Re: [PATCH v5 1/6] x86/mm/pat: use pr_info() and friends

[Borislav Petkov <bp@suse.de>]

On Thu, Apr 30, 2015 at 01:25:15PM -0700, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@suse.com>
> 
> Use pr_info() instead of the old printk to
> prefix the component where things are coming
> from. With this readers will know exactly where
> the message is coming from. Since pr_fmt is
> already defined in this case we redefine it to
> "PAT: ".
> 
> We leave the users of dprintk() in place, this
> will print only when the debugpat kernel parameter
> is enabled. We want to leave those enabled as a
> debug feature, but also make them use the same
> prefix.
> 
> Cc: Andy Walls <awalls@md.metrocast.net>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: x86@kernel.org
> Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
> ---
>  arch/x86/mm/pat.c          | 41 +++++++++++++++++++++--------------------
>  arch/x86/mm/pat_internal.h |  2 +-
>  arch/x86/mm/pat_rbtree.c   |  5 ++++-
>  3 files changed, 26 insertions(+), 22 deletions(-)
> 
> diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> index 372ad42..8f88c6a 100644
> --- a/arch/x86/mm/pat.c
> +++ b/arch/x86/mm/pat.c
> @@ -33,13 +33,16 @@
>  #include "pat_internal.h"
>  #include "mm_internal.h"
>  
> +#undef pr_fmt
> +#define pr_fmt(fmt)	"PAT: " fmt

Hmm, ok, so those pr_* helpers with the prefix actually make grepping
for the error message not fun. So I take that back about the pr_fmt
thing - it is a bad idea.

Instead, we should still use pr_* because they're shorter but simply add
the prefix before each message so that you can grep for it.

I went and I did that, see below.

---
From: "Luis R. Rodriguez" <mcgrof@suse.com>
Date: Thu, 30 Apr 2015 13:25:15 -0700
Subject: [PATCH] x86/mm/pat: Convert to pr_* usage

Use pr_info() instead of the old printk to prefix the component where
things are coming from. With this readers will know exactly where the
message is coming from. Since pr_fmt is already defined in this case we
redefine it to "x86/PAT: ".

We leave the users of dprintk() in place, this will print only when the
debugpat kernel parameter is enabled. We want to leave those enabled as
a debug feature, but also make them use the same prefix.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: plagnioj@jcrosoft.com
Cc: tomi.valkeinen@ti.com
Cc: x86@kernel.org
Cc: cocci@systeme.lip6.fr
Link: http://lkml.kernel.org/r/1430425520-22275-2-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: 
---
 arch/x86/mm/pat.c          | 41 +++++++++++++++++++----------------------
 arch/x86/mm/pat_internal.h |  2 +-
 arch/x86/mm/pat_rbtree.c   |  2 +-
 3 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 35af6771a95a..8269c784b61c 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -39,7 +39,7 @@ int __read_mostly pat_enabled = 1;
 static inline void pat_disable(const char *reason)
 {
 	pat_enabled = 0;
-	printk(KERN_INFO "%s\n", reason);
+	pr_info("x86/PAT: %s\n", reason);
 }
 
 static int __init nopat(char *str)
@@ -188,7 +188,7 @@ void pat_init_cache_modes(void)
 					   pat_msg + 4 * i);
 		update_cache_mode_entry(i, cache);
 	}
-	pr_info("PAT configuration [0-7]: %s\n", pat_msg);
+	pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);
 }
 
 #define PAT(x, y)	((u64)PAT_ ## y << ((x)*8))
@@ -211,8 +211,7 @@ void pat_init(void)
 			 * switched to PAT on the boot CPU. We have no way to
 			 * undo PAT.
 			 */
-			printk(KERN_ERR "PAT enabled, "
-			       "but not supported by secondary CPU\n");
+			pr_err("x86/PAT: PAT enabled, but not supported by secondary CPU\n");
 			BUG();
 		}
 	}
@@ -347,7 +346,7 @@ static int reserve_ram_pages_type(u64 start, u64 end,
 		page = pfn_to_page(pfn);
 		type = get_page_memtype(page);
 		if (type != -1) {
-			pr_info("reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n",
+			pr_info("x86/PAT: reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n",
 				start, end - 1, type, req_type);
 			if (new_type)
 				*new_type = type;
@@ -451,9 +450,9 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,
 
 	err = rbt_memtype_check_insert(new, new_type);
 	if (err) {
-		printk(KERN_INFO "reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n",
-		       start, end - 1,
-		       cattr_name(new->type), cattr_name(req_type));
+		pr_info("x86/PAT: reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n",
+			start, end - 1,
+			cattr_name(new->type), cattr_name(req_type));
 		kfree(new);
 		spin_unlock(&memtype_lock);
 
