opensbi.git/Makefile, branch v1.8

Makefile: sensible default value for OPENSBI_CC_XLEN.

2025-12-15T13:12:00Z

If guessing the compiler's XLEN fails, use 64 rather than garbage. The previous behavior could silently break e.g. OPENSBI_CC_SUPPORT_VECTOR when cross-compiling with a system's native clang. Signed-off-by: Benedikt Freisen Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20251114203842.13396-3-b.freisen@gmx.net Signed-off-by: Anup Patel

Makefile: define C language standard to "gnu11"

2025-12-01T06:22:55Z

C language standard was not specified, implying default that is depending on the compiler version. Force "gnu11", same as for the Linux kernel Signed-off-by: Vladimir Kondratiev Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20251113081648.2708990-1-vladimir.kondratiev@mobileye.com Signed-off-by: Anup Patel

Makefile: Only enable --print-gc-section for verbose (V=1) build

2025-12-01T05:57:50Z

Earlier this option was enabled during debug build which only prints the linker logs of removing the unused sections. Instead enable this for V=1 and keep the debug build clean. Signed-off-by: Rahul Pathak Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20251110164352.163801-1-rpathak@ventanamicro.com Signed-off-by: Anup Patel

Makefile: Add flag for reprodubility compiler flags

2025-06-15T12:58:55Z

Provides mechanism to remove absolute paths from binaries using -ffile-prefix-map It will help distros (e.g. yocto based ones ) which want to ship the .elf files but need to scrub absolute paths in objects Reviewed-by: Anup Patel Signed-off-by: Khem Raj Link: https://lore.kernel.org/r/20250515025931.3383142-1-raj.khem@gmail.com Signed-off-by: Anup Patel

Makefile: Make $(LLVM) more flexible

2025-06-14T04:41:11Z

Introduce a way for developers to easily switch between LLVM versions with LLVM=/path/to/llvm/ and LLVM=-version. This is a useful addition to the existing LLVM=1 variable which will select the first clang and llvm binutils available on the path. Reviewed-by: Anup Patel Tested-by: Anup Patel Signed-off-by: Charlie Jenkins Link: https://lore.kernel.org/r/20250430-improve_llvm_building-v1-1-caae96cc6be6@rivosinc.com Signed-off-by: Anup Patel

Makefile: fix missing .debug_frame DWARF section for GCC

2025-05-15T13:22:38Z

When OpenSBI is built with a relatively new compiler (gcc-13 and greater) I observed that GDB is unable to produce proper backtraces and some variable values appear corrupted (even if the associated DWARF location descriptor is correct). Turns out that to properly work with debug information, debuggers often need to unwind the stack. They generally rely on Call Frame Information (CFI) records provided by the compiler to facilitate this task. Currently, the GCC compiler offers two mechanisms: - `.debug_frame` section (as described in the DWARF specification). - `.eh_frame` sections (as described in LSB documents). The latter (`.eh_frame`) supports stack unwinding at runtime, providing a framework for C++ exceptions or enabling backtrace generation using libraries like libunwind. However, the downside of this approach is that these sections should be part of loadable segments. The former (`.debug_frame`) is simply an ordinary debug section. Starting from GCC 13, Linux targets enable the `-fasynchronous-unwind-tables` and `-funwind-tables` flags by default. Relevant commit: https://github.com/gcc-mirror/gcc/commit/3cd08f7168 When these flags are active, the compiler generates `.eh_frame` sections instead of `.debug_frame`. Since OpenSBI is built using the **Linux toolchain**, this behavior applies to OpenSBI as well. The problem arises because the SBI build system uses `-Wl,--gc-sections`, which discards the `.eh_frame` section. Possible Fixes: 1. Enforce `.debug_frame` generation – Modify compiler flags to generate `.debug_frame` instead of `.eh_frame`. 2. Preserve `.eh_frame` in the linker script – Add `KEEP(*(.eh_frame))` to ensure the section is not discarded. I chose Option 1 because it avoids any runtime overhead. Signed-off-by: Parshintsev Anatoly Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20250421124729.36364-1-anatoly.parshintsev@syntacore.com Signed-off-by: Anup Patel

Makefile: Avoid repeated evaluation of shell commands

2025-04-13T16:19:14Z

Recursively expanded variables (defined with '=') are expanded at evaluation time. These version information variables are evaluated inside a recipe as part of GENFLAGS. As a result, the shell commands are executed separately for each compiler invocation. Convert the version information variables to be simply expanded, so the shell commands are executed only once, at Makefile evaluation time. This speeds up the build by as much as 75%. A separate check is needed to maintain the behavior of preferring the value of OPENSBI_BUILD_TIME_STAMP from the environment. Signed-off-by: Samuel Holland Reviewed-by: Xiang W Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20250313035755.3796610-1-samuel.holland@sifive.com Signed-off-by: Anup Patel

lib: sbi: Avoid GOT indirection for global symbol references

2025-03-24T11:30:59Z

OpenSBI is compiled with -fPIE, which generally implies dynamic linking. This causes the compiler to generate GOT references for global symbols in order to support runtime symbol interposition. However, OpenSBI does not actually perform dynamic linking, so the GOT indirection just adds unnecessary overhead. The GOT references can be avoided by declaring global symbols with hidden visibility, thus making them local to this dynamic object and non-interposable. GCC/Clang's -fvisibility parameter is insufficient for this purpose when referencing objects from other translation units; either __attribute__((visibility(...)) or the pragma is required. Use the pragma since it is easier to apply to every symbol. Additionally clean up the one GOT reference from inline assembly. With this change, a firmware linked with LLD does not contain either a GOT or a PLT, and a firmware linked with BFD ld contains only a GOT with a single (unreferenced, legacy) _GLOBAL_OFFSET_TABLE_ entry. Signed-off-by: Samuel Holland Reviewed-by: Anup Patel

Makefile: remove carry output if scripts/carray.sh fails

2024-12-15T07:00:47Z

If the script fails, we end up trying to build either an empty or damaged .c file. Just remove it and let gcc fail on non-existent file. Signed-off-by: Ben Dooks Reviewed-by: Anup Patel

Makefile: Don't enable V-extension using -march option

2024-12-15T06:00:48Z

Enabling V-extension using -march option causes OpenSBI boot-time hang with LLVM compiler. As a work-around, don't enable V-extension using -march option and instead use a custom OpenSBI specific define inform availability of V-extension to lib/sbi/sbi_trap_v_ldst.c. Fixes: c2acc5e5b0d8 ("lib: sbi_misaligned_ldst: Add handling of vector load/store") Signed-off-by: Anup Patel Reviewed-by: Samuel Holland