Load/store indexed instructions where the index register RA=R0, such
as "lfdx f1,0,r3", are not illegal.
Load/store indexed with update instructions where the index register
RA=R0, such as "lfdux f1,0,r3", are invalid, and, to be consistent
with existing math-emu behavior for other invalid instruction forms,
will signal as illegal.
Signed-off-by: James Yang <James.Yang@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
In the current kernel, the function flush_fp_to_thread() is not
dependent on CONFIG_PPC_FPU. So most invocations of this function
is not wrapped by CONFIG_PPC_FPU. Even through we don't really
save the FPRs to the thread struct if CONFIG_PPC_FPU is not enabled,
but there does have some runtime overhead such as the check for
tsk->thread.regs and preempt disable and enable. It really make
no sense to do that. So make it a nop when CONFIG_PPC_FPU is
disabled. Also remove the wrapped #ifdef CONFIG_PPC_FPU
when invoking this function.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
For some SoC (such as the FSL BookE) even though there does have
a hardware FPU, but not all floating point instructions are
implemented. Unfortunately some versions of gcc do use these
unimplemented instructions. Then we have to enable the math emulation
to workaround this issue. It seems a little redundant to have the
support to emulate all the floating point instructions in this case.
So split the math emulation into two parts. One is for the SoC which
doesn't have FPU at all and the other for the SoC which does have the
hardware FPU and only need some special floating point instructions to
be emulated.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
By doing this we can make sure that the FPU state is only flushed to
the thread struct when it is really needed.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The math.c is only built when CONFIG_MATH_EMULATION is enabled.
So the #ifdef check for CONFIG_MATH_EMULATION in it seems redundant.
Drop all of them.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The math.c is only built when CONFIG_MATH_EMULATION is enabled.
So we would never get into the case that CONFIG_MATH_EMULATION
is not defined in this file.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The decoding of some instructions such as fsqrt{s} was incorrect,
using the wrong registers, and thus could not work.
This fixes it and also adds a couple of place holders for missing
instructions.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We already have cpu a005 errata handler when instruction cannot be
recognized. Before we lookup the inst, there's type checking, and we also
need to handle it in errata handler when the type checking failed.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Conversion from float to integer should based on both the instruction
encoding and the sign of the operand.
A simple testcase to show the issue:
static float fm;
static signed int si_min = (-2147483647 - 1);
static unsigned int ui;
int main()
{
fm = (float) si_min; ;
ui = (unsigned int)fm;
printf("ui=%d, should be %d\n", ui, si_min);
return 0;
}
Result: ui=-1, should be -2147483648
Signed-off-by: Shan Hai <shan.hai@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This erratum can occur if a single-precision floating-point,
double-precision floating-point or vector floating-point instruction on a
mispredicted branch path signals one of the floating-point data interrupts
which are enabled by the SPEFSCR (FINVE, FDBZE, FUNFE or FOVFE bits). This
interrupt must be recorded in a one-cycle window when the misprediction is
resolved. If this extremely rare event should occur, the result could be:
The SPE Data Exception from the mispredicted path may be reported
erroneously if a single-precision floating-point, double-precision
floating-point or vector floating-point instruction is the second
instruction on the correct branch path.
According to errata description, some efp instructions which are not
supposed to trigger SPE exceptions can trigger the exceptions in this case.
However, as we haven't emulated these instructions here, a signal will
send to userspace, and userspace application would exit.
This patch re-issue the efp instruction that we haven't emulated,
so that hardware can properly execute it again if this case happen.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y.
Signed-off-by: matt mooney <mfm@muteddisk.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
There is no dependece between efp and math-emu. But when disable math-emu
the efp code cannot be built.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This patch add the handlers of SPE/EFP exceptions.
The code is used to emulate float point arithmetic,
when MSR(SPE) is enabled and receive EFP data interrupt or EFP round interrupt.
This patch has no conflict with or dependence on FP math-emu.
The code has been tested by TestFloat.
Now the code doesn't support SPE/EFP instructions emulation
(it won't be called when receive program interrupt),
but it could be easily added.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
FP_DECL_EX is already used, so ret is redundant.
And FP_SET_EXCEPTION will add status into return value.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
The math emulation code is centered around a set of generic macros that
provide the core of the emulation that are shared by the various
architectures and other projects (like glibc). Each arch implements its
own sfp-machine.h to specific various arch specific details.
For historic reasons that are now lost the powerpc math-emu code had
its own version of the common headers. This moves us to using the
kernel generic version and thus getting fixes when those are updated.
Also cleaned up exception/error reporting from the FP emulation functions.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
We are going to change where the floating point registers are stored
in the thread_struct, so in preparation add some macros to access the
floating point registers. Update all code to use these new macros.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Synchronize it to the definition in include/math-emu/op-4.h for short term.
Signed-off-by: Liu Yu <Yu.Liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This patch fixes rounding bug in emulation for double float operating on PowerPC platform.
When pack double float operand, it need to truncate the tail due to the limited precision.
If the truncated part is not zero, the last bit of work bit (totally 3 bits) need to '|' 1.
This patch is completed in _FP_FRAC_SRS_2(X,N,sz) (arch/powerpc/math-emu/op-2.h).
Originally the code leftwards rotates the operand to just keep the truncated part,
then check whether it is zero. However, the number it rotates is not correct when
N is not smaller than _FP_W_TYPE_SIZE, and it will cause the work bit '|' 1 in the improper case.
This patch fixes this issue.
Signed-off-by: Liu Yu <b13201@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Its legal for the stfiwx instruction to have RA = 0 as part of its
effective address calculation. This is illegal for all other XE
form instructions.
Add code to compute the proper effective address for stfiwx if
RA = 0 rather than treating it as illegal.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
... since they deal with internal function with that name.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Towards the goal of having arch/powerpc not build anything over in arch/ppc
move math-emu over. Also, killed some references to arch/ppc/ in the
arch/powerpc Makefile which should belong in drivers/ when the particular
sub-arch's move over to arch/powerpc.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
James Yang