diff mbox series

[bpf-next,v3,04/11] libbpf: Add __PT_PARM1_REG_SYSCALL macro

Message ID 20220204145018.1983773-5-iii@linux.ibm.com (mailing list archive)
State Accepted
Commit 3a9d84aafb8ccb5599a43745d5d1ca7f80c3dcce
Delegated to: BPF
Headers show
Series libbpf: Fix accessing syscall arguments | expand

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Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 7 maintainers not CCed: andrii@kernel.org kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com yhs@fb.com netdev@vger.kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 94 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next success VM_Test

Commit Message

Ilya Leoshkevich Feb. 4, 2022, 2:50 p.m. UTC 
Some architectures have a special way to access the first syscall
argument. There already exists __PT_PARM4_REG_SYSCALL for the
fourth argument, so define a similar macro for the first one.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tools/lib/bpf/bpf_tracing.h | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Naveen N. Rao Feb. 4, 2022, 4:15 p.m. UTC | #1 
Ilya Leoshkevich wrote:
> Some architectures have a special way to access the first syscall
> argument. There already exists __PT_PARM4_REG_SYSCALL for the
> fourth argument, so define a similar macro for the first one.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  tools/lib/bpf/bpf_tracing.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
> index 032ba809f3e5..30f0964f8c9e 100644
> --- a/tools/lib/bpf/bpf_tracing.h
> +++ b/tools/lib/bpf/bpf_tracing.h
> @@ -265,7 +265,11 @@ struct pt_regs;
> 
>  #endif
> 
> +#ifdef __PT_PARM1_REG_SYSCALL
> +#define PT_REGS_PARM1_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM1_REG_SYSCALL)
> +#else /* __PT_PARM1_REG_SYSCALL */
>  #define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1(x)
> +#endif
>  #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
> @@ -275,7 +279,11 @@ struct pt_regs;
>  #endif
>  #define PT_REGS_PARM5_SYSCALL(x) PT_REGS_PARM5(x)
> 
> +#ifdef __PT_PARM1_REG_SYSCALL
> +#define PT_REGS_PARM1_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_REG_SYSCALL)
> +#else /* __PT_PARM1_REG_SYSCALL */
>  #define PT_REGS_PARM1_CORE_SYSCALL(x) PT_REGS_PARM1_CORE(x)
> +#endif
>  #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

When I was contemplating implementing this for powerpc, I came up with 
the below patch which looked cleaner to me, and also makes it easy for 
architectures to over-ride any other syscall parameter in future. Feel 
free to include this in your series if it makes sense.

- Naveen

--
libbpf: Generalize overriding syscall parameter access macros

Instead of conditionally overriding PT_REGS_PARM4_SYSCALL, provide
default fallback for all _REG_SYSCALL macros so that architectures can
simply override a specific syscall parameter macro.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 tools/lib/bpf/bpf_tracing.h | 40 ++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 032ba809f3e57a..2e2f057c7ec7c5 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -265,25 +265,33 @@ 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)
+#ifndef __PT_PARM1_REG_SYSCALL
+#define __PT_PARM1_REG_SYSCALL __PT_PARM1_REG
+#endif
+#ifndef __PT_PARM2_REG_SYSCALL
+#define __PT_PARM2_REG_SYSCALL __PT_PARM2_REG
+#endif
+#ifndef __PT_PARM3_REG_SYSCALL
+#define __PT_PARM3_REG_SYSCALL __PT_PARM3_REG
+#endif
+#ifndef __PT_PARM4_REG_SYSCALL
+#define __PT_PARM4_REG_SYSCALL __PT_PARM4_REG
 #endif
-#define PT_REGS_PARM5_SYSCALL(x) PT_REGS_PARM5(x)
+#ifndef __PT_PARM5_REG_SYSCALL
+#define __PT_PARM5_REG_SYSCALL __PT_PARM5_REG
+#endif
+
+#define PT_REGS_PARM1_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM1_REG_SYSCALL)
+#define PT_REGS_PARM2_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM2_REG_SYSCALL)
+#define PT_REGS_PARM3_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM3_REG_SYSCALL)
+#define PT_REGS_PARM4_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM4_REG_SYSCALL)
+#define PT_REGS_PARM5_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM5_REG_SYSCALL)
 
-#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_PARM1_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_REG_SYSCALL)
+#define PT_REGS_PARM2_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM2_REG_SYSCALL)
+#define PT_REGS_PARM3_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM3_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)
+#define PT_REGS_PARM5_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM5_REG_SYSCALL)
 
 #else /* defined(bpf_target_defined) */
diff mbox series

Patch

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 032ba809f3e5..30f0964f8c9e 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -265,7 +265,11 @@  struct pt_regs;
 
 #endif
 
+#ifdef __PT_PARM1_REG_SYSCALL
+#define PT_REGS_PARM1_SYSCALL(x) (__PT_REGS_CAST(x)->__PT_PARM1_REG_SYSCALL)
+#else /* __PT_PARM1_REG_SYSCALL */
 #define PT_REGS_PARM1_SYSCALL(x) PT_REGS_PARM1(x)
+#endif
 #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
@@ -275,7 +279,11 @@  struct pt_regs;
 #endif
 #define PT_REGS_PARM5_SYSCALL(x) PT_REGS_PARM5(x)
 
+#ifdef __PT_PARM1_REG_SYSCALL
+#define PT_REGS_PARM1_CORE_SYSCALL(x) BPF_CORE_READ(__PT_REGS_CAST(x), __PT_PARM1_REG_SYSCALL)
+#else /* __PT_PARM1_REG_SYSCALL */
 #define PT_REGS_PARM1_CORE_SYSCALL(x) PT_REGS_PARM1_CORE(x)
+#endif
 #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