Commit 35d8945b authored by Rong Zhang's avatar Rong Zhang Committed by Thomas Bogendoerfer
Browse files

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: 3989ed41 ("MIPS: Loongson64: env: Fixup serial clock-frequency when using LEFI")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarYao Zi <me@ziyao.cc>
Signed-off-by: default avatarRong Zhang <rongrong@oss.cipunited.com>
Reviewed-by: default avatarJiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent 6de23f81

arch/mips/loongson64/env.c

+17 −1
Original line number Diff line number Diff line
@@ -17,7 +17,9 @@ 
#include <linux/dma-map-ops.h>

#include <linux/export.h>

#include <linux/libfdt.h>

#include <linux/minmax.h>

#include <linux/pci_ids.h>

#include <linux/serial_core.h>

#include <linux/string_choices.h>

#include <asm/bootinfo.h>

#include <loongson.h>
@@ -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);

		/*