Blackfin: simplify SYSCFG code a bit and ignore attempts to change it
We don't want to let user space modify the SYSCFG register arbitrarily as the settings are system wide (SNEN/CNEN) and can cause misbehavior. The only other bit here (SSSTEP) has proper controls via PTRACE_SINGLESTEP. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
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@ -31,12 +31,6 @@
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* in exit.c or in signal.c.
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*/
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/* determines which bits in the SYSCFG reg the user has access to. */
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/* 1 = access 0 = no access */
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#define SYSCFG_MASK 0x0007 /* SYSCFG reg */
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/* sets the trace bits. */
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#define TRACE_BITS 0x0001
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/* Find the stack offset for a register, relative to thread.esp0. */
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#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
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@ -162,9 +156,8 @@ static inline int is_user_addr_valid(struct task_struct *child,
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void ptrace_enable(struct task_struct *child)
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{
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unsigned long tmp;
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tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
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put_reg(child, PT_SYSCFG, tmp);
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struct pt_regs *regs = task_pt_regs(child);
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regs->syscfg |= SYSCFG_SSSTEP;
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}
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/*
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@ -174,10 +167,8 @@ void ptrace_enable(struct task_struct *child)
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*/
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void ptrace_disable(struct task_struct *child)
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{
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unsigned long tmp;
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/* make sure the single step bit is not set. */
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tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
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put_reg(child, PT_SYSCFG, tmp);
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struct pt_regs *regs = task_pt_regs(child);
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regs->syscfg &= ~SYSCFG_SSSTEP;
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}
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long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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@ -343,14 +334,11 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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break;
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}
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if (addr >= (sizeof(struct pt_regs))) {
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/* Ignore writes to SYSCFG and other pseudo regs */
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if (addr >= PT_SYSCFG) {
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ret = 0;
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break;
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}
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if (addr == PT_SYSCFG) {
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data &= SYSCFG_MASK;
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data |= get_reg(child, PT_SYSCFG);
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}
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ret = put_reg(child, addr, data);
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break;
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