fbdev: offb: Fix OF node name handling

Message ID 20190107173132.27316-1-robh@kernel.org
State New
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Series
  • fbdev: offb: Fix OF node name handling
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Commit Message

Rob Herring Jan. 7, 2019, 5:31 p.m.
Commit 5c63e407aaab ("fbdev: Convert to using %pOFn instead of
device_node.name") changed how the OF FB driver handles the OF node
name. This missed the case where the node name is passed to
offb_init_palette_hacks(). This results in a NULL ptr dereference
in strncmp and breaks any system except ones using bootx with no display
node.

Fix this by making offb_init_palette_hacks() use the OF node pointer and
use of_node_name_prefix() helper function instead for node name
comparisons. This helps in moving all OF node name accesses to helper
functions in preparation to remove struct device_node.name pointer.

Fixes: 5c63e407aaab ("fbdev: Convert to using %pOFn instead of device_node.name")

Reported-by: Mathieu Malaterre <malat@debian.org>
Cc: stable@vger.kernel.org # v4.19+
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

---
 drivers/video/fbdev/offb.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

-- 
2.19.1

Comments

Mathieu Malaterre Jan. 7, 2019, 8:36 p.m. | #1
Hi Rob,

On Mon, Jan 7, 2019 at 9:11 PM Mathieu Malaterre <malat@debian.org> wrote:
>

> On Mon, Jan 7, 2019 at 6:31 PM Rob Herring <robh@kernel.org> wrote:

> >

> > Commit 5c63e407aaab ("fbdev: Convert to using %pOFn instead of

> > device_node.name") changed how the OF FB driver handles the OF node

> > name. This missed the case where the node name is passed to

> > offb_init_palette_hacks(). This results in a NULL ptr dereference

> > in strncmp and breaks any system except ones using bootx with no display

> > node.

> >

> > Fix this by making offb_init_palette_hacks() use the OF node pointer and

> > use of_node_name_prefix() helper function instead for node name

> > comparisons. This helps in moving all OF node name accesses to helper

> > functions in preparation to remove struct device_node.name pointer.

> >

> > Fixes: 5c63e407aaab ("fbdev: Convert to using %pOFn instead of device_node.name")

>

> Looks good to me:

>

> ...

> [    0.000000] Linux version 5.0.0-rc1+ (malat@debian.org) (gcc

> version 6.3.0 20170516 (Debian 6.3.0-18)) #21 Mon Jan 7 21:03:53 CET

> 2019

> ...

>

> So here is my :

>

> Tested-by: Mathieu Malaterre <malat@debian.org>


Just for curiosity, why would you keep:

     if (strcmp(dp->name, "valkyrie") == 0)



> > Reported-by: Mathieu Malaterre <malat@debian.org>

> > Cc: stable@vger.kernel.org # v4.19+

> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

> > Cc: dri-devel@lists.freedesktop.org

> > Cc: linux-fbdev@vger.kernel.org

> > Signed-off-by: Rob Herring <robh@kernel.org>

> > ---

> >  drivers/video/fbdev/offb.c | 18 +++++++++---------

> >  1 file changed, 9 insertions(+), 9 deletions(-)

> >

> > diff --git a/drivers/video/fbdev/offb.c b/drivers/video/fbdev/offb.c

> > index 31f769d67195..057d3cdef92e 100644

> > --- a/drivers/video/fbdev/offb.c

> > +++ b/drivers/video/fbdev/offb.c

> > @@ -318,28 +318,28 @@ static void __iomem *offb_map_reg(struct device_node *np, int index,

> >  }

> >

> >  static void offb_init_palette_hacks(struct fb_info *info, struct device_node *dp,

> > -                                   const char *name, unsigned long address)

> > +                                   unsigned long address)

> >  {

> >         struct offb_par *par = (struct offb_par *) info->par;

> >

> > -       if (dp && !strncmp(name, "ATY,Rage128", 11)) {

> > +       if (of_node_name_prefix(dp, "ATY,Rage128")) {

> >                 par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);

> >                 if (par->cmap_adr)

> >                         par->cmap_type = cmap_r128;

> > -       } else if (dp && (!strncmp(name, "ATY,RageM3pA", 12)

> > -                         || !strncmp(name, "ATY,RageM3p12A", 14))) {

> > +       } else if (of_node_name_prefix(dp, "ATY,RageM3pA") ||

> > +                  of_node_name_prefix(dp, "ATY,RageM3p12A")) {

> >                 par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);

> >                 if (par->cmap_adr)

> >                         par->cmap_type = cmap_M3A;

> > -       } else if (dp && !strncmp(name, "ATY,RageM3pB", 12)) {

> > +       } else if (of_node_name_prefix(dp, "ATY,RageM3pB")) {

> >                 par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);

> >                 if (par->cmap_adr)

> >                         par->cmap_type = cmap_M3B;

> > -       } else if (dp && !strncmp(name, "ATY,Rage6", 9)) {

> > +       } else if (of_node_name_prefix(dp, "ATY,Rage6")) {

> >                 par->cmap_adr = offb_map_reg(dp, 1, 0, 0x1fff);

> >                 if (par->cmap_adr)

> >                         par->cmap_type = cmap_radeon;

> > -       } else if (!strncmp(name, "ATY,", 4)) {

> > +       } else if (of_node_name_prefix(dp, "ATY,")) {

> >                 unsigned long base = address & 0xff000000UL;

> >                 par->cmap_adr =

> >                         ioremap(base + 0x7ff000, 0x1000) + 0xcc0;

> > @@ -350,7 +350,7 @@ static void offb_init_palette_hacks(struct fb_info *info, struct device_node *dp

