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| author | Chris Zankel <chris@zankel.net> | 2014-01-28 22:09:51 -0800 |
|---|---|---|
| committer | Chris Zankel <chris@zankel.net> | 2014-01-29 13:47:26 -0800 |
| commit | c0e50d41126e4786d9cf1105bdf783e55c99f915 (patch) | |
| tree | a4b3b7cfe0e0d8fe23008b5c44a5d4ff43081738 | |
| parent | 6b5a1f74e50170e64104135490dc32b657483594 (diff) | |
| download | op-kernel-dev-c0e50d41126e4786d9cf1105bdf783e55c99f915.zip op-kernel-dev-c0e50d41126e4786d9cf1105bdf783e55c99f915.tar.gz | |
xtensa: fix fast_syscall_spill_registers
The original implementation could clobber registers under certain conditions.
The Xtensa processor architecture uses windowed registers and the original
implementation was using a4 as a temporary register, which under certain
conditions could be register a0 of the oldest window frame, and didn't always
restore the content correctly.
By moving the _spill_registers routine inside the fast system call, it frees
up one more register (the return address is not required anymore) for the
spill routine.
Signed-off-by: Chris Zankel <chris@zankel.net>
| -rw-r--r-- | arch/xtensa/kernel/vectors.S | 2 | ||||
| -rw-r--r-- | arch/xtensa/kernel/xtensa_ksyms.c | 2 |
2 files changed, 1 insertions, 3 deletions
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S index cb8fd44..f9e1ec3 100644 --- a/arch/xtensa/kernel/vectors.S +++ b/arch/xtensa/kernel/vectors.S @@ -235,7 +235,7 @@ ENTRY(_DoubleExceptionVector) /* Check for overflow/underflow exception, jump if overflow. */ - _bbci.l a0, 6, _DoubleExceptionVector_WindowOverflow + bbci.l a0, 6, _DoubleExceptionVector_WindowOverflow /* * Restart window underflow exception. diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c index 74a60c7..80b33ed 100644 --- a/arch/xtensa/kernel/xtensa_ksyms.c +++ b/arch/xtensa/kernel/xtensa_ksyms.c @@ -122,9 +122,7 @@ EXPORT_SYMBOL(insw); EXPORT_SYMBOL(insl); extern long common_exception_return; -extern long _spill_registers; EXPORT_SYMBOL(common_exception_return); -EXPORT_SYMBOL(_spill_registers); #ifdef CONFIG_FUNCTION_TRACER EXPORT_SYMBOL(_mcount); |
