From 8c2c3f2d40b6c4f40eddc099916dffac6171bf2e Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 20 Jun 2018 01:08:30 +0900 Subject: MIPS/kprobes: Remove jprobe implementation Remove arch dependent setjump/longjump functions and unused fields in kprobe_ctlblk for jprobes from arch/mips. Signed-off-by: Masami Hiramatsu Acked-by: Thomas Gleixner Cc: Ananth N Mavinakayanahalli Cc: Andrew Morton Cc: James Hogan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Steven Rostedt Cc: linux-arch@vger.kernel.org Cc: linux-mips@linux-mips.org Link: https://lore.kernel.org/lkml/152942451058.15209.3459785416221980965.stgit@devbox Signed-off-by: Ingo Molnar --- arch/mips/include/asm/kprobes.h | 13 ------------ arch/mips/kernel/kprobes.c | 45 ----------------------------------------- 2 files changed, 58 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/include/asm/kprobes.h b/arch/mips/include/asm/kprobes.h index ad1a99948f27..a72dfbf1babb 100644 --- a/arch/mips/include/asm/kprobes.h +++ b/arch/mips/include/asm/kprobes.h @@ -68,16 +68,6 @@ struct prev_kprobe { unsigned long saved_epc; }; -#define MAX_JPROBES_STACK_SIZE 128 -#define MAX_JPROBES_STACK_ADDR \ - (((unsigned long)current_thread_info()) + THREAD_SIZE - 32 - sizeof(struct pt_regs)) - -#define MIN_JPROBES_STACK_SIZE(ADDR) \ - ((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \ - ? MAX_JPROBES_STACK_ADDR - (ADDR) \ - : MAX_JPROBES_STACK_SIZE) - - #define SKIP_DELAYSLOT 0x0001 /* per-cpu kprobe control block */ @@ -86,12 +76,9 @@ struct kprobe_ctlblk { unsigned long kprobe_old_SR; unsigned long kprobe_saved_SR; unsigned long kprobe_saved_epc; - unsigned long jprobe_saved_sp; - struct pt_regs jprobe_saved_regs; /* Per-thread fields, used while emulating branches */ unsigned long flags; unsigned long target_epc; - u8 jprobes_stack[MAX_JPROBES_STACK_SIZE]; struct prev_kprobe prev_kprobe; }; diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index f5c8bce70db2..efdcd0b1ce12 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -468,51 +468,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, return ret; } -int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct jprobe *jp = container_of(p, struct jprobe, kp); - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - kcb->jprobe_saved_regs = *regs; - kcb->jprobe_saved_sp = regs->regs[29]; - - memcpy(kcb->jprobes_stack, (void *)kcb->jprobe_saved_sp, - MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); - - regs->cp0_epc = (unsigned long)(jp->entry); - - return 1; -} - -/* Defined in the inline asm below. */ -void jprobe_return_end(void); - -void __kprobes jprobe_return(void) -{ - /* Assembler quirk necessitates this '0,code' business. */ - asm volatile( - "break 0,%0\n\t" - ".globl jprobe_return_end\n" - "jprobe_return_end:\n" - : : "n" (BRK_KPROBE_BP) : "memory"); -} - -int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - if (regs->cp0_epc >= (unsigned long)jprobe_return && - regs->cp0_epc <= (unsigned long)jprobe_return_end) { - *regs = kcb->jprobe_saved_regs; - memcpy((void *)kcb->jprobe_saved_sp, kcb->jprobes_stack, - MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); - preempt_enable_no_resched(); - - return 1; - } - return 0; -} - /* * Function return probe trampoline: * - init_kprobes() establishes a probepoint here -- cgit From 9b85753da73c5c10a9bee4d573be9503ad726b45 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 20 Jun 2018 01:13:49 +0900 Subject: MIPS/kprobes: Don't call the ->break_handler() in MIPS kprobes code Don't call the ->break_handler() from the MIPS kprobes code, because it was only used by jprobes which got removed. Signed-off-by: Masami Hiramatsu Acked-by: Thomas Gleixner Cc: Ananth N Mavinakayanahalli Cc: Andrew Morton Cc: James Hogan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Steven Rostedt Cc: linux-arch@vger.kernel.org Cc: linux-mips@linux-mips.org Link: https://lore.kernel.org/lkml/152942482953.15209.843924518200700137.stgit@devbox Signed-off-by: Ingo Molnar --- arch/mips/kernel/kprobes.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index efdcd0b1ce12..7fd277bc59b9 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -326,19 +326,13 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) preempt_enable_no_resched(); } return 1; - } else { - if (addr->word != breakpoint_insn.word) { - /* - * The breakpoint instruction was removed by - * another cpu right after we hit, no further - * handling of this interrupt is appropriate - */ - ret = 1; - goto no_kprobe; - } - p = __this_cpu_read(current_kprobe); - if (p->break_handler && p->break_handler(p, regs)) - goto ss_probe; + } else if (addr->word != breakpoint_insn.word) { + /* + * The breakpoint instruction was removed by + * another cpu right after we hit, no further + * handling of this interrupt is appropriate + */ + ret = 1; } goto no_kprobe; } @@ -367,7 +361,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) return 1; } -ss_probe: prepare_singlestep(p, regs, kcb); if (kcb->flags & SKIP_DELAYSLOT) { kcb->kprobe_status = KPROBE_HIT_SSDONE; -- cgit From cce188bd58cfbd603b904dbce75f34de2eff959a Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 20 Jun 2018 01:15:45 +0900 Subject: bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobe Clear current_kprobe and enable preemption in kprobe even if pre_handler returns !0. This simplifies function override using kprobes. Jprobe used to require to keep the preemption disabled and keep current_kprobe until it returned to original function entry. For this reason kprobe_int3_handler() and similar arch dependent kprobe handers checks pre_handler result and exit without enabling preemption if the result is !0. After removing the jprobe, Kprobes does not need to keep preempt disabled even if user handler returns !0 anymore. But since the function override handler in error-inject and bpf is also returns !0 if it overrides a function, to balancing the preempt count, it enables preemption and reset current kprobe by itself. That is a bad design that is very buggy. This fixes such unbalanced preempt-count and current_kprobes setting in kprobes, bpf and error-inject. Note: for powerpc and x86, this removes all preempt_disable from kprobe_ftrace_handler because ftrace callbacks are called under preempt disabled. Signed-off-by: Masami Hiramatsu Acked-by: Thomas Gleixner Acked-by: Naveen N. Rao Cc: Alexei Starovoitov Cc: Ananth N Mavinakayanahalli Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: David S. Miller Cc: Fenghua Yu Cc: Heiko Carstens Cc: James Hogan Cc: Josef Bacik Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Rich Felker Cc: Russell King Cc: Steven Rostedt Cc: Tony Luck Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Link: https://lore.kernel.org/lkml/152942494574.15209.12323837825873032258.stgit@devbox Signed-off-by: Ingo Molnar --- arch/mips/kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index 7fd277bc59b9..54cd675c5d1d 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -358,6 +358,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) if (p->pre_handler && p->pre_handler(p, regs)) { /* handler has already set things up, so skip ss setup */ + reset_current_kprobe(); + preempt_enable_no_resched(); return 1; } @@ -543,9 +545,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, kretprobe_assert(ri, orig_ret_address, trampoline_address); instruction_pointer(regs) = orig_ret_address; - reset_current_kprobe(); kretprobe_hash_unlock(current, &flags); - preempt_enable_no_resched(); hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { hlist_del(&ri->hlist); -- cgit