[RFC PATCH 0/2] Add ioremap_exec enhancements

[RFC PATCH 0/2] Add ioremap_exec enhancements

[Dave Gerlach]

Hi,

Some platforms need the ability to ioremap memory for use with small
chunks of code, like in certain PM applications that run from sram.

This series provides a common way to call an arch's ioremap_exec, which
currently only exists for ARM, so that we can use it in the generic
sram driver in a forthcoming patch.

This patch is part of a patch series split into several smaller sets
for introducing suspend on AM335x. I plan to use it to copy several
pieces of ASM code from an EMIF driver and the SoC PM code to run from
SRAM on the SoC. I have pushed a branch here [1] based on v3.18-rc6
with all required patches so that the higher level plan for these
patches can be seen.

Regards,
Dave

[1] https://github.com/dgerlach/linux-pm/tree/rfc-pm-am335x-v3.18-rc6

Russ Dill (2):
  asm-generic: io: Add exec versions of ioremap
  lib: devres: Add exec versions of devm_ioremap_resource and friends

 arch/arm/include/asm/io.h   |   2 +
 include/asm-generic/iomap.h |   5 ++
 include/linux/device.h      |  19 ++++++-
 include/linux/io.h          |   9 +++-
 lib/devres.c                | 125 ++++++++++++++++++++++++++++++++++++++++++--
 5 files changed, 154 insertions(+), 6 deletions(-)

-- 
2.1.0

[RFC PATCH 1/2] asm-generic: io: Add exec versions of ioremap

[Dave Gerlach]

From: Russ Dill <Russ.Dill@ti.com>

If code is to be copied into and area (such as SRAM) and run,
it needs to be marked as exec. Currently only an ARM version
of this exists.

Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
---
 arch/arm/include/asm/io.h   | 2 ++
 include/asm-generic/iomap.h | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index 1805674..1d99d42 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -344,6 +344,8 @@ extern void _memset_io(volatile void __iomem *, int, size_t);
 #define ioremap_nocache(cookie,size)	__arm_ioremap((cookie), (size), MT_DEVICE)
 #define ioremap_cache(cookie,size)	__arm_ioremap((cookie), (size), MT_DEVICE_CACHED)
 #define ioremap_wc(cookie,size)		__arm_ioremap((cookie), (size), MT_DEVICE_WC)
+#define ioremap_exec(cookie,size)	__arm_ioremap_exec((cookie), (size), true)
+#define ioremap_exec_nocache(cookie,size) __arm_ioremap_exec((cookie), (size), false)
 #define iounmap				__arm_iounmap
 
 /*
diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
index 1b41011..6648ff3 100644
--- a/include/asm-generic/iomap.h
+++ b/include/asm-generic/iomap.h
@@ -66,6 +66,11 @@ extern void ioport_unmap(void __iomem *);
 #define ioremap_wc ioremap_nocache
 #endif
 
+#ifndef ARCH_HAS_IOREMAP_EXEC
+#define ioremap_exec ioremap
+#define ioremap_exec_nocache ioremap_nocache
+#endif
+
 #ifdef CONFIG_PCI
 /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */
 struct pci_dev;
-- 
2.1.0

Re: [RFC PATCH 1/2] asm-generic: io: Add exec versions of ioremap

[Arnd Bergmann]

On Wednesday 26 November 2014 15:14:00 Dave Gerlach wrote:
> @@ -66,6 +66,11 @@ extern void ioport_unmap(void __iomem *);
>  #define ioremap_wc ioremap_nocache
>  #endif
>  
> +#ifndef ARCH_HAS_IOREMAP_EXEC
> +#define ioremap_exec ioremap
> +#define ioremap_exec_nocache ioremap_nocache
> +#endif
> +
>  #ifdef CONFIG_PCI
>  /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */
>  struct pci_dev;
> 

ioremap and ioremap_nocache are the same, and there is no
architecture-independent interface to map an MMIO range as
cached because a lot of architectures can't do that.

Also, I think there are architectures that cannot execute
from uncached memory, so I think adding this as a generic
API is not a good idea.

	Arnd

[RFC PATCH 2/2] lib: devres: Add exec versions of devm_ioremap_resource and friends

[Dave Gerlach]

From: Russ Dill <Russ.Dill@ti.com>

Now that there is an _exec version of ioremap, add devm support for it.

Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
---
 include/linux/device.h |  19 +++++++-
 include/linux/io.h     |   9 +++-
 lib/devres.c           | 125 +++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 147 insertions(+), 6 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index ce1f2160..d336465 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -635,7 +635,24 @@ extern unsigned long devm_get_free_pages(struct device *dev,
 					 gfp_t gfp_mask, unsigned int order);
 extern void devm_free_pages(struct device *dev, unsigned long addr);
 
-void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
+void __iomem *__devm_ioremap_resource(struct device *dev, struct resource *res,
+				      bool exec);
+static inline void __iomem *devm_ioremap_resource(struct device *dev,
+						  struct resource *res)
+{
+	return __devm_ioremap_resource(dev, res, false);
+}
+void __iomem *devm_request_and_ioremap(struct device *dev,
+				       struct resource *res);
+
+static inline void __iomem *devm_ioremap_exec_resource(struct device *dev,
+						       struct resource *res)
+{
+	return __devm_ioremap_resource(dev, res, true);
+}
+
+void __iomem *devm_request_and_ioremap_exec(struct device *dev,
+					    struct resource *res);
 
 /* allows to add/remove a custom action to devres stack */
 int devm_add_action(struct device *dev, void (*action)(void *), void *data);
diff --git a/include/linux/io.h b/include/linux/io.h
index d5fc9b8..0c6405a 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -61,9 +61,14 @@ static inline void devm_ioport_unmap(struct device *dev, void __iomem *addr)
 #define IOMEM_ERR_PTR(err) (__force void __iomem *)ERR_PTR(err)
 
 void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
-			    unsigned long size);
+			   unsigned long size);
 void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
-				    unsigned long size);
+				   unsigned long size);
+void __iomem *devm_ioremap_exec(struct device *dev, resource_size_t offset,
+				unsigned long size);
+void __iomem *devm_ioremap_exec_nocache(struct device *dev,
+					resource_size_t offset,
+					unsigned long size);
 void devm_iounmap(struct device *dev, void __iomem *addr);
 int check_signature(const volatile void __iomem *io_addr,
 			const unsigned char *signature, int length);
diff --git a/lib/devres.c b/lib/devres.c
index f4a195a..f5d0eac 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -72,6 +72,64 @@ void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
 EXPORT_SYMBOL(devm_ioremap_nocache);
 
 /**
+ * devm_ioremap_exec - Managed ioremap_exec()
+ * @dev: Generic device to remap IO address for
+ * @offset: BUS offset to map
+ * @size: Size of map
+ *
+ * Managed ioremap_exec().  Map is automatically unmapped on driver detach.
+ */
+void __iomem *devm_ioremap_exec(struct device *dev, resource_size_t offset,
+				unsigned long size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = ioremap_exec(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_ioremap_exec);
+
+/**
+ * devm_ioremap_exec_nocache - Managed ioremap_exec_nocache()
+ * @dev: Generic device to remap IO address for
+ * @offset: BUS offset to map
+ * @size: Size of map
+ *
+ * Managed ioremap_exec_nocache().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *devm_ioremap_exec_nocache(struct device *dev,
+					resource_size_t offset,
+					unsigned long size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = ioremap_exec_nocache(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_ioremap_exec_nocache);
+
+/**
  * devm_iounmap - Managed iounmap()
  * @dev: Generic device to unmap for
  * @addr: Address to unmap
@@ -104,7 +162,8 @@ EXPORT_SYMBOL(devm_iounmap);
  *	if (IS_ERR(base))
  *		return PTR_ERR(base);
  */
-void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
+void __iomem *__devm_ioremap_resource(struct device *dev, struct resource *res,
+				      bool exec)
 {
 	resource_size_t size;
 	const char *name;
@@ -125,7 +184,11 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 		return IOMEM_ERR_PTR(-EBUSY);
 	}
 
-	if (res->flags & IORESOURCE_CACHEABLE)
+	if (exec && res->flags & IORESOURCE_CACHEABLE)
+		dest_ptr = devm_ioremap_exec(dev, res->start, size);
+	else if (exec)
+		dest_ptr = devm_ioremap_exec_nocache(dev, res->start, size);
+	else if (res->flags & IORESOURCE_CACHEABLE)
 		dest_ptr = devm_ioremap(dev, res->start, size);
 	else
 		dest_ptr = devm_ioremap_nocache(dev, res->start, size);
@@ -138,7 +201,63 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
 
