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/fpreg.c | 233 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 arch/alpha/lib/fpreg.c (limited to 'arch/alpha/lib/fpreg.c') diff --git a/arch/alpha/lib/fpreg.c b/arch/alpha/lib/fpreg.c new file mode 100644 index 000000000..3d3216504 --- /dev/null +++ b/arch/alpha/lib/fpreg.c @@ -0,0 +1,233 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * arch/alpha/lib/fpreg.c + * + * (C) Copyright 1998 Linus Torvalds + */ + +#include +#include +#include +#include +#include + +#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67) +#define STT(reg,val) asm volatile ("ftoit $f"#reg",%0" : "=r"(val)); +#else +#define STT(reg,val) asm volatile ("stt $f"#reg",%0" : "=m"(val)); +#endif + +unsigned long +alpha_read_fp_reg (unsigned long reg) +{ + unsigned long val; + + if (unlikely(reg >= 32)) + return 0; + preempt_disable(); + if (current_thread_info()->status & TS_SAVED_FP) + val = current_thread_info()->fp[reg]; + else switch (reg) { + case 0: STT( 0, val); break; + case 1: STT( 1, val); break; + case 2: STT( 2, val); break; + case 3: STT( 3, val); break; + case 4: STT( 4, val); break; + case 5: STT( 5, val); break; + case 6: STT( 6, val); break; + case 7: STT( 7, val); break; + case 8: STT( 8, val); break; + case 9: STT( 9, val); break; + case 10: STT(10, val); break; + case 11: STT(11, val); break; + case 12: STT(12, val); break; + case 13: STT(13, val); break; + case 14: STT(14, val); break; + case 15: STT(15, val); break; + case 16: STT(16, val); break; + case 17: STT(17, val); break; + case 18: STT(18, val); break; + case 19: STT(19, val); break; + case 20: STT(20, val); break; + case 21: STT(21, val); break; + case 22: STT(22, val); break; + case 23: STT(23, val); break; + case 24: STT(24, val); break; + case 25: STT(25, val); break; + case 26: STT(26, val); break; + case 27: STT(27, val); break; + case 28: STT(28, val); break; + case 29: STT(29, val); break; + case 30: STT(30, val); break; + case 31: STT(31, val); break; + } + preempt_enable(); + return val; +} +EXPORT_SYMBOL(alpha_read_fp_reg); + +#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67) +#define LDT(reg,val) asm volatile ("itoft %0,$f"#reg : : "r"(val)); +#else +#define LDT(reg,val) asm volatile ("ldt $f"#reg",%0" : : "m"(val)); +#endif + +void +alpha_write_fp_reg (unsigned long reg, unsigned long val) +{ + if (unlikely(reg >= 32)) + return; + + preempt_disable(); + if (current_thread_info()->status & TS_SAVED_FP) { + current_thread_info()->status |= TS_RESTORE_FP; + current_thread_info()->fp[reg] = val; + } else switch (reg) { + case 0: LDT( 0, val); break; + case 1: LDT( 1, val); break; + case 2: LDT( 2, val); break; + case 3: LDT( 3, val); break; + case 4: LDT( 4, val); break; + case 5: LDT( 5, val); break; + case 6: LDT( 6, val); break; + case 7: LDT( 7, val); break; + case 8: LDT( 8, val); break; + case 9: LDT( 9, val); break; + case 10: LDT(10, val); break; + case 11: LDT(11, val); break; + case 12: LDT(12, val); break; + case 13: LDT(13, val); break; + case 14: LDT(14, val); break; + case 15: LDT(15, val); break; + case 16: LDT(16, val); break; + case 17: LDT(17, val); break; + case 18: LDT(18, val); break; + case 19: LDT(19, val); break; + case 20: LDT(20, val); break; + case 21: LDT(21, val); break; + case 22: LDT(22, val); break; + case 23: LDT(23, val); break; + case 24: LDT(24, val); break; + case 25: LDT(25, val); break; + case 26: