[PATCH 3/3] riscv: convert pgtable_l4_enabled to static key
Jisheng Zhang
jszhang at kernel.org
Tue Jan 25 08:50:36 PST 2022
On a specific HW platform, pgtable_l4_enabled won't change after
boot, and the check sits at hot code path, this characteristic make it
suitable for optimization with static key.
Signed-off-by: Jisheng Zhang <jszhang at kernel.org>
---
arch/riscv/include/asm/cpufeature.h | 6 ++++++
arch/riscv/include/asm/pgalloc.h | 8 ++++----
arch/riscv/include/asm/pgtable-64.h | 21 ++++++++++-----------
arch/riscv/include/asm/pgtable.h | 3 +--
arch/riscv/kernel/cpu.c | 2 +-
arch/riscv/mm/init.c | 23 ++++++++++-------------
arch/riscv/mm/kasan_init.c | 6 +++---
arch/riscv/tools/cpucaps | 1 +
8 files changed, 36 insertions(+), 34 deletions(-)
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 634a653c7fa2..10af83d6fb2a 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -96,4 +96,10 @@ static inline bool system_supports_fpu(void)
return IS_ENABLED(CONFIG_FPU) && !cpus_have_final_cap(RISCV_HAS_NO_FPU);
}
+static inline bool system_supports_sv48(void)
+{
+ return IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_XIP_KERNEL) &&
+ !cpus_have_const_cap(RISCV_HAS_NO_SV48);
+}
+
#endif
diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index 11823004b87a..cd37f3777ff1 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -41,7 +41,7 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud)
{
- if (pgtable_l4_enabled) {
+ if (system_supports_sv48()) {
unsigned long pfn = virt_to_pfn(pud);
set_p4d(p4d, __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
@@ -51,7 +51,7 @@ static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud)
static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d,
pud_t *pud)
{
- if (pgtable_l4_enabled) {
+ if (system_supports_sv48()) {
unsigned long pfn = virt_to_pfn(pud);
set_p4d_safe(p4d,
@@ -62,7 +62,7 @@ static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d,
#define pud_alloc_one pud_alloc_one
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return __pud_alloc_one(mm, addr);
return NULL;
@@ -71,7 +71,7 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
#define pud_free pud_free
static inline void pud_free(struct mm_struct *mm, pud_t *pud)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
__pud_free(mm, pud);
}
diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index bbbdd66e5e2f..5ad4311f9c6e 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -7,14 +7,13 @@
#define _ASM_RISCV_PGTABLE_64_H
#include <linux/const.h>
-
-extern bool pgtable_l4_enabled;
+#include <asm/cpufeature.h>
#define PGDIR_SHIFT_L3 30
#define PGDIR_SHIFT_L4 39
#define PGDIR_SIZE_L3 (_AC(1, UL) << PGDIR_SHIFT_L3)
-#define PGDIR_SHIFT (pgtable_l4_enabled ? PGDIR_SHIFT_L4 : PGDIR_SHIFT_L3)
+#define PGDIR_SHIFT (system_supports_sv48() ? PGDIR_SHIFT_L4 : PGDIR_SHIFT_L3)
/* Size of region mapped by a page global directory */
#define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE - 1))
@@ -102,7 +101,7 @@ static inline struct page *pud_page(pud_t pud)
#define mm_pud_folded mm_pud_folded
static inline bool mm_pud_folded(struct mm_struct *mm)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return false;
return true;
@@ -130,7 +129,7 @@ static inline unsigned long _pmd_pfn(pmd_t pmd)
static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
*p4dp = p4d;
else
set_pud((pud_t *)p4dp, (pud_t){ p4d_val(p4d) });
@@ -138,7 +137,7 @@ static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
static inline int p4d_none(p4d_t p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return (p4d_val(p4d) == 0);
return 0;
@@ -146,7 +145,7 @@ static inline int p4d_none(p4d_t p4d)
static inline int p4d_present(p4d_t p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return (p4d_val(p4d) & _PAGE_PRESENT);
return 1;
@@ -154,7 +153,7 @@ static inline int p4d_present(p4d_t p4d)
static inline int p4d_bad(p4d_t p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return !p4d_present(p4d);
return 0;
@@ -162,13 +161,13 @@ static inline int p4d_bad(p4d_t p4d)
static inline void p4d_clear(p4d_t *p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
set_p4d(p4d, __p4d(0));
}
static inline pud_t *p4d_pgtable(p4d_t p4d)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return (pud_t *)pfn_to_virt(p4d_val(p4d) >> _PAGE_PFN_SHIFT);
return (pud_t *)pud_pgtable((pud_t) { p4d_val(p4d) });
@@ -184,7 +183,7 @@ static inline struct page *p4d_page(p4d_t p4d)
#define pud_offset pud_offset
static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
{
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
return p4d_pgtable(*p4d) + pud_index(address);
return (pud_t *)p4d;
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 7e949f25c933..40d999950e5b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -62,7 +62,7 @@
* position vmemmap directly below the VMALLOC region.
*/
#ifdef CONFIG_64BIT
-#define VA_BITS (pgtable_l4_enabled ? 48 : 39)
+#define VA_BITS (system_supports_sv48() ? 48 : 39)
#else
#define VA_BITS 32
#endif
@@ -735,7 +735,6 @@ extern uintptr_t _dtb_early_pa;
#define dtb_early_pa _dtb_early_pa
#endif /* CONFIG_XIP_KERNEL */
extern u64 satp_mode;
-extern bool pgtable_l4_enabled;
void paging_init(void);
void misc_mem_init(void);
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index ad0a7e9f828b..ce38319232ec 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -79,7 +79,7 @@ static void print_mmu(struct seq_file *f)
#if defined(CONFIG_32BIT)
strncpy(sv_type, "sv32", 5);
#elif defined(CONFIG_64BIT)
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
strncpy(sv_type, "sv48", 5);
else
strncpy(sv_type, "sv39", 5);
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 35586688a1b6..8a84606f99f0 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -44,9 +44,6 @@ u64 satp_mode __ro_after_init = SATP_MODE_32;
#endif
EXPORT_SYMBOL(satp_mode);
-bool pgtable_l4_enabled = IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_XIP_KERNEL);
-EXPORT_SYMBOL(pgtable_l4_enabled);
-
phys_addr_t phys_ram_base __ro_after_init;
EXPORT_SYMBOL(phys_ram_base);
@@ -459,19 +456,19 @@ static void __init create_pud_mapping(pud_t *pudp,
}
#define pgd_next_t pud_t
-#define alloc_pgd_next(__va) (pgtable_l4_enabled ? \
+#define alloc_pgd_next(__va) (system_supports_sv48() ? \
pt_ops.alloc_pud(__va) : pt_ops.alloc_pmd(__va))
-#define get_pgd_next_virt(__pa) (pgtable_l4_enabled ? \
+#define get_pgd_next_virt(__pa) (system_supports_sv48() ? \
pt_ops.get_pud_virt(__pa) : (pgd_next_t *)pt_ops.get_pmd_virt(__pa))
#define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot) \
- (pgtable_l4_enabled ? \
+ (system_supports_sv48() ? \
create_pud_mapping(__nextp, __va, __pa, __sz, __prot) : \
create_pmd_mapping((pmd_t *)__nextp, __va, __pa, __sz, __prot))
-#define fixmap_pgd_next (pgtable_l4_enabled ? \
+#define fixmap_pgd_next (system_supports_sv48() ? \
(uintptr_t)fixmap_pud : (uintptr_t)fixmap_pmd)
-#define trampoline_pgd_next (pgtable_l4_enabled ? \
+#define trampoline_pgd_next (system_supports_sv48() ? \
(uintptr_t)trampoline_pud : (uintptr_t)trampoline_pmd)
-#define early_dtb_pgd_next (pgtable_l4_enabled ? \
+#define early_dtb_pgd_next (system_supports_sv48() ? \
(uintptr_t)early_dtb_pud : (uintptr_t)early_dtb_pmd)
#else
#define pgd_next_t pte_t
@@ -575,7 +572,7 @@ static __init pgprot_t pgprot_from_va(uintptr_t va)
#ifdef CONFIG_64BIT
