diff mbox series

[RFC,v1,03/19] powerpc/ptrace: Consolidate reg index calculation

Message ID 17430b14a0b2a9da8fc24dfaeca79aec0180df5c.1597233555.git.christophe.leroy@csgroup.eu (mailing list archive)
State RFC
Headers show
Series powerpc: Switch signal 32 to using user_access_begin() and friends | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (f04b169e953c4db1a3a3c1d23eea09c726f01ee5)
snowpatch_ozlabs/checkpatch warning total: 0 errors, 2 warnings, 2 checks, 32 lines checked
snowpatch_ozlabs/needsstable success Patch has no Fixes tags

Commit Message

Christophe Leroy Aug. 12, 2020, 12:05 p.m. UTC 
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 mbox series

Patch

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);