tools headers UAPI: Sync openat2.h with the kernel sources

[linux-2.6-microblaze.git] / arch / Kconfig

diff --git a/arch/Kconfig b/arch/Kconfig
index 9fc4eb8..2bb3067 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -603,6 +603,96 @@ config SHADOW_CALL_STACK
          reading and writing arbitrary memory may be able to locate them
          and hijack control flow by modifying the stacks.
 
+config LTO
+       bool
+       help
+         Selected if the kernel will be built using the compiler's LTO feature.
+
+config LTO_CLANG
+       bool
+       select LTO
+       help
+         Selected if the kernel will be built using Clang's LTO feature.
+
+config ARCH_SUPPORTS_LTO_CLANG
+       bool
+       help
+         An architecture should select this option if it supports:
+         - compiling with Clang,
+         - compiling inline assembly with Clang's integrated assembler,
+         - and linking with LLD.
+
+config ARCH_SUPPORTS_LTO_CLANG_THIN
+       bool
+       help
+         An architecture should select this option if it can support Clang's
+         ThinLTO mode.
+
+config HAS_LTO_CLANG
+       def_bool y
+       # Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
+       depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD
+       depends on $(success,test $(LLVM) -eq 1)
+       depends on $(success,test $(LLVM_IAS) -eq 1)
+       depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
+       depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
+       depends on ARCH_SUPPORTS_LTO_CLANG
+       depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
+       depends on !KASAN
+       depends on !GCOV_KERNEL
+       help
+         The compiler and Kconfig options support building with Clang's
+         LTO.
+
+choice
+       prompt "Link Time Optimization (LTO)"
+       default LTO_NONE
+       help
+         This option enables Link Time Optimization (LTO), which allows the
+         compiler to optimize binaries globally.
+
+         If unsure, select LTO_NONE. Note that LTO is very resource-intensive
+         so it's disabled by default.
+
+config LTO_NONE
+       bool "None"
+       help
+         Build the kernel normally, without Link Time Optimization (LTO).
+
+config LTO_CLANG_FULL
+       bool "Clang Full LTO (EXPERIMENTAL)"
+       depends on HAS_LTO_CLANG
+       depends on !COMPILE_TEST
+       select LTO_CLANG
+       help
+          This option enables Clang's full Link Time Optimization (LTO), which
+          allows the compiler to optimize the kernel globally. If you enable
+          this option, the compiler generates LLVM bitcode instead of ELF
+          object files, and the actual compilation from bitcode happens at
+          the LTO link step, which may take several minutes depending on the
+          kernel configuration. More information can be found from LLVM's
+          documentation:
+
+           https://llvm.org/docs/LinkTimeOptimization.html
+
+         During link time, this option can use a large amount of RAM, and
+         may take much longer than the ThinLTO option.
+
+config LTO_CLANG_THIN
+       bool "Clang ThinLTO (EXPERIMENTAL)"
+       depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
+       select LTO_CLANG
+       help
+         This option enables Clang's ThinLTO, which allows for parallel
+         optimization and faster incremental compiles compared to the
+         CONFIG_LTO_CLANG_FULL option. More information can be found
+         from Clang's documentation:
+
+           https://clang.llvm.org/docs/ThinLTO.html
+
+         If unsure, say Y.
+endchoice
+
 config HAVE_ARCH_WITHIN_STACK_FRAMES
        bool
        help
@@ -731,6 +821,12 @@ config HAVE_IRQ_EXIT_ON_IRQ_STACK
          This spares a stack switch and improves cache usage on softirq
          processing.
 
+config HAVE_SOFTIRQ_ON_OWN_STACK
+       bool
+       help
+         Architecture provides a function to run __do_softirq() on a
+         seperate stack.
+
 config PGTABLE_LEVELS
        int
        default 2