search for: km_max_idx

...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 def...

...andatory-y += local.h --- /dev/null +++ b/include/asm-generic/kmap_size.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_KMAP_SIZE_H +#define _ASM_GENERIC_KMAP_SIZE_H + +/* For debug this provides guard pages between the maps */ +#ifdef CONFIG_DEBUG_HIGHMEM +# define KM_MAX_IDX 33 +#else +# define KM_MAX_IDX 16 +#endif + +#endif

...M */ + +#ifdef CONFIG_KMAP_LOCAL + +#include <asm/kmap_size.h> + +static DEFINE_PER_CPU(int, __kmap_local_idx); + +static inline int kmap_local_idx_push(void) +{ + int idx = __this_cpu_inc_return(__kmap_local_idx) - 1; + + WARN_ON_ONCE(in_irq() && !irqs_disabled()); + BUG_ON(idx >= KM_MAX_IDX); + return idx; +} + +static inline int kmap_local_idx(void) +{ + return __this_cpu_read(__kmap_local_idx) - 1; +} + +static inline void kmap_local_idx_pop(void) +{ + int idx = __this_cpu_dec_return(__kmap_local_idx); + + BUG_ON(idx < 0); +} + +#ifndef arch_kmap_local_post_map +# define arch_kma...

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

Following up to the discussion in: https://lore.kernel.org/r/20200914204209.256266093 at linutronix.de and the second version of this: https://lore.kernel.org/r/20201029221806.189523375 at linutronix.de this series provides a preemptible variant of kmap_atomic & related interfaces. This is achieved by: - Removing the RT dependency from migrate_disable/enable() - Consolidating all

...-#include <asm/kmap_types.h> +#include <asm/kmap_size.h> #endif enum fixed_addresses { @@ -14,7 +14,7 @@ enum fixed_addresses { FIX_KMAP_RESERVED, FIX_KMAP_BEGIN, #ifdef CONFIG_HIGHMEM - FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS), + FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, #endif FIX_EARLYCON_MEM_BASE, __end_of_fixed_addresses --- a/arch/nds32/include/asm/highmem.h +++ b/arch/nds32/include/asm/highmem.h @@ -5,7 +5,6 @@ #define _ASM_HIGHMEM_H #include <asm/proc-fns.h> -#include <asm/kmap_types.h> #include <asm/fixmap.h> /...

...t; +#include <asm/kmap_size.h> #endif /* @@ -52,7 +52,7 @@ enum fixed_addresses { #ifdef CONFIG_HIGHMEM /* reserved pte's for temporary kernel mappings */ FIX_KMAP_BEGIN = FIX_CMAP_END + 1, - FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, + FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, #endif __end_of_fixed_addresses }; --- a/arch/mips/include/asm/highmem.h +++ b/arch/mips/include/asm/highmem.h @@ -24,7 +24,7 @@ #include <linux/interrupt.h> #include <linux/uaccess.h> #include <asm/cpu-features.h> -#include <asm/kmap_types.h> +#includ...

...@@ enum fixed_addresses { FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+(ALIGN(SZ_128K, PAGE_SIZE)/PAGE_SIZE)-1, #ifdef CONFIG_HIGHMEM FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ - FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, + FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, #endif #ifdef CONFIG_PPC_8xx /* For IMMR we need an aligned 512K area */ --- a/arch/powerpc/include/asm/highmem.h +++ b/arch/powerpc/include/asm/highmem.h @@ -24,12 +24,10 @@ #ifdef __KERNEL__ #include <linux/interrupt.h> -#include <asm/kmap_types.h> #include &l...

...t;asm/kmap_types.h> +#include <asm/kmap_size.h> enum fixed_addresses { FIX_EARLYCON_MEM_BASE, __end_of_permanent_fixed_addresses, FIX_KMAP_BEGIN = __end_of_permanent_fixed_addresses, - FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1, + FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, /* Support writing RO kernel text via kprobes, jump labels, etc. */ FIX_TEXT_POKE0, --- a/arch/arm/include/asm/highmem.h +++ b/arch/arm/include/asm/highmem.h @@ -2,7 +2,7 @@ #ifndef _ASM_HIGHMEM_H #define _ASM_HIGHMEM_H -#include <asm/kmap_types.h> +#include <asm/...

...* slot is unused which acts as a guard page @@ -379,23 +377,21 @@ static DEFINE_PER_CPU(int, __kmap_local_ static inline int kmap_local_idx_push(void) { - int idx = __this_cpu_add_return(__kmap_local_idx, KM_INCR) - 1; - WARN_ON_ONCE(in_irq() && !irqs_disabled()); - BUG_ON(idx >= KM_MAX_IDX); - return idx; + current->kmap_ctrl.idx += KM_INCR; + BUG_ON(current->kmap_ctrl.idx >= KM_TYPE_NR); + return current->kmap_ctrl.idx - 1; } static inline int kmap_local_idx(void) { - return __this_cpu_read(__kmap_local_idx) - 1; + return current->kmap_ctrl.idx - 1; } static...