2015-08-26 01:24:49

by yalin wang

Subject: [PATCH] arm: insn: use set_fixmap_offset to make it more clear

A little change to patch_map() function,
use set_fixmap_offset() to make code more clear.

Signed-off-by: yalin wang <[email protected]>
---
arch/arm/kernel/patch.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
index 69bda1a..5779105 100644
--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -36,9 +36,8 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
else
__acquire(&patch_lock);

- set_fixmap(fixmap, page_to_phys(page));
-
- return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
+ return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
+ (uintaddr & ~PAGE_MASK));
}

static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
--
1.9.1

2015-08-27 17:26:55

by Rabin Vincent

Subject: Re: [PATCH] arm: insn: use set_fixmap_offset to make it more clear

On Wed, Aug 26, 2015 at 09:24:26AM +0800, yalin wang wrote:
> A little change to patch_map() function,
> use set_fixmap_offset() to make code more clear.
>
> Signed-off-by: yalin wang <[email protected]>
> ---
> arch/arm/kernel/patch.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
> index 69bda1a..5779105 100644
> --- a/arch/arm/kernel/patch.c
> +++ b/arch/arm/kernel/patch.c
> @@ -36,9 +36,8 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
> else
> __acquire(&patch_lock);
>
> - set_fixmap(fixmap, page_to_phys(page));
> -
> - return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
> + return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
> + (uintaddr & ~PAGE_MASK));
> }

Perhaps a temporary variable to make it clearerer? Something like this:

diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
index 69bda1a..0b8e594 100644
--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -23,6 +23,7 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
unsigned int uintaddr = (uintptr_t) addr;
bool module = !core_kernel_text(uintaddr);
struct page *page;
+ phys_addr_t phys;

if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
page = vmalloc_to_page(addr);
@@ -36,9 +37,8 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
else
__acquire(&patch_lock);

- set_fixmap(fixmap, page_to_phys(page));
-
- return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
+ phys = page_to_phys(page) + (uintaddr & ~PAGE_MASK);
+ return (void *) set_fixmap_offset(fixmap, phys);
}

static void __kprobes patch_unmap(int fixmap, unsigned long *flags)