powerpc/code-patching: Inline create_branch()

create_branch() is a good candidate for inlining because:
- Flags can be folded in.
- Range tests are likely to be already done.

Hence reducing the create_branch() to only a set of instructions.

So inline it.

It improves ftrace activation by 10%.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/69851cc9a7bf8f03d025e6d29e165f2d0bd3bb6e.1652074503.git.christophe.leroy@csgroup.eu

1 files changed, 20 insertions, 2 deletions

diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
index 378b70545a32..947d4ae062f5 100644
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -51,8 +51,26 @@ static inline bool is_offset_in_cond_branch_range(long offset)
 	return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
 }
 
-int create_branch(ppc_inst_t *instr, const u32 *addr,
-		  unsigned long target, int flags);
+static inline int create_branch(ppc_inst_t *instr, const u32 *addr,
+				unsigned long target, int flags)
+{
+	long offset;
+
+	*instr = ppc_inst(0);
+	offset = target;
+	if (! (flags & BRANCH_ABSOLUTE))
+		offset = offset - (unsigned long)addr;
+
+	/* Check we can represent the target in the instruction format */
+	if (!is_offset_in_branch_range(offset))
+		return 1;
+
+	/* Mask out the flags and target, so they don't step on each other. */
+	*instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC));
+
+	return 0;
+}
+
 int create_cond_branch(ppc_inst_t *instr, const u32 *addr,
 		       unsigned long target, int flags);
 int patch_branch(u32 *addr, unsigned long target, int flags);