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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>
This commit is contained in:
Oleg Nesterov 2013-07-08 16:00:59 -07:00 committed by Linus Torvalds
parent 29a5551341
commit 9afe33ada2
1 changed files with 51 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
arch/x86/kernel/ptrace.c
View File

@ -601,23 +601,49 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
return dr7;
}
static int
ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
struct task_struct *tsk, int disabled)
static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
int len, int type, bool disabled)
{
int err;
int gen_len, gen_type;
struct perf_event_attr attr;
int err, bp_len, bp_type;
err = arch_bp_generic_fields(len, type, &gen_len, &gen_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;
attr = bp->attr;
attr.bp_len = gen_len;
attr.bp_type = gen_type;
attr.disabled = disabled;
return modify_user_hw_breakpoint(bp, &attr);
}
@ -653,7 +679,7 @@ restore:
break;
}
rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);
rc = ptrace_modify_breakpoint(bp, len, type, disabled);
if (rc)
break;
}
@ -693,26 +719,14 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
unsigned long addr)
{
struct perf_event *bp;
struct thread_struct *t = &tsk->thread;
struct perf_event_attr attr;
struct perf_event *bp = t->ptrace_bps[nr];
int err = 0;
if (!t->ptrace_bps[nr]) {
ptrace_breakpoint_init(&attr);
/*
* Put stub len and type to register (reserve) an inactive but
* correct bp
*/
attr.bp_addr = addr;
attr.bp_len = HW_BREAKPOINT_LEN_1;
attr.bp_type = HW_BREAKPOINT_W;
attr.disabled = 1;
bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
NULL, tsk);
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.
@ -721,20 +735,20 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
* writing for the user. And anyway this is the previous
* behaviour.
*/
if (IS_ERR(bp)) {
bp = ptrace_register_breakpoint(tsk,
X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
addr, true);
if (IS_ERR(bp))
err = PTR_ERR(bp);
goto out;
}
t->ptrace_bps[nr] = bp;
else
t->ptrace_bps[nr] = bp;
} else {
bp = t->ptrace_bps[nr];
struct perf_event_attr attr = bp->attr;
attr = bp->attr;
attr.bp_addr = addr;
err = modify_user_hw_breakpoint(bp, &attr);
}
out:
return err;
}