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/alpha/lib/memset.S | 133 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 arch/alpha/lib/memset.S (limited to 'arch/alpha/lib/memset.S') diff --git a/arch/alpha/lib/memset.S b/arch/alpha/lib/memset.S new file mode 100644 index 000000000..9075d6918 --- /dev/null +++ b/arch/alpha/lib/memset.S @@ -0,0 +1,133 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * linux/arch/alpha/lib/memset.S + * + * This is an efficient (and small) implementation of the C library "memset()" + * function for the alpha. + * + * (C) Copyright 1996 Linus Torvalds + * + * This routine is "moral-ware": you are free to use it any way you wish, and + * the only obligation I put on you is a moral one: if you make any improvements + * to the routine, please send me your improvements for me to use similarly. + * + * The scheduling comments are according to the EV5 documentation (and done by + * hand, so they might well be incorrect, please do tell me about it..) + */ +#include + .set noat + .set noreorder +.text + .globl memset + .globl __memset + .globl ___memset + .globl __memset16 + .globl __constant_c_memset + + .ent ___memset +.align 5 +___memset: + .frame $30,0,$26,0 + .prologue 0 + + and $17,255,$1 /* E1 */ + insbl $17,1,$17 /* .. E0 */ + bis $17,$1,$17 /* E0 (p-c latency, next cycle) */ + sll $17,16,$1 /* E1 (p-c latency, next cycle) */ + + bis $17,$1,$17 /* E0 (p-c latency, next cycle) */ + sll $17,32,$1 /* E1 (p-c latency, next cycle) */ + bis $17,$1,$17 /* E0 (p-c latency, next cycle) */ + ldq_u $31,0($30) /* .. E1 */ + +.align 5 +__constant_c_memset: + addq $18,$16,$6 /* E0 */ + bis $16,$16,$0 /* .. E1 */ + xor $16,$6,$1 /* E0 */ + ble $18,end /* .. E1 */ + + bic $1,7,$1 /* E0 */ + beq $1,within_one_quad /* .. E1 (note EV5 zero-latency forwarding) */ + and $16,7,$3 /* E0 */ + beq $3,aligned /* .. E1 (note EV5 zero-latency forwarding) */ + + ldq_u $4,0($16) /* E0 */ + bis $16,$16,$5 /* .. E1 */ + insql $17,$16,$2 /* E0 */ + subq $3,8,$3 /* .. E1 */ + + addq $18,$3,$18 /* E0 $18 is new count ($3 is negative) */ + mskql $4,$16,$4 /* .. E1 (and possible load stall) */ + subq $16,$3,$16 /* E0 $16 is new aligned destination */ + bis $2,$4,$1 /* .. E1 */ + + bis $31,$31,$31 /* E0 */ + ldq_u $31,0($30) /* .. E1 */ + stq_u $1,0($5) /* E0 */ + bis $31,$31,$31 /* .. E1 */ + +.align 4 +aligned: + sra $18,3,$3 /* E0 */ + and $18,7,$18 /* .. E1 */ + bis $16,$16,$5 /* E0 */ + beq $3,no_quad /* .. E1 */ + +.align 3 +loop: + stq $17,0($5) /* E0 */ + subq $3,1,$3 /* .. E1 */ + addq $5,8,$5 /* E0 */ + bne $3,loop /* .. E1 */ + +no_quad: + bis $31,$31,$31 /* E0 */ + beq $18,end /* .. E1 */ + ldq $7,0($5) /* E0 */ + mskqh $7,$6,$2 /* .. E1 (and load stall) */ + + insqh $17,$6,$4 /* E0 */ + bis $2,$4,$1 /* .. E1 */ + stq $1,0($5) /* E0 */ + ret $31,($26),1 /* .. E1 */ + +.align 3 +within_one_quad: + ldq_u $1,0($16) /* E0 */ + insql $17,$16,$2 /* E1 */ + mskql $1,$16,$4 /* E0 (after load stall) */ + bis $2,$4,$2 /* E0 */ + + mskql $2,$6,$4 /* E0 */ + mskqh $1,$6,$2 /* .. E1 */ + bis $2,$4,$1 /* E0 */ + stq_u $1,0($16) /* E0 */ + +end: + ret $31,($26),1 /* E1 */ + .end ___memset +EXPORT_SYMBOL(___memset) +EXPORT_SYMBOL(__constant_c_memset) + + .align 5 + .ent __memset16 +__memset16: + .prologue 0 + + inswl $17,0,$1 /* E0 */ + inswl $17,2,$2 /* E0 */ + inswl $17,4,$3 /* E0 */ + or $1,$2,$1 /* .. E1 */ + inswl $17,6,$4 /* E0 */ + or $1,$3,$1 /* .. E1 */ + or $1,$4,$17 /* E0 */ + br __constant_c_memset /* .. E1 */ + + .end __memset16 +EXPORT_SYMBOL(__memset16) + +memset = ___memset +__memset = ___memset + EXPORT_SYMBOL(memset) + EXPORT_SYMBOL(__memset) -- cgit v1.3.1