From 3351047f01fe012abbb585b400d1c51b57ed011d Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Tue, 19 Nov 2013 17:30:35 +0000 Subject: [PATCH] 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 Reviewed-by: Qais Yousef Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6144/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/ptrace.c | 40 +++-------------------------------- arch/mips/kernel/ptrace32.c | 42 +++---------------------------------- 2 files changed, 6 insertions(+), 76 deletions(-) diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 4137a49eae26..94144bad5727 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -501,44 +501,10 @@ long arch_ptrace(struct task_struct *child, long 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 long irqflags; - unsigned int mtflags; -#endif /* CONFIG_MIPS_MT_SMTC */ - - preempt_disable(); - if (!cpu_has_fpu) { - preempt_enable(); - 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; 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;