[PATCH v2 1/6] bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type

From: Hendrik Brueckner
Date: Mon Dec 04 2017 - 04:59:35 EST

Commit 0515e5999a466dfe ("bpf: introduce BPF_PROG_TYPE_PERF_EVENT
program type") introduced the bpf_perf_event_data structure which
exports the pt_regs structure. This is OK for multiple architectures
but fail for s390 and arm64 which do not export pt_regs. Programs
using them, for example, the bpf selftest fail to compile on these
architectures.

For s390, exporting the pt_regs is not an option because s390 wants
to allow changes to it. For arm64, there is a user_pt_regs structure
that covers parts of the pt_regs structure for use by user space.

To solve the broken uapi for s390 and arm64, introduce an abstract
type for pt_regs and add an asm/bpf_perf_event.h file that concretes
the type. An asm-generic header file covers the architectures that
export pt_regs today.

The arch-specific enablement for s390 and arm64 follows in separate
commits.

Reported-by: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Fixes: 0515e5999a466dfe ("bpf: introduce BPF_PROG_TYPE_PERF_EVENT program type")
Signed-off-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Reviewed-and-tested-by: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
---
arch/alpha/include/uapi/asm/Kbuild | 2 ++
arch/arc/include/uapi/asm/Kbuild | 1 +
arch/arm/include/uapi/asm/Kbuild | 1 +
arch/blackfin/include/uapi/asm/Kbuild | 1 +
arch/c6x/include/uapi/asm/Kbuild | 1 +
arch/cris/include/uapi/asm/Kbuild | 1 +
arch/frv/include/uapi/asm/Kbuild | 2 ++
arch/h8300/include/uapi/asm/Kbuild | 1 +
arch/hexagon/include/uapi/asm/Kbuild | 1 +
arch/ia64/include/uapi/asm/Kbuild | 1 +
arch/m32r/include/uapi/asm/Kbuild | 1 +
arch/m68k/include/uapi/asm/Kbuild | 1 +
arch/metag/include/uapi/asm/Kbuild | 1 +
arch/microblaze/include/uapi/asm/Kbuild | 1 +
arch/mips/include/uapi/asm/Kbuild | 1 +
arch/mn10300/include/uapi/asm/Kbuild | 1 +
arch/nios2/include/uapi/asm/Kbuild | 1 +
arch/openrisc/include/uapi/asm/Kbuild | 1 +
arch/parisc/include/uapi/asm/Kbuild | 1 +
arch/powerpc/include/uapi/asm/Kbuild | 1 +
arch/riscv/include/uapi/asm/Kbuild | 1 +
arch/score/include/uapi/asm/Kbuild | 1 +
arch/sh/include/uapi/asm/Kbuild | 1 +
arch/sparc/include/uapi/asm/Kbuild | 1 +
arch/tile/include/uapi/asm/Kbuild | 1 +
arch/unicore32/include/uapi/asm/Kbuild | 1 +
arch/x86/include/uapi/asm/Kbuild | 1 +
arch/xtensa/include/uapi/asm/Kbuild | 1 +
include/linux/perf_event.h | 6 +++++-
include/uapi/asm-generic/bpf_perf_event.h | 9 +++++++++
include/uapi/linux/bpf_perf_event.h | 5 ++---
kernel/events/core.c | 2 +-
32 files changed, 47 insertions(+), 5 deletions(-)
create mode 100644 include/uapi/asm-generic/bpf_perf_event.h

