On Thu, Jun 13, 2019 at 06:38:01PM +0200, Anisse Astier wrote:
> Otherwise this will create userspace build issues for any program
> (strace, qemu) that includes both <sys/prctl.h> (with musl libc) and
> <linux/ptrace.h> (which then includes <asm/ptrace.h>), like this:
>
> error: redefinition of 'struct prctl_mm_map'
> struct prctl_mm_map {
>
> See
> https://github.com/foundriesio/meta-lmp/commit/6d4a106e191b5d79c41b9ac78fd321316d3013c0
> for a public example of people working around this issue.
>
> This fixes an UAPI regression introduced in commit 43d4da2c45b2
> ("arm64/sve: ptrace and ELF coredump support").
>
> Cc: sta...@vger.kernel.org
Consider adding a Fixes: tag.
> Signed-off-by: Anisse Astier <aast...@freebox.fr>
> ---
> arch/arm64/include/uapi/asm/ptrace.h | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/uapi/asm/ptrace.h
> b/arch/arm64/include/uapi/asm/ptrace.h
> index d78623acb649..03b6d6f029fc 100644
> --- a/arch/arm64/include/uapi/asm/ptrace.h
> +++ b/arch/arm64/include/uapi/asm/ptrace.h
> @@ -65,8 +65,6 @@
>
> #ifndef __ASSEMBLY__
>
> -#include <linux/prctl.h>
> -
> /*
> * User structures for general purpose, floating point and debug registers.
> */
> @@ -113,10 +111,10 @@ struct user_sve_header {
>
> /*
> * Common SVE_PT_* flags:
> - * These must be kept in sync with prctl interface in <linux/ptrace.h>
> + * These must be kept in sync with prctl interface in <linux/prctl.h>
Ack
> */
> -#define SVE_PT_VL_INHERIT (PR_SVE_VL_INHERIT >> 16)
> -#define SVE_PT_VL_ONEXEC (PR_SVE_SET_VL_ONEXEC >> 16)
> +#define SVE_PT_VL_INHERIT (1 << 1) /* PR_SVE_VL_INHERIT */
> +#define SVE_PT_VL_ONEXEC (1 << 2) /* PR_SVE_SET_VL_ONEXEC */
Makes sense, but...
Since sve_context.h was already introduced to solve a closely related
problem, I wonder whether we can provide shadow definitions there,
similarly to way the arm64/include/uapi/asm/ptrace.h definitions are
derived. Although it's a slight abuse of that header, I think that
would be my preferred approach.
Otherwise, at least make the required relationship between ptrace.h and
prctl.h constants a bit more obvious, say,
#define SVE_PT_VL_INHERIT ((1 << 17) /* PR_SVE_SET_VL_INHERIT */ >> 16)
etc.
Cheers
---Dave
