The read_csr macro returns the CSR value as a `unsigned long`. However,
the format specifier presently treats it as a `uint32_t`. This causes
a -Wformat error to be emitted by Clang 18:
cpu/riscv_common/irq_arch.c:149:49: error: format specifies type 'unsigned int'
but the argument has type 'unsigned long' [-Werror,-Wformat]
149 | printf(" mepc: 0x%" PRIx32 "\n", read_csr(mepc));
The handle_trap function is used internally by the trap_entry
implementation from the same file. However, the trap_entry
implementation calls handle_trap from inline assembly. This makes it
difficult for the compiler to infer that the handle_trap function is
used at all. This causes issues when LTO is enabled.
Without this patch compiling any RISC-V RIOT code with `LTO=1` causes
the following linker error:
/home/soeren/src/RIOT/cpu/riscv_common/irq_arch.c:134: undefined reference to `handle_trap'
/tmp/hello-world.elf.Nngidp.ltrans0.ltrans.o:cpu/riscv_common/irq_arch.c:134:(.text.trap_entry+0x34):
relocation truncated to fit: R_RISCV_GPREL_I against undefined symbol `handle_trap'
This commit fixes LTO support for RISC-V.
While at it, also mark the function as static as it is only used by the
trap_entry function from the same compilation unit.
read_csr() returns an unsigned long, not a uint32_t. This causes a
-Wformat warning to be emitted when compiling with clang. This commit
fixes the warning by changing the format string.
