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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>
Cc:     Tero Kristo <tero.kristo@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: [PATCH bpf-next v2 11/28] samples/bpf: add a report descriptor fixup
Date:   Fri,  4 Mar 2022 18:28:35 +0100
Message-Id: <20220304172852.274126-12-benjamin.tissoires@redhat.com>
In-Reply-To: <20220304172852.274126-1-benjamin.tissoires@redhat.com>
References: <20220304172852.274126-1-benjamin.tissoires@redhat.com>
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the program inverts the definition of X and Y at a given place in the
report descriptor of my mouse.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v2:
- split the series by bpf/libbpf/hid/selftests and samples
---
 samples/bpf/hid_mouse_kern.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/samples/bpf/hid_mouse_kern.c b/samples/bpf/hid_mouse_kern.c
index c24a12e06b40..958820caaf5d 100644
--- a/samples/bpf/hid_mouse_kern.c
+++ b/samples/bpf/hid_mouse_kern.c
@@ -62,5 +62,30 @@ int hid_x_event(struct hid_bpf_ctx *ctx)
 	return 0;
 }
 
+SEC("hid/rdesc_fixup")
+int hid_rdesc_fixup(struct hid_bpf_ctx *ctx)
+{
+	if (ctx->type != HID_BPF_RDESC_FIXUP)
+		return 0;
+
+	bpf_printk("rdesc: %02x %02x %02x",
+		   ctx->data[0],
+		   ctx->data[1],
+		   ctx->data[2]);
+	bpf_printk("       %02x %02x %02x",
+		   ctx->data[3],
+		   ctx->data[4],
+		   ctx->data[5]);
+	bpf_printk("       %02x %02x %02x ...",
+		   ctx->data[6],
+		   ctx->data[7],
+		   ctx->data[8]);
+
+	ctx->data[39] = 0x31;
+	ctx->data[41] = 0x30;
+
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";
 u32 _version SEC("version") = LINUX_VERSION_CODE;
-- 
2.35.1