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From:   Mike Rapoport <rppt@kernel.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
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        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
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        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Mike Rapoport <rppt@kernel.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
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        Tycho Andersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>,
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        x86@kernel.org, Palmer Dabbelt <palmerdabbelt@google.com>
Subject: [PATCH v12 09/10] arch, mm: wire up memfd_secret system call were relevant
Date:   Wed, 25 Nov 2020 11:22:07 +0200
Message-Id: <20201125092208.12544-10-rppt@kernel.org>
In-Reply-To: <20201125092208.12544-1-rppt@kernel.org>
References: <20201125092208.12544-1-rppt@kernel.org>
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From: Mike Rapoport <rppt@linux.ibm.com>

Wire up memfd_secret system call on architectures that define
ARCH_HAS_SET_DIRECT_MAP, namely arm64, risc-v and x86.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm64/include/uapi/asm/unistd.h   | 1 +
 arch/riscv/include/asm/unistd.h        | 1 +
 arch/x86/entry/syscalls/syscall_32.tbl | 1 +
 arch/x86/entry/syscalls/syscall_64.tbl | 1 +
 include/linux/syscalls.h               | 1 +
 include/uapi/asm-generic/unistd.h      | 6 +++++-
 mm/secretmem.c                         | 3 +++
 scripts/checksyscalls.sh               | 4 ++++
 8 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/uapi/asm/unistd.h b/arch/arm64/include/uapi/asm/unistd.h
index f83a70e07df8..ce2ee8f1e361 100644
--- a/arch/arm64/include/uapi/asm/unistd.h
+++ b/arch/arm64/include/uapi/asm/unistd.h
@@ -20,5 +20,6 @@
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_TIME32_SYSCALLS
 #define __ARCH_WANT_SYS_CLONE3
+#define __ARCH_WANT_MEMFD_SECRET
 
 #include <asm-generic/unistd.h>
diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h
index 977ee6181dab..6c316093a1e5 100644
--- a/arch/riscv/include/asm/unistd.h
+++ b/arch/riscv/include/asm/unistd.h
@@ -9,6 +9,7 @@
  */
 
 #define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_MEMFD_SECRET
 
 #include <uapi/asm/unistd.h>
 
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c52ab1c4a755..109e6681b8fa 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -446,3 +446,4 @@
 439	i386	faccessat2		sys_faccessat2
 440	i386	process_madvise		sys_process_madvise
 441	i386	watch_mount		sys_watch_mount
+442	i386	memfd_secret		sys_memfd_secret
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index f3270a9ef467..742cf17d7725 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -363,6 +363,7 @@
 439	common	faccessat2		sys_faccessat2
 440	common	process_madvise		sys_process_madvise
 441	common	watch_mount		sys_watch_mount
+442	common	memfd_secret		sys_memfd_secret
 
 #
 # Due to a historical design error, certain syscalls are numbered differently
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 6d55324363ab..f9d93fbf9b69 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1010,6 +1010,7 @@ asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
 asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
 asmlinkage long sys_watch_mount(int dfd, const char __user *path,
 				unsigned int at_flags, int watch_fd, int watch_id);
+asmlinkage long sys_memfd_secret(unsigned long flags);
 
 /*
  * Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 5df46517260e..51151888f330 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -861,9 +861,13 @@ __SYSCALL(__NR_faccessat2, sys_faccessat2)
 __SYSCALL(__NR_process_madvise, sys_process_madvise)
 #define __NR_watch_mount 441
 __SYSCALL(__NR_watch_mount, sys_watch_mount)
+#ifdef __ARCH_WANT_MEMFD_SECRET
+#define __NR_memfd_secret 442
+__SYSCALL(__NR_memfd_secret, sys_memfd_secret)
+#endif
 
 #undef __NR_syscalls
-#define __NR_syscalls 442
+#define __NR_syscalls 443
 
 /*
  * 32 bit systems traditionally used different
diff --git a/mm/secretmem.c b/mm/secretmem.c
index f7398eb810c5..6ee378852482 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -415,6 +415,9 @@ static int __init secretmem_setup(char *str)
 	unsigned long reserved_size;
 	int err;
 
+	if (!can_set_direct_map())
+		return 0;
+
 	reserved_size = memparse(str, NULL);
 	if (!reserved_size)
 		return 0;
diff --git a/scripts/checksyscalls.sh b/scripts/checksyscalls.sh
index a18b47695f55..b7609958ee36 100755
--- a/scripts/checksyscalls.sh
+++ b/scripts/checksyscalls.sh
@@ -40,6 +40,10 @@ cat << EOF
 #define __IGNORE_setrlimit	/* setrlimit */
 #endif
 
+#ifndef __ARCH_WANT_MEMFD_SECRET
+#define __IGNORE_memfd_secret
+#endif
+
 /* Missing flags argument */
 #define __IGNORE_renameat	/* renameat2 */
 
-- 
2.28.0