Re: [Minios-devel] [PATCH 09/40] arm64: add the basic helpers for arm64

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Shijie,

I guess this is the best place to ask this question. Why does the BUG() 
helper was kept unmodified for Arm64?
The instruction used for Arm32 is part of the always undefined opcodes. 
Such things does not exist on Arm64.
Cheers,

On 03/11/17 03:11, Huang Shijie wrote:
> This patch adds the basic helpers in header os.h for arm32 and arm64:
>      0.) mb/rmb/wmb
>      1.) local_irq_disable/local_irq_enable
>      2.) local_irq_save/local_irq_restore/local_save_flags
>      3.) __ffs
>
> This patch refers to Chen Baozi's patch:
>       "Initial codes for arm64"
>
> Change-Id: Id9025f016968a815029dfba7ee275d9f757974f0
> Jira: ENTOS-247
> Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx>
> ---
>   include/arm/arm32/os.h | 29 ++++++++++++++++++++++
>   include/arm/arm64/os.h | 35 +++++++++++++++++++++++++++
>   include/arm/os.h       | 65 ++++++--------------------------------------------
>   3 files changed, 71 insertions(+), 58 deletions(-)
>   create mode 100644 include/arm/arm32/os.h
>   create mode 100644 include/arm/arm64/os.h
>
> diff --git a/include/arm/arm32/os.h b/include/arm/arm32/os.h
> new file mode 100644
> index 0000000..6da604f
> --- /dev/null
> +++ b/include/arm/arm32/os.h
> @@ -0,0 +1,29 @@
> +#ifndef _ARM32_OS_H
> +#define _ARM32_OS_H
> +
> +static inline void local_irq_disable(void) {
> +    __asm__ __volatile__("cpsid i":::"memory");
> +}
> +
> +static inline void local_irq_enable(void) {
> +    __asm__ __volatile__("cpsie i":::"memory");
> +}
> +
> +#define local_irq_save(x) { \
> +    __asm__ __volatile__("mrs %0, cpsr;cpsid i":"=r"(x)::"memory");    \
> +}
> +
> +#define local_irq_restore(x) {    \
> +    __asm__ __volatile__("msr cpsr_c, %0"::"r"(x):"memory");    \
> +}
> +
> +#define local_save_flags(x)    { \
> +    __asm__ __volatile__("mrs %0, cpsr":"=r"(x)::"memory");    \
> +}
> +
> +/* We probably only need "dmb" here, but we'll start by being paranoid. */
> +#define mb() __asm__("dsb":::"memory");
> +#define rmb() __asm__("dsb":::"memory");
> +#define wmb() __asm__("dsb":::"memory");
> +
> +#endif
> diff --git a/include/arm/arm64/os.h b/include/arm/arm64/os.h
> new file mode 100644
> index 0000000..cb2ab14
> --- /dev/null
> +++ b/include/arm/arm64/os.h
> @@ -0,0 +1,35 @@
> +#ifndef _ARM64_OS_H_
> +#define _ARM64_OS_H_
> +
> +static inline void local_irq_disable(void)
> +{
> +    __asm__ __volatile__("msr daifset, #2": : :"memory");
> +}
> +
> +static inline void local_irq_enable(void)
> +{
> +    __asm__ __volatile__("msr daifclr, #2": : :"memory");
> +}
> +
> +#define local_irq_save(x) { \
> +    __asm__ __volatile__("mrs %0, daif; msr daifset, #2":"=r"(x)::"memory"); \
> +}
> +
> +#define local_irq_restore(x) { \
> +    __asm__ __volatile__("msr daif, %0": :"r"(x):"memory"); \
> +}
> +
> +#define local_save_flags(x) { \
> +    __asm__ __volatile__("mrs %0, daif":"=r"(x): :"memory"); \
> +}
> +
> +#define isb()           __asm__ __volatile("isb" : : : "memory")
> +
> +#define dmb(opt)        __asm__ __volatile("dmb " #opt : : : "memory")
