[U-Boot] [PATCH 0/3] make ERR_PTR/PTR_ERR architecture specific

[U-Boot] [PATCH 0/3] make ERR_PTR/PTR_ERR architecture specific

[Simon Goldschmidt]

Some U-Boot pointers have redundant information, so we can use a scheme
where we can return either an error code or a pointer with the same
return value. The default implementation just casts the pointer to a
number, however, this may fail on platforms where the end of the address
range is used for valid pointers (e.g. 0xffffff00 is a valid heap pointer
in socfpga SPL). For such platforms, this value provides an upper range
of those error pointer values - up to 'MAX_ERRNO' bytes below this value
must be unused/invalid addresses.


Simon Goldschmidt (3):
  Kconfig add config ERR_PTR_OFFSET
  linux err: make ERR_PTR/PTR_ERR architecture specific
  arm: socfpga: gen5: fix ERR_PTR_OFFSET

 Kconfig                       | 14 ++++++++++++++
 arch/arm/mach-socfpga/Kconfig |  3 +++
 include/linux/err.h           |  8 ++++----
 3 files changed, 21 insertions(+), 4 deletions(-)

-- 
2.20.1

[U-Boot] [PATCH 1/3] Kconfig add config ERR_PTR_OFFSET

[Simon Goldschmidt]

Some U-Boot pointers have redundant information, so we can use a scheme
where we can return either an error code or a pointer with the same
return value. The default implementation just casts the pointer to a
number, however, this may fail on platforms where the end of the address
range is used for valid pointers (e.g. 0xffffff00 is a valid heap pointer
in socfpga SPL). For such platforms, this value provides an upper range
of those error pointer values - up to 'MAX_ERRNO' bytes below this value
must be unused/invalid addresses.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
---

 Kconfig | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Kconfig b/Kconfig
index 66b059f749..cda4f58ff7 100644
--- a/Kconfig
+++ b/Kconfig
@@ -281,6 +281,20 @@ config SYS_LDSCRIPT
 	  Path within the source tree to the linker script to use for the
 	  main U-Boot binary.
 
+config ERR_PTR_OFFSET
+	hex
+	default 0x0
+	help
+	  Some U-Boot pointers have redundant information, so we can use a
+	  scheme where we can return either an error code or a pointer with the
+	  same return value. The default implementation just casts the pointer
+	  to a number, however, this may fail on platforms where the end of the
+	  address range is used for valid pointers (e.g. 0xffffff00 is a valid
+	  heap pointer in socfpga SPL).
+	  For such platforms, this value provides an upper range of those error
+	  pointer values - up to 'MAX_ERRNO' bytes below this value must be
+	  unused/invalid addresses.
+
 endmenu		# General setup
 
 menu "Boot images"
-- 
2.20.1

[U-Boot] [PATCH 1/3] Kconfig add config ERR_PTR_OFFSET

[Tom Rini]

On Tue, Oct 22, 2019 at 09:29:46PM +0200, Simon Goldschmidt wrote:

> Some U-Boot pointers have redundant information, so we can use a scheme
> where we can return either an error code or a pointer with the same
> return value. The default implementation just casts the pointer to a
> number, however, this may fail on platforms where the end of the address
> range is used for valid pointers (e.g. 0xffffff00 is a valid heap pointer
> in socfpga SPL). For such platforms, this value provides an upper range
> of those error pointer values - up to 'MAX_ERRNO' bytes below this value
> must be unused/invalid addresses.
> 
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Applied to u-boot/master, thanks!

-- 
Tom
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[U-Boot] [PATCH 2/3] linux err: make ERR_PTR/PTR_ERR architecture specific

[Simon Goldschmidt]

This patch changes ERR_PTR/PTR_ERR to use CONFIG_ERR_PTR_OFFSET to map
errno values into a pointer region that cannot contain valid pointers.

IS_ERR and IS_ERR_OR_NULL have to be converted to use PTR_ERR, too,
for this to work.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
---

 include/linux/err.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/err.h b/include/linux/err.h
index 22e5756edd..5ede82432d 100644
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -23,22 +23,22 @@
 
 static inline void *ERR_PTR(long error)
 {
-	return (void *) error;
+	return (void *)(CONFIG_ERR_PTR_OFFSET + error);
 }
 
 static inline long PTR_ERR(const void *ptr)
 {
-	return (long) ptr;
+	return ((long)ptr - CONFIG_ERR_PTR_OFFSET);
 }
 
 static inline long IS_ERR(const void *ptr)
 {
-	return IS_ERR_VALUE((unsigned long)ptr);
+	return IS_ERR_VALUE((unsigned long)PTR_ERR(ptr));
 }
 
 static inline bool IS_ERR_OR_NULL(const void *ptr)
 {
-	return !ptr || IS_ERR_VALUE((unsigned long)ptr);
+	return !ptr || IS_ERR_VALUE((unsigned long)PTR_ERR(ptr));
 }
 
 /**
-- 
2.20.1

[U-Boot] [PATCH 2/3] linux err: make ERR_PTR/PTR_ERR architecture specific

[Tom Rini]

On Tue, Oct 22, 2019 at 09:29:47PM +0200, Simon Goldschmidt wrote:

> This patch changes ERR_PTR/PTR_ERR to use CONFIG_ERR_PTR_OFFSET to map
> errno values into a pointer region that cannot contain valid pointers.
> 
> IS_ERR and IS_ERR_OR_NULL have to be converted to use PTR_ERR, too,
> for this to work.
> 
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Applied to u-boot/master, thanks!

-- 
Tom
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[U-Boot] [PATCH 3/3] arm: socfpga: gen5: fix ERR_PTR_OFFSET

[Simon Goldschmidt]

The default implementation of ERR_PTR/PTR_ERR maps errno values at the
and of the address range (e.g. -EINVAL/-22 gets 0xFFFFFFEA).

For socfpga gen5 SPL, this doesn't really work, as the heap is nearly
at the end of the 32 bit address range.

This patch adjusts the ERR_PTR_OFFSET to map errno values into the range
of the Boot ROM, which should not be used for valid pointers.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
---

 arch/arm/mach-socfpga/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
index fc0a54214f..3770e07258 100644
--- a/arch/arm/mach-socfpga/Kconfig
+++ b/arch/arm/mach-socfpga/Kconfig
@@ -1,5 +1,8 @@
 if ARCH_SOCFPGA
 
+config ERR_PTR_OFFSET
+	default 0xfffec000 if TARGET_SOCFPGA_GEN5 # Boot ROM range
+
 config NR_DRAM_BANKS
 	default 1
 
-- 
2.20.1

[U-Boot] [PATCH 3/3] arm: socfpga: gen5: fix ERR_PTR_OFFSET

[Tom Rini]

On Tue, Oct 22, 2019 at 09:29:48PM +0200, Simon Goldschmidt wrote:

> The default implementation of ERR_PTR/PTR_ERR maps errno values at the
> and of the address range (e.g. -EINVAL/-22 gets 0xFFFFFFEA).
> 
> For socfpga gen5 SPL, this doesn't really work, as the heap is nearly
> at the end of the 32 bit address range.
> 
> This patch adjusts the ERR_PTR_OFFSET to map errno values into the range
> of the Boot ROM, which should not be used for valid pointers.
> 
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

Applied to u-boot/master, thanks!

-- 
Tom
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