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/arm/lib/memmove.S | 206 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 206 insertions(+) create mode 100644 arch/arm/lib/memmove.S (limited to 'arch/arm/lib/memmove.S') diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S new file mode 100644 index 000000000..641055403 --- /dev/null +++ b/arch/arm/lib/memmove.S @@ -0,0 +1,206 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/arch/arm/lib/memmove.S + * + * Author: Nicolas Pitre + * Created: Sep 28, 2005 + * Copyright: (C) MontaVista Software Inc. + */ + +#include +#include +#include + + .text + +/* + * Prototype: void *memmove(void *dest, const void *src, size_t n); + * + * Note: + * + * If the memory regions don't overlap, we simply branch to memcpy which is + * normally a bit faster. Otherwise the copy is done going downwards. This + * is a transposition of the code from copy_template.S but with the copy + * occurring in the opposite direction. + */ + +ENTRY(__memmove) +WEAK(memmove) + UNWIND( .fnstart ) + + subs ip, r0, r1 + cmphi r2, ip + bls __memcpy + UNWIND( .fnend ) + + UNWIND( .fnstart ) + UNWIND( .save {r0, r4, fpreg, lr} ) + stmfd sp!, {r0, r4, UNWIND(fpreg,) lr} + UNWIND( .setfp fpreg, sp ) + UNWIND( mov fpreg, sp ) + add r1, r1, r2 + add r0, r0, r2 + subs r2, r2, #4 + blt 8f + ands ip, r0, #3 + PLD( pld [r1, #-4] ) + bne 9f + ands ip, r1, #3 + bne 10f + +1: subs r2, r2, #(28) + stmfd sp!, {r5, r6, r8, r9} + blt 5f + + CALGN( ands ip, r0, #31 ) + CALGN( sbcsne r4, ip, r2 ) @ C is always set here + CALGN( bcs 2f ) + CALGN( adr r4, 6f ) + CALGN( subs r2, r2, ip ) @ C is set here + CALGN( rsb ip, ip, #32 ) + CALGN( add pc, r4, ip ) + + PLD( pld [r1, #-4] ) +2: PLD( subs r2, r2, #96 ) + PLD( pld [r1, #-32] ) + PLD( blt 4f ) + PLD( pld [r1, #-64] ) + PLD( pld [r1, #-96] ) + +3: PLD( pld [r1, #-128] ) +4: ldmdb r1!, {r3, r4, r5, r6, r8, r9, ip, lr} + subs r2, r2, #32 + stmdb r0!, {r3, r4, r5, r6, r8, r9, ip, lr} + bge 3b + PLD( cmn r2, #96 ) + PLD( bge 4b ) + +5: ands ip, r2, #28 + rsb ip, ip, #32 + addne pc, pc, ip @ C is always clear here + b 7f +6: W(nop) + W(ldr) r3, [r1, #-4]! + W(ldr) r4, [r1, #-4]! + W(ldr) r5, [r1, #-4]! + W(ldr) r6, [r1, #-4]! + W(ldr) r8, [r1, #-4]! + W(ldr) r9, [r1, #-4]! + W(ldr) lr, [r1, #-4]! + + add pc, pc, ip + nop + W(nop) + W(str) r3, [r0, #-4]! + W(str) r4, [r0, #-4]! + W(str) r5, [r0, #-4]! + W(str) r6, [r0, #-4]! + W(str) r8, [r0, #-4]! + W(str) r9, [r0, #-4]! + W(str) lr, [r0, #-4]! + + CALGN( bcs 2b ) + +7: ldmfd sp!, {r5, r6, r8, r9} + +8: movs r2, r2, lsl #31 + ldrbne r3, [r1, #-1]! + ldrbcs r4, [r1, #-1]! + ldrbcs ip, [r1, #-1] + strbne r3, [r0, #-1]! + strbcs r4, [r0, #-1]! + strbcs ip, [r0, #-1] + ldmfd sp!, {r0, r4, UNWIND(fpreg,) pc} + +9: cmp ip, #2 + ldrbgt r3, [r1, #-1]! + ldrbge r4, [r1, #-1]! + ldrb lr, [r1, #-1]! + strbgt r3, [r0, #-1]! + strbge r4, [r0, #-1]! + subs r2, r2, ip + strb lr, [r0, #-1]! + blt 8b + ands ip, r1, #3 + beq 1b + +10: bic r1, r1, #3 + cmp ip, #2 + ldr r3, [r1, #0] + beq 17f + blt 18f + + + .macro backward_copy_shift push pull + + subs r2, r2, #28 + blt 14f + + CALGN( ands ip, r0, #31 ) + CALGN( sbcsne r4, ip, r2 ) @ C is always set here + CALGN( subcc r2, r2, ip ) + CALGN( bcc 15f ) + +11: stmfd sp!, {r5, r6, r8 - r10} + + PLD( pld [r1, #-4] ) + PLD( subs r2, r2, #96 ) + PLD( pld [r1, #-32] ) + PLD( blt 13f ) + PLD( pld [r1, #-64] ) + PLD( pld [r1, #-96] ) + +12: PLD( pld [r1, #-128] ) +13: ldmdb r1!, {r8, r9, r10, ip} + mov lr, r3, lspush #\push + subs r2, r2, #32 + ldmdb r1!, {r3, r4, r5, r6} + orr lr, lr, ip, lspull #\pull + mov ip, ip, lspush #\push + orr ip, ip, r10, lspull #\pull + mov r10, r10, lspush #\push + orr r10, r10, r9, lspull #\pull + mov r9, r9, lspush #\push + orr r9, r9, r8, lspull #\pull + mov r8, r8, lspush #\push + orr r8, r8, r6, lspull #\pull + mov r6, r6, lspush #\push + orr r6, r6, r5, lspull #\pull + mov r5, r5, lspush #\push + orr r5, r5, r4, lspull #\pull + mov r4, r4, lspush #\push + orr r4, r4, r3, lspull #\pull + stmdb r0!, {r4 - r6, r8 - r10, ip, lr} + bge 12b + PLD( cmn r2, #96 ) + PLD( bge 13b ) + + ldmfd sp!, {r5, r6, r8 - r10} + +14: ands ip, r2, #28 + beq 16f + +15: mov lr, r3, lspush #\push + ldr r3, [r1, #-4]! + subs ip, ip, #4 + orr lr, lr, r3, lspull #\pull + str lr, [r0, #-4]! + bgt 15b + CALGN( cmp r2, #0 ) + CALGN( bge 11b ) + +16: add r1, r1, #(\pull / 8) + b 8b + + .endm + + + backward_copy_shift push=8 pull=24 + +17: backward_copy_shift push=16 pull=16 + +18: backward_copy_shift push=24 pull=8 + + UNWIND( .fnend ) +ENDPROC(memmove) +ENDPROC(__memmove) -- cgit v1.3.1