After binutils commit e43d876 which was first included in binutils 2.41, riscv no longer supports dumping in the middle of instructions. Increase the objdump window by 2-bytes to ensure that any instruction that sits on the boundary of the specified stop-address is not cut in half. Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx> --- arch/riscv/Kconfig | 5 +++++ tools/perf/tests/code-reading.c | 17 ++++++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index d4a7ca0388c071b536df59c0eb11d55f9080c7cd..f164047471267936bc62389b7d7d9a7cbdca8f97 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -229,6 +229,11 @@ config GCC_SUPPORTS_DYNAMIC_FTRACE def_bool CC_IS_GCC depends on $(cc-option,-fpatchable-function-entry=8) +config RISCV_OBJDUMP_SUPPORTS_SPLIT_INSTRUCTION + # Some versions of objdump do not support dumping partial instructions + def_bool y + depends on !(OBJDUMP_IS_GNU && OBJDUMP_VERSION > 24100) + config HAVE_SHADOW_CALL_STACK def_bool $(cc-option,-fsanitize=shadow-call-stack) # https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/a484e843e6eeb51f0cb7b8819e50da6d2444d769 diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c index 27c82cfb7e7de42284bf5af9cf7594a3a963052e..605f4a8e1dbc00d8a572503f45053c2f30ad19e3 100644 --- a/tools/perf/tests/code-reading.c +++ b/tools/perf/tests/code-reading.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <errno.h> +#include <linux/kconfig.h> #include <linux/kernel.h> #include <linux/types.h> #include <inttypes.h> @@ -183,9 +184,23 @@ static int read_via_objdump(const char *filename, u64 addr, void *buf, const char *fmt; FILE *f; int ret; + u64 stop_address = addr + len; + + if (IS_ENABLED(__riscv) && !IS_ENABLED(CONFIG_RISCV_OBJDUMP_SUPPORTS_SPLIT_INSTRUCTION)) { + /* + * On some versions of riscv objdump, dumping in the middle of + * instructions is not supported. riscv instructions are aligned along + * 2-byte intervals and can be either 2-bytes or 4-bytes. This makes it + * possible that the stop-address lands in the middle of a 4-byte + * instruction. Increase the stop_address by two to ensure an + * instruction is not cut in half, but leave the len as-is so only the + * expected number of bytes are collected. + */ + stop_address += 2; + } fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; - ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, addr + len, + ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, stop_address, filename); if (ret <= 0 || (size_t)ret >= sizeof(cmd)) return -1; -- 2.34.1
