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Commit a5a70b75 authored by stephane eranian's avatar stephane eranian Committed by Tony Luck
Browse files

[IA64] another perfmon fix (take2) 



- pfm_context_load(): change return value from EINVAL to EBUSY
  when context is already loaded.

- pfm_check_task_state(): pass test if context state is MASKED.
  It is safe to give access on PFM_CTX_MASKED because the PMU
  state (PMD) is stable and saved in software state.
  This helps multiplexing programs such as the example given
  in libpfm-3.1.

Signed-off-by: default avatarstephane eranian <eranian@hpl.hp.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 8df5a500

arch/ia64/kernel/perfmon.c

+20 −10
Original line number Diff line number Diff line
@@ -4215,7 +4215,7 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs) 
		DPRINT(("cannot load to [%d], invalid ctx_state=%d\n",

			req->load_pid,

			ctx->ctx_state));

		return -EINVAL;

		return -EBUSY;

	}



	DPRINT(("load_pid [%d] using_dbreg=%d\n", req->load_pid, ctx->ctx_fl_using_dbreg));
@@ -4716,17 +4716,27 @@ pfm_check_task_state(pfm_context_t *ctx, int cmd, unsigned long flags) 
	 */

	if (task == current || ctx->ctx_fl_system) return 0;



	/*

	 * we are monitoring another thread

	 */

	switch(state) {

		case PFM_CTX_UNLOADED:

			/*

			 * if context is UNLOADED we are safe to go

			 */

	if (state == PFM_CTX_UNLOADED) return 0;



			return 0;

		case PFM_CTX_ZOMBIE:

			/*

			 * no command can operate on a zombie context

			 */

	if (state == PFM_CTX_ZOMBIE) {

			DPRINT(("cmd %d state zombie cannot operate on context\n", cmd));

			return -EINVAL;

		case PFM_CTX_MASKED:

			/*

			 * PMU state has been saved to software even though

			 * the thread may still be running.

			 */

			if (cmd != PFM_UNLOAD_CONTEXT) return 0;

	}



	/*