Merge patch series "riscv: access_ok() optimization"
Samuel Holland <samuel.holland@sifive.com> says:
This series optimizes access_ok() by defining TASK_SIZE_MAX. At Alex's
suggestion, I also tried making TASK_SIZE constant (specifically by
making PGDIR_SHIFT a variable instead of a ternary expression, then
replacing the load with an immediate using ALTERNATIVE). This appeared
to slightly improve performance on some implementations (C906) but
regressed it on others (FU740). So I am leaving further optimizations to
a later series.
* b4-shazam-merge:
riscv: Define TASK_SIZE_MAX for __access_ok()
riscv: Remove PGDIR_SIZE_L3 and TASK_SIZE_MIN
Link: https://lore.kernel.org/r/20240327143858.711792-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index 221a5c1..8c36a88 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -16,8 +16,6 @@ extern bool pgtable_l5_enabled;
#define PGDIR_SHIFT_L3 30
#define PGDIR_SHIFT_L4 39
#define PGDIR_SHIFT_L5 48
-#define PGDIR_SIZE_L3 (_AC(1, UL) << PGDIR_SHIFT_L3)
-
#define PGDIR_SHIFT (pgtable_l5_enabled ? PGDIR_SHIFT_L5 : \
(pgtable_l4_enabled ? PGDIR_SHIFT_L4 : PGDIR_SHIFT_L3))
/* Size of region mapped by a page global directory */
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 55a7c3e..aad8b8c 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -880,7 +880,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
*/
#ifdef CONFIG_64BIT
#define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2)
-#define TASK_SIZE_MIN (PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)
+#define TASK_SIZE_MAX LONG_MAX
#ifdef CONFIG_COMPAT
#define TASK_SIZE_32 (_AC(0x80000000, UL) - PAGE_SIZE)
@@ -892,7 +892,6 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
#else
#define TASK_SIZE FIXADDR_START
-#define TASK_SIZE_MIN TASK_SIZE
#endif
#else /* CONFIG_MMU */
