Messages in this thread | | | Date | Mon, 4 Jul 2016 07:28:02 -0700 | From | Andi Kleen <> | Subject | Re: [PATCH] Syscall arguments are unsigned long (full registers) |
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On Mon, Jul 04, 2016 at 01:52:58PM +0000, Tautschnig, Michael wrote: > All syscall arguments are passed in as types of the same byte size as > unsigned long (width of full registers). Using a smaller type without a > cast may result in losing bits of information. In all other instances > apart from the ones fixed by the patch the code explicitly introduces > type casts (using, e.g., SYSCALL_DEFINE1). > > While goto-cc reported these problems at build time, it is noteworthy > that the calling conventions specified in the System V AMD64 ABI do > ensure that parameters 1-6 are passed via registers, thus there is no > implied risk of misaligned stack access.
Does this actually fix anything?
It seems a big dangerous to me, potentially breaking some existing binaries that rely on these arguments being truncated.
-Andi
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