tile kgdb: fix bug in copy to gdb regs, and optimize memset (77ef8f51) · Commits · 戴 / test

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 ("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 <dcb314@hotmail.com> Signed-off-by:

Chris Metcalf <cmetcalf@ezchip.com>

arch/tile/kernel/kgdb.c

+4 −4

Original line number	Original line	Diff line number	Diff line
	@@ -126,15 +126,15 @@ void
	sleeping_thread_to_gdb_regs(unsigned long gdb_regs, struct task_struct task)		sleeping_thread_to_gdb_regs(unsigned long gdb_regs, struct task_struct task)
	{		{
	struct pt_regs *thread_regs;		struct pt_regs *thread_regs;
			const int NGPRS = TREG_LAST_GPR + 1;

	if (task == NULL)		if (task == NULL)
	return;		return;

	/* Initialize to zero. */
	memset(gdb_regs, 0, NUMREGBYTES);

	thread_regs = task_pt_regs(task);		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_PC_REGNUM] = thread_regs->pc;
	gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum;		gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum;
	}		}

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