[PATCH v2 04/17] arm64: Add level-hinted TLB invalidation helper

Marc Zyngier
2020-06-15T13:27:46Z

Add a level-hinted TLB invalidation helper that only gets used if
ARMv8.4-TTL gets detected.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/include/asm/stage2_pgtable.h | 9 +++++
arch/arm64/include/asm/tlbflush.h | 45 +++++++++++++++++++++++++
2 files changed, 54 insertions(+)

diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h
index b767904f28b1..996bf98f0cab 100644
--- a/arch/arm64/include/asm/stage2_pgtable.h
+++ b/arch/arm64/include/asm/stage2_pgtable.h
@@ -256,4 +256,13 @@ stage2_pgd_addr_end(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
return (boundary - 1 < end - 1) ? boundary : end;
}

+/*
+ * Level values for the ARMv8.4-TTL extension, mapping PUD/PMD/PTE and
+ * the architectural page-table level.
+ */
+#define S2_NO_LEVEL_HINT 0
+#define S2_PUD_LEVEL 1
+#define S2_PMD_LEVEL 2
+#define S2_PTE_LEVEL 3
+
#endif /* __ARM64_S2_PGTABLE_H_ */
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index bc3949064725..e05c31fd0bbc 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -10,6 +10,7 @@

#ifndef __ASSEMBLY__

+#include <linux/bitfield.h>
#include <linux/mm_types.h>
#include <linux/sched.h>
#include <asm/cputype.h>
@@ -59,6 +60,50 @@
__ta; \
})

+/*
+ * Level-based TLBI operations.
+ *
+ * When ARMv8.4-TTL exists, TLBI operations take an additional hint for
+ * the level at which the invalidation must take place. If the level is
+ * wrong, no invalidation may take place. In the case where the level
+ * cannot be easily determined, a 0 value for the level parameter will
+ * perform a non-hinted invalidation.
+ *
+ * For Stage-2 invalidation, use the level values provided to that effect
+ * in asm/stage2_pgtable.h.
+ */
+#define TLBI_TTL_MASK GENMASK_ULL(47, 44)
+#define TLBI_TTL_PS_4K 1
+#define TLBI_TTL_PS_16K 2
+#define TLBI_TTL_PS_64K 3
+
+#define __tlbi_level(op, addr, level) \
+ do { \
+ u64 arg = addr; \
+ \
+ if (cpus_have_const_cap(ARM64_HAS_ARMv8_4_TTL) && \
+ level) { \
+ u64 ttl = level & 3; \
+ \
+ switch (PAGE_SIZE) { \
+ case SZ_4K: \
+ ttl |= TLBI_TTL_PS_4K << 2; \
+ break; \
+ case SZ_16K: \
+ ttl |= TLBI_TTL_PS_16K << 2; \
+ break; \
+ case SZ_64K: \
+ ttl |= TLBI_TTL_PS_64K << 2; \
+ break; \
+ } \
+ \
+ arg &= ~TLBI_TTL_MASK; \
+ arg |= FIELD_PREP(TLBI_TTL_MASK, ttl); \
+ } \
+ \
+ __tlbi(op, arg); \
+ } while(0)
+
/*
* TLB Invalidation
* ================
--
2.27.0