From 43d104db596977a8fddc1e71245859a7fe85a658 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Thu, 17 Sep 2015 17:49:21 +0100 Subject: [PATCH] MIPS: Fix FTLB detection for R6 R6 removed the Config4.MMUExtDef field, with the low 16 bits only allowed to contain FTLB fields, and commit e87569cd6c57 ("MIPS: cpu-probe: Fix VTLB/FTLB configuration for R6") updated the probing of this field to assume an FTLB is always present for R6. However the FTLB may still be absent. The presence of those fields is actually specified by the MMU type in the Config.MT field, so use that (the new cpu_has_ftlb) to determine whether the FTLB is actually present. Fixes: e87569cd6c57 ("MIPS: cpu-probe: Fix VTLB/FTLB configuration for R6") Signed-off-by: James Hogan Cc: Ralf Baechle Cc: Markos Chandras Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11160/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/cpu-probe.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 397551cf2e7b..09a51d091941 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -561,15 +561,18 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c) if (cpu_has_tlb) { if (((config4 & MIPS_CONF4_IE) >> 29) == 2) c->options |= MIPS_CPU_TLBINV; + /* - * This is a bit ugly. R6 has dropped that field from - * config4 and the only valid configuration is VTLB+FTLB so - * set a good value for mmuextdef for that case. + * R6 has dropped the MMUExtDef field from config4. + * On R6 the fields always describe the FTLB, and only if it is + * present according to Config.MT. */ - if (cpu_has_mips_r6) + if (!cpu_has_mips_r6) + mmuextdef = config4 & MIPS_CONF4_MMUEXTDEF; + else if (cpu_has_ftlb) mmuextdef = MIPS_CONF4_MMUEXTDEF_VTLBSIZEEXT; else - mmuextdef = config4 & MIPS_CONF4_MMUEXTDEF; + mmuextdef = 0; switch (mmuextdef) { case MIPS_CONF4_MMUEXTDEF_MMUSIZEEXT: -- 2.30.2