[PATCH -tip v6 08/27] ia64: kprobes: Remove jprobe implementation

Masami Hiramatsu
2018-06-19T16:08:31Z

Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/ia64.

Note that since ia64 jprobes code a bit different
from other arch, this keeps __IA64_BREAK_JPROBE
for checking break_handler. It will be removed
with break_handler() call afterwards.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
---
arch/ia64/include/asm/kprobes.h | 2 -
arch/ia64/kernel/Makefile | 2 -
arch/ia64/kernel/jprobes.S | 90 ---------------------------------------
arch/ia64/kernel/kprobes.c | 70 ------------------------------
4 files changed, 1 insertion(+), 163 deletions(-)
delete mode 100644 arch/ia64/kernel/jprobes.S

diff --git a/arch/ia64/include/asm/kprobes.h b/arch/ia64/include/asm/kprobes.h
index 0302b3664789..580356a2eea6 100644
--- a/arch/ia64/include/asm/kprobes.h
+++ b/arch/ia64/include/asm/kprobes.h
@@ -82,8 +82,6 @@ struct prev_kprobe {
#define ARCH_PREV_KPROBE_SZ 2
struct kprobe_ctlblk {
unsigned long kprobe_status;
- struct pt_regs jprobe_saved_regs;
- unsigned long jprobes_saved_stacked_regs[MAX_PARAM_RSE_SIZE];
unsigned long *bsp;
unsigned long cfm;
atomic_t prev_kprobe_index;
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index 498f3da3f225..d0c0ccdd656a 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -25,7 +25,7 @@ obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_PERFMON) += perfmon_default_smpl.o
obj-$(CONFIG_IA64_CYCLONE) += cyclone.o
obj-$(CONFIG_IA64_MCA_RECOVERY) += mca_recovery.o
-obj-$(CONFIG_KPROBES) += kprobes.o jprobes.o
+obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
diff --git a/arch/ia64/kernel/jprobes.S b/arch/ia64/kernel/jprobes.S
deleted file mode 100644
index f69389c7be1d..000000000000
--- a/arch/ia64/kernel/jprobes.S
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Jprobe specific operations
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Copyright (C) Intel Corporation, 2005
- *
- * 2005-May Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
- * <anil.s.keshavamurthy@intel.com> initial implementation
- *
- * Jprobes (a.k.a. "jump probes" which is built on-top of kprobes) allow a
- * probe to be inserted into the beginning of a function call. The fundamental
- * difference between a jprobe and a kprobe is the jprobe handler is executed
- * in the same context as the target function, while the kprobe handlers
- * are executed in interrupt context.
- *
- * For jprobes we initially gain control by placing a break point in the
- * first instruction of the targeted function. When we catch that specific
- * break, we:
- * * set the return address to our jprobe_inst_return() function
- * * jump to the jprobe handler function
- *
- * Since we fixed up the return address, the jprobe handler will return to our
- * jprobe_inst_return() function, giving us control again. At this point we
- * are back in the parents frame marker, so we do yet another call to our
- * jprobe_break() function to fix up the frame marker as it would normally
- * exist in the target function.
- *
- * Our jprobe_return function then transfers control back to kprobes.c by
- * executing a break instruction using one of our reserved numbers. When we
- * catch that break in kprobes.c, we continue like we do for a normal kprobe
- * by single stepping the emulated instruction, and then returning execution
- * to the correct location.
- */
-#include <asm/asmmacro.h>
-#include <asm/break.h>
-
- /*
- * void jprobe_break(void)
- */
- .section .kprobes.text, "ax"
-ENTRY(jprobe_break)
- break.m __IA64_BREAK_JPROBE
-END(jprobe_break)
-
- /*
- * void jprobe_inst_return(void)
- */
-GLOBAL_ENTRY(jprobe_inst_return)
- br.call.sptk.many b0=jprobe_break
-END(jprobe_inst_return)
-
-GLOBAL_ENTRY(invalidate_stacked_regs)
- movl r16=invalidate_restore_cfm
- ;;
- mov b6=r16
- ;;
- br.ret.sptk.many b6
- ;;
-invalidate_restore_cfm:
- mov r16=ar.rsc
- ;;
- mov ar.rsc=r0
- ;;
- loadrs
- ;;
- mov ar.rsc=r16
- ;;
- br.cond.sptk.many rp
-END(invalidate_stacked_regs)
-
-GLOBAL_ENTRY(flush_register_stack)
- // flush dirty regs to backing store (must be first in insn group)
- flushrs
- ;;
- br.ret.sptk.many rp
-END(flush_register_stack)
-
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index f5f3a5e6fcd1..823e4bd03a18 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -35,8 +35,6 @@
#include <asm/sections.h>
#include <asm/exception.h>

-extern void jprobe_inst_return(void);
-
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

@@ -1040,74 +1038,6 @@ unsigned long arch_deref_entry_point(void *entry)
return ((struct fnptr *)entry)->ip;
}

-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr = arch_deref_entry_point(jp->entry);
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- struct param_bsp_cfm pa;
- int bytes;
-
- /*
- * Callee owns the argument space and could overwrite it, eg
- * tail call optimization. So to be absolutely safe
- * we save the argument space before transferring the control
- * to instrumented jprobe function which runs in
- * the process context
- */
- pa.ip = regs->cr_iip;
- unw_init_running(ia64_get_bsp_cfm, &pa);
- bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
- - (char *)pa.bsp;
- memcpy( kcb->jprobes_saved_stacked_regs,
- pa.bsp,
- bytes );
- kcb->bsp = pa.bsp;
- kcb->cfm = pa.cfm;
-
- /* save architectural state */
- kcb->jprobe_saved_regs = *regs;
-
- /* after rfi, execute the jprobe instrumented function */
- regs->cr_iip = addr & ~0xFULL;
- ia64_psr(regs)->ri = addr & 0xf;
- regs->r1 = ((struct fnptr *)(jp->entry))->gp;
-
- /*
- * fix the return address to our jprobe_inst_return() function
- * in the jprobes.S file
- */
- regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
-
- return 1;
-}
-
-/* ia64 does not need this */
-void __kprobes jprobe_return(void)
-{
-}
-
-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
- struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- int bytes;
-
- /* restoring architectural state */
- *regs = kcb->jprobe_saved_regs;
-
- /* restoring the original argument space */
- flush_register_stack();
- bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
- - (char *)kcb->bsp;
- memcpy( kcb->bsp,
- kcb->jprobes_saved_stacked_regs,
- bytes );
- invalidate_stacked_regs();
-
- preempt_enable_no_resched();
- return 1;
-}
-
static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler
};