Re: [Xen-devel] [PATCH] ACPI/APEI: fix ERST MOVE_DATA instruction implementation

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 17.10.12 at 13:36, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
> --- a/xen/drivers/acpi/apei/erst.c
> +++ b/xen/drivers/acpi/apei/erst.c
> @@ -247,15 +247,64 @@ static int erst_exec_move_data(struct ap
>  {
>       int rc;
>       u64 offset;
> +#ifdef CONFIG_X86
> +     enum fixed_addresses idx;
> +#endif
> +     void *src, *dst;
> +
> +     /* ioremap does not work in interrupt context */
> +     if (in_irq()) {
> +             printk(KERN_WARNING
> +                    "MOVE_DATA cannot be used in interrupt context\n");
> +             return -EBUSY;
> +     }
>  
>       rc = __apei_exec_read_register(entry, &offset);
>       if (rc)
>               return rc;
> -     memmove((void *)(unsigned long)(ctx->dst_base + offset),
> -             (void *)(unsigned long)(ctx->src_base + offset),
> -             ctx->var2);
>  
> -     return 0;
> +#ifdef CONFIG_X86
> +     switch (ctx->var2) {
> +     case 0:
> +             return 0;
> +     case 1 ... PAGE_SIZE:
> +             break;
> +     default:
> +             printk(KERN_WARNING
> +                    "MOVE_DATA cannot be used for %#"PRIx64" bytes of 
> data\n",
> +                    ctx->var2);
> +             return -EOPNOTSUPP;
> +     }
> +
> +     src = __acpi_map_table(ctx->src_base + offset, ctx->var2);
> +#else
> +     src = ioremap(ctx->src_base + offset, ctx->var2);
> +#endif

Before anyone asks - yes, I have added to my todo list to put in
place a proper ioremap() for x86. But since I'm under some time
pressure right now, this was the faster route to something that
can be committed to see whether the regression goes away.

Jan

> +     if (!src)
> +             return -ENOMEM;
> +
> +#ifdef CONFIG_X86
> +     BUILD_BUG_ON(FIX_ACPI_PAGES < 4);
> +     idx = virt_to_fix((unsigned long)src + 2 * PAGE_SIZE);
> +     offset += ctx->dst_base;
> +     dst = (void *)fix_to_virt(idx) + (offset & ~PAGE_MASK);
> +     set_fixmap(idx, offset);
> +     if (PFN_DOWN(offset) != PFN_DOWN(offset + ctx->var2 - 1)) {
> +             idx = virt_to_fix((unsigned long)dst + PAGE_SIZE);
> +             set_fixmap(idx, offset + PAGE_SIZE);
> +     }
> +#else
> +     dst = ioremap(ctx->dst_base + offset, ctx->var2);
> +#endif
> +     if (dst) {
> +             memmove(dst, src, ctx->var2);
> +             iounmap(dst);
> +     } else
> +             rc = -ENOMEM;
> +
> +     iounmap(src);
> +
> +     return rc;
>  }
>  
>  static struct apei_exec_ins_type erst_ins_type[] = {




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