[PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

[PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

[Kuniyuki Iwashima]

Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
make sure all syscalls see 'struct pt_regs' definition and resulted
BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
actual struct.

Without this patch, the BPF verifier refuses to load a tracing prog
which accesses pt_regs.

  bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES

With this patch, we can see the correct error, which saves us time
in debugging the prog.

  bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
  bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
Note the cited commit only exists in the tip tree for now.
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=9440c42941606af4c379afa3cf8624f0dc43a629
---
 arch/arm64/include/asm/syscall_wrapper.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
index b383b4802a7b..d30217c21eff 100644
--- a/arch/arm64/include/asm/syscall_wrapper.h
+++ b/arch/arm64/include/asm/syscall_wrapper.h
@@ -8,7 +8,7 @@
 #ifndef __ASM_SYSCALL_WRAPPER_H
 #define __ASM_SYSCALL_WRAPPER_H
 
-struct pt_regs;
+#include <asm/ptrace.h>
 
 #define SC_ARM64_REGS_TO_ARGS(x, ...)				\
 	__MAP(x,__SC_ARGS					\
-- 
2.30.2


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Re: [PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

[Andrii Nakryiko]

On Mon, Oct 31, 2022 at 2:57 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote:
>
> Add the same change for ARM64 as done in the commit 9440c4294160
> ("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
> make sure all syscalls see 'struct pt_regs' definition and resulted
> BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
> actual struct.
>
> Without this patch, the BPF verifier refuses to load a tracing prog
> which accesses pt_regs.
>
>   bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES
>
> With this patch, we can see the correct error, which saves us time
> in debugging the prog.
>
>   bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
>   bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP
>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
> ---

Some of these problems will be mitigated by [0], but still good to
have completely types if possible. LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

  [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=691488&state=*

> Note the cited commit only exists in the tip tree for now.
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=9440c42941606af4c379afa3cf8624f0dc43a629
> ---
>  arch/arm64/include/asm/syscall_wrapper.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
> index b383b4802a7b..d30217c21eff 100644
> --- a/arch/arm64/include/asm/syscall_wrapper.h
> +++ b/arch/arm64/include/asm/syscall_wrapper.h
> @@ -8,7 +8,7 @@
>  #ifndef __ASM_SYSCALL_WRAPPER_H
>  #define __ASM_SYSCALL_WRAPPER_H
>
> -struct pt_regs;
> +#include <asm/ptrace.h>
>
>  #define SC_ARM64_REGS_TO_ARGS(x, ...)                          \
>         __MAP(x,__SC_ARGS                                       \
> --
> 2.30.2
>

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Re: [PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

[Catalin Marinas]

On Mon, 31 Oct 2022 14:57:28 -0700, Kuniyuki Iwashima wrote:
> Add the same change for ARM64 as done in the commit 9440c4294160
> ("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
> make sure all syscalls see 'struct pt_regs' definition and resulted
> BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
> actual struct.
> 
> Without this patch, the BPF verifier refuses to load a tracing prog
> which accesses pt_regs.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.
      https://git.kernel.org/arm64/c/acfc35cfcee5

-- 
Catalin


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