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Message-Id: <152812739780.10068.9232752880126886142.stgit@devbox>
Date: Tue, 5 Jun 2018 00:49:57 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
linux-arch@...r.kernel.org, x86@...nel.org
Subject: [RFC PATCH -tip v5 03/27] kprobes/x86: Remove jprobe implementation
Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/x86.
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
---
arch/x86/include/asm/kprobes.h | 3 -
arch/x86/kernel/kprobes/core.c | 96 +---------------------------------------
2 files changed, 3 insertions(+), 96 deletions(-)
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 367d99cff426..06782c2efa04 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -111,9 +111,6 @@ struct kprobe_ctlblk {
unsigned long kprobe_status;
unsigned long kprobe_old_flags;
unsigned long kprobe_saved_flags;
- unsigned long *jprobe_saved_sp;
- struct pt_regs jprobe_saved_regs;
- kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
struct prev_kprobe prev_kprobe;
};
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 6f4d42377fe5..1b2d1acba810 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -66,8 +66,6 @@
#include "common.h"
-void jprobe_return_end(void);
-
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -690,10 +688,9 @@ int kprobe_int3_handler(struct pt_regs *regs)
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
- * pre-handler and it returned non-zero, it prepped
- * for calling the break_handler below on re-entry
- * for jprobe processing, so get out doing nothing
- * more here.
+ * pre-handler and it returned non-zero, that means
+ * user handler setup registers to exit to another
+ * instruction, we must skip the single stepping.
*/
if (!p->pre_handler || !p->pre_handler(p, regs))
setup_singlestep(p, regs, kcb, 0);
@@ -1083,93 +1080,6 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
}
NOKPROBE_SYMBOL(kprobe_exceptions_notify);
-int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr;
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- kcb->jprobe_saved_regs = *regs;
- kcb->jprobe_saved_sp = stack_addr(regs);
- addr = (unsigned long)(kcb->jprobe_saved_sp);
-
- /*
- * As Linus pointed out, gcc assumes that the callee
- * owns the argument space and could overwrite it, e.g.
- * tailcall optimization. So, to be absolutely safe
- * we also save and restore enough stack bytes to cover
- * the argument area.
- * Use __memcpy() to avoid KASAN stack out-of-bounds reports as we copy
- * raw stack chunk with redzones:
- */
- __memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, MIN_STACK_SIZE(addr));
- regs->ip = (unsigned long)(jp->entry);
-
- /*
- * jprobes use jprobe_return() which skips the normal return
- * path of the function, and this messes up the accounting of the
- * function graph tracer to get messed up.
- *
- * Pause function graph tracing while performing the jprobe function.
- */
- pause_graph_tracing();
- return 1;
-}
-NOKPROBE_SYMBOL(setjmp_pre_handler);
-
-void jprobe_return(void)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
- /* Unpoison stack redzones in the frames we are going to jump over. */
- kasan_unpoison_stack_above_sp_to(kcb->jprobe_saved_sp);
-
- asm volatile (
-#ifdef CONFIG_X86_64
- " xchg %%rbx,%%rsp \n"
-#else
- " xchgl %%ebx,%%esp \n"
-#endif
- " int3 \n"
- " .globl jprobe_return_end\n"
- " jprobe_return_end: \n"
- " nop \n"::"b"
- (kcb->jprobe_saved_sp):"memory");
-}
-NOKPROBE_SYMBOL(jprobe_return);
-NOKPROBE_SYMBOL(jprobe_return_end);
-
-int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- u8 *addr = (u8 *) (regs->ip - 1);
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- void *saved_sp = kcb->jprobe_saved_sp;
-
- if ((addr > (u8 *) jprobe_return) &&
- (addr < (u8 *) jprobe_return_end)) {
- if (stack_addr(regs) != saved_sp) {
- struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
- printk(KERN_ERR
- "current sp %p does not match saved sp %p\n",
- stack_addr(regs), saved_sp);
- printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
- show_regs(saved_regs);
- printk(KERN_ERR "Current registers\n");
- show_regs(regs);
- BUG();
- }
- /* It's OK to start function graph tracing again */
- unpause_graph_tracing();
- *regs = kcb->jprobe_saved_regs;
- __memcpy(saved_sp, kcb->jprobes_stack, MIN_STACK_SIZE(saved_sp));
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-NOKPROBE_SYMBOL(longjmp_break_handler);
-
bool arch_within_kprobe_blacklist(unsigned long addr)
{
bool is_in_entry_trampoline_section = false;
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