[PATCH v2] spi: cadence: Fix out-of-bounds array access in cdns_mrvl_xspi_setup_clock()

[Josh Poimboeuf]

If requested_clk > 128, cdns_mrvl_xspi_setup_clock() iterates over the
entire cdns_mrvl_xspi_clk_div_list array without breaking out early,
causing 'i' to go beyond the array bounds.

Fix that by stopping the loop when it gets to the last entry, clamping
the clock to the minimum 6.25 MHz.

Fixes the following warning with an UBSAN kernel:

  vmlinux.o: warning: objtool: cdns_mrvl_xspi_setup_clock: unexpected end of section .text.cdns_mrvl_xspi_setup_clock

Fixes: 26d34fdc4971 ("spi: cadence: Add clock configuration for Marvell xSPI overlay")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202503282236.UhfRsF3B-lkp@xxxxxxxxx/
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
v2: Fix typo in commit log

 drivers/spi/spi-cadence-xspi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
index aed98ab14334..b7ac4385c49f 100644
--- a/drivers/spi/spi-cadence-xspi.c
+++ b/drivers/spi/spi-cadence-xspi.c
@@ -432,7 +432,7 @@ static bool cdns_mrvl_xspi_setup_clock(struct cdns_xspi_dev *cdns_xspi,
 	u32 clk_reg;
 	bool update_clk = false;
 
-	while (i < ARRAY_SIZE(cdns_mrvl_xspi_clk_div_list)) {
+	while (i < ARRAY_SIZE(cdns_mrvl_xspi_clk_div_list)-1) {
 		clk_val = MRVL_XSPI_CLOCK_DIVIDED(
 				cdns_mrvl_xspi_clk_div_list[i]);
 		if (clk_val <= requested_clk)
-- 
2.48.1