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selftests/bpf: Fix build of task_pt_regs test for arm64

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struct pt_regs is not exported to userspace on all archs. arm64 and s390
export "user_pt_regs" instead, which causes build failure at the moment:

  progs/test_task_pt_regs.c:8:16: error: variable has incomplete type 'struct pt_regs'
  struct pt_regs current_regs = {};

Instead of using pt_regs from ptrace.h, use the larger kernel struct
from vmlinux.h directly. Since the test runner task_pt_regs.c does not
have access to the kernel struct definition, copy it into a char array.

Fixes: 576d47bb1a ("bpf: selftests: Add bpf_task_pt_regs() selftest")
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20210906163635.302307-1-jean-philippe@linaro.org
This commit is contained in:
Jean-Philippe Brucker 2021-09-06 17:36:38 +01:00 committed by Daniel Borkmann
parent 49ca615320
commit 3a029e1f3d
2 changed files with 13 additions and 7 deletions
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1
tools/testing/selftests/bpf/prog_tests/task_pt_regs.c
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@ -1,7 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <test_progs.h>
#include <linux/ptrace.h>
#include "test_task_pt_regs.skel.h"
void test_task_pt_regs(void)

19
tools/testing/selftests/bpf/progs/test_task_pt_regs.c
View File

@ -1,12 +1,17 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/ptrace.h>
#include <linux/bpf.h>
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
struct pt_regs current_regs = {};
struct pt_regs ctx_regs = {};
#define PT_REGS_SIZE sizeof(struct pt_regs)
/*
* The kernel struct pt_regs isn't exported in its entirety to userspace.
* Pass it as an array to task_pt_regs.c
*/
char current_regs[PT_REGS_SIZE] = {};
char ctx_regs[PT_REGS_SIZE] = {};
int uprobe_res = 0;
SEC("uprobe/trigger_func")
@ -17,8 +22,10 @@ int handle_uprobe(struct pt_regs *ctx)
current = bpf_get_current_task_btf();
regs = (struct pt_regs *) bpf_task_pt_regs(current);
__builtin_memcpy(&current_regs, regs, sizeof(*regs));
__builtin_memcpy(&ctx_regs, ctx, sizeof(*ctx));
if (bpf_probe_read_kernel(current_regs, PT_REGS_SIZE, regs))
return 0;
if (bpf_probe_read_kernel(ctx_regs, PT_REGS_SIZE, ctx))
return 0;
/* Prove that uprobe was run */
uprobe_res = 1;