memory access instruction has the same register number as rd and rj,
the execution will trigger an Instruction Non-defined Exception, so
mark the above instruction as INSN_BUG type to fix the warning.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
If the break immediate code is 0, it should mark the type as
INSN_TRAP. If the break immediate code is 1, it should mark the
type as INSN_BUG.
While at it, format the code style and add the code comment for nop.
Cc: stable@vger.kernel.org
Suggested-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
JITs can set bpf_jit_bypass_spec_v1/v4() if they want the verifier to
skip analysis/patching for the respective vulnerability, it is safe to
set both bpf_jit_bypass_spec_v1/v4(), because there is no speculation
barrier instruction for LoongArch.
Suggested-by: Luis Gerhorst <luis.gerhorst@fau.de>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Use BPF_TRAMP_F_INDIRECT flag to detect struct ops and emit proper
prologue and epilogue for this case.
With this patch, all of the struct_ops related testcases (except
struct_ops_multi_pages) passed on LoongArch.
The testcase struct_ops_multi_pages failed is because the actual
image_pages_cnt is 40 which is bigger than MAX_TRAMP_IMAGE_PAGES.
Before:
$ sudo ./test_progs -t struct_ops -d struct_ops_multi_pages
...
WATCHDOG: test case struct_ops_module/struct_ops_load executes for 10 seconds...
After:
$ sudo ./test_progs -t struct_ops -d struct_ops_multi_pages
...
#15 bad_struct_ops:OK
...
#399 struct_ops_autocreate:OK
...
#400 struct_ops_kptr_return:OK
...
#401 struct_ops_maybe_null:OK
...
#402 struct_ops_module:OK
...
#404 struct_ops_no_cfi:OK
...
#405 struct_ops_private_stack:SKIP
...
#406 struct_ops_refcounted:OK
Summary: 8/25 PASSED, 3 SKIPPED, 0 FAILED
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
arch_uprobe_skip_sstep() returns true if instruction was emulated, that
is to say, there is no need to single step for the emulated instructions.
regs->csr_era will point to the destination address directly after the
exception, so the resume_era related code is redundant, just remove them.
Cc: stable@vger.kernel.org
Fixes: 19bc6cb64092 ("LoongArch: Add uprobes support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When executing the "perf probe" and "perf stat" test cases about some
cryptographic algorithm, the output shows that "Trace/breakpoint trap".
This is because it uses the software singlestep breakpoint for uprobes
on LoongArch, and no need to use the hardware singlestep. So just remove
the related function call to user_{en,dis}able_single_step() for uprobes
on LoongArch.
How to reproduce:
Please make sure CONFIG_UPROBE_EVENTS is set and openssl supports sm2
algorithm, then execute the following command.
cd tools/perf && make
./perf probe -x /usr/lib64/libcrypto.so BN_mod_mul_montgomery
./perf stat -e probe_libcrypto:BN_mod_mul_montgomery openssl speed sm2
Cc: stable@vger.kernel.org
Fixes: 19bc6cb64092 ("LoongArch: Add uprobes support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Like the other relevant symbols, export some fp, lsx, lasx and lbt
assembly symbols and put the function declarations in header files
rather than source files.
While at it, use "asmlinkage" for the other existing C prototypes
of assembly functions and also do not use the "extern" keyword with
function declarations according to the document coding-style.rst.
Cc: stable@vger.kernel.org # 6.6+
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Currently, interrupts need to be disabled before single-step mode is
set, it requires that CSR_PRMD_PIE be cleared in save_local_irqflag()
which is called by setup_singlestep(), this is reasonable.
But in the first kprobe breakpoint exception, if the irq is enabled at
the beginning of do_bp(), it will not be disabled at the end of do_bp()
due to the CSR_PRMD_PIE has been cleared in save_local_irqflag(). So for
this case, it may corrupt exception context when restoring the exception
after do_bp() in handle_bp(), this is not reasonable.
In order to restore exception safely in handle_bp(), it needs to ensure
the irq is disabled at the end of do_bp(), so just add a local variable
to record the original interrupt status in the parent context, then use
it as the check condition to enable and disable irq in do_bp().
