From e6a7d6077106e5c72f0519ec113d986df67ee001 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov <oleg@redhat.com> Date: Mon, 8 Jul 2013 16:00:56 -0700 Subject: 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> --- arch/x86/kernel/ptrace.c | 40 +++++++++++++++------------------------- 1 file changed, 15 insertions(+), 25 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 7a98b21945aa..0649f166d7c6 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -637,9 +637,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) struct thread_struct *thread = &(tsk->thread); unsigned long old_dr7; int i, orig_ret = 0, rc = 0; - int enabled, second_pass = 0; - unsigned len, type; - struct perf_event *bp; + int second_pass = 0; data &= ~DR_CONTROL_RESERVED; old_dr7 = ptrace_get_dr7(thread->ptrace_bps); @@ -649,30 +647,22 @@ restore: * appropriate changes to each. */ for (i = 0; i < HBP_NUM; i++) { - enabled = decode_dr7(data, i, &len, &type); - bp = thread->ptrace_bps[i]; - - if (!enabled) { - if (bp) { - /* - * Don't unregister the breakpoints right-away, - * unless all register_user_hw_breakpoint() - * requests have succeeded. This prevents - * any window of opportunity for debug - * register grabbing by other users. - */ - if (!second_pass) - continue; - - rc = ptrace_modify_breakpoint(bp, len, type, - tsk, 1); - if (rc) - break; - } - continue; + unsigned len, type; + bool disabled = !decode_dr7(data, i, &len, &type); + struct perf_event *bp = thread->ptrace_bps[i]; + + if (disabled) { + /* + * Don't unregister the breakpoints right-away, unless + * all register_user_hw_breakpoint() requests have + * succeeded. This prevents any window of opportunity + * for debug register grabbing by other users. + */ + if (!bp || !second_pass) + continue; } - rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0); + rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled); if (rc) break; } -- cgit v1.2.2