From d197f7988721221fac64f899efd7657c15281810 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Mon, 31 Jul 2017 11:37:28 -0700 Subject: [PATCH 1/5] clocksource/drivers/arm_arch_timer: Fix mem frame loop initialization The loop to find the best memory frame in arch_timer_mem_acpi_init() initializes the loop counter with itself ('i = i'), which is suspicious in the first place and pointed out by clang. The loop condition is 'i < timer_count' and a prior for loop exits when 'i' reaches 'timer_count', therefore the second loop is never executed. Initialize the loop counter with 0 to iterate over all timers, which supposedly was the intention before the typo monster attacked. Fixes: c2743a36765d3 ("clocksource: arm_arch_timer: add GTDT support for memory-mapped timer") Signed-off-by: Matthias Kaehlcke Reported-by: Ard Biesheuvel Acked-by: Mark Rutland Signed-off-by: Daniel Lezcano --- drivers/clocksource/arm_arch_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index aae87c4c546e..72bbfccef113 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1440,7 +1440,7 @@ static int __init arch_timer_mem_acpi_init(int platform_timer_count) * While unlikely, it's theoretically possible that none of the frames * in a timer expose the combination of feature we want. */ - for (i = i; i < timer_count; i++) { + for (i = 0; i < timer_count; i++) { timer = &timers[i]; frame = arch_timer_mem_find_best_frame(timer); From 5c23a558a65406cac472df07fd26a2688a42cad2 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Fri, 30 Jun 2017 01:14:45 -0500 Subject: [PATCH 2/5] clocksource/drivers/em_sti: Fix error return codes in em_sti_probe() Propagate the return values of platform_get_irq and devm_request_irq on failure. Cc: Frans Klaver Signed-off-by: Gustavo A. R. Silva Signed-off-by: Daniel Lezcano --- drivers/clocksource/em_sti.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c index bc48cbf6a795..269db74a0658 100644 --- a/drivers/clocksource/em_sti.c +++ b/drivers/clocksource/em_sti.c @@ -305,7 +305,7 @@ static int em_sti_probe(struct platform_device *pdev) irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "failed to get irq\n"); - return -EINVAL; + return irq; } /* map memory, let base point to the STI instance */ @@ -314,11 +314,12 @@ static int em_sti_probe(struct platform_device *pdev) if (IS_ERR(p->base)) return PTR_ERR(p->base); - if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt, - IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, - dev_name(&pdev->dev), p)) { + ret = devm_request_irq(&pdev->dev, irq, em_sti_interrupt, + IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, + dev_name(&pdev->dev), p); + if (ret) { dev_err(&pdev->dev, "failed to request low IRQ\n"); - return -ENOENT; + return ret; } /* get hold of clock */ From 9e80dbd87286d3252ac2f78c6465c16e2ec8d476 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Mon, 10 Jul 2017 10:22:25 +0300 Subject: [PATCH 3/5] clocksource/drivers/timer-of: Checking for IS_ERR() instead of NULL The current code checks the return value of the of_io_request_and_map() function as it was returning a NULL pointer in case of error. However, it returns an error code encoded in the pointer return value, not a NULL value. Fix this by checking the returned pointer against IS_ERR() and return the error with PTR_ERR(). Signed-off-by: Dan Carpenter Signed-off-by: Daniel Lezcano --- drivers/clocksource/timer-of.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/clocksource/timer-of.c b/drivers/clocksource/timer-of.c index d509b500a7b5..4d7aef9d9c15 100644 --- a/drivers/clocksource/timer-of.c +++ b/drivers/clocksource/timer-of.c @@ -128,9 +128,9 @@ static __init int timer_base_init(struct device_node *np, const char *name = of_base->name ? of_base->name : np->full_name; of_base->base = of_io_request_and_map(np, of_base->index, name); - if (!of_base->base) { + if (IS_ERR(of_base->base)) { pr_err("Failed to iomap (%s)\n", name); - return -ENXIO; + return PTR_ERR(of_base->base); } return 0; From 599dc457c79bde8bd4fe8bbb2ba1f30ef3d7a5c8 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Tue, 18 Jul 2017 09:25:39 +0100 Subject: [PATCH 4/5] clocksource/drivers/Kconfig: Fix CLKSRC_PISTACHIO dependencies In v4.13, CLKSRC_PISTACHIO can select TIMER_OF on architectures without GENERIC_CLOCKEVENTS, resulting in a struct clock_event_device missing some required features and build breakage compiling timer_of.c. One of the symbols selecting TIMER_OF is CLKSRC_PISTACHIO, so add the dependency on GENERIC_CLOCKEVENTS. Thanks to kbuild test robot for finding this error (https://lkml.org/lkml/2017/7/16/249) Signed-off-by: Matt Redfearn Suggested-by: Ian Abbott Signed-off-by: Daniel Lezcano --- drivers/clocksource/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index fcae5ca6ac92..54a67f8a28eb 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -262,7 +262,7 @@ config CLKSRC_LPC32XX config CLKSRC_PISTACHIO bool "Clocksource for Pistachio SoC" if COMPILE_TEST - depends on HAS_IOMEM + depends on GENERIC_CLOCKEVENTS && HAS_IOMEM select TIMER_OF help Enables the clocksource for the Pistachio SoC. From adb4f11e0a8f4e29900adb2b7af28b6bbd5c1fa4 Mon Sep 17 00:00:00 2001 From: Ding Tianhong Date: Thu, 10 Aug 2017 10:52:45 +0800 Subject: [PATCH 5/5] clocksource/drivers/arm_arch_timer: Avoid infinite recursion when ftrace is enabled On platforms with an arch timer erratum workaround, it's possible for arch_timer_reg_read_stable() to recurse into itself when certain tracing options are enabled, leading to stack overflows and related problems. For example, when PREEMPT_TRACER and FUNCTION_GRAPH_TRACER are selected, it's possible to trigger this with: $ mount -t debugfs nodev /sys/kernel/debug/ $ echo function_graph > /sys/kernel/debug/tracing/current_tracer The problem is that in such cases, preempt_disable() instrumentation attempts to acquire a timestamp via trace_clock(), resulting in a call back to arch_timer_reg_read_stable(), and hence recursion. This patch changes arch_timer_reg_read_stable() to use preempt_{disable,enable}_notrace(), which avoids this. This problem is similar to the fixed by upstream commit 96b3d28bf4 ("sched/clock: Prevent tracing recursion in sched_clock_cpu()"). Fixes: 6acc71ccac71 ("arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs") Signed-off-by: Ding Tianhong Acked-by: Mark Rutland Acked-by: Marc Zyngier Signed-off-by: Daniel Lezcano --- arch/arm64/include/asm/arch_timer.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index 74d08e44a651..a652ce0a5cb2 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -65,13 +65,13 @@ DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *, u64 _val; \ if (needs_unstable_timer_counter_workaround()) { \ const struct arch_timer_erratum_workaround *wa; \ - preempt_disable(); \ + preempt_disable_notrace(); \ wa = __this_cpu_read(timer_unstable_counter_workaround); \ if (wa && wa->read_##reg) \ _val = wa->read_##reg(); \ else \ _val = read_sysreg(reg); \ - preempt_enable(); \ + preempt_enable_notrace(); \ } else { \ _val = read_sysreg(reg); \ } \