linux-kernel - [PATCH V2 4/4] riscv: mm: Optimize TASK

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Message-Id: <20231221154702.2267684-5-guoren@kernel.org>
Date: Thu, 21 Dec 2023 10:47:01 -0500
From: guoren@...nel.org
To: linux-kernel@...r.kernel.org,
	paul.walmsley@...ive.com,
	palmer@...belt.com,
	alexghiti@...osinc.com,
	charlie@...osinc.com,
	xiao.w.wang@...el.com,
	guoren@...nel.org,
	david@...hat.com,
	panqinglin2020@...as.ac.cn,
	rick.p.edgecombe@...el.com,
	willy@...radead.org,
	bjorn@...osinc.com,
	conor.dooley@...rochip.com,
	cleger@...osinc.com,
	leobras@...hat.com
Cc: linux-riscv@...ts.infradead.org,
	Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH V2 4/4] riscv: mm: Optimize TASK_SIZE definition

From: Guo Ren <guoren@...ux.alibaba.com>

Unify the TASK_SIZE definition with VA_BITS for better readability.
Add COMPAT mode user address space info in the comment.

Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Signed-off-by: Guo Ren <guoren@...nel.org>
---
 arch/riscv/include/asm/pgtable.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index e415582276ec..d165ddae3b42 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -866,6 +866,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
  * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
  * Task size is:
  * -        0x9fc00000	(~2.5GB) for RV32.
+ * -        0x80000000	(   2GB) for RV64 compat mode
  * -      0x4000000000	( 256GB) for RV64 using SV39 mmu
  * -    0x800000000000	( 128TB) for RV64 using SV48 mmu
  * - 0x100000000000000	(  64PB) for RV64 using SV57 mmu
@@ -877,11 +878,11 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
  * Similarly for SV57, bits 63–57 must be equal to bit 56.
  */
 #ifdef CONFIG_64BIT
-#define TASK_SIZE_64	(PGDIR_SIZE * PTRS_PER_PGD / 2)
+#define TASK_SIZE_64	(UL(1) << (VA_BITS - 1))
 
 #ifdef CONFIG_COMPAT
-#define TASK_SIZE_32	(_AC(0x80000000, UL))
-#define TASK_SIZE	(test_thread_flag(TIF_32BIT) ? \
+#define TASK_SIZE_32	(UL(1) << (VA_BITS_SV32 - 1))
+#define TASK_SIZE	(is_compat_task() ? \
 			 TASK_SIZE_32 : TASK_SIZE_64)
 #else
 #define TASK_SIZE	TASK_SIZE_64
-- 
2.40.1