Commit db909bd7 authored by Guo Ren (Alibaba DAMO Academy)'s avatar Guo Ren (Alibaba DAMO Academy) Committed by Paul Walmsley
Browse files

riscv: mm: Fixup no5lvl failure when vaddr is invalid 



Unlike no4lvl, no5lvl still continues to detect satp, which
requires va=pa mapping. When pa=0x800000000000, no5lvl
would fail in Sv48 mode due to an illegal VA value of
0x800000000000.

So, prevent detecting the satp flow for no5lvl, when
vaddr is invalid. Add the is_vaddr_valid() function for
checking.

Fixes: 26e7aacb ("riscv: Allow to downgrade paging mode from the command line")
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: default avatarGuo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
Tested-by: default avatarFangyu Yu <fangyu.yu@linux.alibaba.com>
Link: https://patch.msgid.link/20260125055212.433163-1-guoren@kernel.org


[pjw@kernel.org: cleaned up commit message]
Signed-off-by: default avatarPaul Walmsley <pjw@kernel.org>
parent 6ebcbb53

arch/riscv/mm/init.c

+25 −0
Original line number Diff line number Diff line
@@ -792,6 +792,27 @@ static void __init set_mmap_rnd_bits_max(void) 
	mmap_rnd_bits_max = MMAP_VA_BITS - PAGE_SHIFT - 3;

}



static bool __init is_vaddr_valid(unsigned long va)

{

	unsigned long up = 0;



	switch (satp_mode) {

	case SATP_MODE_39:

		up = 1UL << 38;

		break;

	case SATP_MODE_48:

		up = 1UL << 47;

		break;

	case SATP_MODE_57:

		up = 1UL << 56;

		break;

	default:

		return false;

	}



	return (va < up) || (va >= (ULONG_MAX - up + 1));

}



/*

 * There is a simple way to determine if 4-level is supported by the

 * underlying hardware: establish 1:1 mapping in 4-level page table mode
@@ -833,6 +854,9 @@ static __init void set_satp_mode(uintptr_t dtb_pa) 
			   set_satp_mode_pmd + PMD_SIZE,

			   PMD_SIZE, PAGE_KERNEL_EXEC);

retry:

	if (!is_vaddr_valid(set_satp_mode_pmd))

		goto out;



	create_pgd_mapping(early_pg_dir,

			   set_satp_mode_pmd,

			   pgtable_l5_enabled ?
@@ -855,6 +879,7 @@ static __init void set_satp_mode(uintptr_t dtb_pa) 
		disable_pgtable_l4();

	}



out:

	memset(early_pg_dir, 0, PAGE_SIZE);

	memset(early_p4d, 0, PAGE_SIZE);

	memset(early_pud, 0, PAGE_SIZE);