All of lore.kernel.org
 help / color / mirror / Atom feed
From: Kenta Tada <Kenta.Tada@sony.com>
To: andrii@kernel.org, bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, kafai@fb.com,
	songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
	kpsingh@kernel.org, Kenta Tada <Kenta.Tada@sony.com>
Subject: [PATCH v5 2/3] libbpf: Fix the incorrect register read for syscalls on x86_64
Date: Mon, 24 Jan 2022 23:16:21 +0900	[thread overview]
Message-ID: <20220124141622.4378-3-Kenta.Tada@sony.com> (raw)
In-Reply-To: <20220124141622.4378-1-Kenta.Tada@sony.com>

Currently, rcx is read as the fourth parameter of syscall on x86_64.
But x86_64 Linux System Call convention uses r10 actually.
This commit adds the wrapper for users who want to access to
syscall params to analyze the user space.

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
---
 tools/lib/bpf/bpf_tracing.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 90f56b0f585f..032ba809f3e5 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -70,6 +70,7 @@
 #define __PT_PARM2_REG si
 #define __PT_PARM3_REG dx
 #define __PT_PARM4_REG cx
+#define __PT_PARM4_REG_SYSCALL r10 /* syscall uses r10 */
 #define __PT_PARM5_REG r8
 #define __PT_RET_REG sp
 #define __PT_FP_REG bp
@@ -99,6 +100,7 @@
 #define __PT_PARM2_REG rsi
 #define __PT_PARM3_REG rdx
 #define __PT_PARM4_REG rcx
+#define __PT_PARM4_REG_SYSCALL r10 /* syscall uses r10 */
 #define __PT_PARM5_REG r8
 #define __PT_RET_REG rsp
 #define __PT_FP_REG rbp
@@ -263,6 +265,26 @@ struct pt_regs;
 
 #endif
 
+#define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1(x)
+#define PT_REGS_PARM2_SYSCALL(x) PT_REGS_PARM2(x)
+#define PT_REGS_PARM3_SYSCALL(x) PT_REGS_PARM3(x)
+#ifdef __PT_PARM4_REG_SYSCALL
+#define PT_REGS_PARM4_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM4_REG_SYSCALL)
+#else /* __PT_PARM4_REG_SYSCALL */
+#define PT_REGS_PARM4_SYSCALL(x) PT_REGS_PARM4(x)
+#endif
+#define PT_REGS_PARM5_SYSCALL(x) PT_REGS_PARM5(x)
+
+#define PT_REGS_PARM1_CORE_SYSCALL(x) PT_REGS_PARM1_CORE(x)
+#define PT_REGS_PARM2_CORE_SYSCALL(x) PT_REGS_PARM2_CORE(x)
+#define PT_REGS_PARM3_CORE_SYSCALL(x) PT_REGS_PARM3_CORE(x)
+#ifdef __PT_PARM4_REG_SYSCALL
+#define PT_REGS_PARM4_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM4_REG_SYSCALL)
+#else /* __PT_PARM4_REG_SYSCALL */
+#define PT_REGS_PARM4_CORE_SYSCALL(x) PT_REGS_PARM4_CORE(x)
+#endif
+#define PT_REGS_PARM5_CORE_SYSCALL(x) PT_REGS_PARM5_CORE(x)
+
 #else /* defined(bpf_target_defined) */
 
 #define PT_REGS_PARM1(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
@@ -290,6 +312,18 @@ struct pt_regs;
 #define BPF_KPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
 #define BPF_KRETPROBE_READ_RET_IP(ip, ctx) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
 
+#define PT_REGS_PARM1_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
+#define PT_REGS_PARM1_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM2_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM3_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM4_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+#define PT_REGS_PARM5_CORE_SYSCALL(x) ({ _Pragma(__BPF_TARGET_MISSING); 0l; })
+
 #endif /* defined(bpf_target_defined) */
 
 #ifndef ___bpf_concat
-- 
2.32.0


  parent reply	other threads:[~2022-01-24 14:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-24 14:16 [PATCH v5 0/3] Fix the incorrect register read for syscalls on x86_64 Kenta Tada
2022-01-24 14:16 ` [PATCH v5 1/3] libbpf: Extract syscall wrapper Kenta Tada
2022-01-24 14:16 ` Kenta Tada [this message]
2022-01-24 14:16 ` [PATCH v5 3/3] libbpf: Add a test to confirm PT_REGS_PARM4_SYSCALL Kenta Tada
2022-01-25  5:05   ` Andrii Nakryiko
2022-02-01 19:36     ` Andrii Nakryiko
2022-02-01 21:01       ` Ilya Leoshkevich

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220124141622.4378-3-Kenta.Tada@sony.com \
    --to=kenta.tada@sony.com \
    --cc=andrii@kernel.org \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=john.fastabend@gmail.com \
    --cc=kafai@fb.com \
    --cc=kpsingh@kernel.org \
    --cc=songliubraving@fb.com \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.