From 72c70f010dfcc9ea6cc13500602a29e33748452f Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Fri, 19 Aug 2016 18:18:26 +0100 Subject: MIPS: Stop setting I6400 FTLBP The FTLBP field in Config7 for the I6400 is intended as chicken bits for debugging rather than as a field that software actually makes use of. For best performance, FTLBP should be left at its default value of 0 with all TLB writes hitting the FTLB by default. Additionally, since set_ftlb_enable is called from decode_configs before decode_config4 which determines the size of the TLBs, this was previously always setting FTLBP=3 for a 3:1 FTLB:VTLB write ratio which makes abysmal use of the available FTLB resources. This effectively reverts b0c4e1b79d8a ("MIPS: Set up FTLB probability for I6400"). Signed-off-by: Paul Burton Fixes: b0c4e1b79d8a ("MIPS: Set up FTLB probability for I6400") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14021/ Signed-off-by: Ralf Baechle diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h index def9d8d..7dd2dd4 100644 --- a/arch/mips/include/asm/mipsregs.h +++ b/arch/mips/include/asm/mipsregs.h @@ -660,8 +660,6 @@ #define MIPS_CONF7_IAR (_ULCAST_(1) << 10) #define MIPS_CONF7_AR (_ULCAST_(1) << 16) -/* FTLB probability bits for R6 */ -#define MIPS_CONF7_FTLBP_SHIFT (18) /* WatchLo* register definitions */ #define MIPS_WATCHLO_IRW (_ULCAST_(0x7) << 0) diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index a88d442..ae29050 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -555,13 +555,8 @@ static int set_ftlb_enable(struct cpuinfo_mips *c, int enable) write_c0_config6(config & ~MIPS_CONF6_FTLBEN); break; case CPU_I6400: - /* I6400 & related cores use Config7 to configure FTLB */ - config = read_c0_config7(); - /* Clear the old probability value */ - config &= ~(3 << MIPS_CONF7_FTLBP_SHIFT); - write_c0_config7(config | (calculate_ftlb_probability(c) - << MIPS_CONF7_FTLBP_SHIFT)); - break; + /* There's no way to disable the FTLB */ + return !enable; case CPU_LOONGSON3: /* Flush ITLB, DTLB, VTLB and FTLB */ write_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB | -- cgit v0.10.2