While at it, do the similar thing for other do_xyz() exception handlers
to make them more robust.
Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support")
Suggested-by: Jinyang He <hejinyang@loongson.cn>
Suggested-by: Huacai Chen <chenhuacai@loongson.cn>
Co-developed-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
In the current code, the definition of regs_irqs_disabled() is actually
"!(regs->csr_prmd & CSR_CRMD_IE)" because arch_irqs_disabled_flags() is
defined as "!(flags & CSR_CRMD_IE)", it looks a little strange.
Define regs_irqs_disabled() as !(regs->csr_prmd & CSR_PRMD_PIE) directly
to make it more clear, no functional change.
While at it, the return value of regs_irqs_disabled() is true or false,
so change its type to reflect that and also make it always inline.
Fixes: 803b0fc5c3f2 ("LoongArch: Add process management")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling on LoongArch, there exists the following objtool warning
in arch/loongarch/kernel/machine_kexec.o:
kexec_reboot() falls through to next function crash_shutdown_secondary()
Avoid using unreachable() as it can (and will in the absence of UBSAN)
generate fall-through code. Use BUG() so we get a "break BRK_BUG" trap
(with unreachable annotation).
Cc: stable@vger.kernel.org # 6.12+
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The maximum number of load/store watchpoints and fetch instruction
watchpoints is 14 each according to LoongArch Reference Manual, so
extend the maximum number of watchpoints from 8 to 14 for ptrace.
By the way, just simply change 8 to 14 for the definition in struct
user_watch_state at the beginning, but it may corrupt uapi, then add
a new struct user_watch_state_v2 directly.
As far as I can tell, the only users for this struct in the userspace
are GDB and LLDB, there are no any problems of software compatibility
between the application and kernel according to the analysis.
The compatibility problem has been considered while developing and
testing. When the applications in the userspace get watchpoint state,
the length will be specified which is no bigger than the sizeof struct
user_watch_state or user_watch_state_v2, the actual length is assigned
as the minimal value of the application and kernel in the generic code
of ptrace:
kernel/ptrace.c: ptrace_regset():
kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));
if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
kiov->iov_len, kiov->iov_base);
For example, there are four kind of combinations, all of them work well.
(1) "older kernel + older gdb", the actual length is 8+(8+8+4+4)*8=200;
(2) "newer kernel + newer gdb", the actual length is 8+(8+8+4+4)*14=344;
(3) "older kernel + newer gdb", the actual length is 8+(8+8+4+4)*8=200;
(4) "newer kernel + older gdb", the actual length is 8+(8+8+4+4)*8=200.
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints
Cc: stable@vger.kernel.org
Fixes: 1a69f7a161a7 ("LoongArch: ptrace: Expose hardware breakpoints to debuggers")
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
(1) Description of Problem:
When testing BPF JIT with the latest compiler toolchains on LoongArch,
there exist some strange failed test cases, dmesg shows something like
this:
# dmesg -t | grep FAIL | head -1
... ret -3 != -3 (0xfffffffd != 0xfffffffd)FAIL ...
(2) Steps to Reproduce:
# echo 1 > /proc/sys/net/core/bpf_jit_enable
# modprobe test_bpf
(3) Additional Info:
There are no failed test cases compiled with the lower version of GCC
such as 13.3.0, while the problems only appear with higher version of
GCC such as 14.2.0.
This is because the problems were hidden by the lower version of GCC due
to redundant sign extension instructions generated by compiler, but with
optimization of higher version of GCC, the sign extension instructions
have been removed.
(4) Root Cause Analysis:
The LoongArch architecture does not expose sub-registers, and hold all
32-bit values in a sign-extended format. While BPF, on the other hand,
exposes sub-registers, and use zero-extension (similar to arm64/x86).
This has led to some subtle bugs, where a BPF JITted program has not
sign-extended the a0 register (return value in LoongArch land), passed
the return value up the kernel, for example:
| int from_bpf(void);
|
| long foo(void)
| {
| return from_bpf();
| }
Here, a0 would be 0xffffffff instead of the expected 0xffffffffffffffff.
