Re: [PATCH] firmware/dmi_scan: generalize for use by other archs

[Ard Biesheuvel]

Hello all,

Resending this patch to a slightly wider audience.

The point of this patch is reworking the dmi_scan code slightly so it
can be reused on ARM and arm64.
There are no functional changes for x86 or IA-64, just one open
question, i.e., whether the non-EFI fallback probe should be performed
on IA-64 in the first place.

If I could get acks for this patch please (if there are no
objections), I will propose it to be merged through the ARM and/or
arm64 trees as part of the complete series to enable SMBIOS.

Regards,
Ard.


On 21 November 2013 12:40, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> This patch makes a couple of changes to the SMBIOS/DMI scanning
> code so it can be used on other archs (such as ARM and arm64):
> (a) wrap the calls to ioremap()/iounmap(), this allows the use of a
>     flavor of ioremap() more suitable for random unaligned access;
> (b) allow the non-EFI fallback probe into hardcoded physical address
>     0xF0000 to be disabled.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
>
> @Tony: does the fallback probe make any sense at all on IA-64? It was enabled
> before, so I added the #define for IA-64 as well, but perhaps we could remove it
> altogether?
>
>  arch/ia64/include/asm/dmi.h | 10 +++++++---
>  arch/x86/include/asm/dmi.h  |  8 ++++++--
>  drivers/firmware/dmi_scan.c | 20 +++++++++++---------
>  3 files changed, 24 insertions(+), 14 deletions(-)
>
> diff --git a/arch/ia64/include/asm/dmi.h b/arch/ia64/include/asm/dmi.h
> index 185d3d1..61e3b56 100644
> --- a/arch/ia64/include/asm/dmi.h
> +++ b/arch/ia64/include/asm/dmi.h
> @@ -5,8 +5,12 @@
>  #include <asm/io.h>
>
>  /* Use normal IO mappings for DMI */
> -#define dmi_ioremap ioremap
> -#define dmi_iounmap(x,l) iounmap(x)
> -#define dmi_alloc(l) kzalloc(l, GFP_ATOMIC)
> +#define dmi_early_remap                ioremap
> +#define dmi_early_unmap(x,l)   iounmap(x)
> +#define dmi_remap              ioremap
> +#define dmi_unmap              iounmap
> +#define dmi_alloc(l)           kzalloc(l, GFP_ATOMIC)
> +
> +#define DMI_SCAN_MACHINE_NON_EFI_FALLBACK      1
>
>  #endif
> diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h
> index fd8f9e2..bb2b572 100644
> --- a/arch/x86/include/asm/dmi.h
> +++ b/arch/x86/include/asm/dmi.h
> @@ -13,7 +13,11 @@ static __always_inline __init void *dmi_alloc(unsigned len)
>  }
>
>  /* Use early IO mappings for DMI because it's initialized early */
> -#define dmi_ioremap early_ioremap
> -#define dmi_iounmap early_iounmap
> +#define dmi_early_remap                early_ioremap
> +#define dmi_early_unmap                early_iounmap
> +#define dmi_remap              ioremap
> +#define dmi_unmap              iounmap
> +
> +#define DMI_SCAN_MACHINE_NON_EFI_FALLBACK      1
>
>  #endif /* _ASM_X86_DMI_H */
> diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> index fa0affb..2c7c793 100644
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -108,7 +108,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
>  {
>         u8 *buf;
>
> -       buf = dmi_ioremap(dmi_base, dmi_len);
> +       buf = dmi_early_remap(dmi_base, dmi_len);
>         if (buf == NULL)
>                 return -1;
>
> @@ -116,7 +116,7 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
>
>         add_device_randomness(buf, dmi_len);
>
> -       dmi_iounmap(buf, dmi_len);
> +       dmi_early_unmap(buf, dmi_len);
>         return 0;
>  }
>
> @@ -483,18 +483,19 @@ void __init dmi_scan_machine(void)
>                  * needed during early boot.  This also means we can
>                  * iounmap the space when we're done with it.
>                  */
> -               p = dmi_ioremap(efi.smbios, 32);
> +               p = dmi_early_remap(efi.smbios, 32);
>                 if (p == NULL)
>                         goto error;
>                 memcpy_fromio(buf, p, 32);
> -               dmi_iounmap(p, 32);
> +               dmi_early_unmap(p, 32);
>
>                 if (!dmi_present(buf)) {
>                         dmi_available = 1;
>                         goto out;
>                 }
>         } else {
> -               p = dmi_ioremap(0xF0000, 0x10000);
> +#ifdef DMI_SCAN_MACHINE_NON_EFI_FALLBACK
> +               p = dmi_early_remap(0xF0000, 0x10000);
>                 if (p == NULL)
>                         goto error;
>
> @@ -510,12 +511,13 @@ void __init dmi_scan_machine(void)
>                         memcpy_fromio(buf + 16, q, 16);
>                         if (!dmi_present(buf)) {
>                                 dmi_available = 1;
> -                               dmi_iounmap(p, 0x10000);
> +                               dmi_early_unmap(p, 0x10000);
>                                 goto out;
>                         }
>                         memcpy(buf, buf + 16, 16);
>                 }
> -               dmi_iounmap(p, 0x10000);
> +               dmi_early_unmap(p, 0x10000);
> +#endif
>         }
>   error:
>         pr_info("DMI not present or invalid.\n");
> @@ -787,13 +789,13 @@ int dmi_walk(void (*decode)(const struct dmi_header *, void *),
>         if (!dmi_available)
>                 return -1;
>
> -       buf = ioremap(dmi_base, dmi_len);
> +       buf = dmi_remap(dmi_base, dmi_len);
>         if (buf == NULL)
>                 return -1;
>
>         dmi_table(buf, dmi_len, dmi_num, decode, private_data);
>
> -       iounmap(buf);
> +       dmi_unmap(buf);
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(dmi_walk);
> --
> 1.8.3.2
>
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