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Commit 3a51237d authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
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[PATCH] uml: mconsole fixes 



 * when we have stop/sysrq/go, we get pt_regs of whatever executes
   mc_work_proc().  Would be better to see what we had at the time of
   interrupt that got us stop.

 * stop/stop/stop.....  will give stack overflow.  Shouldn't allow stop
   from mconsole_stop().

 * stop/stop/go leaves us inside mconsole_stop() with
	os_set_fd_block(req->originating_fd, 0);
	reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
   just done by nested mconsole_stop().  Ditto.

 * once we'd seen stop, there's a period when INTR commands are executed
   out of order (as they should; we might have the things stuck badly
   enough to never reach mconsole_stop(), but still not badly enough to
   block mconsole_interrupt(); in that situation we _want_ things like
   "cad" to be executed immediately).  Once we enter monsole_stop(), all
   INTR commands will be executed in order, mixed with PROC ones.  We'd
   better let user see that such change of behaviour has happened.
   (Suggested by lennert).

 * stack footprint of monsole_interrupt() is an atrocity; AFAICS we can
   safely make struct mc_request req; static in function there.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Acked-by: default avatarJeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6c504447

arch/um/drivers/mconsole_kern.c

+17 −6
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ static irqreturn_t mconsole_interrupt(int irq, void *dev_id) 
	/* long to avoid size mismatch warnings from gcc */

	long fd;

	struct mconsole_entry *new;

	struct mc_request req;

	static struct mc_request req;	/* that's OK */



	fd = (long) dev_id;

	while (mconsole_get_request(fd, &req)){
@@ -91,6 +91,7 @@ static irqreturn_t mconsole_interrupt(int irq, void *dev_id) 
				mconsole_reply(&req, "Out of memory", 1, 0);

			else {

				new->request = req;

				new->request.regs = get_irq_regs()->regs;

				list_add(&new->list, &mc_requests);

			}

		}
@@ -314,9 +315,21 @@ void mconsole_stop(struct mc_request *req) 
{

	deactivate_fd(req->originating_fd, MCONSOLE_IRQ);

	os_set_fd_block(req->originating_fd, 1);

	mconsole_reply(req, "", 0, 0);

	mconsole_reply(req, "stopped", 0, 0);

	while (mconsole_get_request(req->originating_fd, req)) {

		if(req->cmd->handler == mconsole_go) break;

		if (req->cmd->handler == mconsole_go)

			break;

		if (req->cmd->handler == mconsole_stop) {

			mconsole_reply(req, "Already stopped", 1, 0);

			continue;

		}

		if (req->cmd->handler == mconsole_sysrq) {

			struct pt_regs *old_regs;

			old_regs = set_irq_regs((struct pt_regs *)&req->regs);

			mconsole_sysrq(req);

			set_irq_regs(old_regs);

			continue;

		}

		(*req->cmd->handler)(req);

	}

	os_set_fd_block(req->originating_fd, 0);
@@ -673,9 +686,7 @@ static void with_console(struct mc_request *req, void (*proc)(void *), 
static void sysrq_proc(void *arg)

{

	char *op = arg;

	struct pt_regs *old_regs = set_irq_regs(&current->thread.regs);

	handle_sysrq(*op, NULL);

	set_irq_regs(old_regs);

}



void mconsole_sysrq(struct mc_request *req)

arch/um/drivers/mconsole_user.c

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <sys/un.h>

#include <unistd.h>

#include "user.h"

#include "sysdep/ptrace.h"

#include "mconsole.h"

#include "umid.h"

#include "user_util.h"

arch/um/include/mconsole.h

+1 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct mc_request 


	struct mconsole_request request;

	struct mconsole_command *cmd;

	union uml_pt_regs regs;

};



extern char mconsole_socket_name[];