linux-kernel - [PATCH] riscv: Remove redundant restriction on memory size

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Message-ID: <20240624121723.2186279-1-stuart.menefy@codasip.com>
Date: Mon, 24 Jun 2024 13:17:23 +0100
From: Stuart Menefy <stuart.menefy@...asip.com>
To: Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>
Cc: Stuart Menefy <stuart.menefy@...asip.com>,
	linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] riscv: Remove redundant restriction on memory size

The original reason for reserving the top 4GiB of the direct map
(space for modules/BPF/kernel) hasn't applied since the address
map was reworked for KASAN.

Signed-off-by: Stuart Menefy <stuart.menefy@...asip.com>
---
 arch/riscv/mm/init.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 7e25606f858a..3998d1ca369c 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -1130,13 +1130,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 				0UL : PAGE_OFFSET - kernel_map.phys_addr;
 	kernel_map.va_kernel_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr;
 
-	/*
-	 * The default maximal physical memory size is KERN_VIRT_SIZE for 32-bit
-	 * kernel, whereas for 64-bit kernel, the end of the virtual address
-	 * space is occupied by the modules/BPF/kernel mappings which reduces
-	 * the available size of the linear mapping.
-	 */
-	memory_limit = KERN_VIRT_SIZE - (IS_ENABLED(CONFIG_64BIT) ? SZ_4G : 0);
+	memory_limit = KERN_VIRT_SIZE;
 
 	/* Sanity check alignment and size */
 	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
-- 
2.43.0