160 lines
4.3 KiB
Diff
160 lines
4.3 KiB
Diff
Subject: arm-enable-highmem-for-rt.patch
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 13 Feb 2013 11:03:11 +0100
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.8-rt6.tar.xz
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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arch/arm/Kconfig | 2 -
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arch/arm/include/asm/switch_to.h | 8 ++++++
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arch/arm/mm/highmem.c | 46 ++++++++++++++++++++++++++++++++++-----
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include/linux/highmem.h | 1
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4 files changed, 51 insertions(+), 6 deletions(-)
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--- a/arch/arm/Kconfig
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+++ b/arch/arm/Kconfig
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@@ -1662,7 +1662,7 @@ config HAVE_GENERIC_RCU_GUP
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config HIGHMEM
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bool "High Memory Support"
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- depends on MMU && !PREEMPT_RT_FULL
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+ depends on MMU
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help
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The address space of ARM processors is only 4 Gigabytes large
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and it has to accommodate user address space, kernel address
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--- a/arch/arm/include/asm/switch_to.h
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+++ b/arch/arm/include/asm/switch_to.h
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@@ -3,6 +3,13 @@
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#include <linux/thread_info.h>
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+#if defined CONFIG_PREEMPT_RT_FULL && defined CONFIG_HIGHMEM
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+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p);
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+#else
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+static inline void
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+switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
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+#endif
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+
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/*
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* For v7 SMP cores running a preemptible kernel we may be pre-empted
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* during a TLB maintenance operation, so execute an inner-shareable dsb
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@@ -22,6 +29,7 @@ extern struct task_struct *__switch_to(s
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#define switch_to(prev,next,last) \
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do { \
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+ switch_kmaps(prev, next); \
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last = __switch_to(prev,task_thread_info(prev), task_thread_info(next)); \
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} while (0)
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--- a/arch/arm/mm/highmem.c
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+++ b/arch/arm/mm/highmem.c
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@@ -54,12 +54,13 @@ EXPORT_SYMBOL(kunmap);
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void *kmap_atomic(struct page *page)
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{
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+ pte_t pte = mk_pte(page, kmap_prot);
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unsigned int idx;
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unsigned long vaddr;
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void *kmap;
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int type;
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- preempt_disable();
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+ preempt_disable_nort();
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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@@ -93,7 +94,10 @@ void *kmap_atomic(struct page *page)
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* in place, so the contained TLB flush ensures the TLB is updated
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* with the new mapping.
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*/
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- set_fixmap_pte(idx, mk_pte(page, kmap_prot));
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ current->kmap_pte[type] = pte;
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+#endif
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+ set_fixmap_pte(idx, pte);
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return (void *)vaddr;
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}
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@@ -110,6 +114,9 @@ void __kunmap_atomic(void *kvaddr)
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if (cache_is_vivt())
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__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ current->kmap_pte[type] = __pte(0);
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+#endif
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(vaddr != __fix_to_virt(idx));
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#else
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@@ -122,17 +129,18 @@ void __kunmap_atomic(void *kvaddr)
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kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
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}
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pagefault_enable();
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- preempt_enable();
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+ preempt_enable_nort();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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void *kmap_atomic_pfn(unsigned long pfn)
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{
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+ pte_t pte = pfn_pte(pfn, kmap_prot);
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unsigned long vaddr;
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int idx, type;
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struct page *page = pfn_to_page(pfn);
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- preempt_disable();
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+ preempt_disable_nort();
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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@@ -143,7 +151,10 @@ void *kmap_atomic_pfn(unsigned long pfn)
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
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#endif
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- set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ current->kmap_pte[type] = pte;
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+#endif
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+ set_fixmap_pte(idx, pte);
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return (void *)vaddr;
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}
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@@ -157,3 +168,28 @@ struct page *kmap_atomic_to_page(const v
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return pte_page(get_fixmap_pte(vaddr));
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}
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+
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+#if defined CONFIG_PREEMPT_RT_FULL
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+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
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+{
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+ int i;
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+
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+ /*
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+ * Clear @prev's kmap_atomic mappings
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+ */
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+ for (i = 0; i < prev_p->kmap_idx; i++) {
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+ int idx = i + KM_TYPE_NR * smp_processor_id();
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+
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+ set_fixmap_pte(idx, __pte(0));
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+ }
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+ /*
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+ * Restore @next_p's kmap_atomic mappings
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+ */
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+ for (i = 0; i < next_p->kmap_idx; i++) {
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+ int idx = i + KM_TYPE_NR * smp_processor_id();
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+
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+ if (!pte_none(next_p->kmap_pte[i]))
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+ set_fixmap_pte(idx, next_p->kmap_pte[i]);
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+ }
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+}
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+#endif
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--- a/include/linux/highmem.h
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+++ b/include/linux/highmem.h
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@@ -7,6 +7,7 @@
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#include <linux/mm.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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+#include <linux/sched.h>
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#include <asm/cacheflush.h>
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