Internally, the LoongArch JIT uses a5 as a dedicated register for BPF
return values. That is to say, the LoongArch BPF uses a5 for BPF return
values, which are zero-extended, whereas the LoongArch ABI uses a0 which
is sign-extended.
(5) Final Solution:
Keep a5 zero-extended, but explicitly sign-extend a0 (which is used
outside BPF land). Because libbpf currently defines the return value
of an ebpf program as a 32-bit unsigned integer, just use addi.w to
extend bit 31 into bits 63 through 32 of a5 to a0. This is similar to
commit 2f1b0d3d7331 ("riscv, bpf: Sign-extend return values").
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support")
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Whenever I try to build the kernel with upcoming GCC 15 which defaults
to -std=gnu23 I get a build failure:
CC arch/loongarch/vdso/vgetcpu.o
In file included from ./include/uapi/linux/posix_types.h:5,
from ./include/uapi/linux/types.h:14,
from ./include/linux/types.h:6,
from ./include/linux/kasan-checks.h:5,
from ./include/asm-generic/rwonce.h:26,
from ./arch/loongarch/include/generated/asm/rwonce.h:1,
from ./include/linux/compiler.h:317,
from ./include/asm-generic/bug.h:5,
from ./arch/loongarch/include/asm/bug.h:60,
from ./include/linux/bug.h:5,
from ./include/linux/mmdebug.h:5,
from ./include/linux/mm.h:6,
from ./arch/loongarch/include/asm/vdso.h:10,
from arch/loongarch/vdso/vgetcpu.c:6:
./include/linux/stddef.h:11:9: error: expected identifier before 'false'
11 | false = 0,
| ^~~~~
./include/linux/types.h:35:33: error: two or more data types in declaration specifiers
35 | typedef _Bool bool;
| ^~~~
./include/linux/types.h:35:1: warning: useless type name in empty declaration
35 | typedef _Bool bool;
| ^~~~~~~
The kernel builds explicitly with -std=gnu11 in top Makefile, but
arch/loongarch/vdso does not use KBUILD_CFLAGS from the rest of the
kernel, just add -std=gnu11 flag to arch/loongarch/vdso/Makefile.
By the way, commit e8c07082a810 ("Kbuild: move to -std=gnu11") did a
similar change for arch/arm64/kernel/vdso32/Makefile.
Fixes: c6b99bed6b8f ("LoongArch: Add VDSO and VSYSCALL support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
For now, it is time to remove -fno-jump-tables to enable jump table for
objtool if the compiler has -mannotate-tablejump, otherwise it is better
to remain -fno-jump-tables to keep compatibility with older compilers.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The objtool program need to analysis the control flow of each object file
generated by compiler toolchain, it needs to know all the locations that
a branch instruction may jump into, if a jump table is used, objtool has
to correlate the jump instruction with the table.
On x86 (which is the only port supported by objtool before LoongArch),
there is a relocation type on the jump instruction and directly points
to the table. But on LoongArch, the relocation is on another kind of
instruction prior to the jump instruction, and also with scheduling it
is not very easy to tell the offset of that instruction from the jump
instruction. Furthermore, because LoongArch has -fsection-anchors (often
enabled at -O1 or above) the relocation may actually points to a section
anchor instead of the table itself.
For the jump table of switch cases, a GCC patch "LoongArch: Add support
to annotate tablejump" and a Clang patch "[LoongArch] Add options for
annotate tablejump" have been merged into the upstream mainline, it can
parse the additional section ".discard.tablejump_annotate" which stores
the jump info as pairs of addresses, each pair contains the address of
jump instruction and the address of jump table.
For the jump table of computed gotos, it is indeed not easy to implement
in the compiler, especially if there is more than one computed goto in a
function such as ___bpf_prog_run(). objdump kernel/bpf/core.o shows that
there are many table jump instructions in ___bpf_prog_run(), but there are
no relocations on the table jump instructions and to the table directly on
LoongArch.
Without the help of compiler, in order to figure out the address of goto
table for the special case of ___bpf_prog_run(), since the instruction
sequence is relatively single and stable, it makes sense to add a helper
find_reloc_of_rodata_c_jump_table() to find the relocation which points
to the section ".rodata..c_jump_table".
