MIPS: Fix HTW config on XPA kernel without LPA enabled

The hardware page table walker (HTW) configuration is broken on XPA
kernels where XPA couldn't be enabled (either nohtw or the hardware
doesn't support it). This is because the PWSize.PTEW field (PTE width)
was only set to 8 bytes (an extra shift of 1) in config_htw_params() if
PageGrain.ELPA (enable large physical addressing) is set. On an XPA
kernel though the size of PTEs is fixed at 8 bytes regardless of whether
XPA could actually be enabled.

Fix the initialisation of this field based on sizeof(pte_t) instead.

Fixes: 620119a62535 ("MIPS: Add support for XPA.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven J. Hill <sjhill@realitydiluted.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13113/
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 7153e1fb0cd4529eec297a7462df0f6a8f5cfa14..baad605db878b61b4dbfb1c637deb2863416d9c4 100644 (file)
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -2424,9 +2424,7 @@ static void config_htw_params(void)
        if (CONFIG_PGTABLE_LEVELS >= 3)
                pwsize |= ilog2(PTRS_PER_PMD) << MIPS_PWSIZE_MDW_SHIFT;
 
-       /* If XPA has been enabled, PTEs are 64-bit in size. */
-       if (config_enabled(CONFIG_64BITS) || (read_c0_pagegrain() & PG_ELPA))
-               pwsize |= 1;
+       pwsize |= ilog2(sizeof(pte_t)/4) << MIPS_PWSIZE_PTEW_SHIFT;
 
        write_c0_pwsize(pwsize);