From 4c86231c14a8a1e9838dcb013ded07ebd2f2a1a5 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 12 Dec 2014 10:05:03 +0530 Subject: ARC: fix /proc/cpuinfo for offline cpus Signed-off-by: Vineet Gupta --- arch/arc/kernel/setup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c index 252bf603db9c..900f68a70088 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -412,6 +412,11 @@ static int show_cpuinfo(struct seq_file *m, void *v) char *str; int cpu_id = ptr_to_cpu(v); + if (!cpu_online(cpu_id)) { + seq_printf(m, "processor [%d]\t: Offline\n", cpu_id); + goto done; + } + str = (char *)__get_free_page(GFP_TEMPORARY); if (!str) goto done; @@ -429,7 +434,7 @@ static int show_cpuinfo(struct seq_file *m, void *v) free_page((unsigned long)str); done: - seq_printf(m, "\n\n"); + seq_printf(m, "\n"); return 0; } -- cgit v1.2.3 From 98edfab4c10343bd3ba1ca47d000544b9f964886 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 15 Dec 2014 16:33:39 +0530 Subject: ARC: add some more comments to ret_from_fork Signed-off-by: Vineet Gupta --- arch/arc/kernel/entry.S | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 83a046a7cd06..d868289c5a26 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -736,16 +736,20 @@ ENTRY(ret_from_fork) ; put last task in scheduler queue bl @schedule_tail - ; If kernel thread, jump to its entry-point ld r9, [sp, PT_status32] brne r9, 0, 1f - jl.d [r14] - mov r0, r13 ; arg to payload + jl.d [r14] ; kernel thread entry point + mov r0, r13 ; (see PF_KTHREAD block in copy_thread) 1: - ; special case of kernel_thread entry point returning back due to - ; kernel_execve() - pretend return from syscall to ret to userland + ; Return to user space + ; 1. Any forked task (Reach here via BRne above) + ; 2. First ever init task (Reach here via return from JL above) + ; This is the historic "kernel_execve" use-case, to return to init + ; user mode, in a round about way since that is always done from + ; a kernel thread which is executed via JL above but always returns + ; out whenever kernel_execve (now inline do_fork()) is involved b ret_from_exception END(ret_from_fork) -- cgit v1.2.3 From 7082a29c22ac0ab276b346f2a5c1d24a2102f158 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 15 Dec 2014 18:42:24 +0530 Subject: ARC: use ACCESS_ONCE in cmpxchg loop Signed-off-by: Vineet Gupta --- arch/arc/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index 20ebb602ea2f..6a400b1b0b62 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -221,7 +221,7 @@ static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) * and read back old value */ do { - new = old = *ipi_data_ptr; + new = old = ACCESS_ONCE(*ipi_data_ptr); new |= 1U << msg; } while (cmpxchg(ipi_data_ptr, old, new) != old); -- cgit v1.2.3 From ffb7fcd66f14bc716b9fdf559e71909131fef39b Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Tue, 28 Oct 2014 15:04:05 +0530 Subject: ARC: Dynamically determine BASE_BAUD from DeviceTree 8250 earlycon is broken on multi-platform ARC because the UART clk value (BASE_BAUD) is fixed at build time. Instead, determine the appropriate UART clk at runtime; parse the devicetree early for platforms requiring alternate UART clk values (currently only the TB10X platform). Cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Rob Herring Cc: Arnd Bergmann Reviewed-by: Peter Hurley Acked-by: Greg Kroah-Hartman Signed-off-by: Vineet Gupta --- arch/arc/include/asm/serial.h | 23 +++++------------------ arch/arc/kernel/devtree.c | 24 ++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 18 deletions(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/include/asm/serial.h b/arch/arc/include/asm/serial.h index 602b0970a764..744a6ae15754 100644 --- a/arch/arc/include/asm/serial.h +++ b/arch/arc/include/asm/serial.h @@ -10,26 +10,13 @@ #define _ASM_ARC_SERIAL_H /* - * early-8250 requires BASE_BAUD to be defined and includes this header. - * We put in a typical value: - * (core clk / 16) - i.e. UART samples 16 times per sec. - * Athough in multi-platform-image this might not work, specially if the - * clk driving the UART is different. - * We can't use DeviceTree as this is typically for early serial. + * early 8250 (now earlycon) requires BASE_BAUD to be defined in this header. + * However to still determine it dynamically (for multi-platform images) + * we do this in a helper by parsing the FDT early */ -#include +extern unsigned int __init arc_early_base_baud(void); -#define BASE_BAUD (arc_get_core_freq() / 16) - -/* - * This is definitely going to break early 8250 consoles on multi-platform - * images but hey, it won't add any code complexity for a debug feature of - * one broken driver. - */ -#ifdef CONFIG_ARC_PLAT_TB10X -#undef BASE_BAUD -#define BASE_BAUD (arc_get_core_freq() / 16 / 3) -#endif +#define BASE_BAUD arc_early_base_baud() #endif /* _ASM_ARC_SERIAL_H */ diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c index fffdb5e41b20..5036d4c06996 100644 --- a/arch/arc/kernel/devtree.c +++ b/arch/arc/kernel/devtree.c @@ -17,6 +17,28 @@ #include #include +#ifdef CONFIG_SERIAL_8250_CONSOLE + +static unsigned int __initdata arc_base_baud; + +unsigned int __init arc_early_base_baud(void) +{ + return arc_base_baud/16; +} + +static void __init arc_set_early_base_baud(unsigned long dt_root) +{ + unsigned int core_clk = arc_get_core_freq(); + + if (of_flat_dt_is_compatible(dt_root, "abilis,arc-tb10x")) + arc_base_baud = core_clk/3; + else + arc_base_baud = core_clk; +} +#else +#define arc_set_early_base_baud(dt_root) +#endif + static const void * __init arch_get_next_mach(const char *const **match) { static const struct machine_desc *mdesc = __arch_info_begin; @@ -56,5 +78,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt) if (clk) arc_set_core_freq(of_read_ulong(clk, len/4)); + arc_set_early_base_baud(dt_root); + return mdesc; } -- cgit v1.2.3 From 091f56be10efe8ac7c09d6368d885f41fa7eb809 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Tue, 3 Feb 2015 20:08:52 -0500 Subject: ARC: Fix earlycon build breakage Commit ffb7fcd66f14 ("ARC: Dynamically determine BASE_BAUD from DeviceTree") breaks arc:defconfig build: drivers/built-in.o: In function `of_setup_earlycon': (.init.text+0xb3e): undefined reference to `arc_early_base_baud' drivers/built-in.o: In function `setup_earlycon': (.init.text+0xcd0): undefined reference to `arc_early_base_baud' make: *** [vmlinux] Error 1 BASE_BAUD is only required for earlycon, which should depend on CONFIG_SERIAL_EARLYCON. Reported-by: Guenter Roeck Tested-by: Guenter Roeck Signed-off-by: Peter Hurley Signed-off-by: Vineet Gupta --- arch/arc/kernel/devtree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arc/kernel') diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c index 5036d4c06996..e32b54abff51 100644 --- a/arch/arc/kernel/devtree.c +++ b/arch/arc/kernel/devtree.c @@ -17,7 +17,7 @@ #include #include -#ifdef CONFIG_SERIAL_8250_CONSOLE +#ifdef CONFIG_SERIAL_EARLYCON static unsigned int __initdata arc_base_baud; -- cgit v1.2.3