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From: Amanieu d'Antras <amanieu@gmail.com>
To: linux-arm-kernel@lists.infradead.org
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>
Subject: [RFC PATCH v3 6/8] arm64: Add a compat syscall flag to thread_info
Date: Wed, 21 Apr 2021 20:02:05 +0100	[thread overview]
Message-ID: <20210421190207.1803139-7-amanieu@gmail.com> (raw)
In-Reply-To: <20210421190207.1803139-1-amanieu@gmail.com>

This flag is used by in_compat_syscall to handle compat syscalls coming
from 64-bit tasks.

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      |  5 +++--
 arch/arm64/include/asm/elf.h         | 13 ++++++++++++-
 arch/arm64/include/asm/thread_info.h |  3 +++
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index a2f5001f7793..71de0ba8b160 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -190,13 +190,14 @@ static inline bool is_compat_thread(struct thread_info *thread)
 
 static inline bool in_compat_syscall(void)
 {
-	return is_compat_task();
+	return is_compat_task() ||
+		current_thread_info()->aarch64_compat_syscall;
 }
 #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);
+	return is_compat_thread(thread) || thread->aarch64_compat_syscall;
 }
 
 #else /* !CONFIG_COMPAT */
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index e21964898d06..f4f4ffe37ee5 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -158,10 +158,20 @@ typedef struct user_fpsimd_state elf_fpregset_t;
  */
 #define ELF_PLAT_INIT(_r, load_addr)	(_r)->regs[0] = 0
 
+#ifdef CONFIG_COMPAT
+#define CLEAR_AARCH64_COMPAT_SYSCALL()				\
+({								\
+	current_thread_info()->aarch64_compat_syscall = false;	\
+})
+#else
+#define CLEAR_AARCH64_COMPAT_SYSCALL()	((void)0)
+#endif
+
 #define SET_PERSONALITY(ex)						\
 ({									\
 	clear_thread_flag(TIF_32BIT);					\
 	current->personality &= ~READ_IMPLIES_EXEC;			\
+	CLEAR_AARCH64_COMPAT_SYSCALL();					\
 })
 
 /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
@@ -228,7 +238,8 @@ typedef compat_elf_greg_t		compat_elf_gregset_t[COMPAT_ELF_NGREG];
 #define COMPAT_SET_PERSONALITY(ex)					\
 ({									\
 	set_thread_flag(TIF_32BIT);					\
- })
+	CLEAR_AARCH64_COMPAT_SYSCALL();					\
+})
 #ifdef CONFIG_COMPAT_VDSO
 #define COMPAT_ARCH_DLINFO						\
 do {									\
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 6623c99f0984..756e977fc37a 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -42,6 +42,9 @@ struct thread_info {
 	void			*scs_base;
 	void			*scs_sp;
 #endif
+#ifdef CONFIG_COMPAT
+	bool			aarch64_compat_syscall;
+#endif
 };
 
 #define thread_saved_pc(tsk)	\
-- 
2.31.1


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  parent reply	other threads:[~2021-04-21 19:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-21 19:01 [RFC PATCH v3 0/8] arm64: Allow 64-bit tasks to invoke compat syscalls Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 1/8] mm: Add arch_get_mmap_base_topdown macro Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 2/8] hugetlbfs: Use arch_get_mmap_* macros Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 3/8] mm: Support mmap_compat_base with the generic layout Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 4/8] arm64: Separate in_compat_syscall from is_compat_task Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 5/8] arm64: mm: Use HAVE_ARCH_COMPAT_MMAP_BASES Amanieu d'Antras
2021-04-21 19:02 ` Amanieu d'Antras [this message]
2021-04-22  8:37   ` [RFC PATCH v3 6/8] arm64: Add a compat syscall flag to thread_info David Laight
2021-04-22 13:14     ` Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 7/8] arm64: Forbid calling compat sigreturn from 64-bit tasks Amanieu d'Antras
2021-04-21 19:02 ` [RFC PATCH v3 8/8] arm64: Allow 64-bit tasks to invoke compat syscalls Amanieu d'Antras

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