Commit c5b367835cfc ("MIPS: Add support for XPA.") added generation of a
shift by _PAGE_PRESENT_SHIFT in build_pte_present() and
build_pte_writable(), however except for the XPA case this is always
zero making it unnecessary.
Make the shift conditional upon _PAGE_PRESENT_SHIFT being non-zero to
save an instruction in those cases.
Fixes: c5b367835cfc ("MIPS: Add support for XPA.")
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Steven J. Hill <Steven.Hill@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/mm/tlbex.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index d998fea7fc93..eabd6363934e 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -1608,22 +1608,29 @@ build_pte_present(u32 **p, struct uasm_reloc **r,
int pte, int ptr, int scratch, enum label_id lid)
{
int t = scratch >= 0 ? scratch : pte;
+ int cur = pte;
if (cpu_has_rixi) {
if (use_bbit_insns()) {
uasm_il_bbit0(p, r, pte, ilog2(_PAGE_PRESENT), lid);
uasm_i_nop(p);
} else {
- uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT);
- uasm_i_andi(p, t, t, 1);
+ if (_PAGE_PRESENT_SHIFT) {
+ uasm_i_srl(p, t, cur, _PAGE_PRESENT_SHIFT);
+ cur = t;
+ }
+ uasm_i_andi(p, t, cur, 1);
uasm_il_beqz(p, r, t, lid);
if (pte == t)
/* You lose the SMP race :-(*/
iPTE_LW(p, pte, ptr);
}
} else {
- uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT);
- uasm_i_andi(p, t, t,
+ if (_PAGE_PRESENT_SHIFT) {
+ uasm_i_srl(p, t, cur, _PAGE_PRESENT_SHIFT);
+ cur = t;
+ }
+ uasm_i_andi(p, t, cur,
(_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
uasm_i_xori(p, t, t,
(_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
@@ -1654,9 +1661,13 @@ build_pte_writable(u32 **p, struct uasm_reloc **r,
enum label_id lid)
{
int t = scratch >= 0 ? scratch : pte;
+ int cur = pte;
- uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT);
- uasm_i_andi(p, t, t,
+ if (_PAGE_PRESENT_SHIFT) {
+ uasm_i_srl(p, t, cur, _PAGE_PRESENT_SHIFT);
+ cur = t;
+ }
+ uasm_i_andi(p, t, cur,
(_PAGE_PRESENT | _PAGE_WRITE) >> _PAGE_PRESENT_SHIFT);
uasm_i_xori(p, t, t,
(_PAGE_PRESENT | _PAGE_WRITE) >> _PAGE_PRESENT_SHIFT);
--
2.0.5
