ptrace/x86: simplify the "disable" logic in ptrace_write_dr7()
ptrace_write_dr7() looks unnecessarily overcomplicated. We can factor out ptrace_modify_breakpoint() and do not do "continue" twice, just we need to pass the proper "disabled" argument to ptrace_modify_breakpoint(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -637,9 +637,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
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struct thread_struct *thread = &(tsk->thread);
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unsigned long old_dr7;
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int i, orig_ret = 0, rc = 0;
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int enabled, second_pass = 0;
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unsigned len, type;
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struct perf_event *bp;
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int second_pass = 0;
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data &= ~DR_CONTROL_RESERVED;
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old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
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@ -649,30 +647,22 @@ restore:
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* appropriate changes to each.
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*/
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for (i = 0; i < HBP_NUM; i++) {
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enabled = decode_dr7(data, i, &len, &type);
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bp = thread->ptrace_bps[i];
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unsigned len, type;
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bool disabled = !decode_dr7(data, i, &len, &type);
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struct perf_event *bp = thread->ptrace_bps[i];
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if (!enabled) {
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if (bp) {
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if (disabled) {
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/*
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* Don't unregister the breakpoints right-away,
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* unless all register_user_hw_breakpoint()
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* requests have succeeded. This prevents
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* any window of opportunity for debug
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* register grabbing by other users.
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* Don't unregister the breakpoints right-away, unless
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* all register_user_hw_breakpoint() requests have
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* succeeded. This prevents any window of opportunity
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* for debug register grabbing by other users.
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*/
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if (!second_pass)
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continue;
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rc = ptrace_modify_breakpoint(bp, len, type,
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tsk, 1);
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if (rc)
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break;
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}
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if (!bp || !second_pass)
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continue;
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}
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rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
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rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);
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if (rc)
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break;
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}
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