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| author |  Andy Lutomirski <luto@amacapital.net>
| 2014-11-22 18:00:32 -0800 |
|---|---|---|
| committer |  Linus Torvalds <torvalds@linux-foundation.org>
| 2014-11-23 13:56:19 -0800 |
| commit | 6f442be2fb22be02cafa606f1769fa1e6f894441 (patch) | |
| tree | 1173ca6feb0cdda19b5383e713e2f19152d88940 /Documentation/x86 | |
| parent | x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C (diff) | |
| download | linux-6f442be2fb22.tar.gz linux-6f442be2fb22.tar.bz2 linux-6f442be2fb22.zip | |
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 <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/x86')
0 files changed, 0 insertions, 0 deletions