> +#define dsb(opt)        __asm__ __volatile("dsb " #opt : : : "memory")
> +
> +#define mb()            dmb(sy) /* Full system memory barrier all */
> +#define wmb()           dmb(st) /* Full system memory barrier store */
> +#define rmb()           dmb(ld) /* Full system memory barrier load */
> +
> +#endif
> diff --git a/include/arm/os.h b/include/arm/os.h
> index 6a1cc37..37fb007 100644
> --- a/include/arm/os.h
> +++ b/include/arm/os.h
> @@ -22,27 +22,11 @@ extern void *device_tree;
>   
>   extern shared_info_t *HYPERVISOR_shared_info;
>   
> -// disable interrupts
> -static inline void local_irq_disable(void) {
> -    __asm__ __volatile__("cpsid i":::"memory");
> -}
> -
> -// enable interrupts
> -static inline void local_irq_enable(void) {
> -    __asm__ __volatile__("cpsie i":::"memory");
> -}
> -
> -#define local_irq_save(x) { \
> -    __asm__ __volatile__("mrs %0, cpsr;cpsid i":"=r"(x)::"memory");    \
> -}
> -
> -#define local_irq_restore(x) {    \
> -    __asm__ __volatile__("msr cpsr_c, %0"::"r"(x):"memory");    \
> -}
> -
> -#define local_save_flags(x)    { \
> -    __asm__ __volatile__("mrs %0, cpsr":"=r"(x)::"memory");    \
> -}
> +#if defined(__arm__)
> +#include <arm32/os.h>
> +#elif defined(__aarch64__)
> +#include <arm64/os.h>
> +#endif
>   
>   static inline int irqs_disabled(void) {
>       int x;
> @@ -50,14 +34,7 @@ static inline int irqs_disabled(void) {
>       return x & 0x80;
>   }
>   
> -/* We probably only need "dmb" here, but we'll start by being paranoid. */
> -#define mb() __asm__("dsb":::"memory");
> -#define rmb() __asm__("dsb":::"memory");
> -#define wmb() __asm__("dsb":::"memory");
> -
> -/************************** arm *******************************/
>   #ifdef __INSIDE_MINIOS__
> -#if defined (__arm__)
>   #define xchg(ptr,v) __atomic_exchange_n(ptr, v, __ATOMIC_SEQ_CST)
>   
>   /**
> @@ -121,39 +98,11 @@ static __inline__ void clear_bit(int nr, volatile unsigned 
> long *addr)
>       test_and_clear_bit(nr, addr);
>   }
>   
> -/**
> - * __ffs - find first (lowest) set bit in word.
> - * @word: The word to search
> - *
> - * Undefined if no bit exists, so code should check against 0 first.
> - */
> -static __inline__ unsigned long __ffs(unsigned long word)
> +static inline unsigned long __ffs(unsigned long word)
>   {
> -    int clz;
> -
> -    /* xxxxx10000 = word
> -     * xxxxx01111 = word - 1
> -     * 0000011111 = word ^ (word - 1)
> -     *      4     = 31 - clz(word ^ (word - 1))
> -     */
> -
> -    __asm__ (
> -        "sub r0, %[word], #1\n"
> -        "eor r0, r0, %[word]\n"
> -        "clz %[clz], r0\n":
> -        /* Outputs: */
> -        [clz] "=r"(clz):
> -        /* Inputs: */
> -        [word] "r"(word):
> -        /* Clobbers: */
> -        "r0");
> -
> -    return 31 - clz;
> +       return __builtin_ctzl(word);
>   }
>   
> -#else /* ifdef __arm__ */
> -#error "Unsupported architecture"
> -#endif
>   #endif /* ifdef __INSIDE_MINIOS */
>   
>   /********************* common arm32 and arm64  ****************************/
--
Julien Grall

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