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From: Amanieu d'Antras <amanieu@gmail.com>
Cc: Amanieu d'Antras <amanieu@gmail.com>,
	Ryan Houdek <Houdek.Ryan@fex-emu.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Steven Price <steven.price@arm.com>,
	Arnd Bergmann <arnd@kernel.org>,
	David Laight <David.Laight@aculab.com>,
	Mark Brown <broonie@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 4/8] arm64: Separate in_compat_syscall from is_compat_task
Date: Fri, 30 Apr 2021 21:37:53 +0100	[thread overview]
Message-ID: <20210430203757.47653-3-amanieu@gmail.com> (raw)
In-Reply-To: <20210430202810.44092-1-amanieu@gmail.com>

This is preliminary work for allowing 64-bit processes to invoke compat
syscalls.

Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
Co-developed-by: Ryan Houdek <Houdek.Ryan@fex-emu.org>
Signed-off-by: Ryan Houdek <Houdek.Ryan@fex-emu.org>
---
 arch/arm64/include/asm/compat.h  | 24 ++++++++++++++++++++----
 arch/arm64/include/asm/ftrace.h  |  2 +-
 arch/arm64/include/asm/syscall.h |  6 +++---
 arch/arm64/kernel/ptrace.c       |  2 +-
 arch/arm64/kernel/syscall.c      |  2 +-
 5 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index 23a9fb73c04f..a2f5001f7793 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -178,21 +178,37 @@ struct compat_shmid64_ds {
 	compat_ulong_t __unused5;
 };
 
-static inline int is_compat_task(void)
+static inline bool is_compat_task(void)
 {
 	return test_thread_flag(TIF_32BIT);
 }
 
-static inline int is_compat_thread(struct thread_info *thread)
+static inline bool is_compat_thread(struct thread_info *thread)
 {
 	return test_ti_thread_flag(thread, TIF_32BIT);
 }
 
+static inline bool in_compat_syscall(void)
+{
+	return is_compat_task();
+}
+#define in_compat_syscall in_compat_syscall	/* override the generic impl */
+
+static inline bool thread_in_compat_syscall(struct thread_info *thread)
+{
+	return is_compat_thread(thread);
+}
+
 #else /* !CONFIG_COMPAT */
 
-static inline int is_compat_thread(struct thread_info *thread)
+static inline bool is_compat_thread(struct thread_info *thread)
+{
+	return false;
+}
+
+static inline bool thread_in_compat_syscall(struct thread_info *thread)
 {
-	return 0;
+	return false;
 }
 
 #endif /* CONFIG_COMPAT */
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 91fa4baa1a93..f41aad92c67a 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -88,7 +88,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
 {
-	return is_compat_task();
+	return in_compat_syscall();
 }
 
 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index cfc0672013f6..0dfc01ea386c 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -35,7 +35,7 @@ static inline long syscall_get_error(struct task_struct *task,
 {
 	unsigned long error = regs->regs[0];
 
-	if (is_compat_thread(task_thread_info(task)))
+	if (thread_in_compat_syscall(task_thread_info(task)))
 		error = sign_extend64(error, 31);
 
 	return IS_ERR_VALUE(error) ? error : 0;
@@ -54,7 +54,7 @@ static inline void syscall_set_return_value(struct task_struct *task,
 	if (error)
 		val = error;
 
-	if (is_compat_thread(task_thread_info(task)))
+	if (thread_in_compat_syscall(task_thread_info(task)))
 		val = lower_32_bits(val);
 
 	regs->regs[0] = val;
@@ -88,7 +88,7 @@ static inline void syscall_set_arguments(struct task_struct *task,
  */
 static inline int syscall_get_arch(struct task_struct *task)
 {
-	if (is_compat_thread(task_thread_info(task)))
+	if (thread_in_compat_syscall(task_thread_info(task)))
 		return AUDIT_ARCH_ARM;
 
 	return AUDIT_ARCH_AARCH64;
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 170f42fd6101..017a82b24f49 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1721,7 +1721,7 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 	 * 32-bit children use an extended user_aarch32_ptrace_view to allow
 	 * access to the TLS register.
 	 */
-	if (is_compat_task())
+	if (in_compat_syscall())
 		return &user_aarch32_view;
 	else if (is_compat_thread(task_thread_info(task)))
 		return &user_aarch32_ptrace_view;
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index b9cf12b271d7..e0e9d54de0a2 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -51,7 +51,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno,
 		ret = do_ni_syscall(regs, scno);
 	}
 
-	if (is_compat_task())
+	if (in_compat_syscall())
 		ret = lower_32_bits(ret);
 
 	regs->regs[0] = ret;
-- 
2.31.1


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  parent reply	other threads:[~2021-04-30 20:41 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-30 20:28 [PATCH v4 0/8] arm64: Allow 64-bit tasks to invoke compat syscalls Amanieu d'Antras
2021-04-30 20:28 ` [PATCH v4 1/8] mm: Add arch_get_mmap_base_topdown macro Amanieu d'Antras
2021-04-30 20:37 ` [PATCH v4 2/8] hugetlbfs: Use arch_get_mmap_* macros Amanieu d'Antras
2021-04-30 20:37 ` [PATCH v4 3/8] mm: Support mmap_compat_base with the generic layout Amanieu d'Antras
2021-04-30 20:37 ` Amanieu d'Antras [this message]
2021-04-30 20:37 ` [PATCH v4 5/8] arm64: mm: Use HAVE_ARCH_COMPAT_MMAP_BASES Amanieu d'Antras
2021-04-30 20:37 ` [PATCH v4 6/8] arm64: Add a compat syscall flag to thread_info Amanieu d'Antras
2021-04-30 20:37 ` [PATCH v4 7/8] arm64: Forbid calling compat sigreturn from 64-bit tasks Amanieu d'Antras
2021-04-30 20:37 ` [PATCH v4 8/8] arm64: Allow 64-bit tasks to invoke compat syscalls Amanieu d'Antras

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