diff --git a/arch/alpha/include/uapi/asm/Kbuild b/arch/alpha/include/uapi/asm/Kbuild
index b15bf6b..14a2e9a 100644
--- a/arch/alpha/include/uapi/asm/Kbuild
+++ b/arch/alpha/include/uapi/asm/Kbuild
@@ -1,2 +1,4 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm
+
+generic-y += bpf_perf_event.h
diff --git a/arch/arc/include/uapi/asm/Kbuild b/arch/arc/include/uapi/asm/Kbuild
index fa6d0ff..170b5db 100644
--- a/arch/arc/include/uapi/asm/Kbuild
+++ b/arch/arc/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/arm/include/uapi/asm/Kbuild b/arch/arm/include/uapi/asm/Kbuild
index 4d53de3..4d1cc18 100644
--- a/arch/arm/include/uapi/asm/Kbuild
+++ b/arch/arm/include/uapi/asm/Kbuild
@@ -7,6 +7,7 @@ generated-y += unistd-oabi.h
generated-y += unistd-eabi.h

generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += ioctl.h
generic-y += ipcbuf.h
diff --git a/arch/blackfin/include/uapi/asm/Kbuild b/arch/blackfin/include/uapi/asm/Kbuild
index aa624b4..2240b38 100644
--- a/arch/blackfin/include/uapi/asm/Kbuild
+++ b/arch/blackfin/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += ioctl.h
generic-y += ipcbuf.h
diff --git a/arch/c6x/include/uapi/asm/Kbuild b/arch/c6x/include/uapi/asm/Kbuild
index 67ee896..26644e1 100644
--- a/arch/c6x/include/uapi/asm/Kbuild
+++ b/arch/c6x/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/cris/include/uapi/asm/Kbuild b/arch/cris/include/uapi/asm/Kbuild
index 3687b54..3470c6e 100644
--- a/arch/cris/include/uapi/asm/Kbuild
+++ b/arch/cris/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/frv/include/uapi/asm/Kbuild b/arch/frv/include/uapi/asm/Kbuild
index b15bf6b..14a2e9a 100644
--- a/arch/frv/include/uapi/asm/Kbuild
+++ b/arch/frv/include/uapi/asm/Kbuild
@@ -1,2 +1,4 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm
+
+generic-y += bpf_perf_event.h
diff --git a/arch/h8300/include/uapi/asm/Kbuild b/arch/h8300/include/uapi/asm/Kbuild
index 187aed8..2f65f78 100644
--- a/arch/h8300/include/uapi/asm/Kbuild
+++ b/arch/h8300/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/hexagon/include/uapi/asm/Kbuild b/arch/hexagon/include/uapi/asm/Kbuild
index cb5df3a..41a176d 100644
--- a/arch/hexagon/include/uapi/asm/Kbuild
+++ b/arch/hexagon/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/ia64/include/uapi/asm/Kbuild b/arch/ia64/include/uapi/asm/Kbuild
index 13a97aa..f5c6967 100644
--- a/arch/ia64/include/uapi/asm/Kbuild
+++ b/arch/ia64/include/uapi/asm/Kbuild
@@ -1,4 +1,5 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += kvm_para.h
diff --git a/arch/m32r/include/uapi/asm/Kbuild b/arch/m32r/include/uapi/asm/Kbuild
index 1c44d3b..451bf60 100644
--- a/arch/m32r/include/uapi/asm/Kbuild
+++ b/arch/m32r/include/uapi/asm/Kbuild
@@ -1,5 +1,6 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += kvm_para.h
generic-y += siginfo.h
diff --git a/arch/m68k/include/uapi/asm/Kbuild b/arch/m68k/include/uapi/asm/Kbuild
index 3717b64..c2e26a4 100644
--- a/arch/m68k/include/uapi/asm/Kbuild
+++ b/arch/m68k/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += ioctl.h
generic-y += ipcbuf.h
diff --git a/arch/metag/include/uapi/asm/Kbuild b/arch/metag/include/uapi/asm/Kbuild
index 6ac763d..f9eaf07 100644
--- a/arch/metag/include/uapi/asm/Kbuild
+++ b/arch/metag/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/microblaze/include/uapi/asm/Kbuild b/arch/microblaze/include/uapi/asm/Kbuild
index 06609ca..2c6a6bf 100644
--- a/arch/microblaze/include/uapi/asm/Kbuild
