From: Sam Ravnborg <sam@xxxxxxxxxxxx> Date: Tue, 3 Jan 2012 21:45:16 +0100 > - kern_addr_valid is (temporary) disabled > I could not grock the code allocating sparc_valid_addr_bitmap > and I noticed most archs do not implement this check Is it hard to grok where the memory is allocated from or the calculation of the bitmap memory's size? :-) To be honest, leaving this defined to "0" is no real crime. It just means that /proc/kcore isn't going to be supported as that is the only place this test is really used. On sparc64 we allocate the bitmap statically in the kernel image because we use it in the TLB miss handler to validate addresses when handling misses in the PAGE_OFFSET linear translation area. On sparc64 the memory error (or hypervisor error, since when we load TLB entries via the hypervisor it checks the address too) is harder to recover from than just noticing the problem earlier in the TLB miss handler. So that's why we do it this way. And since we have the table we use it to implement kern_addr_valid() too since that's essentially free. If the platform would properly fault on any bogus kernel address access, kern_addr_valid() can seemingly just be defined to the constant "1". -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
