Question about rsdp test?

[Alex Hung]

FWTS only generates this error message when both are RSDT and XSDT
aren't zero && they aren't not pointing to the same address, as below.
Is there any reason why your firmware to point to different two
differently? Recent 64 bit OS will have no problem choosing XSDT, but
older 32 bit OS may pick RSDT which is never tested and that can
potentially cause problems.

        if (rsdp->rsdt_address != 0 && rsdp->xsdt_address != 0)
                if ((uint64_t)rsdp->rsdt_address == rsdp->xsdt_address) {
                        fwts_warning(fw,
                                     "Both RSDT and XSDT addresses are set. "
                                     "Since they are the same address, this "
                                     "is unambiguous to the OS.");
                        fwts_advice(fw,
                                    "Set only one of the 32-bit RSDT or the "
                                    "64-bit XSDT addresses.  Recent versions "
                                    "of the spec require that only one of "
                                    "these be used but as a practical matter, "
                                    "many vendors do use both.  If both "
                                    "fields must be used, make sure they at "
                                    "least contain the same value so that "
                                    "the OS can unambiguously determine "
                                    "which address is the correct one.");
                } else {
                        fwts_failed(fw, LOG_LEVEL_MEDIUM,
                                    "RSDPBothAddressesFound",
                                    "RSDP: only one of RsdtAddress or "
                                    "XsdtAddress should be non-zero.  Both "
                                    "fields are non-zero.");
                }
        else
                fwts_passed(fw,
                            "RSDP: only one of RsdtAddress or XsdtAddress "
                            "is non-zero.");

On Wed, Jul 20, 2016 at 9:39 AM, Dong, Eric <eric.dong at intel.com> wrote:
>> On 07/18/2016 06:06 AM, Dong, Eric wrote:
>> > When I do the Fwts test, I got below error for the rsdp test.
>> >
>> > rsdp           ;HED rsdp: RSDP Root System Description Pointer test.
>> >
>> > rsdp           ;SEP ------------------------------------------------------------
>> >
>> > rsdp           ;INF Test 1 of 1: RSDP Root System Description Pointer test.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP first checksum is correct
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: oem_id contains only printable
>> >
>> > rsdp           ;PAS characters.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: revision is 2.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: at least one of RsdtAddress or
>> >
>> > rsdp           ;PAS XsdtAddress is non-zero.
>> >
>> > rsdp           ;FAL FAILED [MEDIUM] RSDPBothAddressesFound: Test 1, RSDP: only
>> >
>> > rsdp           ;FAL one of RsdtAddress or XsdtAddress should be non-zero. Both
>> >
>> > rsdp           ;FAL fields are non-zero.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: the correct RSDT/XSDT address is being
>> >
>> > rsdp           ;PAS used.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: the table is the correct length.
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP second checksum is correct
>> >
>> > rsdp           ;PAS PASSED: Test 1, RSDP: the reserved field is zero.
>> >
>> > rsdp           ;NLN
>> >
>> > rsdp           ;SEP ============================================================
>> >
>> > rsdp           ;SUM 8 passed, 1 failed, 0 warning, 0 aborted, 0 skipped, 0 info
>> >
>> > rsdp           ;SUM only.
>> >
>> > rsdp           ;SEP ============================================================
>> >
>> >
>> >
>> > I think it caused by both Rsdt and Xsdt address are not zero. But From ACPI 6.0
>> > spec: (page 115)
>> >
>> > Notice that both the XSDT and the RSDT can be pointed to by the RSDP structure.
>> > An ACPI-compatible OS must use the XSDT if present.
>> >
>> >
>> >
>> > From the above description, I think the spec allowed the case of both Xsdt and
>> > Rsdt are not zero.  So I think Fwts tool should not report error for this case,
>> > am I correct?
>> >
>> >
>> >
>> > Thanks,
>> >
>> > Eric
>>
>> On what architecture?  If this is on ARMv8, we should not be using an RSDT,
>> according to SBSA/SBBR specifications.  If this is on x86, or perhaps ia64,
>> then the test probably needs to allow for that, if it doesn't already.
>>
>> Personally, I'd really like to discourage new systems from using the 32-bit
>> tables.
>>
>
> Yes, I use the x86 system. I think it's an optional choice, Fwts should not report it as an error, maybe a warning is ok.
>
>> --
>> ciao,
>> al
>> -----------------------------------
>> Al Stone
>> Software Engineer
>> Linaro Enterprise Group
>> al.stone at linaro.org
>> -----------------------------------
>
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-- 
Cheers,
Alex Hung