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| author | Miguel Ojeda <ojeda@kernel.org> | 2026-08-16 15:32:33 +0200 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2026-08-23 21:27:17 +0200 |
| commit | 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 (patch) | |
| tree | 93a1ed1d337bc53adf1e572c2586d347703b286e /Documentation/ABI/testing/debugfs-tpmi | |
| download | linux-stable-5febf432df1cfa5b25d99b54c32103fafbdd0eb9.tar.gz linux-stable-5febf432df1cfa5b25d99b54c32103fafbdd0eb9.zip | |
kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted
Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:
vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd
The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.
This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.
Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.
Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'Documentation/ABI/testing/debugfs-tpmi')
| -rw-r--r-- | Documentation/ABI/testing/debugfs-tpmi | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/debugfs-tpmi b/Documentation/ABI/testing/debugfs-tpmi new file mode 100644 index 000000000..c493a1403 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-tpmi @@ -0,0 +1,40 @@ +What: /sys/kernel/debug/tpmi-<n>/pfs_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +The PFS (PM Feature Structure) table, shows details of each power +management feature. This includes: +tpmi_id, number of entries, entry size, offset, vsec offset, lock status +and disabled status. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-<n>/tpmi-id-<n>/mem_dump +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Shows the memory dump of the MMIO region for a TPMI ID. +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-<n>/tpmi-id-<n>/mem_write +Date: November 2023 +KernelVersion: 6.6 +Contact: srinivas.pandruvada@linux.intel.com +Description: +Allows to write at any offset. It doesn't check for Read/Write access +as hardware will not allow to write at read-only memory. This write is +at offset multiples of 4. The format is instance,offset,contents. +Example: +echo 0,0x20,0xff > mem_write +echo 1,64,64 > mem_write +Users: Debugging, any user space test suite + +What: /sys/kernel/debug/tpmi-<n>/plr/domain<n>/status +Date: Aug 2024 +KernelVersion: 6.11 +Contact: Tero Kristo <tero.kristo@linux.intel.com> +Description: +Shows the currently active Performance Limit Reasons for die level and the +individual CPUs under the die. The contents of this file are sticky, and +clearing all the statuses can be done by writing "0\n" to this file. |