LDT(26, val); break; + case 27: LDT(27, val); break; + case 28: LDT(28, val); break; + case 29: LDT(29, val); break; + case 30: LDT(30, val); break; + case 31: LDT(31, val); break; + } + preempt_enable(); +} +EXPORT_SYMBOL(alpha_write_fp_reg); + +#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67) +#define STS(reg,val) asm volatile ("ftois $f"#reg",%0" : "=r"(val)); +#else +#define STS(reg,val) asm volatile ("sts $f"#reg",%0" : "=m"(val)); +#endif + +unsigned long +alpha_read_fp_reg_s (unsigned long reg) +{ + unsigned long val; + + if (unlikely(reg >= 32)) + return 0; + + preempt_disable(); + if (current_thread_info()->status & TS_SAVED_FP) { + LDT(0, current_thread_info()->fp[reg]); + STS(0, val); + } else switch (reg) { + case 0: STS( 0, val); break; + case 1: STS( 1, val); break; + case 2: STS( 2, val); break; + case 3: STS( 3, val); break; + case 4: STS( 4, val); break; + case 5: STS( 5, val); break; + case 6: STS( 6, val); break; + case 7: STS( 7, val); break; + case 8: STS( 8, val); break; + case 9: STS( 9, val); break; + case 10: STS(10, val); break; + case 11: STS(11, val); break; + case 12: STS(12, val); break; + case 13: STS(13, val); break; + case 14: STS(14, val); break; + case 15: STS(15, val); break; + case 16: STS(16, val); break; + case 17: STS(17, val); break; + case 18: STS(18, val); break; + case 19: STS(19, val); break; + case 20: STS(20, val); break; + case 21: STS(21, val); break; + case 22: STS(22, val); break; + case 23: STS(23, val); break; + case 24: STS(24, val); break; + case 25: STS(25, val); break; + case 26: STS(26, val); break; + case 27: STS(27, val); break; + case 28: STS(28, val); break; + case 29: STS(29, val); break; + case 30: STS(30, val); break; + case 31: STS(31, val); break; + } + preempt_enable(); + return val; +} +EXPORT_SYMBOL(alpha_read_fp_reg_s); + +#if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67) +#define LDS(reg,val) asm volatile ("itofs %0,$f"#reg : : "r"(val)); +#else +#define LDS(reg,val) asm volatile ("lds $f"#reg",%0" : : "m"(val)); +#endif + +void +alpha_write_fp_reg_s (unsigned long reg, unsigned long val) +{ + if (unlikely(reg >= 32)) + return; + + preempt_disable(); + if (current_thread_info()->status & TS_SAVED_FP) { + current_thread_info()->status |= TS_RESTORE_FP; + LDS(0, val); + STT(0, current_thread_info()->fp[reg]); + } else switch (reg) { + case 0: LDS( 0, val); break; + case 1: LDS( 1, val); break; + case 2: LDS( 2, val); break; + case 3: LDS( 3, val); break; + case 4: LDS( 4, val); break; + case 5: LDS( 5, val); break; + case 6: LDS( 6, val); break; + case 7: LDS( 7, val); break; + case 8: LDS( 8, val); break; + case 9: LDS( 9, val); break; + case 10: LDS(10, val); break; + case 11: LDS(11, val); break; + case 12: LDS(12, val); break; + case 13: LDS(13, val); break; + case 14: LDS(14, val); break; + case 15: LDS(15, val); break; + case 16: LDS(16, val); break; + case 17: LDS(17, val); break; + case 18: LDS(18, val); break; + case 19: LDS(19, val); break; + case 20: LDS(20, val); break; + case 21: LDS(21, val); break; + case 22: LDS(22, val); break; + case 23: LDS(23, val); break; + case 24: LDS(24, val); break; + case 25: LDS(25, val); break; + case 26: LDS(26, val); break; + case 27: LDS(27, val); break; + case 28: LDS(28, val); break; + case 29: LDS(29, val); break; + case 30: LDS(30, val); break; + case 31: LDS(31, val); break; + } + preempt_enable(); +} +EXPORT_SYMBOL(alpha_write_fp_reg_s); -- cgit v1.3.1