linux-kernel - [PATCH] riscv: mm: remove the BUG_ON check of mapping the last 4K bytes of memory

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Message-Id: <20220125155542.3753-1-jszhang@kernel.org>
Date:   Tue, 25 Jan 2022 23:55:42 +0800
From:   Jisheng Zhang <jszhang@...nel.org>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Alexandre Ghiti <alex@...ti.fr>
Subject: [PATCH] riscv: mm: remove the BUG_ON check of mapping the last 4K bytes of memory

remove the BUG_ON check of mapping the last 4K bytes of the addressable
memory since "this is true for every kernel actually" as pointed out
by Alexandre.

Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
Reviewed-by: Alexandre Ghiti <alex@...ti.fr>
---
 arch/riscv/mm/init.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index cf4d018b7d66..8347d0fda8cd 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -811,14 +811,6 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
 	BUG_ON((kernel_map.phys_addr % PMD_SIZE) != 0);
 
-#ifdef CONFIG_64BIT
-	/*
-	 * The last 4K bytes of the addressable memory can not be mapped because
-	 * of IS_ERR_VALUE macro.
-	 */
-	BUG_ON((kernel_map.virt_addr + kernel_map.size) > ADDRESS_SPACE_END - SZ_4K);
-#endif
-
 	pt_ops_set_early();
 
 	/* Setup early PGD for fixmap */
-- 
2.34.1