static void __init disable_pgtable_l4(void)
{
- pgtable_l4_enabled = false;
+ cpus_set_cap(RISCV_HAS_NO_SV48);
kernel_map.page_offset = PAGE_OFFSET_L3;
satp_mode = SATP_MODE_39;
}
@@ -691,7 +688,7 @@ static void __init create_fdt_early_page_table(pgd_t *pgdir, uintptr_t dtb_pa)
PGDIR_SIZE,
IS_ENABLED(CONFIG_64BIT) ? PAGE_TABLE : PAGE_KERNEL);
- if (pgtable_l4_enabled) {
+ if (system_supports_sv48()) {
create_pud_mapping(early_dtb_pud, DTB_EARLY_BASE_VA,
(uintptr_t)early_dtb_pmd, PUD_SIZE, PAGE_TABLE);
}
@@ -819,7 +816,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
#ifndef __PAGETABLE_PMD_FOLDED
/* Setup fixmap PUD and PMD */
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
create_pud_mapping(fixmap_pud, FIXADDR_START,
(uintptr_t)fixmap_pmd, PUD_SIZE, PAGE_TABLE);
create_pmd_mapping(fixmap_pmd, FIXADDR_START,
@@ -827,7 +824,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
/* Setup trampoline PGD and PMD */
create_pgd_mapping(trampoline_pg_dir, kernel_map.virt_addr,
trampoline_pgd_next, PGDIR_SIZE, PAGE_TABLE);
- if (pgtable_l4_enabled)
+ if (system_supports_sv48())
create_pud_mapping(trampoline_pud, kernel_map.virt_addr,
(uintptr_t)trampoline_pmd, PUD_SIZE, PAGE_TABLE);
#ifdef CONFIG_XIP_KERNEL
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index f61f7ca6fe0f..3d456c5b55c8 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -149,11 +149,11 @@ static void __init kasan_populate_pud(pgd_t *pgd,
set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
}
-#define kasan_early_shadow_pgd_next (pgtable_l4_enabled ? \
+#define kasan_early_shadow_pgd_next (system_supports_sv48() ? \
(uintptr_t)kasan_early_shadow_pud : \
(uintptr_t)kasan_early_shadow_pmd)
#define kasan_populate_pgd_next(pgdp, vaddr, next, early) \
- (pgtable_l4_enabled ? \
+ (system_supports_sv48() ? \
kasan_populate_pud(pgdp, vaddr, next, early) : \
kasan_populate_pmd((pud_t *)pgdp, vaddr, next))
@@ -211,7 +211,7 @@ asmlinkage void __init kasan_early_init(void)
(__pa((uintptr_t)kasan_early_shadow_pte)),
PAGE_TABLE));
- if (pgtable_l4_enabled) {
+ if (system_supports_sv48()) {
for (i = 0; i < PTRS_PER_PUD; ++i)
set_pud(kasan_early_shadow_pud + i,
pfn_pud(PFN_DOWN
diff --git a/arch/riscv/tools/cpucaps b/arch/riscv/tools/cpucaps
index cb1ff2747859..1aea959f225d 100644
--- a/arch/riscv/tools/cpucaps
+++ b/arch/riscv/tools/cpucaps
@@ -3,3 +3,4 @@
# Internal CPU capabilities constants, keep this list sorted
HAS_NO_FPU
+HAS_NO_SV48
--
2.34.1
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