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Commit 6f442be2 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Linus Torvalds
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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: default avatarAndy Lutomirski <luto@amacapital.net>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent af726f21
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