Patches for 34K APRP

APRP operation of the 34K has been multiply broken in 2.6.24.4. The following patch set gets things working seemingly reliably. The first two were previously submitted to Ralf as essential to get RP programs to launch safely. The larger third patch is new, and gets the Linux I/O services for the RP working again, and fixes formatting in a few places.

Note that SMTC has scheduling problems in 2.6.24, so testing under SMTC has been limited to boots with only one TC acting as a Linux CPU.

Regards,

Kevin K.

Sigh. Some mailers (including Thunderbird for Windows) seem to be unable to handle the attachment of the patch files by Thunderbird. So I attach them as a .tgz, which even Outlook should be able to deal with correctly.

Quoted 1 line

From d164aa1b9dba720ee08a6a773e1a81b62aea7d10 Mon Sep 17 00:00:00 2001

From: Kevin D. Kissell <[email protected]>
Date: Thu, 10 Apr 2008 02:07:38 +0200
Subject: [PATCH] Fixes necessary for non-SMP kernels and non-relocatable binaries

(quoted diff) +0 -2

 		struct elf_phdr *phdr = (struct elf_phdr *) ((char *)hdr + hdr->e_phoff);
 
 		for (i = 0; i < hdr->e_phnum; i++) {
-			if (phdr->p_type != PT_LOAD)
-				continue;

 arch/mips/kernel/setup.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

arch/mips/kernel/setup.c +0 -0

index f8a535a..a6a0d62 100644

Quoted 3 lines · Kevin D. Kissell

 arch/mips/kernel/setup.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

arch/mips/kernel/setup.c static void __init bootmem_init(void) · line 343

Quoted 13 lines

arch/mips/kernel/setup.c +4 -0

index f8a535a..a6a0d62 100644
@@ -336,6 +336,10 @@ static void __init bootmem_init(void)
 #endif
 		max_low_pfn = PFN_DOWN(HIGHMEM_START);
 	}
+	/*
+	 * Propagate final value of max_low_pfn to max_pfn
+	 */
+	max_pfn = max_low_pfn;
 

That will be incorrect for systems with highmem. So I think the right fix is to replace all references to max_pfn in vpe.c with max_low_pfn.

Quoted 3 lines

That will be incorrect for systems with highmem. So I think the right fix is to replace all references to max_pfn in vpe.c with max_low_pfn.

Which will still be incorrect for systems with highmem, right? The reason I propose fixing max_pfn instead of just hacking vpe.c is that, as per my email of a couple of weeks ago, there are other, architecture independent, bits of code in the 2.6.24 kernel where max_pfn is assumed to be sane, and the value of zero may result in otherwise inexplicable Bad Things happening. So even if you want to change vpe.c to use max_low_pfn instead of max_pfn, I believe that we really want that patch to setup.c until such time as we've verified that the kernel is max_pfn-free.

arch/mips/kernel/kspd.c +1 -1

@@ -257,7 +257,7 @@ void sp_work_handle_request(void)
 
 		vcwd = vpe_getcwd(tclimit);
 
- 		/* change to the cwd of the process that loaded the SP program */
+ 		/* change to cwd of the process that loaded the SP program */
 		old_fs = get_fs();
 		set_fs(KERNEL_DS);
 		sys_chdir(vcwd);

arch/mips/kernel/kspd.c +0 -0

 }
 
 static int channel_open = 0;

arch/mips/kernel/rtlx.c +41 -31

index 1ba00c1..c0bb347 100644
@@ -73,6 +73,15 @@ static void rtlx_dispatch(void)
 static irqreturn_t rtlx_interrupt(int irq, void *dev_id)
 {
 	int i;
+	unsigned int flags, vpeflags;
+
+	/* Ought not to be strictly necessary for SMTC builds */
+	local_irq_save(flags);
+	vpeflags = dvpe();
+	set_c0_status(0x100 << MIPS_CPU_RTLX_IRQ);
+	irq_enable_hazard();
+	evpe(vpeflags);
+	local_irq_restore(flags);
 
 	for (i = 0; i < RTLX_CHANNELS; i++) {
 			wake_up(&channel_wqs[i].lx_queue);

@@ -109,7 +118,8 @@ static void __used dump_rtlx(void)
 static int rtlx_init(struct rtlx_info *rtlxi)
 {
 	if (rtlxi->id != RTLX_ID) {
-		printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id);
+		printk(KERN_ERR "no valid RTLX id at 0x%p 0x%lx\n", 
+			rtlxi, rtlxi->id);
 		return -ENOEXEC;
 	}
 

