From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- arch/microblaze/lib/modsi3.S | 74 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 arch/microblaze/lib/modsi3.S (limited to 'arch/microblaze/lib/modsi3.S') diff --git a/arch/microblaze/lib/modsi3.S b/arch/microblaze/lib/modsi3.S new file mode 100644 index 000000000..64154865c --- /dev/null +++ b/arch/microblaze/lib/modsi3.S @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include + +/* +* modulo operation for 32 bit integers. +* Input : op1 in Reg r5 +* op2 in Reg r6 +* Output: op1 mod op2 in Reg r3 +*/ + + .text + .globl __modsi3 + .type __modsi3, @function + .ent __modsi3 + +__modsi3: + .frame r1, 0, r15 + + addik r1, r1, -16 + swi r28, r1, 0 + swi r29, r1, 4 + swi r30, r1, 8 + swi r31, r1, 12 + + beqi r6, div_by_zero /* div_by_zero division error */ + beqi r5, result_is_zero /* result is zero */ + bgeid r5, r5_pos + /* get the sign of the result [ depends only on the first arg] */ + add r28, r5, r0 + rsubi r5, r5, 0 /* make r5 positive */ +r5_pos: + bgei r6, r6_pos + rsubi r6, r6, 0 /* make r6 positive */ +r6_pos: + addik r3, r0, 0 /* clear mod */ + addik r30, r0, 0 /* clear div */ + addik r29, r0, 32 /* initialize the loop count */ +/* first part try to find the first '1' in the r5 */ +div1: + add r5, r5, r5 /* left shift logical r5 */ + bgeid r5, div1 + addik r29, r29, -1 +div2: + /* left shift logical r5 get the '1' into the carry */ + add r5, r5, r5 + addc r3, r3, r3 /* move that bit into the mod register */ + rsub r31, r6, r3 /* try to subtract (r30 a r6) */ + blti r31, mod_too_small + /* move the r31 to mod since the result was positive */ + or r3, r0, r31 + addik r30, r30, 1 +mod_too_small: + addik r29, r29, -1 + beqi r29, loop_end + add r30, r30, r30 /* shift in the '1' into div */ + bri div2 /* div2 */ +loop_end: + bgei r28, return_here + brid return_here + rsubi r3, r3, 0 /* negate the result */ +div_by_zero: +result_is_zero: + or r3, r0, r0 /* set result to 0 [both mod as well as div are 0] */ +return_here: +/* restore values of csrs and that of r3 and the divisor and the dividend */ + lwi r28, r1, 0 + lwi r29, r1, 4 + lwi r30, r1, 8 + lwi r31, r1, 12 + rtsd r15, 8 + addik r1, r1, 16 + +.size __modsi3, . - __modsi3 +.end __modsi3 -- cgit v1.3.1