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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-03-01 22:05:54 +0300
committerIngo Molnar <mingo@kernel.org>2017-03-02 10:11:19 +0300
commitd1eb98143c56f24fef125f5bbed49ae0b52fb7d6 (patch)
treea16cf1a9365bb65fd68d7e7f40903fb368d2005e /drivers/firmware
parent52e51f16407b7b34e26affb500a21e250d9fce0b (diff)
downloadlinux-d1eb98143c56f24fef125f5bbed49ae0b52fb7d6.tar.xz
efi/arm: Fix boot crash with CONFIG_CPUMASK_OFFSTACK=y
On ARM and arm64, we use a dedicated mm_struct to map the UEFI Runtime Services regions, which allows us to map those regions on demand, and in a way that is guaranteed to be compatible with incoming kernels across kexec. As it turns out, we don't fully initialize the mm_struct in the same way as process mm_structs are initialized on fork(), which results in the following crash on ARM if CONFIG_CPUMASK_OFFSTACK=y is enabled: ... EFI Variables Facility v0.08 2004-May-17 Unable to handle kernel NULL pointer dereference at virtual address 00000000 [...] Process swapper/0 (pid: 1) ... __memzero() check_and_switch_context() virt_efi_get_next_variable() efivar_init() efivars_sysfs_init() do_one_initcall() ... This is due to a missing call to mm_init_cpumask(), so add it. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: <stable@vger.kernel.org> # v4.5+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1488395154-29786-1-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/arm-runtime.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 349dc3e1e52e..974c5a31a005 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -65,6 +65,7 @@ static bool __init efi_virtmap_init(void)
bool systab_found;
efi_mm.pgd = pgd_alloc(&efi_mm);
+ mm_init_cpumask(&efi_mm);
init_new_context(NULL, &efi_mm);
systab_found = false;