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| author | Feng Tang <feng.tang@intel.com> | 2018-09-20 10:58:28 +0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-20 23:17:22 +0200 |
| commit | 05ab1d8a4b36ee912b7087c6da127439ed0a903e (patch) | |
| tree | 8efaac1479f992936ada15c1de0038af7d6289b3 /arch/x86/include/asm/fixmap.h | |
| parent | 9068a427ee0beb1365a0925e8c33f338f09f5e97 (diff) | |
| download | linux-0-day-05ab1d8a4b36ee912b7087c6da127439ed0a903e.tar.gz linux-0-day-05ab1d8a4b36ee912b7087c6da127439ed0a903e.tar.xz | |
x86/mm: Expand static page table for fixmap space
We met a kernel panic when enabling earlycon, which is due to the fixmap
address of earlycon is not statically setup.
Currently the static fixmap setup in head_64.S only covers 2M virtual
address space, while it actually could be in 4M space with different
kernel configurations, e.g. when VSYSCALL emulation is disabled.
So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2,
and add a build time check to ensure that the fixmap is covered by the
initial static page tables.
Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com> (Xen parts)
Cc: H Peter Anvin <hpa@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com
Diffstat (limited to 'arch/x86/include/asm/fixmap.h')
| -rw-r--r-- | arch/x86/include/asm/fixmap.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index e203169931c72..6390bd8c141b4 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -14,6 +14,16 @@ #ifndef _ASM_X86_FIXMAP_H #define _ASM_X86_FIXMAP_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 +/* fixmap starts downwards from the 507th entry in level2_fixmap_pgt */ +#define FIXMAP_PMD_TOP 507 + #ifndef __ASSEMBLY__ #include <linux/kernel.h> #include <asm/acpi.h> |