From patchwork Thu Jan 5 05:31:55 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ding Tianhong X-Patchwork-Id: 9498411 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 55BD360235 for ; Thu, 5 Jan 2017 05:37:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 47D3F271BC for ; Thu, 5 Jan 2017 05:37:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3CBD227F0B; Thu, 5 Jan 2017 05:37:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 8036F271BC for ; Thu, 5 Jan 2017 05:37:46 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cP0kC-0006y1-0c; Thu, 05 Jan 2017 05:37:44 +0000 Received: from szxga01-in.huawei.com ([58.251.152.64]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cP0jx-0006bW-Sw for linux-arm-kernel@lists.infradead.org; Thu, 05 Jan 2017 05:37:42 +0000 Received: from 172.24.1.136 (EHLO szxeml428-hub.china.huawei.com) ([172.24.1.136]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DXL17454; Thu, 05 Jan 2017 13:32:10 +0800 (CST) Received: from localhost (10.177.23.32) by szxeml428-hub.china.huawei.com (10.82.67.183) with Microsoft SMTP Server id 14.3.235.1; Thu, 5 Jan 2017 13:32:03 +0800 From: Ding Tianhong To: , , , , , , , , , Subject: [PATCH v6 2/4] arm64: arch_timer: Introduce a generic erratum handing mechanism for fsl-a008585 Date: Thu, 5 Jan 2017 13:31:55 +0800 Message-ID: <1483594317-10732-3-git-send-email-dingtianhong@huawei.com> X-Mailer: git-send-email 1.8.5.2.msysgit.0 In-Reply-To: <1483594317-10732-1-git-send-email-dingtianhong@huawei.com> References: <1483594317-10732-1-git-send-email-dingtianhong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.23.32] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.586DDA5B.023D, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: caae509298e88c60f395c3929d9add04 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170104_213738_303237_305D0794 X-CRM114-Status: GOOD ( 19.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ding Tianhong Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP The workaround for hisilicon,161601 will check the return value of the system counter by different way, in order to distinguish with the fsl-a008585 workaround, introduce a new generic erratum handing mechanism for fsl-a008585 and rename some functions. v2: Introducing a new generic erratum handling mechanism for fsl erratum a008585. v3: Introducing the erratum_workaround_set_sne generic function for fsl erratum a008585 and make the #define __fsl_a008585_read_reg to be private to the .c file instead of being globally visible. After discussion with Marc and Will, a consensus decision was made to remove the commandline parameter for enabling fsl,erratum-a008585 erratum, and make some generic name more specific, export timer_unstable_counter_workaround for module access. v5: Adapt the new documentation for kernel-parameters.txt. v6: Mark the fsl_a008585_read_xxx_el0 with notrace, if CONFIG_FUNCTION_GRAPH_TRACER selected, fsl_a008585_read_xxx_el0 will be related to ftrace_graph_caller which will calling sched_clock to read system counter again, it will cause the system stall into an endless loop. Signed-off-by: Ding Tianhong --- Documentation/admin-guide/kernel-parameters.txt | 9 --- arch/arm64/include/asm/arch_timer.h | 36 ++++-------- drivers/clocksource/arm_arch_timer.c | 78 +++++++++++++++---------- 3 files changed, 58 insertions(+), 65 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 21e2d88..76437ad 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -539,15 +539,6 @@ loops can be debugged more effectively on production systems. - clocksource.arm_arch_timer.fsl-a008585= - [ARM64] - Format: - Enable/disable the workaround of Freescale/NXP - erratum A-008585. This can be useful for KVM - guests, if the guest device tree doesn't show the - erratum. If unspecified, the workaround is - enabled based on the device tree. - clearcpuid=BITNUM [X86] Disable CPUID feature X for the kernel. See arch/x86/include/asm/cpufeatures.h for the valid bit diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index eaa5bbe..f882c7c 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -31,39 +31,27 @@ #if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585) extern struct static_key_false arch_timer_read_ool_enabled; -#define needs_fsl_a008585_workaround() \ +#define needs_unstable_timer_counter_workaround() \ static_branch_unlikely(&arch_timer_read_ool_enabled) #else -#define needs_fsl_a008585_workaround() false +#define needs_unstable_timer_counter_workaround() false #endif -u32 __fsl_a008585_read_cntp_tval_el0(void); -u32 __fsl_a008585_read_cntv_tval_el0(void); -u64 __fsl_a008585_read_cntvct_el0(void); -/* - * The number of retries is an arbitrary value well beyond the highest number - * of iterations the loop has been observed to take. - */ -#define __fsl_a008585_read_reg(reg) ({ \ - u64 _old, _new; \ - int _retries = 200; \ - \ - do { \ - _old = read_sysreg(reg); \ - _new = read_sysreg(reg); \ - _retries--; \ - } while (unlikely(_old != _new) && _retries); \ - \ - WARN_ON_ONCE(!