[PATCH] lib: fwts_acpi_tables: re-work fwts_acpi_get_rsdp, less memory copies

[Naresh Bhat]

On 12 August 2017 at 00:14, Colin King <colin.king at canonical.com> wrote:

> From: Colin Ian King <colin.king at canonical.com>
>
> Re-work fwts_acpi_get_rsdp so there are less memory copioes of the RSDP
>
> Signed-off-by: Colin Ian King <colin.king at canonical.com>
> ---
>  src/lib/src/fwts_acpi_tables.c | 32 +++++++++++++++-----------------
>  1 file changed, 15 insertions(+), 17 deletions(-)
>
> diff --git a/src/lib/src/fwts_acpi_tables.c b/src/lib/src/fwts_acpi_
> tables.c
> index f7547c43..9b2312e5 100644
> --- a/src/lib/src/fwts_acpi_tables.c
> +++ b/src/lib/src/fwts_acpi_tables.c
> @@ -146,39 +146,37 @@ static void *fwts_acpi_find_rsdp_bios(void)
>  static fwts_acpi_table_rsdp *fwts_acpi_get_rsdp(fwts_framework *fw, void
> *addr, size_t *rsdp_len)
>  {
>         uint8_t *mem;
> -       fwts_acpi_table_rsdp *rsdp = NULL;
> +       fwts_acpi_table_rsdp *rsdp;
>         *rsdp_len = 0;
>
> +       /* Assume version 2.0 size, we don't care about a few bytes over
> allocation if it's version 1.0 */
> +       if ((rsdp = (fwts_acpi_table_rsdp*)fwts_low_calloc(1,
> sizeof(fwts_acpi_table_rsdp))) == NULL) {
> +               fwts_log_error(fw, "Cannot allocate cached RSDP, out of
> low memory.");
> +               return NULL;
> +       }
> +
>         if ((mem = fwts_mmap((off_t)addr, sizeof(fwts_acpi_table_rsdp)))
> == FWTS_MAP_FAILED)
>                 return NULL;
>
> -       if (fwts_safe_memread(mem, sizeof(fwts_acpi_table_rsdp)) !=
> FWTS_OK) {
> -               fwts_log_error(fw, "Cannot safely read RSDP from address
> %p.", mem);
> -               goto out;
> +       if (fwts_safe_memcpy(rsdp, mem, sizeof(fwts_acpi_table_rsdp)) !=
> FWTS_OK) {
> +               fwts_log_error(fw, "Cannot safely copy RSDP from address
> %p.", mem);
> +               goto err;
>         }
>
> -       rsdp = (fwts_acpi_table_rsdp*)mem;
>         /* Determine original RSDP size from revision. */
>         *rsdp_len = (rsdp->revision < 1) ? 20 : 36;
>
>         /* Must have the correct signature */
>         if (strncmp(rsdp->signature, "RSD PTR ", 8)) {
>                 fwts_log_error(fw, "RSDP did not have expected
> signature.");
> -               rsdp = NULL;
> -               goto out;
> -       }
> -
> -       /* Assume version 2.0 size, we don't care about a few bytes over
> allocation if it's version 1.0 */
> -       if ((rsdp = (fwts_acpi_table_rsdp*)fwts_low_calloc(1,
> sizeof(fwts_acpi_table_rsdp))) == NULL) {
> -               rsdp = NULL;
> -               goto out;
> +               goto err;
>         }
> +       return rsdp;
>
> -       memcpy(rsdp, mem, *rsdp_len);
> -out:
> +err:
>         (void)fwts_munmap(mem, sizeof(fwts_acpi_table_rsdp));
> -
> -       return rsdp;
> +       fwts_low_free(rsdp);
> +       return NULL;
>  }
>
>  /*
> --
> 2.11.0
>

Thanks Colin,

Reviewed-By/Tested-By: Naresh Bhat <naresh.bhat at linaro.org>


>
>
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