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Re: [XEN PATCH for-4.19] xen/bitmap: amend MISRA C deviation for Rule 20.7
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
- Date: Tue, 09 Jul 2024 12:15:45 +0200
- Cc: sstabellini@xxxxxxxxxx, michal.orzel@xxxxxxx, xenia.ragiadakou@xxxxxxx, ayan.kumar.halder@xxxxxxx, consulting@xxxxxxxxxxx, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Tue, 09 Jul 2024 10:15:57 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 2024-07-09 11:40, Jan Beulich wrote:
On 09.07.2024 11:34, Nicola Vetrini wrote:
As noticed in the gitlab analyses, deviating bitmap_switch
for Rule 20.7 in this way does not work for ECLAIR.
Instead, the deviation should be put in the macro invocation.
Why is this? I ask in particular because ...
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -103,18 +103,16 @@ extern int bitmap_allocate_region(unsigned long
*bitmap, int pos, int order);
#define bitmap_switch(nbits, zero, small, large) \
unsigned int n__ = (nbits); \
if (__builtin_constant_p(nbits) && !n__) { \
- /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
zero; \
} else if (__builtin_constant_p(nbits) && n__ <= BITS_PER_LONG) { \
- /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
small; \
} else { \
- /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
large; \
}
static inline void bitmap_zero(unsigned long *dst, unsigned int
nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = 0UL,
memset(dst, 0, bitmap_bytes(nbits)));
@@ -139,6 +137,7 @@ static inline void bitmap_fill(unsigned long *dst,
unsigned int nbits)
static inline void bitmap_copy(unsigned long *dst, const unsigned
long *src,
unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = *src,
memcpy(dst, src, bitmap_bytes(nbits)));
@@ -147,6 +146,7 @@ static inline void bitmap_copy(unsigned long *dst,
const unsigned long *src,
static inline void bitmap_and(unsigned long *dst, const unsigned long
*src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = *src1 & *src2,
__bitmap_and(dst, src1, src2, nbits));
@@ -155,6 +155,7 @@ static inline void bitmap_and(unsigned long *dst,
const unsigned long *src1,
static inline void bitmap_or(unsigned long *dst, const unsigned long
*src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = *src1 | *src2,
__bitmap_or(dst, src1, src2, nbits));
@@ -163,6 +164,7 @@ static inline void bitmap_or(unsigned long *dst,
const unsigned long *src1,
static inline void bitmap_xor(unsigned long *dst, const unsigned long
*src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = *src1 ^ *src2,
__bitmap_xor(dst, src1, src2, nbits));
@@ -171,6 +173,7 @@ static inline void bitmap_xor(unsigned long *dst,
const unsigned long *src1,
static inline void bitmap_andnot(unsigned long *dst, const unsigned
long *src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = *src1 & ~*src2,
__bitmap_andnot(dst, src1, src2, nbits));
@@ -179,6 +182,7 @@ static inline void bitmap_andnot(unsigned long
*dst, const unsigned long *src1,
static inline void bitmap_complement(unsigned long *dst, const
unsigned long *src,
unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,,
*dst = ~*src & BITMAP_LAST_WORD_MASK(nbits),
__bitmap_complement(dst, src, nbits));
@@ -187,6 +191,7 @@ static inline void bitmap_complement(unsigned long
*dst, const unsigned long *sr
static inline int bitmap_equal(const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,
return -1,
return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)),
@@ -196,6 +201,7 @@ static inline int bitmap_equal(const unsigned long
*src1,
static inline int bitmap_intersects(const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,
return -1,
return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0,
@@ -205,6 +211,7 @@ static inline int bitmap_intersects(const unsigned
long *src1,
static inline int bitmap_subset(const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,
return -1,
return !((*src1 & ~*src2) & BITMAP_LAST_WORD_MASK(nbits)),
@@ -213,6 +220,7 @@ static inline int bitmap_subset(const unsigned
long *src1,
static inline int bitmap_empty(const unsigned long *src, unsigned int
nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,
return -1,
return !(*src & BITMAP_LAST_WORD_MASK(nbits)),
@@ -221,6 +229,7 @@ static inline int bitmap_empty(const unsigned long
*src, unsigned int nbits)
static inline int bitmap_full(const unsigned long *src, unsigned int
nbits)
{
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */
bitmap_switch(nbits,
return -1,
return !(~*src & BITMAP_LAST_WORD_MASK(nbits)),
... having the same comment on every invocation is naturally quite a
bit
less desirable. So far I was under the impression that macro-specific
deviations can be dealt with by marking the macro definition
accordingly.
Not with a comment-based one, but one based on ECL.
As stated under the cut:
An alternative approach would be to use an ecl configuration, but that
would be tool-specific.
Stefano had a preference for a tool-agnostic SAF comment, so that's what
I used.
I've been assuming this is a general pattern. If it isn't, would you
please first clarify what Eclair's specific requirements are for a SAF
marker to take effect when involving a macro?
it should be put directly above macro invocations. ECLAIR has a
tool-specific comment-based deviation that essentially deviates a range
of lines, but that is not supported by the SAF framework, so I avoided
that.
Is it safe to say that the uses of bitmap_switch will likely not change
much over time?
Thanks,
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)
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