summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/head64.c
diff options
context:
space:
mode:
authorFeng Tang <feng.tang@intel.com>2018-09-20 05:58:28 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-09-21 00:17:22 +0300
commit05ab1d8a4b36ee912b7087c6da127439ed0a903e (patch)
tree8efaac1479f992936ada15c1de0038af7d6289b3 /arch/x86/kernel/head64.c
parent9068a427ee0beb1365a0925e8c33f338f09f5e97 (diff)
downloadlinux-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/kernel/head64.c')
-rw-r--r--arch/x86/kernel/head64.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index c16af27eb23f..ddee1f0870c4 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -35,6 +35,7 @@
#include <asm/bootparam_utils.h>
#include <asm/microcode.h>
#include <asm/kasan.h>
+#include <asm/fixmap.h>
/*
* Manage page tables very early on.
@@ -166,7 +167,8 @@ unsigned long __head __startup_64(unsigned long physaddr,
pud[511] += load_delta;
pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
- pmd[506] += load_delta;
+ for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
+ pmd[i] += load_delta;
/*
* Set up the identity mapping for the switchover. These