+++ b/arch/microblaze/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/mips/include/uapi/asm/Kbuild b/arch/mips/include/uapi/asm/Kbuild
index a0266fe..7a4becd 100644
--- a/arch/mips/include/uapi/asm/Kbuild
+++ b/arch/mips/include/uapi/asm/Kbuild
@@ -1,4 +1,5 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += ipcbuf.h
diff --git a/arch/mn10300/include/uapi/asm/Kbuild b/arch/mn10300/include/uapi/asm/Kbuild
index c94ee54..81271d3 100644
--- a/arch/mn10300/include/uapi/asm/Kbuild
+++ b/arch/mn10300/include/uapi/asm/Kbuild
@@ -1,4 +1,5 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += siginfo.h
diff --git a/arch/nios2/include/uapi/asm/Kbuild b/arch/nios2/include/uapi/asm/Kbuild
index ffca24d..13a3d77 100644
--- a/arch/nios2/include/uapi/asm/Kbuild
+++ b/arch/nios2/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/openrisc/include/uapi/asm/Kbuild b/arch/openrisc/include/uapi/asm/Kbuild
index 62286db..130c16c 100644
--- a/arch/openrisc/include/uapi/asm/Kbuild
+++ b/arch/openrisc/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/parisc/include/uapi/asm/Kbuild b/arch/parisc/include/uapi/asm/Kbuild
index 196d2a4..286ef5a 100644
--- a/arch/parisc/include/uapi/asm/Kbuild
+++ b/arch/parisc/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
+generic-y += bpf_perf_event.h
generic-y += kvm_para.h
generic-y += param.h
generic-y += poll.h
diff --git a/arch/powerpc/include/uapi/asm/Kbuild b/arch/powerpc/include/uapi/asm/Kbuild
index 0d960ef..1a6ed59 100644
--- a/arch/powerpc/include/uapi/asm/Kbuild
+++ b/arch/powerpc/include/uapi/asm/Kbuild
@@ -1,6 +1,7 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += param.h
generic-y += poll.h
generic-y += resource.h
diff --git a/arch/riscv/include/uapi/asm/Kbuild b/arch/riscv/include/uapi/asm/Kbuild
index 5ded96b..7e91f48 100644
--- a/arch/riscv/include/uapi/asm/Kbuild
+++ b/arch/riscv/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += setup.h
generic-y += unistd.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/score/include/uapi/asm/Kbuild b/arch/score/include/uapi/asm/Kbuild
index c94ee54..81271d3 100644
--- a/arch/score/include/uapi/asm/Kbuild
+++ b/arch/score/include/uapi/asm/Kbuild
@@ -1,4 +1,5 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += siginfo.h
diff --git a/arch/sh/include/uapi/asm/Kbuild b/arch/sh/include/uapi/asm/Kbuild
index e285313..ba4d39c 100644
--- a/arch/sh/include/uapi/asm/Kbuild
+++ b/arch/sh/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/sparc/include/uapi/asm/Kbuild b/arch/sparc/include/uapi/asm/Kbuild
index 2178c78..4680ba2 100644
--- a/arch/sparc/include/uapi/asm/Kbuild
+++ b/arch/sparc/include/uapi/asm/Kbuild
@@ -1,4 +1,5 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += types.h
diff --git a/arch/tile/include/uapi/asm/Kbuild b/arch/tile/include/uapi/asm/Kbuild
index 5711de0..cc43961 100644
--- a/arch/tile/include/uapi/asm/Kbuild
+++ b/arch/tile/include/uapi/asm/Kbuild
@@ -1,6 +1,7 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/unicore32/include/uapi/asm/Kbuild b/arch/unicore32/include/uapi/asm/Kbuild
index 759a714..8611ef9 100644
--- a/arch/unicore32/include/uapi/asm/Kbuild
+++ b/arch/unicore32/include/uapi/asm/Kbuild
@@ -3,6 +3,7 @@ include include/uapi/asm-generic/Kbuild.asm

generic-y += auxvec.h
generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/arch/x86/include/uapi/asm/Kbuild b/arch/x86/include/uapi/asm/Kbuild
index da1489c..1e901e4 100644
--- a/arch/x86/include/uapi/asm/Kbuild
+++ b/arch/x86/include/uapi/asm/Kbuild
@@ -1,6 +1,7 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm

