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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-11-18 22:48:41 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-11-24 16:42:09 +0300 |
| commit | 14df32670291588036a498051a54cd8462d7f611 (patch) | |
| tree | b3285fcdb143e581c262a49f4e021c38ac362ceb /arch/x86/include/asm/fixmap.h | |
| parent | 0e91a0c6984c837a7c6760e3f28e8e1c532abf87 (diff) | |
| download | linux-14df32670291588036a498051a54cd8462d7f611.tar.xz | |
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 <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20201118204007.169209557@linutronix.de
Diffstat (limited to 'arch/x86/include/asm/fixmap.h')
| -rw-r--r-- | arch/x86/include/asm/fixmap.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 8eba66a33e39..9f1a0a987e5e 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 |