 	return dest_ptr;
 }
-EXPORT_SYMBOL(devm_ioremap_resource);
+EXPORT_SYMBOL(__devm_ioremap_resource);
+
+/**
+ * devm_request_and_ioremap() - Check, request region, and ioremap resource
+ * @dev: Generic device to handle the resource for
+ * @res: resource to be handled
+ *
+ * Takes all necessary steps to ioremap a mem resource. Uses managed device, so
+ * everything is undone on driver detach. Checks arguments, so you can feed
+ * it the result from e.g. platform_get_resource() directly. Returns the
+ * remapped pointer or NULL on error. Usage example:
+ *
+ *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ *	base = devm_request_and_ioremap(&pdev->dev, res);
+ *	if (!base)
+ *		return -EADDRNOTAVAIL;
+ */
+void __iomem *devm_request_and_ioremap(struct device *device,
+				       struct resource *res)
+{
+	void __iomem *dest_ptr;
+
+	dest_ptr = devm_ioremap_resource(device, res);
+	if (IS_ERR(dest_ptr))
+		return NULL;
+
+	return dest_ptr;
+}
+EXPORT_SYMBOL(devm_request_and_ioremap);
+
+/**
+ * devm_request_and_ioremap_exec() - Check, request region, and ioremap resource
+ * @dev: Generic device to handle the resource for
+ * @res: resource to be handled
+ *
+ * Takes all necessary steps to ioremap a mem resource. Uses managed device, so
+ * everything is undone on driver detach. Checks arguments, so you can feed
+ * it the result from e.g. platform_get_resource() directly. Returns the
+ * remapped pointer or NULL on error. Usage example:
+ *
+ *	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ *	base = devm_request_and_ioremap_exec(&pdev->dev, res);
+ *	if (!base)
+ *		return -EADDRNOTAVAIL;
+ */
+void __iomem *devm_request_and_ioremap_exec(struct device *device,
+					    struct resource *res)
+{
+	void __iomem *dest_ptr;
+
+	dest_ptr = devm_ioremap_exec_resource(device, res);
+	if (IS_ERR(dest_ptr))
+		return NULL;
+
+	return dest_ptr;
+}
+EXPORT_SYMBOL(devm_request_and_ioremap_exec);
 
 #ifdef CONFIG_HAS_IOPORT_MAP
 /*
-- 
2.1.0

Re: [RFC PATCH 2/2] lib: devres: Add exec versions of devm_ioremap_resource and friends

[Geert Uytterhoeven]

On Wed, Nov 26, 2014 at 10:14 PM, Dave Gerlach <d-gerlach@ti.com> wrote:
> --- a/lib/devres.c
> +++ b/lib/devres.c
> @@ -72,6 +72,64 @@ void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
>  EXPORT_SYMBOL(devm_ioremap_nocache);
>
>  /**
> + * devm_ioremap_exec - Managed ioremap_exec()
> + * @dev: Generic device to remap IO address for
> + * @offset: BUS offset to map
> + * @size: Size of map
> + *
> + * Managed ioremap_exec().  Map is automatically unmapped on driver detach.
> + */
> +void __iomem *devm_ioremap_exec(struct device *dev, resource_size_t offset,
> +                               unsigned long size)
> +{

[...]

> +       addr = ioremap_exec(offset, size);

[...]

> +}
> +EXPORT_SYMBOL(devm_ioremap_exec);
> +
> +/**
> + * devm_ioremap_exec_nocache - Managed ioremap_exec_nocache()
> + * @dev: Generic device to remap IO address for
> + * @offset: BUS offset to map
> + * @size: Size of map
> + *
> + * Managed ioremap_exec_nocache().  Map is automatically unmapped on driver
> + * detach.
> + */
> +void __iomem *devm_ioremap_exec_nocache(struct device *dev,
> +                                       resource_size_t offset,
> +                                       unsigned long size)
> +{

[...]

> +       addr = ioremap_exec_nocache(offset, size);

[...]

> +}
> +EXPORT_SYMBOL(devm_ioremap_exec_nocache);
> +

Both of these are identical to the already-existing devm_ioremap() and
devm_ioremap_nocache(), except for the call to the underlying
ioremap*() variant.

Can't the variant selection be done by passing a flag around, set by
the top-level inline functions, to avoid code duplication?
Some architecture-specific ioremap() implementations already work that
way, cfr. arch/m68k/include/asm/io_mm.h:

static inline void __iomem *ioremap(unsigned long physaddr, unsigned long size)
{
        return __ioremap(physaddr, size, IOMAP_NOCACHE_SER);
}
static inline void __iomem *ioremap_nocache(unsigned long physaddr,
unsigned lonn
g size)
{
        return __ioremap(physaddr, size, IOMAP_NOCACHE_SER);
}
static inline void __iomem *ioremap_writethrough(unsigned long physaddr,
                                         unsigned long size)
{
        return __ioremap(physaddr, size, IOMAP_WRITETHROUGH);
}
static inline void __iomem *ioremap_fullcache(unsigned long physaddr,
                                      unsigned long size)
{
        return __ioremap(physaddr, size, IOMAP_FULL_CACHING);
}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds