[PATCH 1/1 fyi] tools headers UAPI: Sync files changed by new fchmod2 and map_shadow_stack syscalls with the kernel sources

From: Arnaldo Carvalho de Melo
Date: Mon Sep 11 2023 - 17:28:05 EST


tldr; Just FYI, I'm carrying this on the perf tools tree.

- Arnaldo

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

$ ls -1 tools/perf/trace/beauty/*.sh | head -5
tools/perf/trace/beauty/arch_errno_names.sh
tools/perf/trace/beauty/drm_ioctl.sh
tools/perf/trace/beauty/fadvise.sh
tools/perf/trace/beauty/fsconfig.sh
tools/perf/trace/beauty/fsmount.sh
$
$ tools/perf/trace/beauty/fadvise.sh
static const char *fadvise_advices[] = {
[0] = "NORMAL",
[1] = "RANDOM",
[2] = "SEQUENTIAL",
[3] = "WILLNEED",
[4] = "DONTNEED",
[5] = "NOREUSE",
};
$

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

---

To pick the changes in these csets:

c35559f94ebc3e3b ("x86/shstk: Introduce map_shadow_stack syscall")
78252deb023cf087 ("arch: Register fchmodat2, usually as syscall 452")

That add support for this new syscall in tools such as 'perf trace'.

For instance, this is now possible:

# perf trace -v -e fchmodat*,map_shadow_stack --max-events=4
Using CPUID AuthenticAMD-25-21-0
Reusing "openat" BPF sys_enter augmenter for "fchmodat"
event qualifier tracepoint filter: (common_pid != 3499340 && common_pid != 11259) && (id == 268 || id == 452 || id == 453)
^C#

And it'll work as with other syscalls, for instance openat:

# perf trace -e openat* --max-events=4
0.000 ( 0.015 ms): systemd-oomd/1150 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 11
0.068 ( 0.019 ms): systemd-oomd/1150 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1001.slice/user@1001.service/memory.pressure", flags: RDONLY|CLOEXEC) = 11
0.119 ( 0.008 ms): systemd-oomd/1150 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1001.slice/user@1001.service/memory.current", flags: RDONLY|CLOEXEC) = 11
0.138 ( 0.006 ms): systemd-oomd/1150 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1001.slice/user@1001.service/memory.min", flags: RDONLY|CLOEXEC) = 11
#

That is the filter expression attached to the raw_syscalls:sys_{enter,exit}
tracepoints.

$ find tools/perf/arch/ -name "syscall*tbl" | xargs grep -E fchmodat\|sys_map_shadow_stack
tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl:258 n64 fchmodat sys_fchmodat
tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl:452 n64 fchmodat2 sys_fchmodat2
tools/perf/arch/powerpc/entry/syscalls/syscall.tbl:297 common fchmodat sys_fchmodat
tools/perf/arch/powerpc/entry/syscalls/syscall.tbl:452 common fchmodat2 sys_fchmodat2
tools/perf/arch/s390/entry/syscalls/syscall.tbl:299 common fchmodat sys_fchmodat sys_fchmodat
tools/perf/arch/s390/entry/syscalls/syscall.tbl:452 common fchmodat2 sys_fchmodat2 sys_fchmodat2
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl:268 common fchmodat sys_fchmodat
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl:452 common fchmodat2 sys_fchmodat2
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl:453 64 map_shadow_stack sys_map_shadow_stack
$

$ grep -Ew map_shadow_stack\|fchmodat2 /tmp/build/perf-tools/arch/x86/include/generated/asm/syscalls_64.c
[452] = "fchmodat2",
[453] = "map_shadow_stack",
$

This addresses these perf build warnings:

Warning: Kernel ABI header differences:
diff -u tools/include/uapi/asm-generic/unistd.h include/uapi/asm-generic/unistd.h
diff -u tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl
diff -u tools/perf/arch/powerpc/entry/syscalls/syscall.tbl arch/powerpc/kernel/syscalls/syscall.tbl
diff -u tools/perf/arch/s390/entry/syscalls/syscall.tbl arch/s390/kernel/syscalls/syscall.tbl
diff -u tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl arch/mips/kernel/syscalls/syscall_n64.tbl

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/include/uapi/asm-generic/unistd.h | 5 ++++-
tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl | 1 +
tools/perf/arch/powerpc/entry/syscalls/syscall.tbl | 1 +
tools/perf/arch/s390/entry/syscalls/syscall.tbl | 1 +
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl | 2 ++
5 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h
index fd6c1cb585db43c4..abe087c53b4b0434 100644
--- a/tools/include/uapi/asm-generic/unistd.h
+++ b/tools/include/uapi/asm-generic/unistd.h
@@ -820,8 +820,11 @@ __SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
#define __NR_cachestat 451
__SYSCALL(__NR_cachestat, sys_cachestat)

+#define __NR_fchmodat2 452
+__SYSCALL(__NR_fchmodat2, sys_fchmodat2)
+
#undef __NR_syscalls
-#define __NR_syscalls 452
+#define __NR_syscalls 453

/*
* 32 bit systems traditionally used different
diff --git a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
index cfda2511badf3ad0..cb5e757f6621c885 100644
--- a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
+++ b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
@@ -366,3 +366,4 @@
449 n64 futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 n64 cachestat sys_cachestat
+452 n64 fchmodat2 sys_fchmodat2
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index 8c0b08b7a80ec4b7..20e50586e8a26c34 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
@@ -538,3 +538,4 @@
449 common futex_waitv sys_futex_waitv
450 nospu set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common fchmodat2 sys_fchmodat2
diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
index a6935af2235cab6c..0122cc156952cf55 100644
--- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
@@ -454,3 +454,4 @@
449 common futex_waitv sys_futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat sys_cachestat
+452 common fchmodat2 sys_fchmodat2 sys_fchmodat2
diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
index 227538b0ce801eeb..1d6eee30eceb22ab 100644
--- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
@@ -373,6 +373,8 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common fchmodat2 sys_fchmodat2
+453 64 map_shadow_stack sys_map_shadow_stack

#
# Due to a historical design error, certain syscalls are numbered differently
--
2.37.1