@@ -163,51 +173,51 @@ int rtlx_open(int index, int can_sleep)
 
 	if (rtlx == NULL) {
 		if( (p = vpe_get_shared(tclimit)) == NULL) {
-			if (can_sleep) {
-				__wait_event_interruptible(channel_wqs[index].lx_queue,
-				                           (p = vpe_get_shared(tclimit)),
-				                           ret);
-				if (ret)
-					goto out_fail;
-			} else {
-				printk(KERN_DEBUG "No SP program loaded, and device "
-					"opened with O_NONBLOCK\n");
-				ret = -ENOSYS;
+		    if (can_sleep) {
+			__wait_event_interruptible(channel_wqs[index].lx_queue,
+				(p = vpe_get_shared(tclimit)), ret);
+			if (ret)
 				goto out_fail;
-			}
+		    } else {
+			printk(KERN_DEBUG "No SP program loaded, and device "
+					"opened with O_NONBLOCK\n");
+			ret = -ENOSYS;
+			goto out_fail;
+		    }
 		}
 
 		smp_rmb();
 		if (*p == NULL) {
-			if (can_sleep) {
-				DEFINE_WAIT(wait);
-
-				for (;;) {
-					prepare_to_wait(&channel_wqs[index].lx_queue, &wait, TASK_INTERRUPTIBLE);
-					smp_rmb();
-					if (*p != NULL)
-						break;
-					if (!signal_pending(current)) {
-						schedule();
-						continue;
-					}
-					ret = -ERESTARTSYS;
-					goto out_fail;
+		    if (can_sleep) {
+			DEFINE_WAIT(wait);
+
+			for (;;) {
+				prepare_to_wait(&channel_wqs[index].lx_queue, 
+						&wait, TASK_INTERRUPTIBLE);
+				smp_rmb();
+				if (*p != NULL)
+					break;
+				if (!signal_pending(current)) {
+					schedule();
+					continue;
 				}
-				finish_wait(&channel_wqs[index].lx_queue, &wait);
-			} else {
-				printk(" *vpe_get_shared is NULL. "
-				       "Has an SP program been loaded?\n");
-				ret = -ENOSYS;
+				ret = -ERESTARTSYS;
 				goto out_fail;
 			}
+			finish_wait(&channel_wqs[index].lx_queue, &wait);
+		    } else {
+			printk(" *vpe_get_shared is NULL. "
+			       "Has an SP program been loaded?\n");
+				ret = -ENOSYS;
+				goto out_fail;
+		    }
 		}

arch/mips/kernel/rtlx.c +5 -3

 			if (ret)
 				return ret;
 

@@ -283,7 +297,9 @@ static inline int write_spacefree(int read, int write, int size)
 unsigned int rtlx_write_poll(int index)
 {
 	struct rtlx_channel *chan = &rtlx->channel[index];
-	return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
+
+	return write_spacefree(chan->rt_read, chan->rt_write, 
+				chan->buffer_size);
 }
 
 ssize_t rtlx_read(int index, void __user *buff, size_t count)

@@ -345,8 +361,8 @@ ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
 	rt_read = rt->rt_read;
 
 	/* total number of bytes to copy */
-	count = min(count,
-		    (size_t)write_spacefree(rt_read, rt->rt_write, rt->buffer_size));
+	count = min(count, (size_t)write_spacefree(rt_read, rt->rt_write, 
+							rt->buffer_size));
 
 	/* first bit from write pointer to the end of the buffer, or count */
 	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);

arch/mips/kernel/rtlx.c +3 -0

+		err = -ENODEV;
+		goto out_chrdev;
+	}
 
 	rtlx_irq.dev_id = rtlx;
 	setup_irq(rtlx_irq_num, &rtlx_irq);

include/asm-mips/rtlx.h +1 -1

index 65778c8..20b6660 100644
@@ -29,13 +29,13 @@ extern unsigned int rtlx_read_poll(int index, int can_sleep);
 extern unsigned int rtlx_write_poll(int index);
 
 enum rtlx_state {
-	RTLX_STATE_UNUSED,
+	RTLX_STATE_UNUSED = 0,

Quoted 6 lines · Kevin D. Kissell

arch/mips/kernel/kspd.c +0 -0

@@ -257,7 +257,7 @@ void sp_work_handle_request(void)
 
 		vcwd = vpe_getcwd(tclimit);
 

arch/mips/kernel/kspd.c static void sp_cleanup(void) · line 329

Quoted 13 lines

arch/mips/kernel/kspd.c +4 -1

- 		/* change to the cwd of the process that loaded the SP program */
+ 		/* change to cwd of the process that loaded the SP program */
 		old_fs = get_fs();
 		set_fs(KERNEL_DS);
 		sys_chdir(vcwd);

@@ -323,6 +323,9 @@ static void sp_cleanup(void)
 			set >>= 1;
 		}
 	}
+
+	/* Put daemon cwd back to root to avoid umount problems */
+	sys_chdir("/");
 

Still not kosher; there might be multiple roots on a system ...