> >                 par->cmap_adr = offb_map_reg(dp, 0, 0x6000, 0x1000);

> >                 if (par->cmap_adr)

> >                         par->cmap_type = cmap_gxt2000;

> > -       } else if (dp && !strncmp(name, "vga,Display-", 12)) {

> > +       } else if (of_node_name_prefix(dp, "vga,Display-")) {

> >                 /* Look for AVIVO initialized by SLOF */

> >                 struct device_node *pciparent = of_get_parent(dp);

> >                 const u32 *vid, *did;

> > @@ -438,7 +438,7 @@ static void __init offb_init_fb(const char *name,

> >

> >         par->cmap_type = cmap_unknown;

> >         if (depth == 8)

> > -               offb_init_palette_hacks(info, dp, name, address);

> > +               offb_init_palette_hacks(info, dp, address);

> >         else

> >                 fix->visual = FB_VISUAL_TRUECOLOR;

> >

> > --

> > 2.19.1

> >
Bartlomiej Zolnierkiewicz Jan. 11, 2019, 12:53 p.m. | #2
On 01/07/2019 09:11 PM, Mathieu Malaterre wrote:
> On Mon, Jan 7, 2019 at 6:31 PM Rob Herring <robh@kernel.org> wrote:

>>

>> Commit 5c63e407aaab ("fbdev: Convert to using %pOFn instead of

>> device_node.name") changed how the OF FB driver handles the OF node

>> name. This missed the case where the node name is passed to

>> offb_init_palette_hacks(). This results in a NULL ptr dereference

>> in strncmp and breaks any system except ones using bootx with no display

>> node.

>>

>> Fix this by making offb_init_palette_hacks() use the OF node pointer and

>> use of_node_name_prefix() helper function instead for node name

>> comparisons. This helps in moving all OF node name accesses to helper

>> functions in preparation to remove struct device_node.name pointer.

>>

>> Fixes: 5c63e407aaab ("fbdev: Convert to using %pOFn instead of device_node.name")

> 

> Looks good to me:

> 

> ...

> [    0.000000] Linux version 5.0.0-rc1+ (malat@debian.org) (gcc

> version 6.3.0 20170516 (Debian 6.3.0-18)) #21 Mon Jan 7 21:03:53 CET

> 2019

> ...

> 

> So here is my :

> 

> Tested-by: Mathieu Malaterre <malat@debian.org>


Patch queued for 5.0, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

Patch

diff --git a/drivers/video/fbdev/offb.c b/drivers/video/fbdev/offb.c
index 31f769d67195..057d3cdef92e 100644
--- a/drivers/video/fbdev/offb.c
+++ b/drivers/video/fbdev/offb.c
@@ -318,28 +318,28 @@  static void __iomem *offb_map_reg(struct device_node *np, int index,
 }
 
 static void offb_init_palette_hacks(struct fb_info *info, struct device_node *dp,
-				    const char *name, unsigned long address)
+				    unsigned long address)
 {
 	struct offb_par *par = (struct offb_par *) info->par;
 
-	if (dp && !strncmp(name, "ATY,Rage128", 11)) {
+	if (of_node_name_prefix(dp, "ATY,Rage128")) {
 		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
 		if (par->cmap_adr)
 			par->cmap_type = cmap_r128;
-	} else if (dp && (!strncmp(name, "ATY,RageM3pA", 12)
-			  || !strncmp(name, "ATY,RageM3p12A", 14))) {
+	} else if (of_node_name_prefix(dp, "ATY,RageM3pA") ||
+		   of_node_name_prefix(dp, "ATY,RageM3p12A")) {
 		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
 		if (par->cmap_adr)
 			par->cmap_type = cmap_M3A;
-	} else if (dp && !strncmp(name, "ATY,RageM3pB", 12)) {
+	} else if (of_node_name_prefix(dp, "ATY,RageM3pB")) {
 		par->cmap_adr = offb_map_reg(dp, 2, 0, 0x1fff);
 		if (par->cmap_adr)
 			par->cmap_type = cmap_M3B;
-	} else if (dp && !strncmp(name, "ATY,Rage6", 9)) {
+	} else if (of_node_name_prefix(dp, "ATY,Rage6")) {
 		par->cmap_adr = offb_map_reg(dp, 1, 0, 0x1fff);
 		if (par->cmap_adr)
 			par->cmap_type = cmap_radeon;
-	} else if (!strncmp(name, "ATY,", 4)) {
+	} else if (of_node_name_prefix(dp, "ATY,")) {
 		unsigned long base = address & 0xff000000UL;
 		par->cmap_adr =
 			ioremap(base + 0x7ff000, 0x1000) + 0xcc0;
@@ -350,7 +350,7 @@  static void offb_init_palette_hacks(struct fb_info *info, struct device_node *dp
 		par->cmap_adr = offb_map_reg(dp, 0, 0x6000, 0x1000);
 		if (par->cmap_adr)
 			par->cmap_type = cmap_gxt2000;
-	} else if (dp && !strncmp(name, "vga,Display-", 12)) {
+	} else if (of_node_name_prefix(dp, "vga,Display-")) {
 		/* Look for AVIVO initialized by SLOF */
 		struct device_node *pciparent = of_get_parent(dp);
 		const u32 *vid, *did;
@@ -438,7 +438,7 @@  static void __init offb_init_fb(const char *name,
 
 	par->cmap_type = cmap_unknown;
 	if (depth == 8)
-		offb_init_palette_hacks(info, dp, name, address);
+		offb_init_palette_hacks(info, dp, address);
 	else
 		fix->visual = FB_VISUAL_TRUECOLOR;