powerpc: setcontext.S uses power6 mtfsf when not supported [BZ #18116]

The attached patch fixes a glibc build failure with gcc 5 on powerpc64le
caused by a recent change in gcc where the compiler defines the
_ARCH_PWR6 macro when processing assembly files but doesn't invoke the
assembler in the corresponding machine mode (unless it has been
explicitly configured to target POWER 6 or later).  A bug had been filed
with gcc for this (65341) but was closed as won't fix. Glibc relies on
the _ARCH_PWR6 macro in a few .S files to make use of Power ISA 2.5
instructions (specifically, the four-argument form of the mtfsf insn).
A similar problem had occurred in the past (bug 10118) but the fix that
was committed for it didn't anticipate this new problem.
This commit is contained in:
Martin Sebor 2015-06-01 14:12:09 -03:00 committed by Tulio Magno Quites Machado Filho
parent 0cd2828695
commit db8fed87d9
3 changed files with 61 additions and 14 deletions

View File

@ -1,3 +1,12 @@
2015-03-11 Martin Sebor <msebor@redhat.com>
[BZ #18116]
* sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S
(__setcontext): Use extended four-operand version of mtsf whenever
possible.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S
(__novec_swapcontext): Likewise.
2015-06-01 Siddhesh Poyarekar <siddhesh@redhat.com>
* benchtests/scripts/compare_bench.py: New file.

View File

@ -81,22 +81,31 @@ ENTRY(__novec_setcontext)
# ifdef _ARCH_PWR6
/* Use the extended four-operand version of the mtfsf insn. */
mtfsf 0xff,fp0,1,0
# else
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
# else
/* Availability of DFP indicates a 64-bit FPSCR. */
andi. r6,r5,PPC_FEATURE_HAS_DFP
beq 5f
/* Use the extended four-operand version of the mtfsf insn. */
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
b 6f
/* Continue to operate on the FPSCR as if it were 32-bits. */
5:
mtfsf 0xff,fp0
6:
.machine pop
# endif /* _ARCH_PWR6 */
lfd fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r31)
lfd fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r31)
lfd fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r31)
@ -364,22 +373,31 @@ L(has_no_vec):
# ifdef _ARCH_PWR6
/* Use the extended four-operand version of the mtfsf insn. */
mtfsf 0xff,fp0,1,0
# else
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
# else
/* Availability of DFP indicates a 64-bit FPSCR. */
andi. r6,r5,PPC_FEATURE_HAS_DFP
beq 7f
/* Use the extended four-operand version of the mtfsf insn. */
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
b 8f
/* Continue to operate on the FPSCR as if it were 32-bits. */
7:
mtfsf 0xff,fp0
8:
.machine pop
# endif /* _ARCH_PWR6 */
lfd fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r31)
lfd fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r31)
lfd fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r31)

View File

@ -173,24 +173,34 @@ ENTRY(__novec_swapcontext)
lfd fp0,(SIGCONTEXT_FP_REGS+(32*8))(r31)
lfd fp31,(SIGCONTEXT_FP_REGS+(PT_R31*8))(r31)
lfd fp30,(SIGCONTEXT_FP_REGS+(PT_R30*8))(r31)
# ifdef _ARCH_PWR6
/* Use the extended four-operand version of the mtfsf insn. */
mtfsf 0xff,fp0,1,0
# else
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
# else
/* Availability of DFP indicates a 64-bit FPSCR. */
andi. r6,r8,PPC_FEATURE_HAS_DFP
beq 5f
/* Use the extended four-operand version of the mtfsf insn. */
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
b 6f
/* Continue to operate on the FPSCR as if it were 32-bits. */
5:
mtfsf 0xff,fp0
6:
.machine pop
#endif /* _ARCH_PWR6 */
lfd fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r31)
lfd fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r31)
lfd fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r31)
@ -652,24 +662,34 @@ L(has_no_vec2):
lfd fp0,(SIGCONTEXT_FP_REGS+(32*8))(r31)
lfd fp31,(SIGCONTEXT_FP_REGS+(PT_R31*8))(r31)
lfd fp30,(SIGCONTEXT_FP_REGS+(PT_R30*8))(r31)
# ifdef _ARCH_PWR6
/* Use the extended four-operand version of the mtfsf insn. */
mtfsf 0xff,fp0,1,0
# else
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
# else
/* Availability of DFP indicates a 64-bit FPSCR. */
andi. r6,r8,PPC_FEATURE_HAS_DFP
beq 7f
/* Use the extended four-operand version of the mtfsf insn. */
.machine push
.machine "power6"
mtfsf 0xff,fp0,1,0
.machine pop
b 8f
/* Continue to operate on the FPSCR as if it were 32-bits. */
7:
mtfsf 0xff,fp0
8:
.machine pop
#endif /* _ARCH_PWR6 */
lfd fp29,(SIGCONTEXT_FP_REGS+(PT_R29*8))(r31)
lfd fp28,(SIGCONTEXT_FP_REGS+(PT_R28*8))(r31)
lfd fp27,(SIGCONTEXT_FP_REGS+(PT_R27*8))(r31)