On 03/15/15 at 12:49am, Yinghai Lu wrote: > Index: linux-2.6/arch/x86/kernel/setup.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/setup.c > +++ linux-2.6/arch/x86/kernel/setup.c > @@ -429,7 +429,18 @@ static void __init reserve_initrd(void) > > static void __init parse_kaslr_setup(u64 pa_data, u32 data_len) > { > - kaslr_enabled = (bool)(pa_data + sizeof(struct setup_data)); > + /* kaslr_setup_data is defined in aslr.c */ > + unsigned char *data; > + unsigned long offset = sizeof(struct setup_data); > + > + data = early_memremap(pa_data, offset + 1); > + if (!data) {
It's good to check the ret value as Boris suggested. However it could fail since early_memremap self fail, e.g slot not found. In this case making kaslr_enabled true may not be good. As Minfei talked with you kaslr_setup_data is a global variable inside kernel code, it has been ident mapped. Just derefencing the physical address which is virtual address too and getting the real stored value may be safer. And also parse_kaslr_setup is a function specified to handle kaslr, it doesn't make me uncomfortable to implement with a specific knowledge which here means the setup_data is a global varialbe in kernel code and no need to do early_memremap since mapping has been built . Thanks Baoquan > + kaslr_enabled = true; > + return; > + } > + > + kaslr_enabled = *(data + offset); > + early_memunmap(data, offset + 1); > } > > static void __init parse_setup_data(void) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/