+generic-y += bpf_perf_event.h
generated-y += unistd_32.h
generated-y += unistd_64.h
generated-y += unistd_x32.h
diff --git a/arch/xtensa/include/uapi/asm/Kbuild b/arch/xtensa/include/uapi/asm/Kbuild
index a5bcdfb..837d4dd 100644
--- a/arch/xtensa/include/uapi/asm/Kbuild
+++ b/arch/xtensa/include/uapi/asm/Kbuild
@@ -2,6 +2,7 @@
include include/uapi/asm-generic/Kbuild.asm

generic-y += bitsperlong.h
+generic-y += bpf_perf_event.h
generic-y += errno.h
generic-y += fcntl.h
generic-y += ioctl.h
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 2c9c87d..7546822 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -15,6 +15,7 @@
#define _LINUX_PERF_EVENT_H

#include <uapi/linux/perf_event.h>
+#include <uapi/linux/bpf_perf_event.h>

/*
* Kernel-internal data types and definitions:
@@ -787,7 +788,7 @@ struct perf_output_handle {
};

struct bpf_perf_event_data_kern {
- struct pt_regs *regs;
+ bpf_user_pt_regs_t *regs;
struct perf_sample_data *data;
struct perf_event *event;
};
@@ -1177,6 +1178,9 @@ extern void perf_tp_event(u16 event_type, u64 count, void *record,
(user_mode(regs) ? PERF_RECORD_MISC_USER : PERF_RECORD_MISC_KERNEL)
# define perf_instruction_pointer(regs) instruction_pointer(regs)
#endif
+#ifndef perf_arch_bpf_user_pt_regs
+# define perf_arch_bpf_user_pt_regs(regs) regs
+#endif

static inline bool has_branch_stack(struct perf_event *event)
{
diff --git a/include/uapi/asm-generic/bpf_perf_event.h b/include/uapi/asm-generic/bpf_perf_event.h
new file mode 100644
index 0000000..53815d2
--- /dev/null
+++ b/include/uapi/asm-generic/bpf_perf_event.h
@@ -0,0 +1,9 @@
+#ifndef _UAPI__ASM_GENERIC_BPF_PERF_EVENT_H__
+#define _UAPI__ASM_GENERIC_BPF_PERF_EVENT_H__
+
+#include <linux/ptrace.h>
+
+/* Export kernel pt_regs structure */
+typedef struct pt_regs bpf_user_pt_regs_t;
+
+#endif /* _UAPI__ASM_GENERIC_BPF_PERF_EVENT_H__ */
diff --git a/include/uapi/linux/bpf_perf_event.h b/include/uapi/linux/bpf_perf_event.h
index af549d4..8f95303 100644
--- a/include/uapi/linux/bpf_perf_event.h
+++ b/include/uapi/linux/bpf_perf_event.h
@@ -8,11 +8,10 @@
#ifndef _UAPI__LINUX_BPF_PERF_EVENT_H__
#define _UAPI__LINUX_BPF_PERF_EVENT_H__

-#include <linux/types.h>
-#include <linux/ptrace.h>
+#include <asm/bpf_perf_event.h>

struct bpf_perf_event_data {
- struct pt_regs regs;
+ bpf_user_pt_regs_t regs;
__u64 sample_period;
};

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 16beab4..ba957b9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7987,11 +7987,11 @@ static void bpf_overflow_handler(struct perf_event *event,
{
struct bpf_perf_event_data_kern ctx = {
.data = data,
- .regs = regs,
.event = event,
};
int ret = 0;

+ ctx.regs = perf_arch_bpf_user_pt_regs(regs);
preempt_disable();
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
goto out;
--
1.8.3.1