MIPS: tlbex: Fix broken offsets on r2 without XPA

Commit c5b367835cfc ("MIPS: Add support for XPA.") changed
build_pte_present() and build_pte_writable() to assume a constant offset
of _PAGE_READ and _PAGE_WRITE relative to _PAGE_PRESENT, however this is
no longer true for some MIPS32R2 builds since commit be0c37c985ed
("MIPS: Rearrange PTE bits into fixed positions.") which moved the
_PAGE_READ PTE bit away from the _PAGE_PRESENT bit, with the _PAGE_WRITE
bit falling into its place.

Make use of the _PAGE_READ and _PAGE_WRITE definitions to calculate the
correct mask to apply instead of hard coding 3 (for _PAGE_PRESENT |
_PAGE_READ) or 5 (for _PAGE_PRESENT | _PAGE_WRITE).

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/9888/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index d7db82c3fbcef849d4dead980504bf73521d3daa..50292878384cc0519f8a82a3f6d903bd0577a0d8 100644 (file)
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -1623,8 +1623,10 @@ build_pte_present(u32 **p, struct uasm_reloc **r,
                }
        } else {
                uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT);
-               uasm_i_andi(p, t, t, 3);
-               uasm_i_xori(p, t, t, 3);
+               uasm_i_andi(p, t, t,
+                       (_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
+               uasm_i_xori(p, t, t,
+                       (_PAGE_PRESENT | _PAGE_READ) >> _PAGE_PRESENT_SHIFT);
                uasm_il_bnez(p, r, t, lid);
                if (pte == t)
                        /* You lose the SMP race :-(*/
@@ -1654,8 +1656,10 @@ build_pte_writable(u32 **p, struct uasm_reloc **r,
        int t = scratch >= 0 ? scratch : pte;
 
        uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT);
-       uasm_i_andi(p, t, t, 5);
-       uasm_i_xori(p, t, t, 5);
+       uasm_i_andi(p, t, t,
+                   (_PAGE_PRESENT | _PAGE_WRITE) >> _PAGE_PRESENT_SHIFT);
+       uasm_i_xori(p, t, t,
+                   (_PAGE_PRESENT | _PAGE_WRITE) >> _PAGE_PRESENT_SHIFT);
        uasm_il_bnez(p, r, t, lid);
        if (pte == t)
                /* You lose the SMP race :-(*/