From 97a5b81fa4d3a11dcdf224befc577f2e0abadc0b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 2 May 2013 16:21:15 +0200 Subject: x86: Fix idle consolidation fallout The core code expects the arch idle code to return with interrupts enabled. The conversion missed two x86 cases which fail to do that. Reported-and-tested-by: Markus Trippelsdorf Tested-by: Borislav Petkov Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1305021557030.3972@ionos Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 607af0d..4e7a37f 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -312,6 +312,8 @@ void arch_cpu_idle(void) { if (cpuidle_idle_call()) x86_idle(); + else + local_irq_enable(); } /* @@ -368,9 +370,6 @@ void amd_e400_remove_cpu(int cpu) */ static void amd_e400_idle(void) { - if (need_resched()) - return; - if (!amd_e400_c1e_detected) { u32 lo, hi; -- cgit v1.1 From 074d72ff57f65de779e2f70d5906964c0ba1c123 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 8 May 2013 12:13:03 -0400 Subject: x86/microcode: Add local mutex to fix physical CPU hot-add deadlock This can easily be triggered if a new CPU is added (via ACPI hotplug mechanism) and from user-space you do: echo 1 > /sys/devices/system/cpu/cpu3/online (or wait for UDEV to do it) on a newly appeared physical CPU. The deadlock is that the "store_online" in drivers/base/cpu.c takes the cpu_hotplug_driver_lock() lock, then calls "cpu_up". "cpu_up" eventually ends up calling "save_mc_for_early" which also takes the cpu_hotplug_driver_lock() lock. And here is that lockdep thinks of it: smpboot: Stack at about ffff880075c39f44 smpboot: CPU3: has booted. microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x25 ============================================= [ INFO: possible recursive locking detected ] 3.9.0upstream-10129-g167af0e #1 Not tainted --------------------------------------------- sh/2487 is trying to acquire lock: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [] cpu_hotplug_driver_lock+0x12/0x20 but task is already holding lock: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [] cpu_hotplug_driver_lock+0x12/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(x86_cpu_hotplug_driver_mutex); lock(x86_cpu_hotplug_driver_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by sh/2487: #0: (sb_writers#5){.+.+.+}, at: [] vfs_write+0x17d/0x190 #1: (&buffer->mutex){+.+.+.}, at: [] sysfs_write_file+0x3f/0x160 #2: (s_active#20){.+.+.+}, at: [] sysfs_write_file+0xc8/0x160 #3: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [] cpu_hotplug_driver_lock+0x12/0x20 #4: (cpu_add_remove_lock){+.+.+.}, at: [] cpu_maps_update_begin+0x12/0x20 #5: (cpu_hotplug.lock){+.+.+.}, at: [] cpu_hotplug_begin+0x27/0x60 Suggested-and-Acked-by: Borislav Petkov Signed-off-by: Konrad Rzeszutek Wilk Cc: fenghua.yu@intel.com Cc: xen-devel@lists.xensource.com Cc: stable@vger.kernel.org # for v3.9 Link: http://lkml.kernel.org/r/1368029583-23337-1-git-send-email-konrad.wilk@oracle.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/microcode_intel_early.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/microcode_intel_early.c b/arch/x86/kernel/microcode_intel_early.c index d893e8e..2e9e128 100644 --- a/arch/x86/kernel/microcode_intel_early.c +++ b/arch/x86/kernel/microcode_intel_early.c @@ -487,6 +487,7 @@ static inline void show_saved_mc(void) #endif #if defined(CONFIG_MICROCODE_INTEL_EARLY) && defined(CONFIG_HOTPLUG_CPU) +static DEFINE_MUTEX(x86_cpu_microcode_mutex); /* * Save this mc into mc_saved_data. So it will be loaded early when a CPU is * hot added or resumes. @@ -507,7 +508,7 @@ int save_mc_for_early(u8 *mc) * Hold hotplug lock so mc_saved_data is not accessed by a CPU in * hotplug. */ - cpu_hotplug_driver_lock(); + mutex_lock(&x86_cpu_microcode_mutex); mc_saved_count_init = mc_saved_data.mc_saved_count; mc_saved_count = mc_saved_data.mc_saved_count; @@ -544,7 +545,7 @@ int save_mc_for_early(u8 *mc) } out: - cpu_hotplug_driver_unlock(); + mutex_unlock(&x86_cpu_microcode_mutex); return ret; } -- cgit v1.1 From cf8b166d5c1c89aad6c436a954fa40fd18a75bfb Mon Sep 17 00:00:00 2001 From: Zhang Yanfei Date: Thu, 9 May 2013 23:57:42 +0800 Subject: x86/mm: Add missing comments for initial kernel direct mapping Two sets of comments were lost during patch-series shuffling: - comments for init_range_memory_mapping() - comments in init_mem_mapping that is helpful for reminding people that the pagetable is setup top-down The comments were written by Yinghai in his patch in: https://lkml.org/lkml/2012/11/28/620 This patch reintroduces them. Originally-From: Yinghai Lu Signed-off-by: Zhang Yanfei Cc: Yasuaki Ishimatsu Cc: Konrad Rzeszutek Wilk Cc: Andrew Morton Link: http://lkml.kernel.org/r/518BC776.7010506@gmail.com [ Tidied it all up a bit. ] Signed-off-by: Ingo Molnar --- arch/x86/mm/init.