Re: [Xen-devel] [PATCH v9 11/27] xsplice: Implement payload loading

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On 04/25/2016 04:34 PM, Konrad Rzeszutek Wilk wrote:
snip
> +static int move_payload(struct payload *payload, struct xsplice_elf *elf)
> +{
> +    uint8_t *text_buf, *ro_buf, *rw_buf;
> +    unsigned int i;
> +    size_t size = 0;
> +    unsigned int *offset;
> +    int rc = 0;
> +
> +    offset = xzalloc_array(unsigned int, elf->hdr->e_shnum);
> +    if ( !offset )
> +        return -ENOMEM;
> +
> +    /* Compute size of different regions. */
> +    for ( i = 1; i < elf->hdr->e_shnum; i++ )
> +    {
> +        if ( (elf->sec[i].sec->sh_flags & (SHF_ALLOC|SHF_EXECINSTR)) ==
> +             (SHF_ALLOC|SHF_EXECINSTR) )
> +            calc_section(&elf->sec[i], &payload->text_size, &offset[i]);
> +        else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> +                  !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> +                  (elf->sec[i].sec->sh_flags & SHF_WRITE) )
> +            calc_section(&elf->sec[i], &payload->rw_size, &offset[i]);
> +        else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> +                  !(elf->sec[i].sec->sh_flags & SHF_EXECINSTR) &&
> +                  !(elf->sec[i].sec->sh_flags & SHF_WRITE) )
> +            calc_section(&elf->sec[i], &payload->ro_size, &offset[i]);
> +        else if ( !elf->sec[i].sec->sh_flags ||
> +                  (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) ||
> +                  (elf->sec[i].sec->sh_flags & SHF_MASKPROC) )
> +            /* Do nothing.*/;
> +        else if ( (elf->sec[i].sec->sh_flags & SHF_ALLOC) &&
> +                  (elf->sec[i].sec->sh_type == SHT_NOBITS) )
> +        {
> +            dprintk(XENLOG_DEBUG, XSPLICE "%s: Not supporting %s section!\n",
> +                    elf->name, elf->sec[i].name);
> +            rc = -EOPNOTSUPP;
> +            goto out;
> +        }
> +        else /* Such as .comment. */
> +            dprintk(XENLOG_DEBUG, XSPLICE "%s: Ignoring %s section!\n",
> +                    elf->name, elf->sec[i].name);
> +    }
> +
> +    /*
> +     * Total of all three regions - RX, RW, and RO. We have to have
> +     * keep them in seperate pages so we PAGE_ALIGN the RX and RW to have
> +     * them on seperate pages. The last one will by default fall on its
> +     * own page.
> +     */
> +    size = PAGE_ALIGN(payload->text_size) + PAGE_ALIGN(payload->rw_size) +
> +                      payload->ro_size;
> +
> +    size = PFN_UP(size); /* Nr of pages. */
> +    text_buf = vzalloc_xen(size * PAGE_SIZE);
> +    if ( !text_buf )
> +    {
> +        dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for 
> payload!\n",
> +                elf->name);
> +        rc = -ENOMEM;
> +        goto out;
> +    }
> +    rw_buf = text_buf +  + PAGE_ALIGN(payload->text_size);
???

The rarely used unary plus operator :-)

> +    ro_buf = rw_buf + PAGE_ALIGN(payload->rw_size);
> +
> +    payload->pages = size;
> +    payload->text_addr = text_buf;
> +    payload->rw_addr = rw_buf;
> +    payload->ro_addr = ro_buf;
> +
> +    for ( i = 1; i < elf->hdr->e_shnum; i++ )
> +    {
> +        if ( elf->sec[i].sec->sh_flags & SHF_ALLOC )
> +        {
> +            uint8_t *buf;
> +            if ( (elf->sec[i].sec->sh_flags & SHF_EXECINSTR) )
> +                buf = text_buf;
> +            else if ( (elf->sec[i].sec->sh_flags & SHF_WRITE) )
> +                buf = rw_buf;
> +             else
> +                buf = ro_buf;
> +
> +            elf->sec[i].load_addr = buf + offset[i];
> +
> +            /*
> +             * Don't copy NOBITS - such as BSS. We don't memset BSS as
> +             * arch_xsplice_alloc_payload has zeroed it out for us.
> +             */
> +            if ( elf->sec[i].sec->sh_type != SHT_NOBITS )
> +            {
> +                memcpy(elf->sec[i].load_addr, elf->sec[i].data,
> +                       elf->sec[i].sec->sh_size);
> +                dprintk(XENLOG_DEBUG, XSPLICE "%s: Loaded %s at %p\n",
> +                        elf->name, elf->sec[i].name, elf->sec[i].load_addr);
--
Ross Lagerwall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel