Hi, Yu > From: Chen, Yu C > Sent: Tuesday, November 10, 2015 5:43 PM > > Hi, Lv > Sorry for my late feedback on the patch, one minor nit below: > > > From: Zheng, Lv > > Sent: Tuesday, November 10, 2015 4:22 PM > > > > From: Chen Yu <[email protected]> > > > > This patch implements acpi_os_readable(). The function is used by ACPI AML > > debugger to validate user specified pointers for the dumpable AML operand > > objects. > > > > Signed-off-by: Chen Yu <[email protected]> > > Signed-off-by: Lv Zheng <[email protected]> > > --- > > +bool __acpi_memory_readable(void *pointer, size_t length) { > > + unsigned long start_pfn, end_pfn; > > + > We should only check the low memory, otherwise the highmem address might > bring unexpected behavior in this function, I think we should add: > if (pointer >= PAGE_OFFSET) > return false;
I think pfn_range_is_mapped() can ensure this. If you want to add some sanity checks, IMO, virt_addr_valid() could be better. > > + start_pfn = page_to_pfn(virt_to_page(pointer)); > > + end_pfn = page_to_pfn(virt_to_page(pointer + length)); > Convert pointer to char* first? > end_pfn = page_to_pfn(virt_to_page((char*)pointer + length)); Either a compiler supports such a conversion or a compiler ends up fatal error by complaining unknown sizeof(void *). So there is no need to do this here as the build test has passed. Thanks and best regards -Lv > > > + /* > > + * Since the acpi address is allocated by kmalloc, we only > > + * need to consider the direct-mapping virtual address, > > + * rather than the kmap/vmalloc/ioremap address. > > + */ > > + return pfn_range_is_mapped(start_pfn, end_pfn) ? true : false; } > > + > Thanks! > > Best Regards, > Yu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