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index fdc5dca..eaac174 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -359,7 +359,17 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, } /* - * would have hole in the middle or ends, and only ram parts will be mapped. + * We need to iterate through the E820 memory map and create direct mappings + * for only E820_RAM and E820_KERN_RESERVED regions. We cannot simply + * create direct mappings for all pfns from [0 to max_low_pfn) and + * [4GB to max_pfn) because of possible memory holes in high addresses + * that cannot be marked as UC by fixed/variable range MTRRs. + * Depending on the alignment of E820 ranges, this may possibly result + * in using smaller size (i.e. 4K instead of 2M or 1G) page tables. + * + * init_mem_mapping() calls init_range_memory_mapping() with big range. + * That range would have hole in the middle or ends, and only ram parts + * will be mapped in init_range_memory_mapping(). */ static unsigned long __init init_range_memory_mapping( unsigned long r_start, @@ -419,6 +429,13 @@ void __init init_mem_mapping(void) max_pfn_mapped = 0; /* will get exact value next */ min_pfn_mapped = real_end >> PAGE_SHIFT; last_start = start = real_end; + + /* + * We start from the top (end of memory) and go to the bottom. + * The memblock_find_in_range() gets us a block of RAM from the + * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages + * for page table. + */ while (last_start > ISA_END_ADDRESS) { if (last_start > step_size) { start = round_down(last_start - 1, step_size); -- cgit v1.1 From b4f711ee03d28f776fd2324fd0bd999cc428e4d2 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Wed, 24 Apr 2013 11:32:56 -0700 Subject: time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons Kay Sievers noted that the ALWAYS_USE_PERSISTENT_CLOCK config, which enables some minor compile time optimization to avoid uncessary code in mostly the suspend/resume path could cause problems for userland. In particular, the dependency for RTC_HCTOSYS on !ALWAYS_USE_PERSISTENT_CLOCK, which avoids setting the time twice and simplifies suspend/resume, has the side effect of causing the /sys/class/rtc/rtcN/hctosys flag to always be zero, and this flag is commonly used by udev to setup the /dev/rtc symlink to /dev/rtcN, which can cause pain for older applications. While the udev rules could use some work to be less fragile, breaking userland should strongly be avoided. Additionally the compile time optimizations are fairly minor, and the code being optimized is likely to be reworked in the future, so lets revert this change. Reported-by: Kay Sievers Signed-off-by: John Stultz Cc: stable #3.9 Cc: Feng Tang Cc: Jason Gunthorpe Link: http://lkml.kernel.org/r/1366828376-18124-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner --- arch/x86/Kconfig | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5db2117..45c4124 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -108,7 +108,6 @@ config X86 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) select GENERIC_TIME_VSYSCALL if X86_64 select KTIME_SCALAR if X86_32 - select ALWAYS_USE_PERSISTENT_CLOCK select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select HAVE_CONTEXT_TRACKING if X86_64 -- cgit v1.1 From 5e427ec2d066b48a5c27b3a5a3315f7e4e729077 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 20 May 2013 11:36:03 -0700 Subject: x86: Fix bit corruption at CPU resume time MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In commit 78d77df71510 ("x86-64, init: Do not set NX bits on non-NX capable hardware") we added the early_pmd_flags that gets the NX bit set when a CPU supports NX. However, the new variable was marked __initdata, because the main _use_ of this is in an __init routine. However, the bit setting happens from secondary_startup_64(), which is called not only at bootup, but on every secondary CPU start. Including resuming from STR and at CPU hotplug time. So the value cannot be __initdata. Reported-bisected-and-tested-by: Michal Hocko Cc: stable@vger.kernel.org # v3.9 Acked-by: Peter Anvin Cc: Fernando Luis Vázquez Cao Signed-off-by: Linus Torvalds --- arch/x86/kernel/head64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index dab95a8..55b6761 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -34,7 +34,7 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; static unsigned int __initdata next_early_pgt = 2; -pmdval_t __initdata early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); +pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); /* Wipe all early page tables except for the kernel symbol map */ static void __init reset_early_page_tables(void) -- cgit v1.1