Commit e4d9c232 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Alexei Starovoitov
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samples/bpf, selftests/bpf: Use bpf_probe_read_kernel 



A handful of samples and selftests fail to build on s390, because
after commit 0ebeea8c ("bpf: Restrict bpf_probe_read{, str}()
only to archs where they work") bpf_probe_read is not available
anymore.

Fix by using bpf_probe_read_kernel.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720114806.88823-1-iii@linux.ibm.com
parent 6bd55727

samples/bpf/offwaketime_kern.c

+6 −1
Original line number Diff line number Diff line
@@ -12,7 +12,12 @@ 
#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



#define _(P) ({typeof(P) val; bpf_probe_read(&val, sizeof(val), &P); val;})

#define _(P)                                                                   \

	({                                                                     \

		typeof(P) val;                                                 \

		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \

		val;                                                           \

	})



#define MINBLOCK_US	1

samples/bpf/test_overhead_kprobe_kern.c

+9 −3
Original line number Diff line number Diff line
@@ -10,7 +10,12 @@ 
#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})

#define _(P)                                                                   \

	({                                                                     \

		typeof(P) val = 0;                                             \

		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \

		val;                                                           \

	})



SEC("kprobe/__set_task_comm")

int prog(struct pt_regs *ctx)
@@ -25,8 +30,9 @@ int prog(struct pt_regs *ctx) 
	tsk = (void *)PT_REGS_PARM1(ctx);



	pid = _(tsk->pid);

	bpf_probe_read(oldcomm, sizeof(oldcomm), &tsk->comm);

	bpf_probe_read(newcomm, sizeof(newcomm), (void *)PT_REGS_PARM2(ctx));

	bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);

	bpf_probe_read_kernel(newcomm, sizeof(newcomm),

			      (void *)PT_REGS_PARM2(ctx));

	signal = _(tsk->signal);

	oom_score_adj = _(signal->oom_score_adj);

	return 0;

samples/bpf/tracex1_kern.c

+7 −2
Original line number Diff line number Diff line
@@ -11,7 +11,12 @@ 
#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})

#define _(P)                                                                   \

	({                                                                     \

		typeof(P) val = 0;                                             \

		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \

		val;                                                           \

	})



/* kprobe is NOT a stable ABI

 * kernel functions can be removed, renamed or completely change semantics.
@@ -34,7 +39,7 @@ int bpf_prog1(struct pt_regs *ctx) 
	dev = _(skb->dev);

	len = _(skb->len);



	bpf_probe_read(devname, sizeof(devname), dev->name);

	bpf_probe_read_kernel(devname, sizeof(devname), dev->name);



	if (devname[0] == 'l' && devname[1] == 'o') {

		char fmt[] = "skb %p len %d\n";

samples/bpf/tracex5_kern.c

+2 −2
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ PROG(SYS__NR_write)(struct pt_regs *ctx) 
{

	struct seccomp_data sd;



	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));

	bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));

	if (sd.args[2] == 512) {

		char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";

		bpf_trace_printk(fmt, sizeof(fmt),
@@ -60,7 +60,7 @@ PROG(SYS__NR_read)(struct pt_regs *ctx) 
{

	struct seccomp_data sd;



	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));

	bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));

	if (sd.args[2] > 128 && sd.args[2] <= 1024) {

		char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";

		bpf_trace_printk(fmt, sizeof(fmt),

tools/bpf/bpftool/skeleton/pid_iter.bpf.c

+2 −1
Original line number Diff line number Diff line
@@ -71,7 +71,8 @@ int iter(struct bpf_iter__task_file *ctx) 


	e.pid = task->tgid;

	e.id = get_obj_id(file->private_data, obj_type);

	bpf_probe_read(&e.comm, sizeof(e.comm), task->group_leader->comm);

	bpf_probe_read_kernel(&e.comm, sizeof(e.comm),

			      task->group_leader->comm);

	bpf_seq_write(ctx->meta->seq, &e, sizeof(e));



	return 0;

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