From: Andy Lutomirski Date: Sun, 23 Nov 2014 02:00:32 +0000 (-0800) Subject: x86_64, traps: Stop using IST for #SS X-Git-Tag: omap-for-v3.19/fixes-for-merge-window~77^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6f442be2fb22be02cafa606f1769fa1e6f894441;p=pandora-kernel.git x86_64, traps: Stop using IST for #SS On a 32-bit kernel, this has no effect, since there are no IST stacks. On a 64-bit kernel, #SS can only happen in user code, on a failed iret to user space, a canonical violation on access via RSP or RBP, or a genuine stack segment violation in 32-bit kernel code. The first two cases don't need IST, and the latter two cases are unlikely fatal bugs, and promoting them to double faults would be fine. This fixes a bug in which the espfix64 code mishandles a stack segment violation. This saves 4k of memory per CPU and a tiny bit of code. Signed-off-by: Andy Lutomirski Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed