Re: [PATCH] riscv: Remove redundant restriction on memory size

From: Alexandre Ghiti
Date: Mon Jul 01 2024 - 08:21:34 EST


Hi Stuart,

On 24/06/2024 14:17, Stuart Menefy wrote:
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@xxxxxxxxxxx>
---
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);


I somehow totally missed this one, I guess this is the third fix you mentioned earlier right?

This is correct so you can add:

Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>

Thanks,

Alex