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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Zhou Yanjie <zhouyanjie@zoho.com>,
	Paul Burton <paul.burton@mips.com>,
	linux-mips@vger.kernel.org, ralf@linux-mips.org,
	paul@crapouillou.net, jhogan@kernel.org, malat@debian.org,
	gregkh@linuxfoundation.org, tglx@linutronix.de,
	allison@lohutok.net, syq@debian.org, chenhc@lemote.com,
	jiaxun.yang@flygoat.com, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.2 01/42] MIPS: Ingenic: Disable broken BTB lookup optimization.
Date: Sun, 29 Sep 2019 13:32:00 -0400	[thread overview]
Message-ID: <20190929173244.8918-1-sashal@kernel.org> (raw)

From: Zhou Yanjie <zhouyanjie@zoho.com>

[ Upstream commit 053951dda71ecb4b554a2cdbe26f5f6f9bee9dd2 ]

In order to further reduce power consumption, the XBurst core
by default attempts to avoid branch target buffer lookups by
detecting & special casing loops. This feature will cause
BogoMIPS and lpj calculate in error. Set cp0 config7 bit 4 to
disable this feature.

Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: ralf@linux-mips.org
Cc: paul@crapouillou.net
Cc: jhogan@kernel.org
Cc: malat@debian.org
Cc: gregkh@linuxfoundation.org
Cc: tglx@linutronix.de
Cc: allison@lohutok.net
Cc: syq@debian.org
Cc: chenhc@lemote.com
Cc: jiaxun.yang@flygoat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/mips/include/asm/mipsregs.h | 4 ++++
 arch/mips/kernel/cpu-probe.c     | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 1e6966e8527e9..bdbdc19a2b8f8 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -689,6 +689,9 @@
 #define MIPS_CONF7_IAR		(_ULCAST_(1) << 10)
 #define MIPS_CONF7_AR		(_ULCAST_(1) << 16)
 
+/* Ingenic Config7 bits */
+#define MIPS_CONF7_BTB_LOOP_EN	(_ULCAST_(1) << 4)
+
 /* Config7 Bits specific to MIPS Technologies. */
 
 /* Performance counters implemented Per TC */
@@ -2813,6 +2816,7 @@ __BUILD_SET_C0(status)
 __BUILD_SET_C0(cause)
 __BUILD_SET_C0(config)
 __BUILD_SET_C0(config5)
+__BUILD_SET_C0(config7)
 __BUILD_SET_C0(intcontrol)
 __BUILD_SET_C0(intctl)
 __BUILD_SET_C0(srsmap)
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 9635c1db3ae6a..e654ffc1c8a0d 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -1964,6 +1964,13 @@ static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu)
 		c->cputype = CPU_JZRISC;
 		c->writecombine = _CACHE_UNCACHED_ACCELERATED;
 		__cpu_name[cpu] = "Ingenic JZRISC";
+		/*
+		 * The XBurst core by default attempts to avoid branch target
+		 * buffer lookups by detecting & special casing loops. This
+		 * feature will cause BogoMIPS and lpj calculate in error.
+		 * Set cp0 config7 bit 4 to disable this feature.
+		 */
+		set_c0_config7(MIPS_CONF7_BTB_LOOP_EN);
 		break;
 	default:
 		panic("Unknown Ingenic Processor ID!");
-- 
2.20.1


             reply	other threads:[~2019-09-29 17:42 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-29 17:32 Sasha Levin [this message]
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 02/42] clk: jz4740: Add TCU clock Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 03/42] MIPS: Don't use bc_false uninitialized in __mm_isBranchInstr Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 04/42] MIPS: tlbex: Explicitly cast _PAGE_NO_EXEC to a boolean Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 05/42] i2c-cht-wc: Fix lockdep warning Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 06/42] mfd: intel-lpss: Remove D3cold delay Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 07/42] PCI: tegra: Fix OF node reference leak Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 08/42] HID: wacom: Fix several minor compiler warnings Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 09/42] mips/atomic: Fix loongson_llsc_mb() wreckage Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 10/42] PCI: pci-hyperv: Fix build errors on non-SYSFS config Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 11/42] PCI: layerscape: Add the bar_fixed_64bit property to the endpoint driver Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 12/42] livepatch: Nullify obj->mod in klp_module_coming()'s error path Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 13/42] mips/atomic: Fix smp_mb__{before,after}_atomic() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 14/42] ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 15/42] soundwire: intel: fix channel number reported by hardware Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 16/42] ARM: 8875/1: Kconfig: default to AEABI w/ Clang Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 17/42] MIPS: lantiq: update the clock alias' for the mainline PCIe PHY driver Sasha Levin
2019-09-29 17:39   ` Hauke Mehrtens
2019-10-05 23:00     ` Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 18/42] firmware: bcm47xx_nvram: Correct size_t printf format Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 19/42] rtc: snvs: fix possible race condition Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 20/42] rtc: pcf85363/pcf85263: fix regmap error in set_time Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 21/42] selinux: fix residual uses of current_security() for the SELinux blob Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 22/42] PCI: Add pci_info_ratelimited() to ratelimit PCI separately Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 23/42] HID: apple: Fix stuck function keys when using FN Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 24/42] PCI: rockchip: Propagate errors for optional regulators Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 25/42] PCI: histb: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 26/42] PCI: imx6: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 27/42] PCI: exynos: Propagate errors for optional PHYs Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 28/42] security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 29/42] PCI: Use static const struct, not const static struct Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 30/42] ARM: 8905/1: Emit __gnu_mcount_nc when using Clang 10.0.0 or newer Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 31/42] ARM: 8903/1: ensure that usable memory in bank 0 starts from a PMD-aligned address Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 32/42] fat: work around race with userspace's read via blockdev while mounting Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 33/42] pktcdvd: remove warning on attempting to register non-passthrough dev Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 34/42] hypfs: Fix error number left in struct pointer member Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 35/42] crypto: hisilicon - Fix double free in sec_free_hw_sgl() Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 36/42] kbuild: clean compressed initramfs image Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 37/42] ocfs2: wait for recovering done after direct unlock request Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 38/42] kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 39/42] arm64: consider stack randomization for mmap base only when necessary Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 40/42] mips: properly account for stack randomization and stack guard gap Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 41/42] arm: " Sasha Levin
2019-09-29 17:32 ` [PATCH AUTOSEL 5.2 42/42] arm: use STACK_TOP when computing mmap base address Sasha Levin

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