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| author | Catalin Marinas <catalin.marinas@arm.com> | 2015-06-12 11:24:41 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-07-30 14:10:48 +0200 |
| commit | 4dd03eff07b66352a307bb3eeb7d3973ec34ecbe (patch) | |
| tree | 613f81109b9097ae670c6c349ae01cfe5765b5e8 | |
| parent | d308de3b8d7ecb33a7b7731b32182e419707a250 (diff) | |
| download | lwn-4dd03eff07b66352a307bb3eeb7d3973ec34ecbe.tar.gz lwn-4dd03eff07b66352a307bb3eeb7d3973ec34ecbe.zip | |
arm64: Do not attempt to use init_mm in reset_context()
commit 565630d503ef24e44c252bed55571b3a0d68455f upstream.
After secondary CPU boot or hotplug, the active_mm of the idle thread is
&init_mm. The init_mm.pgd (swapper_pg_dir) is only meant for TTBR1_EL1
and must not be set in TTBR0_EL1. Since when active_mm == &init_mm the
TTBR0_EL1 is already set to the reserved value, there is no need to
perform any context reset.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | arch/arm64/mm/context.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index baa758d37021..76c1e6cd36fc 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -92,6 +92,14 @@ static void reset_context(void *info) unsigned int cpu = smp_processor_id(); struct mm_struct *mm = current->active_mm; + /* + * current->active_mm could be init_mm for the idle thread immediately + * after secondary CPU boot or hotplug. TTBR0_EL1 is already set to + * the reserved value, so no need to reset any context. + */ + if (mm == &init_mm) + return; + smp_rmb(); asid = cpu_last_asid + cpu; |