Messages in this thread | | | Date | Thu, 18 Apr 2013 21:01:48 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 3/6] ptrace/x86: introduce ptrace_register_breakpoint() |
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On 04/18, Oleg Nesterov wrote: > > 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.
This patch is hardly readable. To simplify the review, I attached the new/modified code below.
Oleg.
static int ptrace_fill_bp_fields(struct perf_event_attr *attr, int len, int type, bool disabled) { int err, bp_len, bp_type;
err = arch_bp_generic_fields(len, type, &bp_len, &bp_type); if (!err) { attr->bp_len = bp_len; attr->bp_type = bp_type; attr->disabled = disabled; }
return err; }
static struct perf_event * ptrace_register_breakpoint(struct task_struct *tsk, int len, int type, unsigned long addr, bool disabled) { struct perf_event_attr attr; int err;
ptrace_breakpoint_init(&attr); attr.bp_addr = addr;
err = ptrace_fill_bp_fields(&attr, len, type, disabled); if (err) return ERR_PTR(err);
return register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, tsk); }
static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, int disabled) { struct perf_event_attr attr = bp->attr; int err;
err = ptrace_fill_bp_fields(&attr, len, type, disabled); if (err) return err;
return modify_user_hw_breakpoint(bp, &attr); }
static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr, unsigned long addr) { struct thread_struct *t = &tsk->thread; struct perf_event *bp = t->ptrace_bps[nr]; int err = 0;
if (!bp) { /* * Put stub len and type to create an inactive but correct bp. * * CHECKME: the previous code returned -EIO if the addr wasn't * a valid task virtual addr. The new one will return -EINVAL in * this case. * -EINVAL may be what we want for in-kernel breakpoints users, * but -EIO looks better for ptrace, since we refuse a register * writing for the user. And anyway this is the previous * behaviour. */ bp = ptrace_register_breakpoint(tsk, X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE, addr, true); if (IS_ERR(bp)) err = PTR_ERR(bp); else t->ptrace_bps[nr] = bp; } else { struct perf_event_attr attr = bp->attr;
attr.bp_addr = addr; err = modify_user_hw_breakpoint(bp, &attr); }
return err; }
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