This is a note to let you know that I've just added the patch titled
x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-cpu_entry_area-sync-cpu_entry_area-to-initial_page_table.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 945fd17ab6bab8a4d05da6c3170519fbcfe62ddb Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Wed, 28 Feb 2018 21:14:26 +0100
Subject: x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit 945fd17ab6bab8a4d05da6c3170519fbcfe62ddb upstream.
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@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Woody Suwalski <terraluna977@xxxxxxxxx>
Cc: William Grant <william.grant@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1802282137290.1392@xxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable_32.h | 1 +
arch/x86/include/asm/pgtable_64.h | 1 +
arch/x86/kernel/setup.c | 17 +++++------------
arch/x86/kernel/setup_percpu.c | 17 ++++-------------
arch/x86/mm/cpu_entry_area.c | 6 ++++++
arch/x86/mm/init_32.c | 15 +++++++++++++++
6 files changed, 32 insertions(+), 25 deletions(-)
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -32,6 +32,7 @@ extern pmd_t initial_pg_pmd[];
static inline void pgtable_cache_init(void) { }
static inline void check_pgt_cache(void) { }
void paging_init(void);
+void sync_initial_page_table(void);
/*
* Define this if things work differently on an i386 and an i486:
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -28,6 +28,7 @@ extern pgd_t init_top_pgt[];
#define swapper_pg_dir init_top_pgt
extern void paging_init(void);
+static inline void sync_initial_page_table(void) { }
#define pte_ERROR(e) \
pr_err("%s:%d: bad pte %p(%016lx)\n", \
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1205,20 +1205,13 @@ void __init setup_arch(char **cmdline_p)
kasan_init();
-#ifdef CONFIG_X86_32
- /* sync back kernel address range */
- clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
- swapper_pg_dir + KERNEL_PGD_BOUNDARY,
- KERNEL_PGD_PTRS);
-
/*
- * sync back low identity map too. It is used for example
- * in the 32-bit EFI stub.
+ * Sync back kernel address range.
+ *
+ * FIXME: Can the later sync in setup_cpu_entry_areas() replace
+ * this call?
*/
- clone_pgd_range(initial_page_table,
- swapper_pg_dir + KERNEL_PGD_BOUNDARY,
- min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
-#endif
+ sync_initial_page_table();
tboot_probe();
--- 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 */
setup_cpu_local_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,
- KERNEL_PGD_PTRS);
-
- /*
- * 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,
- min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
-#endif
+ sync_initial_page_table();
}
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -163,4 +163,10 @@ void __init setup_cpu_entry_areas(void)
for_each_possible_cpu(cpu)
setup_cpu_entry_area(cpu);
+
+ /*
+ * This is the last essential update to swapper_pgdir which needs
+ * to be synchronized to initial_page_table on 32bit.
+ */
+ sync_initial_page_table();
}
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -453,6 +453,21 @@ static inline void permanent_kmaps_init(
}
#endif /* CONFIG_HIGHMEM */
+void __init sync_initial_page_table(void)
+{
+ clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
+ swapper_pg_dir + KERNEL_PGD_BOUNDARY,
+ KERNEL_PGD_PTRS);
+
+ /*
+ * 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,
+ min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
+}
+
void __init native_pagetable_init(void)
{
unsigned long pfn, va;
Patches currently in stable-queue which might be from tglx@xxxxxxxxxxxxx are
queue-4.15/x86-xen-zero-msr_ia32_spec_ctrl-before-suspend.patch
queue-4.15/x86-cpu_entry_area-sync-cpu_entry_area-to-initial_page_table.patch
queue-4.15/x86-platform-intel-mid-handle-intel-edison-reboot-correctly.patch
queue-4.15/timers-forward-timer-base-before-migrating-timers.patch
queue-4.15/hrtimer-ensure-posix-compliance-relative-clock_realtime-hrtimers.patch