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Subject[PATCH] riscv: Define TASK_SIZE_MAX for __access_ok()
Date
TASK_SIZE_MAX should be set to the largest userspace address under any
runtime configuration. This optimizes the check in __access_ok(), which
no longer needs to compute the current value of TASK_SIZE. It is still
safe because addresses between TASK_SIZE and TASK_SIZE_MAX are invalid
at the hardware level.

This removes about half of the references to pgtable_l[45]_enabled.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---

arch/riscv/include/asm/pgtable-64.h | 1 +
arch/riscv/include/asm/pgtable.h | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index b99bd66107a6..a677ef3c0fe2 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -17,6 +17,7 @@ extern bool pgtable_l5_enabled;
#define PGDIR_SHIFT_L4 39
#define PGDIR_SHIFT_L5 48
#define PGDIR_SIZE_L3 (_AC(1, UL) << PGDIR_SHIFT_L3)
+#define PGDIR_SIZE_L5 (_AC(1, UL) << PGDIR_SHIFT_L5)

#define PGDIR_SHIFT (pgtable_l5_enabled ? PGDIR_SHIFT_L5 : \
(pgtable_l4_enabled ? PGDIR_SHIFT_L4 : PGDIR_SHIFT_L3))
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 6066822e7396..2032f8ac5fc5 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -867,6 +867,7 @@ 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 (PGDIR_SIZE_L5 * PTRS_PER_PGD / 2)

#ifdef CONFIG_COMPAT
#define TASK_SIZE_32 (_AC(0x80000000, UL))
--
2.43.1

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