Re: [PATCH 1/2] powerpc/lib/code-patching: refactor patch_instruction()

[Balbir Singh]

On Fri, Nov 24, 2017 at 6:31 PM, Christophe Leroy
 wrote:
> patch_instruction() uses almost the same sequence as
> __patch_instruction()
>
> This patch refactor it so that patch_instruction() uses
> __patch_instruction() instead of duplicating code.
>
> Signed-off-by: Christophe Leroy 
> ---

Acked-by: Balbir Singh 

[PATCH 1/2] powerpc/lib/code-patching: refactor patch_instruction()

[Christophe Leroy]

patch_instruction() uses almost the same sequence as
__patch_instruction()

This patch refactor it so that patch_instruction() uses
__patch_instruction() instead of duplicating code.

Signed-off-by: Christophe Leroy 
---
 arch/powerpc/lib/code-patching.c | 30 +++---
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index d469224c4ada..80954c910b66 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -23,19 +23,26 @@
 #include 
 #include 
 
-static int __patch_instruction(unsigned int *addr, unsigned int instr)
+static int __patch_instruction(unsigned int *exec_addr, unsigned int instr,
+  unsigned int *patch_addr)
 {
int err;
 
-   __put_user_size(instr, addr, 4, err);
+   __put_user_size(instr, patch_addr, 4, err);
if (err)
return err;
 
-   asm ("dcbst 0, %0; sync; icbi 0,%0; sync; isync" :: "r" (addr));
+   asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr),
+   "r" (exec_addr));
 
return 0;
 }
 
+static int raw_patch_instruction(unsigned int *addr, unsigned int instr)
+{
+   return __patch_instruction(addr, instr, addr);
+}
+
 #ifdef CONFIG_STRICT_KERNEL_RWX
 static DEFINE_PER_CPU(struct vm_struct *, text_poke_area);
 
@@ -138,7 +145,7 @@ static inline int unmap_patch_area(unsigned long addr)
 int patch_instruction(unsigned int *addr, unsigned int instr)
 {
int err;
-   unsigned int *dest = NULL;
+   unsigned int *patch_addr = NULL;
unsigned long flags;
unsigned long text_poke_addr;
unsigned long kaddr = (unsigned long)addr;
@@ -149,7 +156,7 @@ int patch_instruction(unsigned int *addr, unsigned int 
instr)
 * to allow patching. We just do the plain old patching
 */
if (!this_cpu_read(*PTRRELOC(&text_poke_area)))
-   return __patch_instruction(addr, instr);
+   return raw_patch_instruction(addr, instr);
 
local_irq_save(flags);
 
@@ -159,17 +166,10 @@ int patch_instruction(unsigned int *addr, unsigned int 
instr)
goto out;
}
 
-   dest = (unsigned int *)(text_poke_addr) +
+   patch_addr = (unsigned int *)(text_poke_addr) +
((kaddr & ~PAGE_MASK) / sizeof(unsigned int));
 
-   /*
-* We use __put_user_size so that we can handle faults while
-* writing to dest and return err to handle faults gracefully
-*/
-   __put_user_size(instr, dest, 4, err);
-   if (!err)
-   asm ("dcbst 0, %0; sync; icbi 0,%0; icbi 0,%1; sync; isync"
-   ::"r" (dest), "r"(addr));
+   __patch_instruction(addr, instr, patch_addr);
 
err = unmap_patch_area(text_poke_addr);
if (err)
@@ -184,7 +184,7 @@ int patch_instruction(unsigned int *addr, unsigned int 
instr)
 
 int patch_instruction(unsigned int *addr, unsigned int instr)
 {
-   return __patch_instruction(addr, instr);
+   return raw_patch_instruction(addr, instr);
 }
 
 #endif /* CONFIG_STRICT_KERNEL_RWX */
-- 
2.13.3