Re: [PATCH v2] linux-user: Implement stracing madvise()

[Ilya Leoshkevich]

On Mon, 2022-09-05 at 23:40 +0200, Ilya Leoshkevich wrote:
> The default implementation has several problems: the first argument
> is
> not displayed as a pointer, making it harder to grep; the third
> argument is not symbolized; and there are several extra unused
> arguments.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
> 
> v1:
> https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg04275.html
> v1 -> v2: Add all enum values (Richard).
> 
>  linux-user/strace.c    | 67
> ++++++++++++++++++++++++++++++++++++++++++
>  linux-user/strace.list |  2 +-
>  2 files changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index 7d882526da..da2ff27512 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -2969,6 +2969,73 @@ print_stat(CPUArchState *cpu_env, const struct
> syscallname *name,
>  #define print_lstat64   print_stat
>  #endif
>  
> +#if defined(TARGET_NR_madvise)
> +#define TARGET_MADV_NORMAL 0
> +#define TARGET_MADV_RANDOM 1
> +#define TARGET_MADV_SEQUENTIAL 2
> +#define TARGET_MADV_WILLNEED 3
> +#define TARGET_MADV_DONTNEED 4
> +#define TARGET_MADV_FREE 8
> +#define TARGET_MADV_REMOVE 9
> +#define TARGET_MADV_DONTFORK 10
> +#define TARGET_MADV_DOFORK 11
> +#define TARGET_MADV_HWPOISON 100
> +#define TARGET_MADV_SOFT_OFFLINE 101
> +#define TARGET_MADV_MERGEABLE 12
> +#define TARGET_MADV_UNMERGEABLE 13
> +#define TARGET_MADV_HUGEPAGE 14
> +#define TARGET_MADV_NOHUGEPAGE 15
> +#define TARGET_MADV_DONTDUMP 16
> +#define TARGET_MADV_DODUMP 17
> +#define TARGET_MADV_WIPEONFORK 18
> +#define TARGET_MADV_KEEPONFORK 19
> +#define TARGET_MADV_COLD 20
> +#define TARGET_MADV_PAGEOUT 21
> +#define TARGET_MADV_POPULATE_READ 22
> +#define TARGET_MADV_POPULATE_WRITE 23
> +#define TARGET_MADV_DONTNEED_LOCKED 24
> +
> +static struct enums madvise_advice[] = {
> +    ENUM_TARGET(MADV_NORMAL),
> +    ENUM_TARGET(MADV_RANDOM),
> +    ENUM_TARGET(MADV_SEQUENTIAL),
> +    ENUM_TARGET(MADV_WILLNEED),
> +    ENUM_TARGET(MADV_DONTNEED),
> +    ENUM_TARGET(MADV_FREE),
> +    ENUM_TARGET(MADV_REMOVE),
> +    ENUM_TARGET(MADV_DONTFORK),
> +    ENUM_TARGET(MADV_DOFORK),
> +    ENUM_TARGET(MADV_HWPOISON),
> +    ENUM_TARGET(MADV_SOFT_OFFLINE),
> +    ENUM_TARGET(MADV_MERGEABLE),
> +    ENUM_TARGET(MADV_UNMERGEABLE),
> +    ENUM_TARGET(MADV_HUGEPAGE),
> +    ENUM_TARGET(MADV_NOHUGEPAGE),
> +    ENUM_TARGET(MADV_DONTDUMP),
> +    ENUM_TARGET(MADV_DODUMP),
> +    ENUM_TARGET(MADV_WIPEONFORK),
> +    ENUM_TARGET(MADV_KEEPONFORK),
> +    ENUM_TARGET(MADV_COLD),
> +    ENUM_TARGET(MADV_PAGEOUT),
> +    ENUM_TARGET(MADV_POPULATE_READ),
> +    ENUM_TARGET(MADV_POPULATE_WRITE),
> +    ENUM_TARGET(MADV_DONTNEED_LOCKED),
> +    ENUM_END,
> +};
> +
> +static void
> +print_madvise(CPUArchState *cpu_env, const struct syscallname *name,
> +              abi_long arg0, abi_long arg1, abi_long arg2,
> +              abi_long arg3, abi_long arg4, abi_long arg5)
> +{
> +    print_syscall_prologue(name);
> +    print_pointer(arg0, 0);
> +    print_raw_param("%d", arg1, 0);
> +    print_enums(madvise_advice, arg2, 1);
> +    print_syscall_epilogue(name);
> +}
> +#endif
> +
>  #if defined(TARGET_NR_fstat) || defined(TARGET_NR_fstat64)
>  static void
>  print_fstat(CPUArchState *cpu_env, const struct syscallname *name,
> diff --git a/linux-user/strace.list b/linux-user/strace.list
> index 72e17b1acf..c93effdbc8 100644
> --- a/linux-user/strace.list
> +++ b/linux-user/strace.list
> @@ -541,7 +541,7 @@
>  { TARGET_NR_lstat64, "lstat64" , NULL, print_lstat64, NULL },
>  #endif
>  #ifdef TARGET_NR_madvise
> -{ TARGET_NR_madvise, "madvise" , NULL, NULL, NULL },
> +{ TARGET_NR_madvise, "madvise" , NULL, print_madvise, NULL },
>  #endif
>  #ifdef TARGET_NR_madvise1
>  { TARGET_NR_madvise1, "madvise1" , NULL, NULL, NULL },

Please disregard this patch.

While fixing a test failure on alpha, I noticed that it uses different
values for MADV_* enum.

I will need to provide per-arch MADV_* definitions and also fix
target_madvise() to use TARGET_MADV_DONTNEED instead of MADV_DONTNEED.

Best regards,
Ilya