David Binderman pointed out that we were doing a full memset()
of the gdb register buffer and then doing a memcpy() to it that
was almost as big. This commit optimizes that by only doing a
memset() of the registers that are intended to be zero.
While making this change I noticed that we were not copying the
link register (LR, number 55) due to a fencepost error in commit
f419e6f63c5a ("arch: tile: kernel: kgdb.c: Use memcpy() instead of
pointer copy one by one"), and I've corrected that as well.
Reported-by: David Binderman <[email protected]>
Signed-off-by: Chris Metcalf <[email protected]>
---
arch/tile/kernel/kgdb.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/tile/kernel/kgdb.c b/arch/tile/kernel/kgdb.c
index a506c2c28943..6ad99925900e 100644
--- a/arch/tile/kernel/kgdb.c
+++ b/arch/tile/kernel/kgdb.c
@@ -126,15 +126,15 @@ void
sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
{
struct pt_regs *thread_regs;
+ const int NGPRS = TREG_LAST_GPR + 1;
if (task == NULL)
return;
- /* Initialize to zero. */
- memset(gdb_regs, 0, NUMREGBYTES);
-
thread_regs = task_pt_regs(task);
- memcpy(gdb_regs, thread_regs, TREG_LAST_GPR * sizeof(unsigned long));
+ memcpy(gdb_regs, thread_regs, NGPRS * sizeof(unsigned long));
+ memset(&gdb_regs[NGPRS], 0,
+ (TILEGX_PC_REGNUM - NGPRS) * sizeof(unsigned long));
gdb_regs[TILEGX_PC_REGNUM] = thread_regs->pc;
gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum;
}
--
2.1.2
