From c24def73a2863a8292693ab49a83303213ef3f23 Mon Sep 17 00:00:00 2001 From: Alexander Egorenkov Date: Fri, 3 Feb 2023 08:39:54 +0100 Subject: [PATCH] watchdog: diag288_wdt: get rid of register asm Using register asm statements has been proven to be very error prone, especially when using code instrumentation where gcc may add function calls, which clobbers register contents in an unexpected way. Therefore, get rid of register asm statements in watchdog code, and make sure this bug class cannot happen. Moreover, remove the register r1 from the clobber list because this register is not changed by DIAG 288. Reviewed-by: Heiko Carstens Signed-off-by: Alexander Egorenkov Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20230203073958.1585738-2-egorenar@linux.ibm.com Signed-off-by: Heiko Carstens --- drivers/watchdog/diag288_wdt.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c index 6ca5d9515d85..07ebbb709af4 100644 --- a/drivers/watchdog/diag288_wdt.c +++ b/drivers/watchdog/diag288_wdt.c @@ -73,20 +73,19 @@ MODULE_ALIAS("vmwatchdog"); static int __diag288(unsigned int func, unsigned int timeout, unsigned long action, unsigned int len) { - register unsigned long __func asm("2") = func; - register unsigned long __timeout asm("3") = timeout; - register unsigned long __action asm("4") = action; - register unsigned long __len asm("5") = len; + union register_pair r1 = { .even = func, .odd = timeout, }; + union register_pair r3 = { .even = action, .odd = len, }; int err; err = -EINVAL; asm volatile( - " diag %1, %3, 0x288\n" - "0: la %0, 0\n" + " diag %[r1],%[r3],0x288\n" + "0: la %[err],0\n" "1:\n" EX_TABLE(0b, 1b) - : "+d" (err) : "d"(__func), "d"(__timeout), - "d"(__action), "d"(__len) : "1", "cc", "memory"); + : [err] "+d" (err) + : [r1] "d" (r1.pair), [r3] "d" (r3.pair) + : "cc", "memory"); return err; }