From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers 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 Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- Documentation/gpu/amdgpu/ras.rst | 62 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 Documentation/gpu/amdgpu/ras.rst (limited to 'Documentation/gpu/amdgpu/ras.rst') diff --git a/Documentation/gpu/amdgpu/ras.rst b/Documentation/gpu/amdgpu/ras.rst new file mode 100644 index 000000000..047f76e39 --- /dev/null +++ b/Documentation/gpu/amdgpu/ras.rst @@ -0,0 +1,62 @@ +==================== + AMDGPU RAS Support +==================== + +The AMDGPU RAS interfaces are exposed via sysfs (for informational queries) and +debugfs (for error injection). + +RAS debugfs/sysfs Control and Error Injection Interfaces +======================================================== + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c + :doc: AMDGPU RAS debugfs control interface + +RAS Reboot Behavior for Unrecoverable Errors +============================================ + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c + :doc: AMDGPU RAS Reboot Behavior for Unrecoverable Errors + +RAS Error Count sysfs Interface +=============================== + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c + :doc: AMDGPU RAS sysfs Error Count Interface + +RAS EEPROM debugfs Interface +============================ + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c + :doc: AMDGPU RAS debugfs EEPROM table reset interface + +RAS VRAM Bad Pages sysfs Interface +================================== + +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c + :doc: AMDGPU RAS sysfs gpu_vram_bad_pages Interface + +Sample Code +=========== +Sample code for testing error injection can be found here: +https://cgit.freedesktop.org/mesa/drm/tree/tests/amdgpu/ras_tests.c + +This is part of the libdrm amdgpu unit tests which cover several areas of the GPU. +There are four sets of tests: + +RAS Basic Test + +The test verifies the RAS feature enabled status and makes sure the necessary sysfs and debugfs files +are present. + +RAS Query Test + +This test checks the RAS availability and enablement status for each supported IP block as well as +the error counts. + +RAS Inject Test + +This test injects errors for each IP. + +RAS Disable Test + +This test tests disabling of RAS features for each IP block. -- cgit v1.3.1