Re: [PATCH 1/9] xen/arm64: address violations of MISRA C:2012 Rule 11.8

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 14 Dec 2023, Simone Ballarin wrote:
> From: Maria Celeste Cesario <maria.celeste.cesario@xxxxxxxxxxx>
> 
> The xen sources contain violations of MISRA C:2012 Rule 11.8 whose
> headline states:
> "A conversion shall not remove any const, volatile or _Atomic qualification
> from the type pointed to by a pointer".
> 
> Add volatile qualifiers missing in casts.
> Arguments p and ptr are originally volatile-qualified.
> There's no reason to drop the qualifiers.
> No functional change.
> 
> Signed-off-by: Maria Celeste Cesario  <maria.celeste.cesario@xxxxxxxxxxx>
> Signed-off-by: Simone Ballarin  <simone.ballarin@xxxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


>  xen/arch/arm/arm64/lib/bitops.c          |  6 ++++--
>  xen/arch/arm/include/asm/arm64/cmpxchg.h | 10 +++++-----
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/arm64/lib/bitops.c b/xen/arch/arm/arm64/lib/bitops.c
> index 20e3f3d6ce..275a780329 100644
> --- a/xen/arch/arm/arm64/lib/bitops.c
> +++ b/xen/arch/arm/arm64/lib/bitops.c
> @@ -32,7 +32,8 @@
>  static always_inline bool int_##name(int nr, volatile void *p, bool timeout,\
>                                       unsigned int max_try)                  \
>  {                                                                           \
> -    volatile uint32_t *ptr = (uint32_t *)p + BITOP_WORD((unsigned int)nr);  \
> +    volatile uint32_t *ptr = (volatile uint32_t *)p +                       \
> +                             BITOP_WORD((unsigned int)nr);                  \
>      const uint32_t mask = BITOP_MASK((unsigned int)nr);                     \
>      unsigned long res, tmp;                                                 \
>                                                                              \
> @@ -67,7 +68,8 @@ bool name##_timeout(int nr, volatile void *p, unsigned int 
> max_try)         \
>  static always_inline bool int_##name(int nr, volatile void *p, int *oldbit, \
>                                       bool timeout, unsigned int max_try)    \
>  {                                                                           \
> -    volatile uint32_t *ptr = (uint32_t *)p + BITOP_WORD((unsigned int)nr);  \
> +    volatile uint32_t *ptr = (volatile uint32_t *)p +                       \
> +                             BITOP_WORD((unsigned int)nr);                  \
>      unsigned int bit = (unsigned int)nr % BITOP_BITS_PER_WORD;              \
>      const uint32_t mask = BITOP_MASK(bit);                                  \
>      unsigned long res, tmp;                                                 \
> diff --git a/xen/arch/arm/include/asm/arm64/cmpxchg.h 
> b/xen/arch/arm/include/asm/arm64/cmpxchg.h
> index dbfaf91567..031fa6d92a 100644
> --- a/xen/arch/arm/include/asm/arm64/cmpxchg.h
> +++ b/xen/arch/arm/include/asm/arm64/cmpxchg.h
> @@ -13,7 +13,7 @@ static inline unsigned long __xchg(unsigned long x, 
> volatile void *ptr, int size
>               "1:     ldxrb   %w0, %2\n"
>               "       stlxrb  %w1, %w3, %2\n"
>               "       cbnz    %w1, 1b\n"
> -                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr)
> +                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(volatile u8 *)ptr)
>                       : "r" (x)
>                       : "memory");
>               break;
> @@ -22,7 +22,7 @@ static inline unsigned long __xchg(unsigned long x, 
> volatile void *ptr, int size
>               "1:     ldxrh   %w0, %2\n"
>               "       stlxrh  %w1, %w3, %2\n"
>               "       cbnz    %w1, 1b\n"
> -                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(u16 *)ptr)
> +                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(volatile u16 *)ptr)
>                       : "r" (x)
>                       : "memory");
>               break;
> @@ -31,7 +31,7 @@ static inline unsigned long __xchg(unsigned long x, 
> volatile void *ptr, int size
>               "1:     ldxr    %w0, %2\n"
>               "       stlxr   %w1, %w3, %2\n"
>               "       cbnz    %w1, 1b\n"
> -                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(u32 *)ptr)
> +                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(volatile u32 *)ptr)
>                       : "r" (x)
>                       : "memory");
>               break;
> @@ -40,7 +40,7 @@ static inline unsigned long __xchg(unsigned long x, 
> volatile void *ptr, int size
>               "1:     ldxr    %0, %2\n"
>               "       stlxr   %w1, %3, %2\n"
>               "       cbnz    %w1, 1b\n"
> -                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(u64 *)ptr)
> +                     : "=&r" (ret), "=&r" (tmp), "+Q" (*(volatile u64 *)ptr)
>                       : "r" (x)
>                       : "memory");
>               break;
> @@ -82,7 +82,7 @@ static inline bool __cmpxchg_case_##name(volatile void 
> *ptr,                \
>               "       stxr" #sz "     %w0, %" #w "4, %2\n"            \
>               "1:\n"                                                  \
>               : "=&r" (res), "=&r" (oldval),                          \
> -               "+Q" (*(unsigned long *)ptr)                          \
> +               "+Q" (*(volatile unsigned long *)ptr) \
>               : "Ir" (*old), "r" (new)                                \
>               : "cc");                                                \
>                                                                       \
> -- 
> 2.40.0
>