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| author |   Paul Burton <paul.burton@imgtec.com> | 2013-11-19 17:30:35 +0000 |
|---|---|---|
| committer |   Ralf Baechle <ralf@linux-mips.org> | 2014-03-31 18:17:12 +0200 |
| commit | 3351047f01fe012abbb585b400d1c51b57ed011d (patch) | |
| tree | 50e921b62fda46b18a9528f0e5b14a031afa168c /arch/mips/kernel/ptrace32.c | |
| parent | MIPS: Use current_cpu_type() instead of c->cputype (diff) | |
| download | linux-dev-3351047f01fe012abbb585b400d1c51b57ed011d.tar.xz linux-dev-3351047f01fe012abbb585b400d1c51b57ed011d.zip | |
MIPS: Simplify PTRACE_PEEKUSR for FPC_EIR
All architecturally defined bits in the FPU implementation register
are read only & unchanging. It contains some implementation-defined
bits but the architecture manual states "This bits are explicitly not
intended to be used for mode control functions" which seems to provide
justification for viewing the register as a whole as unchanging. This
being the case we can simply re-use the value we read at boot rather
than having to re-read it later, and avoid the complexity which that
read entails.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6144/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/ptrace32.c')
| -rw-r--r-- | arch/mips/kernel/ptrace32.c | 42 |
1 files changed, 3 insertions, 39 deletions
diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c index c394d8f74265..b40c3ca60ee5 100644 --- a/arch/mips/kernel/ptrace32.c +++ b/arch/mips/kernel/ptrace32.c @@ -127,46 +127,10 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, case FPC_CSR: tmp = child->thread.fpu.fcr31; break; - case FPC_EIR: { /* implementation / version register */ - unsigned int flags; -#ifdef CONFIG_MIPS_MT_SMTC - unsigned int irqflags; - unsigned int mtflags; -#endif /* CONFIG_MIPS_MT_SMTC */ - - preempt_disable(); - if (!cpu_has_fpu) { - preempt_enable(); - tmp = 0; - break; - } - -#ifdef CONFIG_MIPS_MT_SMTC - /* Read-modify-write of Status must be atomic */ - local_irq_save(irqflags); - mtflags = dmt(); -#endif /* CONFIG_MIPS_MT_SMTC */ - - if (cpu_has_mipsmt) { - unsigned int vpflags = dvpe(); - flags = read_c0_status(); - __enable_fpu(FPU_AS_IS); - __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp)); - write_c0_status(flags); - evpe(vpflags); - } else { - flags = read_c0_status(); - __enable_fpu(FPU_AS_IS); - __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp)); - write_c0_status(flags); - } -#ifdef CONFIG_MIPS_MT_SMTC - emt(mtflags); - local_irq_restore(irqflags); -#endif /* CONFIG_MIPS_MT_SMTC */ - preempt_enable(); + case FPC_EIR: + /* implementation / version register */ + tmp = current_cpu_data.fpu_id; break; - } case DSP_BASE ... DSP_BASE + 5: { dspreg_t *dregs; |