android_kernel_motorola_sm6375/Documentation/powerpc
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Filename Latest commit message Latest commit date
Sam bobroff feba40362b powerpc/tm: Abort syscalls in active transactions
This patch changes the syscall handler to doom (tabort) active
transactions when a syscall is made and return immediately without
performing the syscall.

Currently, the system call instruction automatically suspends an
active transaction which causes side effects to persist when an active
transaction fails.

This does change the kernel's behaviour, but in a way that was
documented as unsupported. It doesn't reduce functionality because
syscalls will still be performed after tsuspend. It also provides a
consistent interface and makes the behaviour of user code
substantially the same across powerpc and platforms that do not
support suspended transactions (e.g. x86 and s390).

Performance measurements using
http://ozlabs.org/~anton/junkcode/null_syscall.c
indicate the cost of a system call increases by about 0.5%.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Acked-By: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-04-11 20:49:19 +10:00
..
00-INDEX cxl: Add documentation for userspace APIs 2014-10-08 20:16:19 +11:00
bootwrapper.txt
cpu_families.txt
cpu_features.txt
cxl.txt cxl: Add documentation for userspace APIs 2014-10-08 20:16:19 +11:00
eeh-pci-error-recovery.txt
firmware-assisted-dump.txt
hvcs.txt
mpc52xx.txt
pmu-ebb.txt
ptrace.txt
qe_firmware.txt
transactional_memory.txt powerpc/tm: Abort syscalls in active transactions 2015-04-11 20:49:19 +10:00