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| author | Andy Lutomirski <luto@amacapital.net> | 2014-11-22 18:00:32 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:59 +0000 |
| commit | 4c414592a79b82ddca76945c7afb4843684aa9a8 (patch) | |
| tree | 4d373a4695b80e86643a27560832fb6d523693b8 /tools/perf/util/scripting-engines/trace-event-python.c | |
| parent | 33496741750c17f2f1b769808f3c228323f27ffa (diff) | |
x86_64, traps: Stop using IST for #SS
commit 6f442be2fb22be02cafa606f1769fa1e6f894441 upstream.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- No need to define trace_stack_segment
- Use the errorentry macro to generate #SS asm code
- Adjust context
- Checked that this matches Luis's backport for Ubuntu]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'tools/perf/util/scripting-engines/trace-event-python.c')
0 files changed, 0 insertions, 0 deletions