linux-kernel - [PATCH v1 1/1] arm64: remove unnecessary ifdefs around is_compat

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Message-ID: <20240105041458.126602-3-leobras@redhat.com>
Date: Fri,  5 Jan 2024 01:15:00 -0300
From: Leonardo Bras <leobras@...hat.com>
To: Oleg Nesterov <oleg@...hat.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Mark Brown <broonie@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	"Steven Rostedt (Google)" <rostedt@...dmis.org>,
	Arnd Bergmann <arnd@...db.de>,
	Leonardo Bras <leobras@...hat.com>,
	Guo Hui <guohui@...ontech.com>
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/1] arm64: remove unnecessary ifdefs around is_compat_task()

Currently some parts of the codebase will test for CONFIG_COMPAT before
testing is_compat_task().

is_compat_task() is a inlined function only present on CONFIG_COMPAT.
On the other hand, for !CONFIG_COMPAT, we have in linux/compat.h:

#define is_compat_task() (0)

Since we have this define available in every usage of is_compat_task() for
!CONFIG_COMPAT, it's unnecessary to keep the ifdefs, since the compiler is
smart enough to optimize-out those snippets on CONFIG_COMPAT=n

Signed-off-by: Leonardo Bras <leobras@...hat.com>
---
Changes since RFCv1:
- Removed unnecessary new inlined is_compat_task() for arm64
- Adjusted commit text and title
Link: https://lore.kernel.org/all/20240104192433.109983-2-leobras@redhat.com/

 arch/arm64/kernel/ptrace.c  | 6 ++----
 arch/arm64/kernel/syscall.c | 5 +----
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 20d7ef82de90a..9f8781f1fdfda 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -173,7 +173,6 @@ static void ptrace_hbptriggered(struct perf_event *bp,
 	struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 	const char *desc = "Hardware breakpoint trap (ptrace)";
 
-#ifdef CONFIG_COMPAT
 	if (is_compat_task()) {
 		int si_errno = 0;
 		int i;
@@ -195,7 +194,7 @@ static void ptrace_hbptriggered(struct perf_event *bp,
 						  desc);
 		return;
 	}
-#endif
+
 	arm64_force_sig_fault(SIGTRAP, TRAP_HWBKPT, bkpt->trigger, desc);
 }
 
@@ -2112,7 +2111,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 {
-#ifdef CONFIG_COMPAT
 	/*
 	 * Core dumping of 32-bit tasks or compat ptrace requests must use the
 	 * user_aarch32_view compatible with arm32. Native ptrace requests on
@@ -2123,7 +2121,7 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 		return &user_aarch32_view;
 	else if (is_compat_thread(task_thread_info(task)))
 		return &user_aarch32_ptrace_view;
-#endif
+
 	return &user_aarch64_view;
 }
 
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 9a70d9746b661..ad198262b9817 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -20,14 +20,11 @@ long sys_ni_syscall(void);
 
 static long do_ni_syscall(struct pt_regs *regs, int scno)
 {
-#ifdef CONFIG_COMPAT
-	long ret;
 	if (is_compat_task()) {
-		ret = compat_arm_syscall(regs, scno);
+		long ret = compat_arm_syscall(regs, scno);
 		if (ret != -ENOSYS)
 			return ret;
 	}
-#endif
 
 	return sys_ni_syscall();
 }
-- 
2.43.0