From db909bd7986c10da074917af3dae83a60fa65093 Mon Sep 17 00:00:00 2001 From: "Guo Ren (Alibaba DAMO Academy)" Date: Sun, 25 Jan 2026 00:52:12 -0500 Subject: [PATCH] riscv: mm: Fixup no5lvl failure when vaddr is invalid MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: 26e7aacb83df ("riscv: Allow to downgrade paging mode from the command line") Cc: Alexandre Ghiti Cc: Björn Töpel Signed-off-by: Guo Ren (Alibaba DAMO Academy) Tested-by: Fangyu Yu Link: https://patch.msgid.link/20260125055212.433163-1-guoren@kernel.org [pjw@kernel.org: cleaned up commit message] Signed-off-by: Paul Walmsley --- arch/riscv/mm/init.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index decd7df40fa4..fa8d2f6f554b 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -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);