[PATCH v5 3/7] arch/*/uprobes: simplify arch_uretprobe_hijack_return_addr

From: Andrzej Hajda <andrzej.hajda@intel.com>
Date: 2023-01-18 15:46:34
Also in: dri-devel, intel-gfx, linux-alpha, linux-arm-kernel, linux-m68k, linux-mips, linux-riscv, linux-s390, linux-sh, lkml, loongarch, sparclinux
Subsystem: arm port, arm64 port (aarch64 architecture), c-sky architecture, linux for powerpc (32-bit and 64-bit), mips, risc-v architecture, s390 architecture, sparc + ultrasparc (sparc/sparc64), the rest, uprobes · Maintainers: Russell King, Catalin Marinas, Will Deacon, Guo Ren, Madhavan Srinivasan, Michael Ellerman, Thomas Bogendoerfer, Paul Walmsley, Palmer Dabbelt, Albert Ou, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, "David S. Miller", Andreas Larsson, Linus Torvalds, Masami Hiramatsu, Oleg Nesterov, Peter Zijlstra

In all architectures, except x86, arch_uretprobe_hijack_return_addr
is just __xchg.

Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
---
 arch/arm/probes/uprobes/core.c     |  8 ++------
 arch/arm64/kernel/probes/uprobes.c |  9 ++-------
 arch/csky/kernel/probes/uprobes.c  |  9 ++-------
 arch/mips/kernel/uprobes.c         | 10 ++--------
 arch/powerpc/kernel/uprobes.c      | 10 ++--------
 arch/riscv/kernel/probes/uprobes.c |  9 ++-------
 arch/s390/kernel/uprobes.c         |  7 ++-----
 arch/sparc/kernel/uprobes.c        |  7 ++-----
 8 files changed, 16 insertions(+), 53 deletions(-)

diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c
index f5f790c6e5f896..77ce8ae431376d 100644
--- a/arch/arm/probes/uprobes/core.c
+++ b/arch/arm/probes/uprobes/core.c

@@ -9,6 +9,7 @@
 #include <linux/highmem.h>
 #include <linux/sched.h>
 #include <linux/uprobes.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/notifier.h>
 
 #include <asm/opcodes.h>

@@ -61,12 +62,7 @@ unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
 				  struct pt_regs *regs)
 {
-	unsigned long orig_ret_vaddr;
-
-	orig_ret_vaddr = regs->ARM_lr;
-	/* Replace the return addr with trampoline addr */
-	regs->ARM_lr = trampoline_vaddr;
-	return orig_ret_vaddr;
+	return __xchg(&regs->ARM_lr, trampoline_vaddr);
 }
 
 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,

diff --git a/arch/arm64/kernel/probes/uprobes.c b/arch/arm64/kernel/probes/uprobes.c
index d49aef2657cdf7..d7171d30ea6681 100644
--- a/arch/arm64/kernel/probes/uprobes.c
+++ b/arch/arm64/kernel/probes/uprobes.c

@@ -3,6 +3,7 @@
  * Copyright (C) 2014-2016 Pratyush Anand <panand@redhat.com>
  */
 #include <linux/highmem.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/ptrace.h>
 #include <linux/uprobes.h>
 #include <asm/cacheflush.h>

@@ -150,13 +151,7 @@ unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
 				  struct pt_regs *regs)
 {
-	unsigned long orig_ret_vaddr;
-
-	orig_ret_vaddr = procedure_link_pointer(regs);
-	/* Replace the return addr with trampoline addr */
-	procedure_link_pointer_set(regs, trampoline_vaddr);
-
-	return orig_ret_vaddr;
+	return __xchg(&procedure_link_pointer(regs), trampoline_vaddr);
 }
 
 int arch_uprobe_exception_notify(struct notifier_block *self,

diff --git a/arch/csky/kernel/probes/uprobes.c b/arch/csky/kernel/probes/uprobes.c
index 2d31a12e46cfee..775fe88b5f0016 100644
--- a/arch/csky/kernel/probes/uprobes.c
+++ b/arch/csky/kernel/probes/uprobes.c

@@ -3,6 +3,7 @@
  * Copyright (C) 2014-2016 Pratyush Anand <panand@redhat.com>
  */
 #include <linux/highmem.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/ptrace.h>
 #include <linux/uprobes.h>
 #include <asm/cacheflush.h>

