linux-kernel - [RFC PATCH 3/4] riscv: Introduce is_compat

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Message-ID: <20231222074605.452452-4-leobras@redhat.com>
Date: Fri, 22 Dec 2023 04:46:03 -0300
From: Leonardo Bras <leobras@...hat.com>
To: Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Eric Biederman <ebiederm@...ssion.com>,
	Kees Cook <keescook@...omium.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Leonardo Bras <leobras@...hat.com>,
	Conor Dooley <conor.dooley@...rochip.com>,
	Andy Chiu <andy.chiu@...ive.com>,
	Greg Ungerer <gerg@...nel.org>,
	Vincent Chen <vincent.chen@...ive.com>,
	Xiao Wang <xiao.w.wang@...el.com>,
	Charlie Jenkins <charlie@...osinc.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alexandre Ghiti <alexghiti@...osinc.com>,
	Kemeng Shi <shikemeng@...weicloud.com>,
	David Hildenbrand <david@...hat.com>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Qinglin Pan <panqinglin2020@...as.ac.cn>,
	Greentime Hu <greentime.hu@...ive.com>,
	Björn Töpel <bjorn@...osinc.com>,
	Clément Léger <cleger@...osinc.com>,
	Guo Ren <guoren@...nel.org>
Cc: linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [RFC PATCH 3/4] riscv: Introduce is_compat_thread() into compat.h

task_user_regset_view() makes use of a function very similar to
is_compat_task(), but pointing to a any thread.

In arm64 asm/compat.h there is a function very similar to that:
is_compat_thread(struct thread_info *thread)

Copy this function to riscv asm/compat.h and make use of it into
task_user_regset_view().

Also, introduce a compile-time test for CONFIG_COMPAT and simplify the
function code by removing the #ifdef.

Signed-off-by: Leonardo Bras <leobras@...hat.com>
---
 arch/riscv/include/asm/compat.h | 8 ++++++++
 arch/riscv/kernel/ptrace.c      | 6 +++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/compat.h b/arch/riscv/include/asm/compat.h
index 91517b51b8e27..da4b28cd01a95 100644
--- a/arch/riscv/include/asm/compat.h
+++ b/arch/riscv/include/asm/compat.h
@@ -20,6 +20,14 @@ static inline int is_compat_task(void)
 	return test_thread_flag(TIF_32BIT);
 }
 
+static inline int is_compat_thread(struct thread_info *thread)
+{
+	if (!IS_ENABLED(CONFIG_COMPAT))
+		return 0;
+
+	return test_ti_thread_flag(thread, TIF_32BIT);
+}
+
 struct compat_user_regs_struct {
 	compat_ulong_t pc;
 	compat_ulong_t ra;
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 2afe460de16a6..f362832123616 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -374,14 +374,14 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 	return ret;
 }
+#else
+static const struct user_regset_view compat_riscv_user_native_view = {};
 #endif /* CONFIG_COMPAT */
 
 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 {
-#ifdef CONFIG_COMPAT
-	if (test_tsk_thread_flag(task, TIF_32BIT))
+	if (is_compat_thread(&task->thread_info))
 		return &compat_riscv_user_native_view;
 	else
-#endif
 		return &riscv_user_native_view;
 }
-- 
2.43.0