@@ -497,8 +496,8 @@ int free_memtype(u64 start, u64 end)
 	spin_unlock(&memtype_lock);
 
 	if (!entry) {
-		printk(KERN_INFO "%s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",
-		       current->comm, current->pid, start, end - 1);
+		pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",
+			current->comm, current->pid, start, end - 1);
 		return -EINVAL;
 	}
 
@@ -628,8 +627,8 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 
 	while (cursor < to) {
 		if (!devmem_is_allowed(pfn)) {
-			printk(KERN_INFO "Program %s tried to access /dev/mem between [mem %#010Lx-%#010Lx], PAT prevents it\n",
-			       current->comm, from, to - 1);
+			pr_info("x86/PAT: Program %s tried to access /dev/mem between [mem %#010Lx-%#010Lx], PAT prevents it\n",
+				current->comm, from, to - 1);
 			return 0;
 		}
 		cursor += PAGE_SIZE;
@@ -698,8 +697,7 @@ int kernel_map_sync_memtype(u64 base, unsigned long size,
 				size;
 
 	if (ioremap_change_attr((unsigned long)__va(base), id_sz, pcm) < 0) {
-		printk(KERN_INFO "%s:%d ioremap_change_attr failed %s "
-			"for [mem %#010Lx-%#010Lx]\n",
+		pr_info("x86/PAT: %s:%d ioremap_change_attr failed %s for [mem %#010Lx-%#010Lx]\n",
 			current->comm, current->pid,
 			cattr_name(pcm),
 			base, (unsigned long long)(base + size-1));
@@ -734,7 +732,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 
 		pcm = lookup_memtype(paddr);
 		if (want_pcm != pcm) {
-			printk(KERN_WARNING "%s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n",
+			pr_warn("x86/PAT: %s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n",
 				current->comm, current->pid,
 				cattr_name(want_pcm),
 				(unsigned long long)paddr,
@@ -755,13 +753,12 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 		if (strict_prot ||
 		    !is_new_memtype_allowed(paddr, size, want_pcm, pcm)) {
 			free_memtype(paddr, paddr + size);
-			printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
-				" for [mem %#010Lx-%#010Lx], got %s\n",
-				current->comm, current->pid,
-				cattr_name(want_pcm),
-				(unsigned long long)paddr,
-				(unsigned long long)(paddr + size - 1),
-				cattr_name(pcm));
+			pr_err("x86/PAT: %s:%d map pfn expected mapping type %s for [mem %#010Lx-%#010Lx], got %s\n",
+			       current->comm, current->pid,
+			       cattr_name(want_pcm),
+			       (unsigned long long)paddr,
+			       (unsigned long long)(paddr + size - 1),
+			       cattr_name(pcm));
 			return -EINVAL;
 		}
 		/*
diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h
index f6411620305d..a739bfc40690 100644
--- a/arch/x86/mm/pat_internal.h
+++ b/arch/x86/mm/pat_internal.h
@@ -4,7 +4,7 @@
 extern int pat_debug_enable;
 
 #define dprintk(fmt, arg...) \
-	do { if (pat_debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
+	do { if (pat_debug_enable) pr_info("x86/PAT: " fmt, ##arg); } while (0)
 
 struct memtype {
 	u64			start;
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 6582adcc8bd9..82b8c6aaf260 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -160,7 +160,7 @@ success:
 	return 0;
 
 failure:
-	printk(KERN_INFO "%s:%d conflicting memory types "
+	pr_info("x86/PAT: %s:%d conflicting memory types "
 		"%Lx-%Lx %s<->%s\n", current->comm, current->pid, start,
 		end, cattr_name(found_type), cattr_name(match->type));
 	return -EBUSY;
-- 
2.3.5

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--