From 77ef8f5177599efd0cedeb52c1950c1bd73fa5e3 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Mon, 25 Jan 2016 15:05:34 -0500 Subject: [PATCH] tile kgdb: fix bug in copy to gdb regs, and optimize memset 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 Signed-off-by: Chris Metcalf --- 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; }