From 35d8945bf9b0c4d9586c7fa9fadeecf2cfc26c23 Mon Sep 17 00:00:00 2001 From: Rong Zhang Date: Mon, 16 Mar 2026 01:28:22 +0800 Subject: [PATCH] MIPS: Loongson64: env: Check UARTs passed by LEFI cautiously Some firmware does not set nr_uarts properly and passes empty items. Iterate at most min(system->nr_uarts, MAX_UARTS) items to prevent out-of-bounds access, and ignore UARTs with addr 0 silently. Meanwhile, our DT only works with UPIO_MEM but theoretically firmware may pass other IO types, so explicitly check against that. Tested on Loongson-LS3A4000-7A1000-NUC-SE. Fixes: 3989ed418483 ("MIPS: Loongson64: env: Fixup serial clock-frequency when using LEFI") Cc: stable@vger.kernel.org Reviewed-by: Yao Zi Signed-off-by: Rong Zhang Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer --- arch/mips/loongson64/env.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/mips/loongson64/env.c b/arch/mips/loongson64/env.c index 11ddf02d6a15..7abcca7ab4ed 100644 --- a/arch/mips/loongson64/env.c +++ b/arch/mips/loongson64/env.c @@ -17,7 +17,9 @@ #include #include #include +#include #include +#include #include #include #include @@ -106,9 +108,23 @@ static void __init lefi_fixup_fdt(struct system_loongson *system) is_loongson64g = (read_c0_prid() & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64G; - for (i = 0; i < system->nr_uarts; i++) { + for (i = 0; i < min(system->nr_uarts, MAX_UARTS); i++) { uartdev = &system->uarts[i]; + /* + * Some firmware does not set nr_uarts properly and passes empty + * items. Ignore them silently. + */ + if (uartdev->uart_base == 0) + continue; + + /* Our DT only works with UPIO_MEM. */ + if (uartdev->iotype != UPIO_MEM) { + pr_warn("Ignore UART 0x%llx with iotype %u passed by firmware\n", + uartdev->uart_base, uartdev->iotype); + continue; + } + ret = lefi_fixup_fdt_serial(fdt_buf, uartdev->uart_base, uartdev->uartclk); /*