[PATCH v12 1/3] riscv: mm: modify pte format for Svnapot
Qinglin Pan
panqinglin2020 at iscas.ac.cn
Wed Feb 8 19:13:35 PST 2023
Add one alternative to enable/disable svnapot support, enable this static
key when "svnapot" is in the "riscv,isa" field of fdt and SVNAPOT compile
option is set. It will influence the behavior of has_svnapot. All code
dependent on svnapot should make sure that has_svnapot return true firstly.
Modify PTE definition for Svnapot, and creates some functions in pgtable.h
to mark a PTE as napot and check if it is a Svnapot PTE. Until now, only
64KB napot size is supported in spec, so some macros has only 64KB version.
Signed-off-by: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7c814fbf9527..5b051ca93fa7 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -397,6 +397,25 @@ config RISCV_ISA_C
If you don't know what to do here, say Y.
+config RISCV_ISA_SVNAPOT
+ bool "SVNAPOT extension support"
+ depends on 64BIT && MMU
+ select RISCV_ALTERNATIVE
+ default y
+ help
+ Allow kernel to detect the SVNAPOT ISA-extension dynamically at boot
+ time and enable its usage.
+
+ The SVNAPOT extension is used to mark contiguous PTEs as a range
+ of contiguous virtual-to-physical translations for a naturally
+ aligned power-of-2 (NAPOT) granularity larger than the base 4KB page
+ size. When HUGETLBFS is also selected this option unconditionally
+ allocates some memory for each NAPOT page size supported by the kernel.
+ When optimizing for low memory consumption and for platforms without
+ the SVNAPOT extension, it may be better to say N here.
+
+ If you don't know what to do here, say Y.
+
config RISCV_ISA_SVPBMT
bool "SVPBMT extension support"
depends on 64BIT && MMU
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index ee9c80fe0062..6e368d3f6631 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -43,10 +43,11 @@
#define RISCV_ISA_EXT_SSCOFPMF 26
#define RISCV_ISA_EXT_SSTC 27
#define RISCV_ISA_EXT_SVINVAL 28
-#define RISCV_ISA_EXT_SVPBMT 29
-#define RISCV_ISA_EXT_ZBB 30
-#define RISCV_ISA_EXT_ZICBOM 31
-#define RISCV_ISA_EXT_ZIHINTPAUSE 32
+#define RISCV_ISA_EXT_SVNAPOT 29
+#define RISCV_ISA_EXT_SVPBMT 30
+#define RISCV_ISA_EXT_ZBB 31
+#define RISCV_ISA_EXT_ZICBOM 32
+#define RISCV_ISA_EXT_ZIHINTPAUSE 33
#ifndef __ASSEMBLY__
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 9f432c1b5289..24a3dd265183 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -16,11 +16,6 @@
#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE - 1))
-#ifdef CONFIG_64BIT
-#define HUGE_MAX_HSTATE 2
-#else
-#define HUGE_MAX_HSTATE 1
-#endif
#define HPAGE_SHIFT PMD_SHIFT
#define HPAGE_SIZE (_AC(1, UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
diff --git a/arch/riscv/include/asm/pgtable-64.h
b/arch/riscv/include/asm/pgtable-64.h
index 42a042c0e13e..7a5097202e15 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -78,6 +78,40 @@ typedef struct {
*/
#define _PAGE_PFN_MASK GENMASK(53, 10)
+/*
+ * [63] Svnapot definitions:
+ * 0 Svnapot disabled
+ * 1 Svnapot enabled
+ */
+#define _PAGE_NAPOT_SHIFT 63
+#define _PAGE_NAPOT BIT(_PAGE_NAPOT_SHIFT)
+/*
+ * Only 64KB (order 4) napot ptes supported.
+ */
+#define NAPOT_CONT_ORDER_BASE 4
+enum napot_cont_order {
+ NAPOT_CONT64KB_ORDER = NAPOT_CONT_ORDER_BASE,
+ NAPOT_ORDER_MAX,
+};
+
+#define for_each_napot_order(order) \
+ for (order = NAPOT_CONT_ORDER_BASE; order < NAPOT_ORDER_MAX; order++)
+#define for_each_napot_order_rev(order) \
+ for (order = NAPOT_ORDER_MAX - 1; \
+ order >= NAPOT_CONT_ORDER_BASE; order--)
+#define napot_cont_order(val) (__builtin_ctzl((val.pte >>
_PAGE_PFN_SHIFT) << 1))
+
+#define napot_cont_shift(order) ((order) + PAGE_SHIFT)
+#define napot_cont_size(order) BIT(napot_cont_shift(order))
+#define napot_cont_mask(order) (~(napot_cont_size(order) - 1UL))
+#define napot_pte_num(order) BIT(order)
+
+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+#define HUGE_MAX_HSTATE (2 + (NAPOT_ORDER_MAX - NAPOT_CONT_ORDER_BASE))
+#else
+#define HUGE_MAX_HSTATE 2
+#endif
+
/*
* [62:61] Svpbmt Memory Type definitions:
*
diff --git a/arch/riscv/include/asm/pgtable.h
b/arch/riscv/include/asm/pgtable.h
index 2a88362dffa5..76502bc7bef2 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -264,10 +264,47 @@ static inline pte_t pud_pte(pud_t pud)
return __pte(pud_val(pud));
}
+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+
+static __always_inline bool has_svnapot(void)
+{
+ return riscv_has_extension_likely(RISCV_ISA_EXT_SVNAPOT);
+}
+
+static inline unsigned long pte_napot(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_NAPOT;
+}
+
+static inline pte_t pte_mknapot(pte_t pte, unsigned int order)
+{
+ int pos = order - 1 + _PAGE_PFN_SHIFT;
+ unsigned long napot_bit = BIT(pos);
+ unsigned long napot_mask = ~GENMASK(pos, _PAGE_PFN_SHIFT);
+
+ return __pte((pte_val(pte) & napot_mask) | napot_bit | _PAGE_NAPOT);
+}
+
+#else
+
+static __always_inline bool has_svnapot(void) { return false; }
+
+static inline unsigned long pte_napot(pte_t pte)
+{
+ return 0;
+}
+
+#endif /* CONFIG_RISCV_ISA_SVNAPOT */
+
/* Yields the page frame number (PFN) of a page table entry */
static inline unsigned long pte_pfn(pte_t pte)
{
- return __page_val_to_pfn(pte_val(pte));
+ unsigned long res = __page_val_to_pfn(pte_val(pte));
+
+ if (has_svnapot() && pte_napot(pte))
+ res = res & (res - 1UL);
+
+ return res;
}
#define pte_page(x) pfn_to_page(pte_pfn(x))
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 420228e219f7..5670909619c8 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -191,6 +191,7 @@ static struct riscv_isa_ext_data isa_ext_arr[] = {
__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
+ __RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
};
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 21fb567e1b22..271e391d436d 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -223,6 +223,7 @@ void __init riscv_fill_hwcap(void)
SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);
SET_ISA_EXT_MAP("sstc", RISCV_ISA_EXT_SSTC);
SET_ISA_EXT_MAP("svinval", RISCV_ISA_EXT_SVINVAL);
+ SET_ISA_EXT_MAP("svnapot", RISCV_ISA_EXT_SVNAPOT);
SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);
SET_ISA_EXT_MAP("zbb", RISCV_ISA_EXT_ZBB);
SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);
--
2.39.1
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