[PATCH v2 2/2] perf riscv: fix register name strings

[Martin Kaiser]

On risc-v, pref probe generates an invalid syntax for a named register in
a kprobe.

$ perf probe --debug verbose --add "n_tty_write tty"
...
Writing event: p:probe/n_tty_write _text+8922528 tty=%"%a0":x64
Failed to write event: Invalid argument

The problem is the combination of

   #define REG_DWARFNUM_NAME(reg, idx) [idx] = "%" #reg

and entries such as

   REG_DWARFNUM_NAME("%a0", 10)

where #reg will escape the quotes of the first macro parameter.

Update the macro definition to produce the correct syntax for a named
register in a kprobe, i.e. the unquoted register name with only one
leading %.

Fixes: a90c4519186d ("perf riscv: Remove dwarf-regs.c and add dwarf-regs-table.h")
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
Signed-off-by: Martin Kaiser <martin@xxxxxxxxx>
---
 tools/perf/arch/riscv/include/dwarf-regs-table.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/riscv/include/dwarf-regs-table.h b/tools/perf/arch/riscv/include/dwarf-regs-table.h
index 009a4e3c51ab..8c42806d34f1 100644
--- a/tools/perf/arch/riscv/include/dwarf-regs-table.h
+++ b/tools/perf/arch/riscv/include/dwarf-regs-table.h
@@ -3,7 +3,7 @@
 /* This is included in perf/util/dwarf-regs.c */
 
 #undef REG_DWARFNUM_NAME
-#define REG_DWARFNUM_NAME(reg, idx)	[idx] = "%" #reg
+#define REG_DWARFNUM_NAME(reg, idx)	[idx] = reg
 
 static const char * const riscv_regstr_tbl[] = {
 	REG_DWARFNUM_NAME("%zero", 0),
-- 
2.43.7