[PATCH 2/5] s390/bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type
From: Hendrik Brueckner <hidden>
Date: 2017-12-01 14:22:27
Also in:
linux-arch, linux-kselftest, linux-perf-users, linux-s390, lkml, netdev
Subsystem:
performance events subsystem, ptrace support, s390 architecture, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Oleg Nesterov, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds
To mitigate and correct the broken uapi for the BPF_PROG_TYPE_PERF_EVENT program type, introduce a user_pt_regs structure (similar to arm64) that exports parts from the beginnig of the pt_regs structure. The export must start with the beginning of the pt_regs structure because to correctly calculate BPF prologues for perf (regs_query_register_offset()). For BPF_PROG_TYPE_PERF_EVENT program types, the BPF program is then passed a user_pt_regs structure. Note: Depending on future changes to the s390 pt_regs structure, consider the user_pt_regs structure to be stable for a particular kernel version only. (Of course, s390 tries to ensure keep it stable as much as possible.) Signed-off-by: Hendrik Brueckner <redacted> Reviewed-and-tested-by: Thomas Richter [off-list ref] Cc: Martin Schwidefsky <redacted> Cc: Heiko Carstens <redacted> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> --- arch/s390/include/asm/perf_event.h | 1 + arch/s390/include/asm/ptrace.h | 11 ++++++++--- arch/s390/include/uapi/asm/bpf_perf_event.h | 9 +++++++++ arch/s390/include/uapi/asm/ptrace.h | 11 +++++++++++ 4 files changed, 29 insertions(+), 3 deletions(-) create mode 100644 arch/s390/include/uapi/asm/bpf_perf_event.h
diff --git a/arch/s390/include/asm/perf_event.h b/arch/s390/include/asm/perf_event.h
index d6c9d1e..b9c0e36 100644
--- a/arch/s390/include/asm/perf_event.h
+++ b/arch/s390/include/asm/perf_event.h@@ -40,6 +40,7 @@ extern ssize_t cpumf_events_sysfs_show(struct device *dev, extern unsigned long perf_instruction_pointer(struct pt_regs *regs); extern unsigned long perf_misc_flags(struct pt_regs *regs); #define perf_misc_flags(regs) perf_misc_flags(regs) +#define perf_arch_bpf_user_pt_regs(regs) ®s->user_regs /* Perf pt_regs extension for sample-data-entry indicators */ struct perf_sf_sde_regs {
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index a3788da..6f70d81 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h@@ -74,9 +74,14 @@ enum { */ struct pt_regs { - unsigned long args[1]; - psw_t psw; - unsigned long gprs[NUM_GPRS]; + union { + user_pt_regs user_regs; + struct { + unsigned long args[1]; + psw_t psw; + unsigned long gprs[NUM_GPRS]; + }; + }; unsigned long orig_gpr2; unsigned int int_code; unsigned int int_parm;
diff --git a/arch/s390/include/uapi/asm/bpf_perf_event.h b/arch/s390/include/uapi/asm/bpf_perf_event.h
new file mode 100644
index 0000000..cefe7c7
--- /dev/null
+++ b/arch/s390/include/uapi/asm/bpf_perf_event.h@@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _UAPI__ASM_BPF_PERF_EVENT_H__ +#define _UAPI__ASM_BPF_PERF_EVENT_H__ + +#include <asm/ptrace.h> + +typedef user_pt_regs bpf_user_pt_regs_t; + +#endif /* _UAPI__ASM_BPF_PERF_EVENT_H__ */
diff --git a/arch/s390/include/uapi/asm/ptrace.h b/arch/s390/include/uapi/asm/ptrace.h
index 0d23c8f..70f7cb2 100644
--- a/arch/s390/include/uapi/asm/ptrace.h
+++ b/arch/s390/include/uapi/asm/ptrace.h@@ -291,6 +291,17 @@ } s390_regs; /* + * The user_pt_regs structure exports the beginning of + * the in-kernel pt_regs structure to user space. + */ +typedef struct +{ + unsigned long args[1]; + psw_t psw; + unsigned long gprs[NUM_GPRS]; +} user_pt_regs; + +/* * Now for the user space program event recording (trace) definitions. * The following structures are used only for the ptrace interface, don't * touch or even look at it if you don't want to modify the user-space
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1.8.3.1