The following commit has been merged into the core/mm branch of tip: Commit-ID: 14df32670291588036a498051a54cd8462d7f611 Gitweb: https://git.kernel.org/tip/14df32670291588036a498051a54cd8462d7f611 Author: Thomas Gleixner <t...@linutronix.de> AuthorDate: Wed, 18 Nov 2020 20:48:41 +01:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Tue, 24 Nov 2020 14:42:09 +01:00
x86: Support kmap_local() forced debugging kmap_local() and related interfaces are NOOPs on 64bit and only create temporary fixmaps for highmem pages on 32bit. That means the test coverage for this code is pretty small. CONFIG_KMAP_LOCAL can be enabled independent from CONFIG_HIGHMEM, which allows to provide support for enforced kmap_local() debugging even on 64bit. For 32bit the support is unconditional, for 64bit it's only supported when CONFIG_NR_CPUS <= 4096 as supporting it for 8192 CPUs would require to set up yet another fixmap PGT. If CONFIG_KMAP_LOCAL_FORCE_DEBUG is enabled then kmap_local()/kmap_atomic() will use the temporary fixmap mapping path. Signed-off-by: Thomas Gleixner <t...@linutronix.de> Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> Link: https://lore.kernel.org/r/20201118204007.169209...@linutronix.de --- arch/x86/Kconfig | 1 + arch/x86/include/asm/fixmap.h | 12 +++++++++--- arch/x86/include/asm/pgtable_64_types.h | 6 +++++- 3 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 33c273c..b5137cc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -93,6 +93,7 @@ config X86 select ARCH_SUPPORTS_ACPI select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 + select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP if NR_CPUS <= 4096 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 8eba66a..9f1a0a9 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -14,13 +14,20 @@ #ifndef _ASM_X86_FIXMAP_H #define _ASM_X86_FIXMAP_H +#include <asm/kmap_size.h> + /* * Exposed to assembly code for setting up initial page tables. Cannot be * calculated in assembly code (fixmap entries are an enum), but is sanity * checked in the actual fixmap C code to make sure that the fixmap is * covered fully. */ -#define FIXMAP_PMD_NUM 2 +#ifndef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP +# define FIXMAP_PMD_NUM 2 +#else +# define KM_PMDS (KM_MAX_IDX * ((CONFIG_NR_CPUS + 511) / 512)) +# define FIXMAP_PMD_NUM (KM_PMDS + 2) +#endif /* fixmap starts downwards from the 507th entry in level2_fixmap_pgt */ #define FIXMAP_PMD_TOP 507 @@ -31,7 +38,6 @@ #include <asm/pgtable_types.h> #ifdef CONFIG_X86_32 #include <linux/threads.h> -#include <asm/kmap_size.h> #else #include <uapi/asm/vsyscall.h> #endif @@ -92,7 +98,7 @@ enum fixed_addresses { FIX_IO_APIC_BASE_0, FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1, #endif -#ifdef CONFIG_X86_32 +#ifdef CONFIG_KMAP_LOCAL FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, #ifdef CONFIG_PCI_MMCONFIG diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 52e5f5f..91ac106 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -143,7 +143,11 @@ extern unsigned int ptrs_per_p4d; #define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE) /* The module sections ends with the start of the fixmap */ -#define MODULES_END _AC(0xffffffffff000000, UL) +#ifndef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP +# define MODULES_END _AC(0xffffffffff000000, UL) +#else +# define MODULES_END _AC(0xfffffffffe000000, UL) +#endif #define MODULES_LEN (MODULES_END - MODULES_VADDR) #define ESPFIX_PGD_ENTRY _AC(-2, UL)