@@ -123,13 +124,7 @@ unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
 				  struct pt_regs *regs)
 {
-	unsigned long ra;
-
-	ra = regs->lr;
-
-	regs->lr = trampoline_vaddr;
-
-	return ra;
+	return __xchg(&regs->lr, trampoline_vaddr);
 }
 
 int arch_uprobe_exception_notify(struct notifier_block *self,

diff --git a/arch/mips/kernel/uprobes.c b/arch/mips/kernel/uprobes.c
index 6c063aa188e626..2b1f375c407b87 100644
--- a/arch/mips/kernel/uprobes.c
+++ b/arch/mips/kernel/uprobes.c

@@ -2,6 +2,7 @@
 #include <linux/highmem.h>
 #include <linux/kdebug.h>
 #include <linux/types.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/notifier.h>
 #include <linux/sched.h>
 #include <linux/uprobes.h>

@@ -197,14 +198,7 @@ void arch_uprobe_abort_xol(struct arch_uprobe *aup,
 unsigned long arch_uretprobe_hijack_return_addr(
 	unsigned long trampoline_vaddr, struct pt_regs *regs)
 {
-	unsigned long ra;
-
-	ra = regs->regs[31];
-
-	/* Replace the return address with the trampoline address */
-	regs->regs[31] = trampoline_vaddr;
-
-	return ra;
+	return __xchg(&regs->regs[31], trampoline_vaddr);
 }
 
 /**

diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index 95a41ae9dfa755..3c15c320315e6c 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c

@@ -7,6 +7,7 @@
  * Adapted from the x86 port by Ananth N Mavinakayanahalli <ananth@in.ibm.com>
  */
 #include <linux/kernel.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/sched.h>
 #include <linux/ptrace.h>
 #include <linux/uprobes.h>

@@ -197,14 +198,7 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs)
 {
-	unsigned long orig_ret_vaddr;
-
-	orig_ret_vaddr = regs->link;
-
-	/* Replace the return addr with trampoline addr */
-	regs->link = trampoline_vaddr;
-
-	return orig_ret_vaddr;
+	return __xchg(&regs->link, trampoline_vaddr);
 }
 
 bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,

diff --git a/arch/riscv/kernel/probes/uprobes.c b/arch/riscv/kernel/probes/uprobes.c
index c976a21cd4bd5b..5c8415e216536d 100644
--- a/arch/riscv/kernel/probes/uprobes.c
+++ b/arch/riscv/kernel/probes/uprobes.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
 #include <linux/highmem.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/ptrace.h>
 #include <linux/uprobes.h>

@@ -122,13 +123,7 @@ unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
 				  struct pt_regs *regs)
 {
-	unsigned long ra;
-
-	ra = regs->ra;
-
-	regs->ra = trampoline_vaddr;
-
-	return ra;
+	return __xchg(&regs->ra, trampoline_vaddr);
 }
 
 int arch_uprobe_exception_notify(struct notifier_block *self,

diff --git a/arch/s390/kernel/uprobes.c b/arch/s390/kernel/uprobes.c
index b88345ef8bd9ed..18591ca40ae7e5 100644
--- a/arch/s390/kernel/uprobes.c
+++ b/arch/s390/kernel/uprobes.c

@@ -11,6 +11,7 @@
 #include <linux/compat.h>
 #include <linux/kdebug.h>
 #include <linux/sched/task_stack.h>
+#include <linux/non-atomic/xchg.h>
 
 #include <asm/switch_to.h>
 #include <asm/facility.h>

@@ -144,11 +145,7 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline,
 						struct pt_regs *regs)
 {
-	unsigned long orig;
-
-	orig = regs->gprs[14];
-	regs->gprs[14] = trampoline;
-	return orig;
+	return __xchg(&regs->gprs[14], trampoline);
 }
 
 bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,

diff --git a/arch/sparc/kernel/uprobes.c b/arch/sparc/kernel/uprobes.c
index 1a0600206bf5c2..1c02653d6de3ba 100644
--- a/arch/sparc/kernel/uprobes.c
+++ b/arch/sparc/kernel/uprobes.c

@@ -11,6 +11,7 @@
 
 #include <linux/kernel.h>
 #include <linux/highmem.h>
+#include <linux/non-atomic/xchg.h>
 #include <linux/uprobes.h>
 #include <linux/uaccess.h>
 #include <linux/sched.h> /* For struct task_struct */

@@ -310,9 +311,5 @@ unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
 				  struct pt_regs *regs)
 {
-	unsigned long orig_ret_vaddr = regs->u_regs[UREG_I7];
-
-	regs->u_regs[UREG_I7] = trampoline_vaddr-8;
-
-	return orig_ret_vaddr + 8;
+	return __xchg(&regs->u_regs[UREG_I7], trampoline_vaddr - 8) + 8;
 }

-- 
2.34.1

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