Commit c838b580 authored by Paul Burton's avatar Paul Burton

MIPS: jump_label: Remove redundant nops

Both arch_static_branch() & arch_static_branch_jump() emit a control
transfer instruction (ie. branch or jump) without disabling assembler
re-ordering. As such the assembler will automatically fill their delay
slots.

Both functions follow their branch or jump with an explicit nop that at
first appears to be there to fill the delay slot, but given that the
assembler will do that the explicit nops serve no purpose & we end up
with our branch or jump followed by 2 nops. Remove the redundant nops.
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
parent ec86e545
...@@ -29,7 +29,7 @@ ...@@ -29,7 +29,7 @@
static __always_inline bool arch_static_branch(struct static_key *key, bool branch) static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
{ {
asm_volatile_goto("1:\t" B_INSN " 2f\n\t" asm_volatile_goto("1:\t" B_INSN " 2f\n\t"
"2:\tnop\n\t" "2:\t.insn\n\t"
".pushsection __jump_table, \"aw\"\n\t" ".pushsection __jump_table, \"aw\"\n\t"
WORD_INSN " 1b, %l[l_yes], %0\n\t" WORD_INSN " 1b, %l[l_yes], %0\n\t"
".popsection\n\t" ".popsection\n\t"
...@@ -43,7 +43,6 @@ static __always_inline bool arch_static_branch(struct static_key *key, bool bran ...@@ -43,7 +43,6 @@ static __always_inline bool arch_static_branch(struct static_key *key, bool bran
static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
{ {
asm_volatile_goto("1:\tj %l[l_yes]\n\t" asm_volatile_goto("1:\tj %l[l_yes]\n\t"
"nop\n\t"
".pushsection __jump_table, \"aw\"\n\t" ".pushsection __jump_table, \"aw\"\n\t"
WORD_INSN " 1b, %l[l_yes], %0\n\t" WORD_INSN " 1b, %l[l_yes], %0\n\t"
".popsection\n\t" ".popsection\n\t"
......
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