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| author | James Hogan <james.hogan@imgtec.com> | 2015-04-27 15:07:18 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2015-06-21 21:53:55 +0200 |
| commit | 8fe4908b837e848efd95c2a1210ec67d48fbe874 (patch) | |
| tree | 2904ada9eebee55add9f878c96cdcec6e925c4be /arch/mips | |
| parent | a3ae565a130a4f34f4a3f45f72c2e8fd8b402b8c (diff) | |
| download | linux-8fe4908b837e848efd95c2a1210ec67d48fbe874.tar.gz linux-8fe4908b837e848efd95c2a1210ec67d48fbe874.tar.bz2 linux-8fe4908b837e848efd95c2a1210ec67d48fbe874.zip | |
MIPS: tlbex: Avoid unnecessary _PAGE_PRESENT shifts
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@imgtec.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9889/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/mm/tlbex.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index 50292878384c..323d1d302f2b 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); |