diff options
author | Ralf Baechle <ralf@linux-mips.org> | 2012-08-15 13:42:19 -0400 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2012-12-13 12:15:27 -0500 |
commit | 51d943f07d3015998d448f9d8353f618e3fe5873 (patch) | |
tree | 7765f573133f87148a594d2e49b3b8543c7a77cf /arch/mips | |
parent | 051ff44a8b508f8e8e342db3220d5ad8296c19ce (diff) |
MIPS: Fix for warning from FPU emulation code
The default implementation of 'cpu_has_fpu' macro calls
smp_processor_id() which causes this warning to be printed when
preemption is enabled:
[ 4.664000] Algorithmics/MIPS FPU Emulator v1.5
[ 4.676000] BUG: using smp_processor_id() in preemptible [00000000] code: ini
[ 4.700000] caller is fpu_emulator_cop1Handler+0x434/0x27b8
This problem got introduced in November 2009 by
af1d2af877ef6c36990671bc86a5b9c5bb50b1da (lmo) [MIPS: Fix emulation of
64-bit FPU on 64-bit CPUs.] rsp. da0bac33413b2888d3623dad3ad19ce76b688f07
(kernel.org) [MIPS: Fix emulation of 64-bit FPU on FPU-less 64-bit CPUs.]
in 2.6.32.
Fixed by rewriting cop1_64bit() to return a constant whenever possible
but most importantly avoid the use pf cpu_has_fpu entirely.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Jayachandran C <jchandra@broadcom.com>
Initial-patch-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: https://patchwork.linux-mips.org/patch/4225/
Diffstat (limited to 'arch/mips')
-rw-r--r-- | arch/mips/math-emu/cp1emu.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c index a03bf00a1a9c..47c77e7ffbf8 100644 --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c | |||
@@ -171,16 +171,17 @@ static int isBranchInstr(mips_instruction * i) | |||
171 | * In the Linux kernel, we support selection of FPR format on the | 171 | * In the Linux kernel, we support selection of FPR format on the |
172 | * basis of the Status.FR bit. If an FPU is not present, the FR bit | 172 | * basis of the Status.FR bit. If an FPU is not present, the FR bit |
173 | * is hardwired to zero, which would imply a 32-bit FPU even for | 173 | * is hardwired to zero, which would imply a 32-bit FPU even for |
174 | * 64-bit CPUs. For 64-bit kernels with no FPU we use TIF_32BIT_REGS | 174 | * 64-bit CPUs so we rather look at TIF_32BIT_REGS. |
175 | * as a proxy for the FR bit so that a 64-bit FPU is emulated. In any | 175 | * FPU emu is slow and bulky and optimizing this function offers fairly |
176 | * case, for a 32-bit kernel which uses the O32 MIPS ABI, only the | 176 | * sizeable benefits so we try to be clever and make this function return |
177 | * even FPRs are used (Status.FR = 0). | 177 | * a constant whenever possible, that is on 64-bit kernels without O32 |
178 | * compatibility enabled and on 32-bit kernels. | ||
178 | */ | 179 | */ |
179 | static inline int cop1_64bit(struct pt_regs *xcp) | 180 | static inline int cop1_64bit(struct pt_regs *xcp) |
180 | { | 181 | { |
181 | if (cpu_has_fpu) | 182 | #if defined(CONFIG_64BIT) && !defined(CONFIG_MIPS32_O32) |
182 | return xcp->cp0_status & ST0_FR; | 183 | return 1; |
183 | #ifdef CONFIG_64BIT | 184 | #elif defined(CONFIG_64BIT) && defined(CONFIG_MIPS32_O32) |
184 | return !test_thread_flag(TIF_32BIT_REGS); | 185 | return !test_thread_flag(TIF_32BIT_REGS); |
185 | #else | 186 | #else |
186 | return 0; | 187 | return 0; |