Merge patch series "riscv: mm: Extend mappable memory up to hint address"

Charlie Jenkins <charlie@rivosinc.com> says:

On riscv, mmap currently returns an address from the largest address
space that can fit entirely inside of the hint address. This makes it
such that the hint address is almost never returned. This patch raises
the mappable area up to and including the hint address. This allows mmap
to often return the hint address, which allows a performance improvement
over searching for a valid address as well as making the behavior more
similar to other architectures.

Note that a previous patch introduced stronger semantics compared to
other architectures for riscv mmap. On riscv, mmap will not use bits in
the upper bits of the virtual address depending on the hint address. On
other architectures, a random address is returned in the address space
requested. On all architectures the hint address will be returned if it
is available. This allows riscv applications to configure how many bits
in the virtual address should be left empty. This has the two benefits
of being able to request address spaces that are smaller than the
default and doesn't require the application to know the page table
layout of riscv.

* b4-shazam-merge:
  docs: riscv: Define behavior of mmap
  selftests: riscv: Generalize mm selftests
  riscv: mm: Use hint address in mmap if available

Link: https://lore.kernel.org/r/20240130-use_mmap_hint_address-v3-0-8a655cfa8bcb@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

1 files changed, 15 insertions, 15 deletions

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9a9fe59b40a831..b2e6965748f214 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -127,17 +127,11 @@
 #define VA_USER_SV48 (UL(1) << (VA_BITS_SV48 - 1))
 #define VA_USER_SV57 (UL(1) << (VA_BITS_SV57 - 1))
 
-#ifdef CONFIG_COMPAT
 #define MMAP_VA_BITS_64 ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)
 #define MMAP_MIN_VA_BITS_64 (VA_BITS_SV39)
 #define MMAP_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_VA_BITS_64)
 #define MMAP_MIN_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_MIN_VA_BITS_64)
 #else
-#define MMAP_VA_BITS ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)
-#define MMAP_MIN_VA_BITS (VA_BITS_SV39)
-#endif /* CONFIG_COMPAT */
-
-#else
 #include <asm/pgtable-32.h>
 #endif /* CONFIG_64BIT */
 
@@ -439,6 +433,12 @@ static inline pte_t pte_mkhuge(pte_t pte)
 	return pte;
 }
 
+#ifdef CONFIG_RISCV_ISA_SVNAPOT
+#define pte_leaf_size(pte)	(pte_napot(pte) ?				\
+					napot_cont_size(napot_cont_order(pte)) :\
+					PAGE_SIZE)
+#endif
+
 #ifdef CONFIG_NUMA_BALANCING
 /*
  * See the comment in include/asm-generic/pgtable.h
@@ -513,12 +513,12 @@ static inline void set_pte(pte_t *ptep, pte_t pteval)
 	WRITE_ONCE(*ptep, pteval);
 }
 
-void flush_icache_pte(pte_t pte);
+void flush_icache_pte(struct mm_struct *mm, pte_t pte);
 
-static inline void __set_pte_at(pte_t *ptep, pte_t pteval)
+static inline void __set_pte_at(struct mm_struct *mm, pte_t *ptep, pte_t pteval)
 {
 	if (pte_present(pteval) && pte_exec(pteval))
-		flush_icache_pte(pteval);
+		flush_icache_pte(mm, pteval);
 
 	set_pte(ptep, pteval);
 }
@@ -529,7 +529,7 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
 	page_table_check_ptes_set(mm, ptep, pteval, nr);
 
 	for (;;) {
-		__set_pte_at(ptep, pteval);
+		__set_pte_at(mm, ptep, pteval);
 		if (--nr == 0)
 			break;
 		ptep++;
@@ -541,7 +541,7 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
 static inline void pte_clear(struct mm_struct *mm,
 	unsigned long addr, pte_t *ptep)
 {
-	__set_pte_at(ptep, __pte(0));
+	__set_pte_at(mm, ptep, __pte(0));
 }
 
 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS	/* defined in mm/pgtable.c */
@@ -713,14 +713,14 @@ static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 				pmd_t *pmdp, pmd_t pmd)
 {
 	page_table_check_pmd_set(mm, pmdp, pmd);
-	return __set_pte_at((pte_t *)pmdp, pmd_pte(pmd));
+	return __set_pte_at(mm, (pte_t *)pmdp, pmd_pte(pmd));
 }
 
 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
 				pud_t *pudp, pud_t pud)
 {
 	page_table_check_pud_set(mm, pudp, pud);
-	return __set_pte_at((pte_t *)pudp, pud_pte(pud));
+	return __set_pte_at(mm, (pte_t *)pudp, pud_pte(pud));
 }
 
 #ifdef CONFIG_PAGE_TABLE_CHECK
@@ -871,8 +871,8 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
 #define TASK_SIZE_MIN	(PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)
 
 #ifdef CONFIG_COMPAT
-#define TASK_SIZE_32	(_AC(0x80000000, UL))
-#define TASK_SIZE	(test_thread_flag(TIF_32BIT) ? \
+#define TASK_SIZE_32	(_AC(0x80000000, UL) - PAGE_SIZE)
+#define TASK_SIZE	(is_compat_task() ? \
 			 TASK_SIZE_32 : TASK_SIZE_64)
 #else
 #define TASK_SIZE	TASK_SIZE_64