Hi, > -----Original Message----- > From: Zheng, Lv > Sent: Wednesday, November 11, 2015 1:07 PM > To: Chen, Yu C > Cc: Lv Zheng; linux-kernel@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > Wysocki, Rafael J; Brown, Len > Subject: RE: [PATCH v2 5/7] ACPI / x86: introduce acpi_os_readable() support > > 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 <yu.c.chen@xxxxxxxxx> > > > > > > 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 <yu.c.chen@xxxxxxxxx> > > > Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx> > > > --- > > > +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. virt_to_page might return an invalid page struct if pointer is not a valid kernel address. > If you want to add some sanity checks, IMO, virt_addr_valid() could be > better. Yes, virt_addr_valid is 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. > OK, got it, thanks. > 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-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html