Re: [PATCH v3 3/5] RISC-V: Improve init_resources

Nick Kossifidis
2021-04-06T08:11:47Z

Hello Geert,

Στις 2021-04-06 10:19, Geert Uytterhoeven έγραψε:
> Hi Nick,
>
> Thanks for your patch!
>
> On Mon, Apr 5, 2021 at 10:57 AM Nick Kossifidis <mick@ics.forth.gr>
> wrote:
>> * Kernel region is always present and we know where it is, no
>> need to look for it inside the loop, just ignore it like the
>> rest of the reserved regions within system's memory.
>>
>> * Don't call memblock_free inside the loop, if called it'll split
>> the region of pre-allocated resources in two parts, messing things
>> up, just re-use the previous pre-allocated resource and free any
>> unused resources after both loops finish.
>>
>> * memblock_alloc may add a region when called, so increase the
>> number of pre-allocated regions by one to be on the safe side
>> (reported and patched by Geert Uytterhoeven)
>>
>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> Where does this SoB come from?
>
>> Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
>
>> --- a/arch/riscv/kernel/setup.c
>> +++ b/arch/riscv/kernel/setup.c
>
>> @@ -129,53 +139,42 @@ static void __init init_resources(void)
>> struct resource *res = NULL;
>> struct resource *mem_res = NULL;
>> size_t mem_res_sz = 0;
>> - int ret = 0, i = 0;
>> -
>> - code_res.start = __pa_symbol(_text);
>> - code_res.end = __pa_symbol(_etext) - 1;
>> - code_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>> -
>> - rodata_res.start = __pa_symbol(__start_rodata);
>> - rodata_res.end = __pa_symbol(__end_rodata) - 1;
>> - rodata_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>> -
>> - data_res.start = __pa_symbol(_data);
>> - data_res.end = __pa_symbol(_edata) - 1;
>> - data_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>> + int num_resources = 0, res_idx = 0;
>> + int ret = 0;
>>
>> - bss_res.start = __pa_symbol(__bss_start);
>> - bss_res.end = __pa_symbol(__bss_stop) - 1;
>> - bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>> + /* + 1 as memblock_alloc() might increase
>> memblock.reserved.cnt */
>> + num_resources = memblock.memory.cnt + memblock.reserved.cnt +
>> 1;
>> + res_idx = num_resources - 1;
>>
>> - mem_res_sz = (memblock.memory.cnt + memblock.reserved.cnt) *
>> sizeof(*mem_res);
>
> Oh, you incorporated my commit ce989f1472ae350e ("RISC-V: Fix
> out-of-bounds
> accesses in init_resources()") (from v5.12-rc4) into your patch.
> Why? This means your patch does not apply against upstream.
>

Sorry if this looks awkward, I'm under the impression that new features
go on for-next instead of fixes and your patch hasn't been merged on
for-next yet. I thought it would be cleaner to have one patch to merge
for init_resources instead of two, and simpler for people to test the
series. I can rebase this on top of fixes if that works better for you
or Palmer.

Regards,
Nick