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/ABI/testing/sysfs-class-rtc | 91 +++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rtc (limited to 'Documentation/ABI/testing/sysfs-class-rtc') diff --git a/Documentation/ABI/testing/sysfs-class-rtc b/Documentation/ABI/testing/sysfs-class-rtc new file mode 100644 index 000000000..95984289a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rtc @@ -0,0 +1,91 @@ +What: /sys/class/rtc/ +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + The rtc/ class subdirectory belongs to the RTC subsystem. + +What: /sys/class/rtc/rtcX/ +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + The /sys/class/rtc/rtc{0,1,2,3,...} directories correspond + to each RTC device. + +What: /sys/class/rtc/rtcX/date +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided date in YYYY-MM-DD format + +What: /sys/class/rtc/rtcX/hctosys +Date: September 2009 +KernelVersion: 2.6.32 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) 1 if the RTC provided the system time at boot via the + CONFIG_RTC_HCTOSYS kernel option, 0 otherwise + +What: /sys/class/rtc/rtcX/max_user_freq +Date: October 2007 +KernelVersion: 2.6.24 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The maximum interrupt rate an unprivileged user may request + from this RTC. + +What: /sys/class/rtc/rtcX/name +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) The name of the RTC corresponding to this sysfs directory + +What: /sys/class/rtc/rtcX/range +Date: January 2018 +KernelVersion: 4.16 +Contact: linux-rtc@vger.kernel.org +Description: + Valid time range for the RTC, as seconds from epoch, formatted + as [min, max] + +What: /sys/class/rtc/rtcX/since_epoch +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided time as the number of seconds since the epoch + +What: /sys/class/rtc/rtcX/time +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided time in 24-hour notation (hh:mm:ss) + +What: /sys/class/rtc/rtcX/offset +Date: February 2016 +KernelVersion: 4.6 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The amount which the rtc clock has been adjusted in + firmware. Visible only if the driver supports clock offset + adjustment. The unit is parts per billion, i.e. The number of + clock ticks which are added to or removed from the rtc's base + clock per billion ticks. A positive value makes a day pass more + slowly, longer, and a negative value makes a day pass more + quickly. + +What: /sys/class/rtc/rtcX/wakealarm +Date: February 2007 +KernelVersion: 2.6.20 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The time at which the clock will generate a system wakeup + event. This is a one shot wakeup event, so must be reset after + wake if a daily wakeup is required. Format is seconds since the + epoch by default, or if there's a leading +, seconds in the + future, or if there is a leading +=, seconds ahead of the + current alarm. -- cgit v1.3.1