ptrace/x86: introduce ptrace_register_breakpoint()
No functional changes, preparation. Extract the "register breakpoint" code from ptrace_get_debugreg() into the new/generic helper, ptrace_register_breakpoint(). It will have more users. The patch also adds another simple helper, ptrace_fill_bp_fields(), to factor out the arch_bp_generic_fields() logic in register/modify. 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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@ -601,23 +601,49 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
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return dr7;
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}
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static int
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ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
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struct task_struct *tsk, int disabled)
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static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
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int len, int type, bool disabled)
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{
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int err;
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int gen_len, gen_type;
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struct perf_event_attr attr;
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int err, bp_len, bp_type;
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err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
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err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
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if (!err) {
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attr->bp_len = bp_len;
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attr->bp_type = bp_type;
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attr->disabled = disabled;
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}
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return err;
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}
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static struct perf_event *
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ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
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unsigned long addr, bool disabled)
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{
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struct perf_event_attr attr;
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int err;
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ptrace_breakpoint_init(&attr);
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attr.bp_addr = addr;
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err = ptrace_fill_bp_fields(&attr, len, type, disabled);
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if (err)
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return ERR_PTR(err);
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return register_user_hw_breakpoint(&attr, ptrace_triggered,
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NULL, tsk);
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}
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static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
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int disabled)
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{
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struct perf_event_attr attr = bp->attr;
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int err;
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err = ptrace_fill_bp_fields(&attr, len, type, disabled);
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if (err)
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return err;
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attr = bp->attr;
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attr.bp_len = gen_len;
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attr.bp_type = gen_type;
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attr.disabled = disabled;
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return modify_user_hw_breakpoint(bp, &attr);
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}
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@ -653,7 +679,7 @@ restore:
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break;
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}
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rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);
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rc = ptrace_modify_breakpoint(bp, len, type, disabled);
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if (rc)
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break;
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}
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@ -693,26 +719,14 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
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static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
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unsigned long addr)
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{
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struct perf_event *bp;
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struct thread_struct *t = &tsk->thread;
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struct perf_event_attr attr;
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struct perf_event *bp = t->ptrace_bps[nr];
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int err = 0;
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if (!t->ptrace_bps[nr]) {
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ptrace_breakpoint_init(&attr);
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/*
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* Put stub len and type to register (reserve) an inactive but
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* correct bp
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*/
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attr.bp_addr = addr;
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attr.bp_len = HW_BREAKPOINT_LEN_1;
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attr.bp_type = HW_BREAKPOINT_W;
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attr.disabled = 1;
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bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
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NULL, tsk);
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if (!bp) {
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/*
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* Put stub len and type to create an inactive but correct bp.
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*
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* CHECKME: the previous code returned -EIO if the addr wasn't
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* a valid task virtual addr. The new one will return -EINVAL in
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* this case.
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@ -721,20 +735,20 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
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* writing for the user. And anyway this is the previous
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* behaviour.
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*/
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if (IS_ERR(bp)) {
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bp = ptrace_register_breakpoint(tsk,
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X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
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addr, true);
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if (IS_ERR(bp))
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err = PTR_ERR(bp);
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goto out;
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}
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else
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t->ptrace_bps[nr] = bp;
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} else {
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bp = t->ptrace_bps[nr];
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struct perf_event_attr attr = bp->attr;
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attr = bp->attr;
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attr.bp_addr = addr;
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err = modify_user_hw_breakpoint(bp, &attr);
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}
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out:
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return err;
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}
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