[PATCH v7 01/12] x86/mm: sparse warning fix for early_memremap

Dave Young
2013-12-20T10:02:11Z

There's a lot of sparse warnings for code like below:
void *a = early_memremap(phys_addr, size);

early_memremap intend to map kernel memory with ioremap facility, the return
pointer should be a kernel ram pointer instead of iomem one.

For making the function clearer and supressing sparse warnings this patch
do below two things:
1. cast to (__force void *) for the return value of early_memremap
2. add early_memunmap function and pass (__force void __iomem *) to iounmap

>From Boris:
> Ingo told me yesterday, it makes sense too. I'd guess we can try it.
> FWIW, all callers of early_memremap use the memory they get remapped as
> normal memory so we should be safe.

Signed-off-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
arch/x86/include/asm/io.h | 3 ++-
arch/x86/mm/ioremap.c | 10 +++++++---
2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 34f69cb..1db414f 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -325,9 +325,10 @@ extern void early_ioremap_init(void);
extern void early_ioremap_reset(void);
extern void __iomem *early_ioremap(resource_size_t phys_addr,
unsigned long size);
-extern void __iomem *early_memremap(resource_size_t phys_addr,
+extern void *early_memremap(resource_size_t phys_addr,
unsigned long size);
extern void early_iounmap(void __iomem *addr, unsigned long size);
+extern void early_memunmap(void *addr, unsigned long size);
extern void fixup_early_ioremap(void);
extern bool is_early_ioremap_ptep(pte_t *ptep);

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 799580c..bbb4504 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -562,10 +562,9 @@ early_ioremap(resource_size_t phys_addr, unsigned long size)
}

/* Remap memory */
-void __init __iomem *
-early_memremap(resource_size_t phys_addr, unsigned long size)
+void __init *early_memremap(resource_size_t phys_addr, unsigned long size)
{
- return __early_ioremap(phys_addr, size, PAGE_KERNEL);
+ return (__force void *)__early_ioremap(phys_addr, size, PAGE_KERNEL);
}

void __init early_iounmap(void __iomem *addr, unsigned long size)
@@ -620,3 +619,8 @@ void __init early_iounmap(void __iomem *addr, unsigned long size)
}
prev_map[slot] = NULL;
}
+
+void __init early_memunmap(void *addr, unsigned long size)
+{
+ early_iounmap((__force void __iomem *)addr, size);
+}
--
1.8.3.1