Re: [PATCH 3/6] contrib/plugins/hwprofile: fix warning when compiling on 32bits host

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

On 8/15/24 05:03, Alex Bennée wrote:
> Thomas Huth <thuth@redhat.com> writes:
> 
>> On 15/08/2024 01.36, Pierrick Bouvier wrote:
>>> Found on debian stable (i386).
>>> ../contrib/plugins/hwprofile.c: In function 'new_location':
>>> ../contrib/plugins/hwprofile.c:172:32: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>>     172 |     g_hash_table_insert(table, (gpointer) off_or_pc, loc);
>>>         |                                ^
>>> ../contrib/plugins/hwprofile.c: In function 'vcpu_haddr':
>>> ../contrib/plugins/hwprofile.c:227:19: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
>>>     227 |             off = (uint64_t) udata;
>>>         |                   ^
>>> ../contrib/plugins/hwprofile.c:232:62: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>>     232 |                                                              (gpointer) off);
>>>         |                                                              ^
>>> ../contrib/plugins/hwprofile.c: In function 'vcpu_tb_trans':
>>> ../contrib/plugins/hwprofile.c:250:26: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>>>     250 |         gpointer udata = (gpointer) (source ? qemu_plugin_insn_vaddr(insn) : 0);
>>>         |
>>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
>>> ---
>>>    contrib/plugins/hwprofile.c | 9 +++++----
>>>    1 file changed, 5 insertions(+), 4 deletions(-)
>>> diff --git a/contrib/plugins/hwprofile.c
>>> b/contrib/plugins/hwprofile.c
>>> index 739ac0c66b5..ee94a74ad94 100644
>>> --- a/contrib/plugins/hwprofile.c
>>> +++ b/contrib/plugins/hwprofile.c
>>> @@ -165,7 +165,7 @@ static DeviceCounts *new_count(const char *name, uint64_t base)
>>>        return count;
>>>    }
>>>    -static IOLocationCounts *new_location(GHashTable *table, uint64_t
>>> off_or_pc)
>>> +static IOLocationCounts *new_location(GHashTable *table, uintptr_t off_or_pc)
>>>    {
>>>        IOLocationCounts *loc = g_new0(IOLocationCounts, 1);
>>>        loc->off_or_pc = off_or_pc;
>>> @@ -201,7 +201,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
>>>            return;
>>>        } else {
>>>            const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
>>> -        uint64_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
>>> +        uintptr_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
>>
>> qemu_plugin_hwaddr_phys_addr() returns an uint64_t, so this looks
>> wrong to me.
> 
> It is. However it just goes to show you should be expecting to
> instrument 64 bit code with a 32 bit host because you can't do pointer
> stuffing tricks like this.
> 
> Maybe we could just disable plugins on 32 bit hosts?
> 

Only two plugins are concerned by this problem, it's worth fixing them 
correctly (i.e. not use 64 bits data directly as a pointer, but allocate 
memory and pass pointer instead).

>>
>>   Thomas
>