Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2018-01-17

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Add initial BPF map offloading for nfp driver. Currently only
   programs were supported so far w/o being able to access maps.
   Offloaded programs are right now only allowed to perform map
   lookups, and control path is responsible for populating the
   maps. BPF core infrastructure along with nfp implementation is
   provided, from Jakub.

2) Various follow-ups to Josef's BPF error injections. More
   specifically that includes: properly check whether the error
   injectable event is on function entry or not, remove the percpu
   bpf_kprobe_override and rather compare instruction pointer
   with original one, separate error-injection from kprobes since
   it's not limited to it, add injectable error types in order to
   specify what is the expected type of failure, and last but not
   least also support the kernel's fault injection framework, all
   from Masami.

3) Various misc improvements and cleanups to the libbpf Makefile.
   That is, fix permissions when installing BPF header files, remove
   unused variables and functions, and also install the libbpf.h
   header, from Jesper.

4) When offloading to nfp JIT and the BPF insn is unsupported in the
   JIT, then reject right at verification time. Also fix libbpf with
   regards to ELF section name matching by properly treating the
   program type as prefix. Both from Quentin.

5) Add -DPACKAGE to bpftool when including bfd.h for the disassembler.
   This is needed, for example, when building libfd from source as
   bpftool doesn't supply a config.h for bfd.h. Fix from Jiong.

6) xdp_convert_ctx_access() is simplified since it doesn't need to
   set target size during verification, from Jesper.

7) Let bpftool properly recognize BPF_PROG_TYPE_CGROUP_DEVICE
   program types, from Roman.

8) Various functions in BPF cpumap were not declared static, from Wei.

9) Fix a double semicolon in BPF samples, from Luis.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 27 insertions, 33 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index ae3a2d519e50..7114c885a78a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -533,9 +533,7 @@ config FUNCTION_PROFILER
 config BPF_KPROBE_OVERRIDE
 	bool "Enable BPF programs to override a kprobed function"
 	depends on BPF_EVENTS
-	depends on KPROBES_ON_FTRACE
-	depends on HAVE_KPROBE_OVERRIDE
-	depends on DYNAMIC_FTRACE_WITH_REGS
+	depends on FUNCTION_ERROR_INJECTION
 	default n
 	help
 	 Allows BPF to override the execution of a probed function and
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index f6d2327ecb59..f274468cbc45 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -14,7 +14,7 @@
 #include <linux/uaccess.h>
 #include <linux/ctype.h>
 #include <linux/kprobes.h>
-#include <asm/kprobes.h>
+#include <linux/error-injection.h>
 
 #include "trace_probe.h"
 #include "trace.h"
@@ -83,9 +83,8 @@ EXPORT_SYMBOL_GPL(trace_call_bpf);
 #ifdef CONFIG_BPF_KPROBE_OVERRIDE
 BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
 {
-	__this_cpu_write(bpf_kprobe_override, 1);
 	regs_set_return_value(regs, rc);
-	arch_ftrace_kprobe_override_function(regs);
+	override_function_with_return(regs);
 	return 0;
 }
 
@@ -800,11 +799,11 @@ int perf_event_attach_bpf_prog(struct perf_event *event,
 	int ret = -EEXIST;
 
 	/*
-	 * Kprobe override only works for ftrace based kprobes, and only if they
-	 * are on the opt-in list.
+	 * Kprobe override only works if they are on the function entry,
+	 * and only if they are on the opt-in list.
 	 */
 	if (prog->kprobe_override &&
-	    (!trace_kprobe_ftrace(event->tp_event) ||
+	    (!trace_kprobe_on_func_entry(event->tp_event) ||
 	     !trace_kprobe_error_injectable(event->tp_event)))
 		return -EINVAL;
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 91f4b57dab82..1fad24acd444 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/uaccess.h>
 #include <linux/rculist.h>
+#include <linux/error-injection.h>
 
 #include "trace_probe.h"
 
