[PATCH v16 10/11] arch, mm: wire up memfd_secret system call where relevant

From: Mike Rapoport <rppt@kernel.org>
Date: 2021-01-21 12:36:53
Also in: linux-api, linux-arch, linux-fsdevel, linux-kselftest, linux-mm, linux-riscv, lkml, nvdimm
Reply to: Mike Rapoport, 2021-01-21

From: Mike Rapoport <redacted>

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 <redacted>
Acked-by: Palmer Dabbelt <redacted>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <redacted>
Cc: Dan Williams <redacted>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <redacted>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hagen Paul Pfeifer <redacted>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <redacted>
Cc: "Kirill A. Shutemov" <redacted>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Kerrisk <redacted>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <redacted>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Roman Gushchin <redacted>
Cc: Shakeel Butt <redacted>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <redacted>
Cc: Tycho Andersen <redacted>
Cc: Will Deacon <will@kernel.org>
---
 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 02a349afaf9c..a1578cdf6d91 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl

@@ -447,3 +447,4 @@
 440	i386	process_madvise		sys_process_madvise
 441	i386	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
 442	i386	watch_mount		sys_watch_mount
+443	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 d9bcc4e02588..d8ecd9df0942 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl

@@ -364,6 +364,7 @@
 440	common	process_madvise		sys_process_madvise
 441	common	epoll_pwait2		sys_epoll_pwait2
 442	common	watch_mount		sys_watch_mount
+443	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 28bde029109d..4bc70ac0e993 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h

@@ -1039,6 +1039,7 @@ 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 ad58f661f4aa..26125974a8a2 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h

@@ -863,9 +863,13 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
 __SC_COMP(__NR_epoll_pwait2, sys_epoll_pwait2, compat_sys_epoll_pwait2)
 #define __NR_watch_mount 442
 __SYSCALL(__NR_watch_mount, sys_watch_mount)
+#ifdef __ARCH_WANT_MEMFD_SECRET
+#define __NR_memfd_secret 443
+__SYSCALL(__NR_memfd_secret, sys_memfd_secret)
+#endif
 
 #undef __NR_syscalls
-#define __NR_syscalls 443
+#define __NR_syscalls 444
 
 /*
  * 32 bit systems traditionally used different

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 6ef32ad08184..3d78b2807a2e 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c

@@ -427,6 +427,9 @@ 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


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