From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 95e3de3590e3 upstream.
We will soon need to invoke a CPU-specific function pointer after changing
page tables, so move post_ttbr_update_workaround out into C code to make
this possible.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxx>
---
arch/arm64/mm/context.c | 9 +++++++++
arch/arm64/mm/proc.S | 3 +--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index efcf1f7..32eeabe91 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -224,6 +224,15 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
cpu_switch_mm(mm->pgd, mm);
}
+/* Errata workaround post TTBRx_EL1 update. */
+asmlinkage void post_ttbr_update_workaround(void)
+{
+ asm(ALTERNATIVE("nop; nop; nop",
+ "ic iallu; dsb nsh; isb",
+ ARM64_WORKAROUND_CAVIUM_27456,
+ CONFIG_CAVIUM_ERRATUM_27456));
+}
+
static int asids_init(void)
{
asid_bits = get_cpu_asid_bits();
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index c2adb0c..cca061a 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -136,8 +136,7 @@ ENTRY(cpu_do_switch_mm)
bfi x0, x1, #48, #16 // set the ASID
msr ttbr0_el1, x0 // set TTBR0
isb
- post_ttbr0_update_workaround
- ret
+ b post_ttbr_update_workaround // Back to C code...
ENDPROC(cpu_do_switch_mm)
.pushsection ".idmap.text", "ax"
--
2.7.4