path: root/arch/x86/kernel/setup_percpu.c
diff options
authorThomas Gleixner <tglx@linutronix.de>2018-02-28 21:14:26 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-03-01 09:48:27 +0100
commit945fd17ab6bab8a4d05da6c3170519fbcfe62ddb (patch)
tree174377d2e0f5a1832931045e5e06b8345d610438 /arch/x86/kernel/setup_percpu.c
parent1402fd8ed7e5bda1b3e7613b70780b0db392d1e6 (diff)
x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table
The separation of the cpu_entry_area from the fixmap missed the fact that on 32bit non-PAE kernels the cpu_entry_area mapping might not be covered in initial_page_table by the previous synchronizations. This results in suspend/resume failures because 32bit utilizes initial page table for resume. The absence of the cpu_entry_area mapping results in a triple fault, aka. insta reboot. With PAE enabled this works by chance because the PGD entry which covers the fixmap and other parts incindentally provides the cpu_entry_area mapping as well. Synchronize the initial page table after setting up the cpu entry area. Instead of adding yet another copy of the same code, move it to a function and invoke it from the various places. It needs to be investigated if the existing calls in setup_arch() and setup_per_cpu_areas() can be replaced by the later invocation from setup_cpu_entry_areas(), but that's beyond the scope of this fix. Fixes: 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap") Reported-by: Woody Suwalski <terraluna977@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Woody Suwalski <terraluna977@gmail.com> Cc: William Grant <william.grant@canonical.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1802282137290.1392@nanos.tec.linutronix.de
Diffstat (limited to 'arch/x86/kernel/setup_percpu.c')
1 files changed, 4 insertions, 13 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 497aa766fab3..ea554f812ee1 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -287,24 +287,15 @@ void __init setup_per_cpu_areas(void)
/* Setup cpu initialized, callin, callout masks */
-#ifdef CONFIG_X86_32
* Sync back kernel address range again. We already did this in
* setup_arch(), but percpu data also needs to be available in
* the smpboot asm. We can't reliably pick up percpu mappings
* using vmalloc_fault(), because exception dispatch needs
* percpu data.
+ *
+ * FIXME: Can the later sync in setup_cpu_entry_areas() replace
+ * this call?
- clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
- swapper_pg_dir + KERNEL_PGD_BOUNDARY,
- /*
- * sync back low identity map too. It is used for example
- * in the 32-bit EFI stub.
- */
- clone_pgd_range(initial_page_table,
- swapper_pg_dir + KERNEL_PGD_BOUNDARY,
+ sync_initial_page_table();