Patch "MIPS: math-emu: MINA.<D|S>: Fix some cases of infinity and zero inputs" has been added to the 4.4-stable tree

Patch "MIPS: math-emu: MINA.<D|S>: Fix some cases of infinity and zero inputs" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    MIPS: math-emu: MINA.<D|S>: Fix some cases of infinity and zero inputs

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-math-emu-mina.-d-s-fix-some-cases-of-infinity-and-zero-inputs.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 304bfe473e70523e591fb1c9223289d355e0bdcb Mon Sep 17 00:00:00 2001
From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Date: Thu, 27 Jul 2017 18:08:53 +0200
Subject: MIPS: math-emu: MINA.<D|S>: Fix some cases of infinity and zero inputs

From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>

commit 304bfe473e70523e591fb1c9223289d355e0bdcb upstream.

Fix following special cases for MINA>.<D|S>:

  - if one of the inputs is zero, and the other is subnormal, normal,
    or infinity, the  value of the former should be returned (that is,
    a zero).
  - if one of the inputs is infinity, and the other input is normal,
    or subnormal, the value of the latter should be returned.

The previous implementation's logic for such cases was incorrect - it
appears as if it implements MAXA, and not MINA instruction.

A relevant example:

MINA.S fd,fs,ft:
  If fs contains 100.0, and ft contains 0.0, fd is going to contain
  0.0 (without this patch, it used to contain 100.0).

Fixes: a79f5f9ba508 ("MIPS: math-emu: Add support for the MIPS R6 MAX{, A} FPU instruction")
Fixes: 4e9561b20e2f ("MIPS: math-emu: Add support for the MIPS R6 MIN{, A} FPU instruction")

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Bo Hu <bohu@google.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: Jin Qian <jinqian@google.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16885/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/math-emu/dp_fmin.c |    4 ++--
 arch/mips/math-emu/sp_fmin.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/mips/math-emu/dp_fmin.c
+++ b/arch/mips/math-emu/dp_fmin.c
@@ -210,14 +210,14 @@ union ieee754dp ieee754dp_fmina(union ie
 	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
-		return x;
+		return y;
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
-		return y;
+		return x;
 
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 		return ieee754dp_zero(xs | ys);
--- a/arch/mips/math-emu/sp_fmin.c
+++ b/arch/mips/math-emu/sp_fmin.c
@@ -210,14 +210,14 @@ union ieee754sp ieee754sp_fmina(union ie
 	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
-		return x;
+		return y;
 
 	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
-		return y;
+		return x;
 
 	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 		return ieee754sp_zero(xs | ys);


Patches currently in stable-queue which might be from aleksandar.markovic@imgtec.com are

queue-4.4/mips-math-emu-max-maxa-min-mina-.-d-s-fix-cases-of-both-inputs-zero.patch
queue-4.4/mips-math-emu-max-min-.-d-s-fix-cases-of-both-inputs-negative.patch
queue-4.4/mips-math-emu-max-maxa-min-mina-.-d-s-fix-quiet-nan-propagation.patch
queue-4.4/mips-math-emu-maxa-mina-.-d-s-fix-cases-of-input-values-with-opposite-signs.patch
queue-4.4/mips-math-emu-maxa-mina-.-d-s-fix-cases-of-both-infinite-inputs.patch
queue-4.4/mips-math-emu-mina.-d-s-fix-some-cases-of-infinity-and-zero-inputs.patch