perf tools: Create generic syscall table support

Currently each architecture in perf independently generates syscall
headers.

Adapt the work that has gone into unifying syscall header
implementations in the kernel to work with perf tools.

Introduce this framework with riscv at first. riscv previously relied on
libaudit, but with this change, perf tools for riscv no longer needs
this external dependency.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Günther Noack <gnoack@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mickaël Salaün <mic@digikod.net>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250108-perf_syscalltbl-v6-1-7543b5293098@rivosinc.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/scripts/Makefile.syscalls

@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: GPL-2.0
+# This Makefile generates headers in
+# tools/perf/arch/$(SRCARCH)/include/generated/asm from the architecture's
+# syscall table. This will either be from the generic syscall table, or from a
+# table that is specific to that architecture.
+
+PHONY := all
+all:
+
+obj := $(OUTPUT)arch/$(SRCARCH)/include/generated/asm
+
+syscall_abis_32  := common,32
+syscall_abis_64  := common,64
+syscalltbl := $(srctree)/tools/scripts/syscall.tbl
+
+# let architectures override $(syscall_abis_%) and $(syscalltbl)
+-include $(srctree)/tools/perf/arch/$(SRCARCH)/entry/syscalls/Makefile.syscalls
+include $(srctree)/tools/build/Build.include
+-include $(srctree)/tools/perf/arch/$(SRCARCH)/entry/syscalls/Kbuild
+
+systbl := $(srctree)/tools/perf/scripts/syscalltbl.sh
+
+syscall-y   := $(addprefix $(obj)/, $(syscall-y))
+
+# Remove stale wrappers when the corresponding files are removed from generic-y
+old-headers := $(wildcard $(obj)/*.h)
+unwanted    := $(filter-out $(syscall-y),$(old-headers))
+
+quiet_cmd_remove = REMOVE  $(unwanted)
+      cmd_remove = rm -f $(unwanted)
+
+quiet_cmd_systbl = SYSTBL  $@
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) \
+		   $(if $(systbl-args-$*),$(systbl-args-$*),$(systbl-args)) \
+		   --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
+		   $< $@
+
+all: $(syscall-y)
+	$(if $(unwanted),$(call cmd,remove))
+	@:
+
+$(obj)/syscalls_%.h: $(syscalltbl) $(systbl) FORCE
+	$(call if_changed,systbl)
+
+targets := $(syscall-y)
+
+# Create output directory. Skip it if at least one old header exists
+# since we know the output directory already exists.
+ifeq ($(old-headers),)
+$(shell mkdir -p $(obj))
+endif
+
+PHONY += FORCE
+
+FORCE:
+
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+.PHONY: $(PHONY)