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Subject[RFC PATCH v1 03/19] powerpc/ptrace: Consolidate reg index calculation
Date
Today we have:

#ifdef CONFIG_PPC32
index = addr >> 2;
if ((addr & 3) || child->thread.regs == NULL)
#else
index = addr >> 3;
if ((addr & 7))
#endif

sizeof(long) has value 4 for PPC32 and value 8 for PPC64.

Dividing by 4 is equivalent to >> 2 and dividing by 8 is equivalent
to >> 3.

And 3 and 7 are respectively (sizeof(long) - 1).

Use sizeof(long) to get rid of the #ifdef CONFIG_PPC32 and consolidate
the calculation and checking.

thread.regs have to be not NULL on both PPC32 and PPC64 so adding
that test on PPC64 is harmless.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/ptrace/ptrace.c | 20 ++++----------------
1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c
index f6e51be47c6e..0b4645a7a1b4 100644
--- a/arch/powerpc/kernel/ptrace/ptrace.c
+++ b/arch/powerpc/kernel/ptrace/ptrace.c
@@ -55,14 +55,8 @@ long arch_ptrace(struct task_struct *child, long request,

ret = -EIO;
/* convert to index and check */
-#ifdef CONFIG_PPC32
- index = addr >> 2;
- if ((addr & 3) || (index > PT_FPSCR)
- || (child->thread.regs == NULL))
-#else
- index = addr >> 3;
- if ((addr & 7) || (index > PT_FPSCR))
-#endif
+ index = addr / sizeof(long);
+ if ((addr & (sizeof(long) - 1)) || (index > PT_FPSCR) || !child->thread.regs)
break;

CHECK_FULL_REGS(child->thread.regs);
@@ -90,14 +84,8 @@ long arch_ptrace(struct task_struct *child, long request,

ret = -EIO;
/* convert to index and check */
-#ifdef CONFIG_PPC32
- index = addr >> 2;
- if ((addr & 3) || (index > PT_FPSCR)
- || (child->thread.regs == NULL))
-#else
- index = addr >> 3;
- if ((addr & 7) || (index > PT_FPSCR))
-#endif
+ index = addr / sizeof(long);
+ if ((addr & (sizeof(long) - 1)) || (index > PT_FPSCR) || !child->thread.regs)
break;

CHECK_FULL_REGS(child->thread.regs);
--
2.25.0
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