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Re: [PATCH 7/7] linux-user: limit check to HOST_LONG_BITS < TARGET_ABI_B
From: |
Thomas Huth |
Subject: |
Re: [PATCH 7/7] linux-user: limit check to HOST_LONG_BITS < TARGET_ABI_BITS |
Date: |
Thu, 28 May 2020 08:45:51 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
On 27/05/2020 18.36, Alex Bennée wrote:
>
> Thomas Huth <thuth@redhat.com> writes:
>
>> On 27/05/2020 16.44, Laurent Vivier wrote:
>>> Le 25/05/2020 à 15:18, Thomas Huth a écrit :
>>>> From: Alex Bennée <alex.bennee@linaro.org>
>>>>
>>>> Newer clangs rightly spot that you can never exceed the full address
>>>> space of 64 bit hosts with:
>>>>
>>>> linux-user/elfload.c:2076:41: error: result of comparison 'unsigned
>>>> long' > 18446744073709551615 is always false
>>>> [-Werror,-Wtautological-type-limit-compare]
>>>> 4685 if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>>>> 4686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
>>>> 4687 1 error generated.
>>>>
>>>> So lets limit the check to 32 bit hosts only.
>>>>
>>>> Fixes: ee94743034bf
>>>> Reported-by: Thomas Huth <thuth@redhat.com>
>>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>>>> [thuth: Use HOST_LONG_BITS < TARGET_ABI_BITS instead of HOST_LONG_BITS ==
>>>> 32]
>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>> ---
>>>> linux-user/elfload.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
>>>> index 01a9323a63..ebc663ea0b 100644
>>>> --- a/linux-user/elfload.c
>>>> +++ b/linux-user/elfload.c
>>>> @@ -2073,12 +2073,14 @@ static void pgb_have_guest_base(const char
>>>> *image_name, abi_ulong guest_loaddr,
>>>> exit(EXIT_FAILURE);
>>>> }
>>>> } else {
>>>> +#if HOST_LONG_BITS < TARGET_ABI_BITS
>>>> if ((guest_hiaddr - guest_base) > ~(uintptr_t)0) {
>>>> error_report("%s: requires more virtual address space "
>>>> "than the host can provide (0x%" PRIx64 ")",
>>>> image_name, (uint64_t)guest_hiaddr - guest_base);
>>>> exit(EXIT_FAILURE);
>>>> }
>>>> +#endif
>>>> }
>>>>
>>>> /*
>>>>
>>>
>>> Philippe sent the same patch:
>>>
>>> https://www.mail-archive.com/qemu-devel@nongnu.org/msg699796.html
>>
>> Indeed, but looking more closely, he's using slightly different
>> locations for the #if and #endif ... not sure what's better though...?
>
> Richard was more inclined to suppress the warning:
>
> Subject: Re: [PATCH v2] linux-user: limit check to HOST_LONG_BITS == 32
> From: Richard Henderson <richard.henderson@linaro.org>
> Message-ID: <3069bc1b-115d-f361-8271-c775bf6957ea@linaro.org>
> Date: Thu, 21 May 2020 20:15:51 -0700
>
> One reason I dropped the f32 patch from my last PR was because this
> wasn't the only warning the latest clang picks up.
... but this is currently the only spot that is required to get the
gitlab CI going again, so I think we should include this patch until we
have a final decision whether to disable the warning or not (and we can
still revert this patch after we disabled the warning). Ok?
Thomas
- Re: [PATCH 4/7] gitlab-ci: Move edk2 and opensbi YAML files to .gitlab-ci.d folder, (continued)