diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2019-02-14 09:49:28 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-20 10:18:27 +0100 |
| commit | ab6c39771d579350bcd9c46514831b05430bd51a (patch) | |
| tree | aa13fe5089a5d051f9840e8c93799e1d333a4566 /arch/arm/kernel/setup.c | |
| parent | 2dbc7e3efe2ca2e9eb614c66ea725c2116103b56 (diff) | |
ARM: spectre-v2: per-CPU vtables to work around big.Little systems
Commit 383fb3ee8024d596f488d2dbaf45e572897acbdb upstream.
In big.Little systems, some CPUs require the Spectre workarounds in
paths such as the context switch, but other CPUs do not. In order
to handle these differences, we need per-CPU vtables.
We are unable to use the kernel's per-CPU variables to support this
as per-CPU is not initialised at times when we need access to the
vtables, so we have to use an array indexed by logical CPU number.
We use an array-of-pointers to avoid having function pointers in
the kernel's read/write .data section.
Note: Added include of linux/slab.h in arch/arm/smp.c.
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/arm/kernel/setup.c')
| -rw-r--r-- | arch/arm/kernel/setup.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 2eebb67fa08b..4764742db7b0 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -115,6 +115,11 @@ EXPORT_SYMBOL(elf_hwcap2); #ifdef MULTI_CPU struct processor processor __ro_after_init; +#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR) +struct processor *cpu_vtable[NR_CPUS] = { + [0] = &processor, +}; +#endif #endif #ifdef MULTI_TLB struct cpu_tlb_fns cpu_tlb __ro_after_init; |