@@ -42,8 +43,6 @@ struct trace_kprobe {
 	(offsetof(struct trace_kprobe, tp.args) +	\
 	(sizeof(struct probe_arg) * (n)))
 
-DEFINE_PER_CPU(int, bpf_kprobe_override);
-
 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
 {
 	return tk->rp.handler != NULL;
@@ -88,13 +87,16 @@ static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 	return nhit;
 }
 
-int trace_kprobe_ftrace(struct trace_event_call *call)
+bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 {
 	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
-	return kprobe_ftrace(&tk->rp.kp);
+
+	return kprobe_on_func_entry(tk->rp.kp.addr,
+			tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
+			tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
 }
 
-int trace_kprobe_error_injectable(struct trace_event_call *call)
+bool trace_kprobe_error_injectable(struct trace_event_call *call)
 {
 	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
 	unsigned long addr;
@@ -106,7 +108,7 @@ int trace_kprobe_error_injectable(struct trace_event_call *call)
 	} else {
 		addr = (unsigned long)tk->rp.kp.addr;
 	}
-	return within_kprobe_error_injection_list(addr);
+	return within_error_injection_list(addr);
 }
 
 static int register_kprobe_event(struct trace_kprobe *tk);
@@ -1202,6 +1204,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
 	int rctx;
 
 	if (bpf_prog_array_valid(call)) {
+		unsigned long orig_ip = instruction_pointer(regs);
 		int ret;
 
 		ret = trace_call_bpf(call, regs);
@@ -1209,12 +1212,13 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
 		/*
 		 * We need to check and see if we modified the pc of the
 		 * pt_regs, and if so clear the kprobe and return 1 so that we
-		 * don't do the instruction skipping.  Also reset our state so
-		 * we are clean the next pass through.
+		 * don't do the single stepping.
+		 * The ftrace kprobe handler leaves it up to us to re-enable
+		 * preemption here before returning if we've modified the ip.
 		 */
-		if (__this_cpu_read(bpf_kprobe_override)) {
-			__this_cpu_write(bpf_kprobe_override, 0);
+		if (orig_ip != instruction_pointer(regs)) {
 			reset_current_kprobe();
+			preempt_enable_no_resched();
 			return 1;
 		}
 		if (!ret)
@@ -1322,15 +1326,8 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
 	if (tk->tp.flags & TP_FLAG_TRACE)
 		kprobe_trace_func(tk, regs);
 #ifdef CONFIG_PERF_EVENTS
-	if (tk->tp.flags & TP_FLAG_PROFILE) {
+	if (tk->tp.flags & TP_FLAG_PROFILE)
 		ret = kprobe_perf_func(tk, regs);
-		/*
-		 * The ftrace kprobe handler leaves it up to us to re-enable
-		 * preemption here before returning if we've modified the ip.
-		 */
-		if (ret)
-			preempt_enable_no_resched();
-	}
 #endif
 	return ret;
 }
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 5e54d748c84c..e101c5bb9eda 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -252,8 +252,8 @@ struct symbol_cache;
 unsigned long update_symbol_cache(struct symbol_cache *sc);
 void free_symbol_cache(struct symbol_cache *sc);
 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
-int trace_kprobe_ftrace(struct trace_event_call *call);
-int trace_kprobe_error_injectable(struct trace_event_call *call);
+bool trace_kprobe_on_func_entry(struct trace_event_call *call);
+bool trace_kprobe_error_injectable(struct trace_event_call *call);
 #else
 /* uprobes do not support symbol fetch methods */
 #define fetch_symbol_u8			NULL
@@ -280,14 +280,14 @@ alloc_symbol_cache(const char *sym, long offset)
 	return NULL;
 }
 
-static inline int trace_kprobe_ftrace(struct trace_event_call *call)
+static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 {
-	return 0;
+	return false;
 }
 
-static inline int trace_kprobe_error_injectable(struct trace_event_call *call)
+static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
 {
-	return 0;
+	return false;
 }
 #endif /* CONFIG_KPROBE_EVENTS */