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SOLARIS: prevent BAD TRAP panic with Studio 12.5

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Starting with Solaris Studio 12.3, it is documented that Solaris kernel
modules (such as libafs) must not use any floating point, vector, or
SIMD/SSE instructions on x86 hardware.  However, each new Studio
compiler release (12.4 and especially 12.5) is more likely to use these
types of instructions by default.

If the libafs kernel module includes any forbidden kernel instructions,
Solaris will panic the system with:
  BAD TRAP:  type=7 (#nm Device not available)

Provide a new autoconfig test to specify the required compiler options
(-xvector=%none -xregs=no%float) when building the OpenAFS kernel module
for Solaris, so that no invalid x86 instructions are used.

In addition, reinstate default kernel module optimization for Solaris.
It had been disabled in commit 80592c53cbb0bce782eb39a5e64860786654be9f
to address this same issue in Studio 12.3 and 12.4.  However, Studio
12.5 started using some SSE instructions even with no optimization.

This commit has been tested with OpenAFS master and Studio 12.5 at all
optimization levels (none, -xO1 through -xO5) and verified to contain no
XMM register instructions via the following command:
  $ gobjdump -dlr libafs64.o | grep xmm | wc -l

[wiesand: limit change to solaris 5.11 for stable branch]

Reviewed-on: https://gerrit.openafs.org/12558
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 22d841a45fff7026318b529a41dd957ce8bb0ddf)

Change-Id: I2e87f26dbac47289694346639b396dfc556368f4
Reviewed-on: https://gerrit.openafs.org/12567
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
This commit is contained in:
Mark Vitale 2017-02-28 18:02:39 -05:00 committed by Stephan Wiesand
parent 58464339da
commit 33b5495e1b
4 changed files with 48 additions and 5 deletions
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2
acinclude.m4
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@ -387,6 +387,8 @@ case $system in
MKAFS_OSTYPE=SOLARIS
AC_MSG_RESULT(sun4)
SOLARIS_PATH_CC
SOLARIS_CC_TAKES_XVECTOR_NONE
AC_SUBST(SOLARIS_CC_KOPTS)
SOLARIS_UFSVFS_HAS_DQRWLOCK
SOLARIS_FS_HAS_FS_ROLLED
SOLARIS_SOLOOKUP_TAKES_SOCKPARAMS

11
src/cf/osconf.m4
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@ -716,6 +716,7 @@ case $AFS_SYSNAME in
MT_CC=$SOLARISCC
MT_CFLAGS='-mt -DAFS_PTHREAD_ENV ${XCFLAGS}'
MT_LIBS="-lpthread -lsocket"
KERN_OPTMZ="-xO3"
PAM_CFLAGS="-KPIC"
PAM_LIBS="-lc -lpam -lsocket -lnsl -lm"
SHLIB_CFLAGS="-KPIC"
@ -736,10 +737,12 @@ if test "x$enable_optimize_kernel" = "x" ; then
AS_CASE([$AFS_SYSNAME],
[sunx86_510|sunx86_511],
dnl Somewhere around Solaris Studio 12.*, the compiler started adding SSE
dnl instructions to optimized code, without any ability to turn it off.
dnl So just default to not optimizing kernel code for the relevant
dnl platforms, until we get a better autoconf test for this.
[enable_optimize_kernel=no],
dnl instructions to optimized code, without any known way to turn it off.
dnl To cope, this condition was added to change the default to
dnl 'no'.
dnl Now that we have an autoconf test to allow disabling the SSE
dnl optimizations, it's safe to once more default to 'yes' here.
[enable_optimize_kernel=yes],
[enable_optimize_kernel=yes])
fi

38
src/cf/solaris-test1.m4 Normal file
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@ -0,0 +1,38 @@
dnl This test is for the Solaris x86 kernel module
dnl build. They prevent newer Solaris compilers (12.3
dnl and up) from using XMM registers (SIMD instructions)
dnl and floating point registers, which are invalid in
dnl Solaris kernel code.
dnl Without this, Solaris may panic in libafs with:
dnl BAD TRAP: type=7 (#nm Device not available)
dnl
dnl
AC_DEFUN([SOLARIS_CC_TAKES_XVECTOR_NONE], [
AC_CACHE_CHECK([if $CC accepts -xvector=%none],
[ac_cv_solaris_cc_takes_xvector_none],
[save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -xvector=%none"
AC_TRY_COMPILE([],
[int x;],
[ac_cv_solaris_cc_takes_xvector_none=yes],
[ac_cv_solaris_cc_takes_xvector_none=no])
CFLAGS="$save_CFLAGS"
])
dnl -xvector=%none first appeared in Studio 11, but has only been
dnl documented as required for Solaris x86 kernel code since Studio
dnl 12.3. Studio 12.3 is when the compiler started making more
dnl aggressive optimizations by using SSE/SIMD instructions with XMM
dnl (floating point/ SIMD) registers. Although -xvector=%none is
dnl required to prevent these optimizations, it is not sufficient.
dnl Experiments have shown that -xregs=no%float is also needed to
dnl 1) eliminate a few optimizations not squelched by -xvector=%none,
dnl and 2) prevent actual use of floating point types in the kernel
dnl module. -xregs=no%float has been present since before Studio 8, so
dnl it is safe to assume its presence when -xvector=%none is present.
dnl
AS_IF([test "$ac_cv_solaris_cc_takes_xvector_none" = "yes"],
[SOLARIS_CC_KOPTS="-xvector=%none -xregs=no%float "])
])

2
src/libafs/MakefileProto.SOLARIS.in
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@ -50,7 +50,7 @@ KDEFS_32 =
KDEFS_64 = -xarch=amd64 -xmodel=kernel
<all>
CFLAGS=-I. -I.. -I${TOP_OBJDIR}/src/config ${FSINCLUDES} $(DEFINES) $(KDEFS) $(KOPTS) ${DBUG}
CFLAGS=-I. -I.. -I${TOP_OBJDIR}/src/config ${FSINCLUDES} $(DEFINES) $(KDEFS) @SOLARIS_CC_KOPTS@ ${DBUG}
<sun4x_58 sunx86_58 sun4x_59 sunx86_59>
LDFLAGS=-r -dy -N drv/ip -N drv/udp -N strmod/rpcmod