diff options
Diffstat (limited to 'debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch')
| -rw-r--r-- | debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch b/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch new file mode 100644 index 000000000..581f1da69 --- /dev/null +++ b/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch @@ -0,0 +1,212 @@ +From 7eeaddc0ba0792dd0d8a1f5f167ff44230b77855 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 3 Nov 2020 10:27:21 +0100 +Subject: [PATCH 032/323] arc/mm/highmem: Use generic kmap atomic + implementation +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz + +Adopt the map ordering to match the other architectures and the generic +code. Also make the maximum entries limited and not dependend on the number +of CPUs. With the original implementation did the following calculation: + + nr_slots = mapsize >> PAGE_SHIFT; + +The results in either 512 or 1024 total slots depending on +configuration. The total slots have to be divided by the number of CPUs to +get the number of slots per CPU (former KM_TYPE_NR). ARC supports up to 4k +CPUs, so this just falls apart in random ways depending on the number of +CPUs and the actual kmap (atomic) nesting. The comment in highmem.c: + + * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE + * slots across NR_CPUS would be more than sufficient (generic code defines + * KM_TYPE_NR as 20). + +is just wrong. KM_TYPE_NR (now KM_MAX_IDX) is the number of slots per CPU +because kmap_local/atomic() needs to support nested mappings (thread, +softirq, interrupt). While KM_MAX_IDX might be overestimated, the above +reasoning is just wrong and clearly the highmem code was never tested with +any system with more than a few CPUs. + +Use the default number of slots and fail the build when it does not +fit. Randomly failing at runtime is not a really good option. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Cc: Vineet Gupta <vgupta@synopsys.com> +Cc: linux-snps-arc@lists.infradead.org +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + arch/arc/Kconfig | 1 + + arch/arc/include/asm/highmem.h | 26 +++++++++++---- + arch/arc/include/asm/kmap_types.h | 14 -------- + arch/arc/mm/highmem.c | 54 +++---------------------------- + 4 files changed, 26 insertions(+), 69 deletions(-) + delete mode 100644 arch/arc/include/asm/kmap_types.h + +diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig +index 0a89cc9def65..d8804001d550 100644 +--- a/arch/arc/Kconfig ++++ b/arch/arc/Kconfig +@@ -507,6 +507,7 @@ config LINUX_RAM_BASE + config HIGHMEM + bool "High Memory Support" + select ARCH_DISCONTIGMEM_ENABLE ++ select KMAP_LOCAL + help + With ARC 2G:2G address split, only upper 2G is directly addressable by + kernel. Enable this to potentially allow access to rest of 2G and PAE +diff --git a/arch/arc/include/asm/highmem.h b/arch/arc/include/asm/highmem.h +index 6e5eafb3afdd..a6b8e2c352c4 100644 +--- a/arch/arc/include/asm/highmem.h ++++ b/arch/arc/include/asm/highmem.h +@@ -9,17 +9,29 @@ + #ifdef CONFIG_HIGHMEM + + #include <uapi/asm/page.h> +-#include <asm/kmap_types.h> ++#include <asm/kmap_size.h> ++ ++#define FIXMAP_SIZE PGDIR_SIZE ++#define PKMAP_SIZE PGDIR_SIZE + + /* start after vmalloc area */ + #define FIXMAP_BASE (PAGE_OFFSET - FIXMAP_SIZE - PKMAP_SIZE) +-#define FIXMAP_SIZE PGDIR_SIZE /* only 1 PGD worth */ +-#define KM_TYPE_NR ((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS) +-#define FIXMAP_ADDR(nr) (FIXMAP_BASE + ((nr) << PAGE_SHIFT)) ++ ++#define FIX_KMAP_SLOTS (KM_MAX_IDX * NR_CPUS) ++#define FIX_KMAP_BEGIN (0UL) ++#define FIX_KMAP_END ((FIX_KMAP_BEGIN + FIX_KMAP_SLOTS) - 1) ++ ++#define FIXADDR_TOP (FIXMAP_BASE + (FIX_KMAP_END << PAGE_SHIFT)) ++ ++/* ++ * This should be converted to the asm-generic version, but of course this ++ * is needlessly different from all other architectures. Sigh - tglx ++ */ ++#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) ++#define __virt_to_fix(x) (((FIXADDR_TOP - ((x) & PAGE_MASK))) >> PAGE_SHIFT) + + /* start after fixmap area */ + #define PKMAP_BASE (FIXMAP_BASE + FIXMAP_SIZE) +-#define PKMAP_SIZE PGDIR_SIZE + #define LAST_PKMAP (PKMAP_SIZE >> PAGE_SHIFT) + #define LAST_PKMAP_MASK (LAST_PKMAP - 1) + #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) +@@ -29,11 +41,13 @@ + + extern void kmap_init(void); + ++#define arch_kmap_local_post_unmap(vaddr) \ ++ local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE) ++ + static inline void flush_cache_kmaps(void) + { + flush_cache_all(); + } +- + #endif + + #endif +diff --git a/arch/arc/include/asm/kmap_types.h b/arch/arc/include/asm/kmap_types.h +deleted file mode 100644 +index fecf7851ec32..000000000000 +--- a/arch/arc/include/asm/kmap_types.h ++++ /dev/null +@@ -1,14 +0,0 @@ +-/* SPDX-License-Identifier: GPL-2.0-only */ +-/* +- * Copyright (C) 2015 Synopsys, Inc. (www.synopsys.com) +- */ +- +-#ifndef _ASM_KMAP_TYPES_H +-#define _ASM_KMAP_TYPES_H +- +-/* +- * We primarily need to define KM_TYPE_NR here but that in turn +- * is a function of PGDIR_SIZE etc. +- * To avoid circular deps issue, put everything in asm/highmem.h +- */ +-#endif +diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c +index 1b9f473c6369..c79912a6b196 100644 +--- a/arch/arc/mm/highmem.c ++++ b/arch/arc/mm/highmem.c +@@ -36,9 +36,8 @@ + * This means each only has 1 PGDIR_SIZE worth of kvaddr mappings, which means + * 2M of kvaddr space for typical config (8K page and 11:8:13 traversal split) + * +- * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE +- * slots across NR_CPUS would be more than sufficient (generic code defines +- * KM_TYPE_NR as 20). ++ * - The fixed KMAP slots for kmap_local/atomic() require KM_MAX_IDX slots per ++ * CPU. So the number of CPUs sharing a single PTE page is limited. + * + * - pkmap being preemptible, in theory could do with more than 256 concurrent + * mappings. However, generic pkmap code: map_new_virtual(), doesn't traverse +@@ -47,48 +46,6 @@ + */ + + extern pte_t * pkmap_page_table; +-static pte_t * fixmap_page_table; +- +-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot) +-{ +- int idx, cpu_idx; +- unsigned long vaddr; +- +- cpu_idx = kmap_atomic_idx_push(); +- idx = cpu_idx + KM_TYPE_NR * smp_processor_id(); +- vaddr = FIXMAP_ADDR(idx); +- +- set_pte_at(&init_mm, vaddr, fixmap_page_table + idx, +- mk_pte(page, prot)); +- +- return (void *)vaddr; +-} +-EXPORT_SYMBOL(kmap_atomic_high_prot); +- +-void kunmap_atomic_high(void *kv) +-{ +- unsigned long kvaddr = (unsigned long)kv; +- +- if (kvaddr >= FIXMAP_BASE && kvaddr < (FIXMAP_BASE + FIXMAP_SIZE)) { +- +- /* +- * Because preemption is disabled, this vaddr can be associated +- * with the current allocated index. +- * But in case of multiple live kmap_atomic(), it still relies on +- * callers to unmap in right order. +- */ +- int cpu_idx = kmap_atomic_idx(); +- int idx = cpu_idx + KM_TYPE_NR * smp_processor_id(); +- +- WARN_ON(kvaddr != FIXMAP_ADDR(idx)); +- +- pte_clear(&init_mm, kvaddr, fixmap_page_table + idx); +- local_flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE); +- +- kmap_atomic_idx_pop(); +- } +-} +-EXPORT_SYMBOL(kunmap_atomic_high); + + static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr) + { +@@ -108,10 +65,9 @@ void __init kmap_init(void) + { + /* Due to recursive include hell, we can't do this in processor.h */ + BUILD_BUG_ON(PAGE_OFFSET < (VMALLOC_END + FIXMAP_SIZE + PKMAP_SIZE)); ++ BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE); ++ BUILD_BUG_ON(FIX_KMAP_SLOTS > PTRS_PER_PTE); + +- BUILD_BUG_ON(KM_TYPE_NR > PTRS_PER_PTE); + pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE); +- +- BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE); +- fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE); ++ alloc_kmap_pgtable(FIXMAP_BASE); + } +-- +2.43.0 + |