Re: git: 9758dd3de1cd - main - stand: Allocate bootinfo rather than have it be static

On Fri, 16 Sep 2022 15:54:04 GMT Warner Losh <imp@FreeBSD.org> wrote:
> The branch main has been updated by imp:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=9758dd3de1cddc8271be8dd6fee69286c5c86535
> 
> commit 9758dd3de1cddc8271be8dd6fee69286c5c86535
> Author:     Warner Losh <imp@FreeBSD.org>
> AuthorDate: 2022-09-16 15:09:41 +0000
> Commit:     Warner Losh <imp@FreeBSD.org>
> CommitDate: 2022-09-16 15:18:57 +0000
> 
>     stand: Allocate bootinfo rather than have it be static
>     
>     This saves 80 bytes (the new bootinfo structure was 84 bytes, and a
>     pointer is 4 bytes). The bi_load32 code is the same size.
>     
>     Sponsored by:           Netflix
>     Reviewed by:            tsoome
>     Differential Revision:  https://reviews.freebsd.org/D36575
> ---
>  stand/i386/libi386/bootinfo32.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/stand/i386/libi386/bootinfo32.c b/stand/i386/libi386/bootinfo32.c
> index 372bced917d6..37a797289f2b 100644
> --- a/stand/i386/libi386/bootinfo32.c
> +++ b/stand/i386/libi386/bootinfo32.c
> @@ -42,7 +42,7 @@ __FBSDID("$FreeBSD$");
>  #include "geliboot.h"
>  #endif
>  
> -static struct bootinfo  bi;
> +static struct bootinfo  *bi;
>  
>  /*
>   * Load the information expected by an i386 kernel.
> @@ -91,11 +91,12 @@ bi_load32(char *args, int *howtop, int *bootdevp, vm_offset_t *bip, vm_offset_t
>      /* XXX - use a default bootdev of 0.  Is this ok??? */
>      bootdevnr = 0;
>  
> +    bi = calloc(sizeof(*bi), 1);
>      switch(rootdev->dd.d_dev->dv_type) {
>      case DEVT_CD:
>      case DEVT_DISK:
>  	/* pass in the BIOS device number of the current disk */
> -	bi.bi_bios_dev = bd_unit2bios(rootdev);
> +	bi->bi_bios_dev = bd_unit2bios(rootdev);
>  	bootdevnr = bd_getdev(rootdev);
>  	break;
>  
> @@ -172,22 +173,22 @@ bi_load32(char *args, int *howtop, int *bootdevp, vm_offset_t *bip, vm_offset_t
>      /* legacy bootinfo structure */
>      kernelname = getenv("kernelname");
>      i386_getdev(NULL, kernelname, &kernelpath);
> -    bi.bi_version = BOOTINFO_VERSION;
> -    bi.bi_size = sizeof(bi);
> -    bi.bi_memsizes_valid = 1;
> -    bi.bi_basemem = bios_basemem / 1024;
> -    bi.bi_extmem = bios_extmem / 1024;
> -    bi.bi_envp = envp;
> -    bi.bi_modulep = *modulep;
> -    bi.bi_kernend = kernend;
> -    bi.bi_kernelname = VTOP(kernelpath);
> -    bi.bi_symtab = ssym;       /* XXX this is only the primary kernel symtab */
> -    bi.bi_esymtab = esym;
> +    bi->bi_version = BOOTINFO_VERSION;
> +    bi->bi_size = sizeof(bi);

sizeof(*bi) here and maybe make bi a function variable?

> +    bi->bi_memsizes_valid = 1;
> +    bi->bi_basemem = bios_basemem / 1024;
> +    bi->bi_extmem = bios_extmem / 1024;
> +    bi->bi_envp = envp;
> +    bi->bi_modulep = *modulep;
> +    bi->bi_kernend = kernend;
> +    bi->bi_kernelname = VTOP(kernelpath);
> +    bi->bi_symtab = ssym;       /* XXX this is only the primary kernel symtab */
> +    bi->bi_esymtab = esym;
>  
>      /* legacy boot arguments */
>      *howtop = howto | RB_BOOTINFO;
>      *bootdevp = bootdevnr;
> -    *bip = VTOP(&bi);
> +    *bip = VTOP(bi);
>  
>      return(0);
>  }