_retries); \ - _new; \ -}) +struct arch_timer_erratum_workaround { + int erratum; /* Indicate the Erratum ID */ + u32 (*read_cntp_tval_el0)(void); + u32 (*read_cntv_tval_el0)(void); + u64 (*read_cntvct_el0)(void); +}; + +extern struct arch_timer_erratum_workaround *timer_unstable_counter_workaround; #define arch_timer_reg_read_stable(reg) \ ({ \ u64 _val; \ - if (needs_fsl_a008585_workaround()) \ - _val = __fsl_a008585_read_##reg(); \ + if (needs_unstable_timer_counter_workaround()) \ + _val = timer_unstable_counter_workaround->read_##reg();\ else \ _val = read_sysreg(reg); \ _val; \ diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 02fef68..f9097b6 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -96,40 +96,53 @@ static int __init early_evtstrm_cfg(char *buf) */ #ifdef CONFIG_FSL_ERRATUM_A008585 -DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled); -EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled); - -static int fsl_a008585_enable = -1; +struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL; +EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround); -static int __init early_fsl_a008585_cfg(char *buf) -{ - int ret; - bool val; +#define FSL_A008585 0x0001 - ret = strtobool(buf, &val); - if (ret) - return ret; - - fsl_a008585_enable = val; - return 0; -} -early_param("clocksource.arm_arch_timer.fsl-a008585", early_fsl_a008585_cfg); +DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled); +EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled); -u32 __fsl_a008585_read_cntp_tval_el0(void) +/* + * The number of retries is an arbitrary value well beyond the highest number + * of iterations the loop has been observed to take. + */ +#define __fsl_a008585_read_reg(reg) ({ \ + u64 _old, _new; \ + int _retries = 200; \ + \ + do { \ + _old = read_sysreg(reg); \ + _new = read_sysreg(reg); \ + _retries--; \ + } while (unlikely(_old != _new) && _retries); \ + \ + WARN_ON_ONCE(!_retries); \ + _new; \ +}) + +static u32 notrace fsl_a008585_read_cntp_tval_el0(void) { return __fsl_a008585_read_reg(cntp_tval_el0); } -u32 __fsl_a008585_read_cntv_tval_el0(void) +static u32 notrace fsl_a008585_read_cntv_tval_el0(void) { return __fsl_a008585_read_reg(cntv_tval_el0); } -u64 __fsl_a008585_read_cntvct_el0(void) +static u64 notrace fsl_a008585_read_cntvct_el0(void) { return __fsl_a008585_read_reg(cntvct_el0); } -EXPORT_SYMBOL(__fsl_a008585_read_cntvct_el0); + +static struct arch_timer_erratum_workaround arch_timer_fsl_a008585 = { + .erratum = FSL_A008585, + .read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0, + .read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0, + .read_cntvct_el0 = fsl_a008585_read_cntvct_el0, +}; #endif /* CONFIG_FSL_ERRATUM_A008585 */ static __always_inline @@ -282,7 +295,7 @@ static __always_inline void set_next_event(const int access, unsigned long evt, } #ifdef CONFIG_FSL_ERRATUM_A008585 -static __always_inline void fsl_a008585_set_next_event(const int access, +static __always_inline void erratum_set_next_event_generic(const int access, unsigned long evt, struct clock_event_device *clk) { unsigned long ctrl; @@ -300,17 +313,17 @@ static __always_inline void fsl_a008585_set_next_event(const int access, arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk); } -static int fsl_a008585_set_next_event_virt(unsigned long evt, +static int erratum_set_next_event_virt(unsigned long evt, struct clock_event_device *clk) { - fsl_a008585_set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk); + erratum_set_next_event_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk); return 0; } -static int fsl_a008585_set_next_event_phys(unsigned long evt, +static int erratum_set_next_event_phys(unsigned long evt, struct clock_event_device *clk) { - fsl_a008585_set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk); + erratum_set_next_event_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk); return 0; } #endif /* CONFIG_FSL_ERRATUM_A008585 */ @@ -343,16 +356,16 @@ static int arch_timer_set_next_event_phys_mem(unsigned long evt, return 0; } -static void fsl_a008585_set_sne(struct clock_event_device *clk) +static void erratum_workaround_set_sne(struct clock_event_device *clk) { #ifdef CONFIG_FSL_ERRATUM_A008585 if (!static_branch_unlikely(&arch_timer_read_ool_enabled)) return; if (arch_timer_uses_ppi == VIRT_PPI) - clk->set_next_event = fsl_a008585_set_next_event_virt; + clk->set_next_event = erratum_set_next_event_virt; else - clk->set_next_event = fsl_a008585_set_next_event_phys; + clk->set_next_event = erratum_set_next_event_phys; #endif } @@ -385,7 +398,7 @@ static void __arch_timer_setup(unsigned type, BUG(); } - fsl_a008585_set_sne(clk); + erratum_workaround_set_sne(clk); } else { clk->features |= CLOCK_EVT_FEAT_DYNIRQ; clk->name = "arch_mem_timer"; @@ -894,9 +907,10 @@ static int __init arch_timer_of_init(struct device_node *np) arch_timer_c3stop = !of_property_read_bool(np, "always-on"); #ifdef CONFIG_FSL_ERRATUM_A008585 - if (fsl_a008585_enable < 0) - fsl_a008585_enable = of_property_read_bool(np, "fsl,erratum-a008585"); - if (fsl_a008585_enable) { + if (!timer_unstable_counter_workaround && of_property_read_bool(np, "fsl,erratum-a008585")) + timer_unstable_counter_workaround = &arch_timer_fsl_a008585; + + if (timer_unstable_counter_workaround) { static_branch_enable(&arch_timer_read_ool_enabled); pr_info("Enabling workaround for FSL erratum A-008585\n"); }