On 01/06/17 21:27, Luc Van Oostenryck wrote:
> sparse will warn if memcpy() (or memset(), copy_from_user(),
> copy_to_user()) is called with a very large static byte-count.
>
> But this warning is given unconditionaly while there are projects
> where this warning may not be not desired.
>
> Change this by making this warning conditional on a new warning
> flag: -Wmemcpy-max-count=COUNT.
As always, the hardest part for me is naming. I can't remember exactly
what I called it, but I wanted something which would kinda sum up
all the functions. So, it was something like -Wmem-move-limit=n, or
something like that, and so the test was disabled by setting it to
zero.
-Wmemcpy-max-count=count is probably a better name! ;-)
>
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> ---
> lib.c | 2 ++
> lib.h | 1 +
> sparse.1 | 8 ++++++++
> sparse.c | 3 ++-
> 4 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/lib.c b/lib.c
> index e1e6a1cbf..90fd2b494 100644
> --- a/lib.c
> +++ b/lib.c
> @@ -229,6 +229,7 @@ int Wdo_while = 0;
> int Winit_cstring = 0;
> int Wenum_mismatch = 1;
> int Wsparse_error = 0;
> +int Wmemcpy_max_count = 1;
> int Wnon_pointer_null = 1;
> int Wold_initializer = 1;
> int Wone_bit_signed_bitfield = 1;
> @@ -506,6 +507,7 @@ static const struct warning {
> { "enum-mismatch", &Wenum_mismatch },
> { "sparse-error", &Wsparse_error },
> { "init-cstring", &Winit_cstring },
> + { "memcpy-max-count", &Wmemcpy_max_count },
> { "non-pointer-null", &Wnon_pointer_null },
> { "old-initializer", &Wold_initializer },
> { "one-bit-signed-bitfield", &Wone_bit_signed_bitfield },
> diff --git a/lib.h b/lib.h
> index 2c8529f93..8090fe247 100644
> --- a/lib.h
> +++ b/lib.h
> @@ -116,6 +116,7 @@ extern int Wdo_while;
> extern int Wenum_mismatch;
> extern int Wsparse_error;
> extern int Winit_cstring;
> +extern int Wmemcpy_max_count;
> extern int Wnon_pointer_null;
> extern int Wold_initializer;
> extern int Wone_bit_signed_bitfield;
> diff --git a/sparse.1 b/sparse.1
> index c924b3a59..efbd78d01 100644
> --- a/sparse.1
> +++ b/sparse.1
> @@ -210,6 +210,14 @@ trouble.
> Sparse does not issue these warnings by default.
> .
> .TP
> +.B \-Wmemcpy\-max\-count
> +Warn about call of \fBmemset()\fR, \fBmemset()\fR, \fBcopy_from_user()\fR, or
^^^^^^^ ^^^^^^^^
memcpy() and memset()
ATB,
Ramsay Jones
> +\fBcopy_to_user()\fR with a large compile-time byte count.
> +
> +Sparse issues these warnings by default. To turn them off, use
> +\fB\-Wno\-memcpy\-max\-count\fR.
> +.
> +.TP
> .B \-Wnon\-pointer\-null
> Warn about the use of 0 as a NULL pointer.
>
> diff --git a/sparse.c b/sparse.c
> index 1cb90e20d..aa5979f1a 100644
> --- a/sparse.c
> +++ b/sparse.c
> @@ -153,7 +153,8 @@ static void check_byte_count(struct instruction *insn, pseudo_t count)
> return;
> if (count->type == PSEUDO_VAL) {
> unsigned long long val = count->value;
> - if (val > 100000ULL)
> + if (Wmemcpy_max_count && val > 100000ULL)
> +
> warning(insn->pos, "%s with byte count of %llu",
> show_ident(insn->func->sym->ident), val);
> return;
>
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