If find_reloc_by_table_annotate() failed, it means there is no relocation
info of switch table address in ".rela.discard.tablejump_annotate", then
objtool may find the relocation info of goto table ".rodata..c_jump_table"
with find_reloc_of_rodata_c_jump_table().
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The objtool program need to analysis the control flow of each object file
generated by compiler toolchain, it needs to know all the locations that
a branch instruction may jump into, if a jump table is used, objtool has
to correlate the jump instruction with the table.
On x86 (which is the only port supported by objtool before LoongArch),
there is a relocation type on the jump instruction and directly points
to the table. But on LoongArch, the relocation is on another kind of
instruction prior to the jump instruction, and also with scheduling it
is not very easy to tell the offset of that instruction from the jump
instruction. Furthermore, because LoongArch has -fsection-anchors (often
enabled at -O1 or above) the relocation may actually points to a section
anchor instead of the table itself.
The good news is that after continuous analysis and discussion, at last
a GCC patch "LoongArch: Add support to annotate tablejump" and a Clang
patch "[LoongArch] Add options for annotate tablejump" have been merged
into the upstream mainline, the compiler changes make life much easier
for switch table support of objtool on LoongArch.
By now, there is an additional section ".discard.tablejump_annotate" to
store the jump info as pairs of addresses, each pair contains the address
of jump instruction and the address of jump table.
In order to find switch table, it is easy to parse the relocation section
".rela.discard.tablejump_annotate" to get table_sec and table_offset, the
rest process is somehow like x86.
Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=0ee028f55640
Link: https://github.com/llvm/llvm-project/commit/4c2c17756739
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with Clang on LoongArch, there are unsorted table offset
of rodata if there exist many jump tables, it will get the wrong table
end and find the wrong jump destination instructions in add_jump_table().
Sort the rodata table offset by parsing ".rela.discard.tablejump_annotate"
and then get each table size of rodata corresponded with each table jump
instruction, it is used to check the table end and will break the process
when parsing ".rela.rodata" to avoid getting the wrong jump destination
instructions.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with Clang on LoongArch, there are unsorted table offset
of rodata if there exist many jump tables, it will get the wrong table
end and find the wrong jump destination instructions in add_jump_table(),
so it needs to check the table size of rodata to break the process when
parsing the relocation section of rodata.
This is preparation for later patch on LoongArch, there is no effect for
the other archs with this patch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with Clang on LoongArch, there exists unreachable entry of
rodata which points to a position after the function return instruction,
this is generated by compiler to fill the non-existent switch case, just
skip the entry when parsing the relocation section of rodata.
This is preparation for later patch on LoongArch, there is no effect for
the other archs with this patch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
In the most cases, the entry size of rodata is 8 bytes because the
relocation type is 64 bit, but when compiling with Clang on LoongArch,
there exists 32 bit relocation type, the entry size of rodata should
be 4 bytes in this case.
This is preparation for later patch on LoongArch, there is no effect
for the other archs with this patch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
There are some "unreachable instruction" objtool warnings when compiling
with Clang on LoongArch, this is because the "break" instruction is set
as dead end due to its type is INSN_BUG in decode_instructions() at the
beginning, and it does not set insn->dead_end of the "break" instruction
as false after checking ".rela.discard.reachable" in add_dead_ends(), so
the next instruction of "break" is marked as unreachable.
Actually, it can find the reachable instruction after parsing the section
".rela.discard.reachable", in some cases, the "break" instruction may not
be the first previous instruction with scheduling by Machine Instruction
Scheduler of LLVM, it should find more times and then set insn->dead_end
of the "break" instruction as false.
This is preparation for later patch on LoongArch, there is no effect for
the other archs with this patch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
In the relocation section ".rela.rodata" of each .o file compiled with
LoongArch toolchain, there are various symbol types such as STT_NOTYPE,
STT_OBJECT, STT_FUNC in addition to the usual STT_SECTION, it needs to
use reloc symbol offset instead of reloc addend to find the destination
instruction in find_jump_table() and add_jump_table().
This is preparation for later patch on LoongArch, there is no effect for
the other archs with this patch.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Tiezhu Yang