Hi Simon,
2015-07-09 23:15 GMT+09:00 Simon Glass <s...@chromium.org>: > With driver model drivers can have things stored in several places. There is > driver-private data, then the uclass can attach things to a device. If the > device is on a bus then its bus may attach parent data to the device too. > > At present everything is done through void pointers. This is also true for driver private data in Linux. > It would be nice to > have a way to check that the correct C struct is used in each case. > > Here is a proposed implementation of a way of checking structures in driver > model. It relies on turning the existing dev_get_priv() function into a > macro which (if checking is enabled) checks that the structure names match. > Each xxx_auto_alloc_size turns into a structure containing a string (the > structure name) and the size. > > The dev_get_priv() macro has an extra parameter which is the structure being > accessed: > > struct eth_pdata *priv = dev_get_priv(dev, struct eth_pdata); > > and you get an error like this when things are wrong: In which scenario do things go wrong? It is still unclear to me why we need this sanity check. > Invalid access to device priv: dev=eth@10002000, expecting > 'struct eth_sandbox_priv', requested 'struct eth_pdata' > > A new Kconfg option is added to turn this on, since it bloats the code a > little. > > The next step would be to extend it to all pointers in the device and > uclass. This is mostly a mechanical code change. > > Finally we should have a way of checking that the device pointer itself is > valid. For example if someone passes an invalid address like 0x12345 as the > 'struct udevice' then at present we will dutifully look for the devices' > driver and perform an invalid memory access. > > If we want to check for memory corruption one way would be to add a magic > numnber before each allocated memory area. Perhaps this is more the role > of dlmalloc(), but if required it could be attached to Masahiro's devres > feature, which already prepends some data to every allocated area. > > Comments welcome. I'd like to figure this out soon as it involves trivial > but invasive patches to change each driver. > > Signed-off-by: Simon Glass <s...@chromium.org> > --- > diff --git a/arch/x86/cpu/mp_init.c b/arch/x86/cpu/mp_init.c > index e686b28..e835b43 100644 > --- a/arch/x86/cpu/mp_init.c > +++ b/arch/x86/cpu/mp_init.c > @@ -238,7 +238,7 @@ static int load_sipi_vector(atomic_t **ap_countp) > > params->stack_size = CONFIG_AP_STACK_SIZE; > size = params->stack_size * CONFIG_MAX_CPUS; > - stack = memalign(size, 4096); > + stack = memalign(4096, size); > if (!stack) > return -ENOMEM; > params->stack_top = (u32)(stack + size); This change seems unrelated to the subject of this patch. -- Best Regards Masahiro Yamada _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
