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Date: Mon, 1 Jun 2020 22:47:13 +0800
From: Zhenyu Ye <yezhenyu2@...wei.com>
To: <catalin.marinas@....com>, <will@...nel.org>,
<suzuki.poulose@....com>, <maz@...nel.org>, <steven.price@....com>,
<guohanjun@...wei.com>, <olof@...om.net>
CC: <yezhenyu2@...wei.com>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-arch@...r.kernel.org>,
<linux-mm@...ck.org>, <arm@...nel.org>, <xiexiangyou@...wei.com>,
<prime.zeng@...ilicon.com>, <zhangshaokun@...ilicon.com>,
<kuhn.chenqun@...wei.com>
Subject: [RFC PATCH v4 2/2] arm64: tlb: Use the TLBI RANGE feature in arm64
Add __TLBI_VADDR_RANGE macro and rewrite __flush_tlb_range().
In this patch, we only use the TLBI RANGE feature if the stride == PAGE_SIZE,
because when stride > PAGE_SIZE, usually only a small number of pages need
to be flushed and classic tlbi intructions are more effective.
We can also use 'end - start < threshold number' to decide which way
to go, however, different hardware may have different thresholds, so
I'm not sure if this is feasible.
Signed-off-by: Zhenyu Ye <yezhenyu2@...wei.com>
---
arch/arm64/include/asm/tlbflush.h | 98 +++++++++++++++++++++++++++----
1 file changed, 86 insertions(+), 12 deletions(-)
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index bc3949064725..818f27c82024 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -50,6 +50,16 @@
__tlbi(op, (arg) | USER_ASID_FLAG); \
} while (0)
+#define __tlbi_last_level(op1, op2, arg, last_level) do { \
+ if (last_level) { \
+ __tlbi(op1, arg); \
+ __tlbi_user(op1, arg); \
+ } else { \
+ __tlbi(op2, arg); \
+ __tlbi_user(op2, arg); \
+ } \
+} while (0)
+
/* This macro creates a properly formatted VA operand for the TLBI */
#define __TLBI_VADDR(addr, asid) \
({ \
@@ -59,6 +69,47 @@
__ta; \
})
+/*
+ * __TG defines translation granule of the system, which is decided by
+ * PAGE_SHIFT. Used by TTL.
+ * - 4KB : 1
+ * - 16KB : 2
+ * - 64KB : 3
+ */
+#define __TG ((PAGE_SHIFT - 12) / 2 + 1)
+
+/*
+ * This macro creates a properly formatted VA operand for the TLBI RANGE.
+ * The value bit assignments are:
+ *
+ * +----------+------+-------+-------+-------+----------------------+
+ * | ASID | TG | SCALE | NUM | TTL | BADDR |
+ * +-----------------+-------+-------+-------+----------------------+
+ * |63 48|47 46|45 44|43 39|38 37|36 0|
+ *
+ * The address range is determined by below formula:
+ * [BADDR, BADDR + (NUM + 1) * 2^(5*SCALE + 1) * PAGESIZE)
+ *
+ */
+#define __TLBI_VADDR_RANGE(addr, asid, scale, num, ttl) \
+ ({ \
+ unsigned long __ta = (addr) >> PAGE_SHIFT; \
+ __ta &= GENMASK_ULL(36, 0); \
+ __ta |= (unsigned long)(ttl) << 37; \
+ __ta |= (unsigned long)(num) << 39; \
+ __ta |= (unsigned long)(scale) << 44; \
+ __ta |= (unsigned long)(__TG) << 46; \
+ __ta |= (unsigned long)(asid) << 48; \
+ __ta; \
+ })
+
+/* This macro defines the range pages of the TLBI RANGE. */
+#define __TLBI_RANGE_SIZES(num, scale) ((num + 1) << (5 * scale + 1) << PAGE_SHIFT)
+
+#define TLB_RANGE_MASK_SHIFT 5
+#define TLB_RANGE_MASK GENMASK_ULL(TLB_RANGE_MASK_SHIFT - 1, 0)
+
+
/*
* TLB Invalidation
* ================
@@ -181,32 +232,55 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
unsigned long stride, bool last_level)
{
+ int num = 0;
+ int scale = 0;
unsigned long asid = ASID(vma->vm_mm);
unsigned long addr;
+ unsigned long range_pages;
start = round_down(start, stride);
end = round_up(end, stride);
+ range_pages = (end - start) >> PAGE_SHIFT;
if ((end - start) >= (MAX_TLBI_OPS * stride)) {
flush_tlb_mm(vma->vm_mm);
return;
}
- /* Convert the stride into units of 4k */
- stride >>= 12;
+ dsb(ishst);
- start = __TLBI_VADDR(start, asid);
- end = __TLBI_VADDR(end, asid);
+ /*
+ * The minimum size of TLB RANGE is 2 pages;
+ * Use normal TLB instruction to handle odd pages.
+ * If the stride != PAGE_SIZE, this will never happen.
+ */
+ if (range_pages % 2 == 1) {
+ addr = __TLBI_VADDR(start, asid);
+ __tlbi_last_level(vale1is, vae1is, addr, last_level);
+ start += 1 << PAGE_SHIFT;
+ range_pages >>= 1;
+ }
- dsb(ishst);
- for (addr = start; addr < end; addr += stride) {
- if (last_level) {
- __tlbi(vale1is, addr);
- __tlbi_user(vale1is, addr);
- } else {
- __tlbi(vae1is, addr);
- __tlbi_user(vae1is, addr);
+ while (range_pages > 0) {
+ if (cpus_have_const_cap(ARM64_HAS_TLBI_RANGE) &&
+ stride == PAGE_SIZE) {
+ num = (range_pages & TLB_RANGE_MASK) - 1;
+ if (num >= 0) {
+ addr = __TLBI_VADDR_RANGE(start, asid, scale,
+ num, 0);
+ __tlbi_last_level(rvale1is, rvae1is, addr,
+ last_level);
+ start += __TLBI_RANGE_SIZES(num, scale);
+ }
+ scale++;
+ range_pages >>= TLB_RANGE_MASK_SHIFT;
+ continue;
}
+
+ addr = __TLBI_VADDR(start, asid);
+ __tlbi_last_level(vale1is, vae1is, addr, last_level);
+ start += stride;
+ range_pages -= stride >> 12;
}
dsb(ish);
}
--
2.19.1
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