Re: [PATCH v3 6/8] RISC-V: annotate entry points with type and size

[Jan Beulich <jbeulich@suse.com>]

On 10.07.2023 10:56, Jan Beulich wrote:
> Use the generic framework in xen/linkage.h. No change in generated code
> except of course the converted symbols change to be hidden ones and gain
> a valid size.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

I'm sorry, the Cc list was incomplete here. Adding back the remaining REST
maintainers.

Jan

> ---
> Probably count_args_exp() should move to macros.h, but I first wanted to
> see whether anyone can suggest any better approach for checking whether
> a defined macro expands to nothing.
> ---
> v3: New.
> 
> --- a/xen/arch/riscv/entry.S
> +++ b/xen/arch/riscv/entry.S
> @@ -5,7 +5,7 @@
>  #include <asm/traps.h>
>  
>  /* WIP: only works while interrupting Xen context */
> -ENTRY(handle_trap)
> +FUNC(handle_trap)
>  
>      /* Exceptions from xen */
>  save_to_stack:
> @@ -92,3 +92,4 @@ restore_registers:
>          REG_L   sp, CPU_USER_REGS_SP(sp)
>  
>          sret
> +END(handle_trap)
> --- a/xen/arch/riscv/include/asm/asm.h
> +++ b/xen/arch/riscv/include/asm/asm.h
> @@ -7,6 +7,7 @@
>  #define _ASM_RISCV_ASM_H
>  
>  #ifdef __ASSEMBLY__
> +#include <xen/linkage.h>
>  #define __ASM_STR(x)	x
>  #else
>  #define __ASM_STR(x)	#x
> --- a/xen/arch/riscv/include/asm/config.h
> +++ b/xen/arch/riscv/include/asm/config.h
> @@ -67,12 +67,8 @@
>  
>  /* Linkage for RISCV */
>  #ifdef __ASSEMBLY__
> -#define ALIGN .align 4
> -
> -#define ENTRY(name)                                \
> -  .globl name;                                     \
> -  ALIGN;                                           \
> -  name:
> +#define CODE_ALIGN 16
> +#define CODE_FILL /* empty */
>  #endif
>  
>  #ifdef CONFIG_RISCV_64
> --- a/xen/arch/riscv/riscv64/head.S
> +++ b/xen/arch/riscv/riscv64/head.S
> @@ -8,7 +8,7 @@
>           *   a0 -> hart_id ( bootcpu_id )
>           *   a1 -> dtb_base 
>           */
> -ENTRY(start)
> +FUNC(start)
>          /* Mask all interrupts */
>          csrw    CSR_SIE, zero
>  
> @@ -30,13 +30,14 @@ ENTRY(start)
>          jal     reset_stack
>  
>          tail    start_xen
> +END(start)
>  
>          .section .text, "ax", %progbits
>  
> -ENTRY(reset_stack)
> +FUNC(reset_stack)
>          la      sp, cpu0_boot_stack
>          li      t0, STACK_SIZE
>          add     sp, sp, t0
>  
>          ret
> -
> +END(reset_stack)
> --- a/xen/include/xen/linkage.h
> +++ b/xen/include/xen/linkage.h
> @@ -37,17 +37,28 @@
>  
>  #define END(name) .size name, . - name
>  
> +/*
> + * CODE_FILL in particular may need to expand to nothing (e.g. for RISC-V), in
> + * which case we also need to get rid of the comma in the .balign directive.
> + */
> +#define count_args_exp(args...) count_args(args)
> +#if count_args_exp(CODE_FILL)
> +# define DO_CODE_ALIGN(algn...) LASTARG(CODE_ALIGN, ## algn), CODE_FILL
> +#else
> +# define DO_CODE_ALIGN(algn...) LASTARG(CODE_ALIGN, ## algn)
> +#endif
> +
>  #define FUNC(name, algn...) \
> -        SYM(name, FUNC, GLOBAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
> +        SYM(name, FUNC, GLOBAL, DO_CODE_ALIGN(algn))
>  #define LABEL(name, algn...) \
> -        SYM(name, NONE, GLOBAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
> +        SYM(name, NONE, GLOBAL, DO_CODE_ALIGN(algn))
>  #define DATA(name, algn...) \
>          SYM(name, DATA, GLOBAL, LASTARG(DATA_ALIGN, ## algn), DATA_FILL)
>  
>  #define FUNC_LOCAL(name, algn...) \
> -        SYM(name, FUNC, LOCAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
> +        SYM(name, FUNC, LOCAL, DO_CODE_ALIGN(algn))
>  #define LABEL_LOCAL(name, algn...) \
> -        SYM(name, NONE, LOCAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
> +        SYM(name, NONE, LOCAL, DO_CODE_ALIGN(algn))
>  #define DATA_LOCAL(name, algn...) \
>          SYM(name, DATA, LOCAL, LASTARG(DATA_ALIGN, ## algn), DATA_FILL)
>  
> 
>