| Message ID | 20201203062949.5484-10-rppt@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: introduce memfd_secret system call to create "secret" memory areas | expand |
On Thu, 3 Dec 2020 08:29:48 +0200 Mike Rapoport <rppt@kernel.org> wrote: > 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. > > ... > > --- 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 Why do we add the ifdef? Can't we simply define the syscall on all architectures and let sys_ni do its thing?
On Thu, Dec 03, 2020 at 03:39:16PM -0800, Andrew Morton wrote: > On Thu, 3 Dec 2020 08:29:48 +0200 Mike Rapoport <rppt@kernel.org> wrote: > > > 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. > > > > ... > > > > --- 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 > > Why do we add the ifdef? Can't we simply define the syscall on all > architectures and let sys_ni do its thing? I quite blindly copied it from clone3. I agree there is no real need for it and sys_ni handles this just fine.
On Thu, 2020-12-03 at 08:29 +0200, Mike Rapoport wrote: > 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 I can't see where was it defined for arm64 after it looks like Andrew has deleted the above chunk. Thus, we have a warning using this .config: https://cailca.coding.net/public/linux/mm/git/files/master/arm64.config <stdin>:1539:2: warning: #warning syscall memfd_secret not implemented [-Wcpp] > > #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 7236f4d9458a..b8a32954ac68 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 */ >
On Mon, Dec 07, 2020 at 09:45:59AM -0500, Qian Cai wrote: > On Thu, 2020-12-03 at 08:29 +0200, Mike Rapoport wrote: ... > > 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 > > I can't see where was it defined for arm64 after it looks like Andrew has > deleted the above chunk. Thus, we have a warning using this .config: > > https://cailca.coding.net/public/linux/mm/git/files/master/arm64.config > > <stdin>:1539:2: warning: #warning syscall memfd_secret not implemented [-Wcpp] I was under the impression that Andrew only removed the #ifdef... Andrew, can you please restore syscall definition for memfd_secret() in include/uapi/asm-generic/unistd.h? > > > > #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 7236f4d9458a..b8a32954ac68 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 */ > > >
On Mon, 7 Dec 2020 18:00:06 +0200 Mike Rapoport <rppt@linux.ibm.com> wrote: > > > > I can't see where was it defined for arm64 after it looks like Andrew has > > deleted the above chunk. Thus, we have a warning using this .config: > > > > https://cailca.coding.net/public/linux/mm/git/files/master/arm64.config > > > > <stdin>:1539:2: warning: #warning syscall memfd_secret not implemented [-Wcpp] > > I was under the impression that Andrew only removed the #ifdef... > > Andrew, can you please restore syscall definition for memfd_secret() in > include/uapi/asm-generic/unistd.h? > urgh, OK, that seems to have got lost in the (moderate amount of) conflict resolution). --- a/include/uapi/asm-generic/unistd.h~arch-mm-wire-up-memfd_secret-system-call-were-relevant-fix +++ a/include/uapi/asm-generic/unistd.h @@ -863,9 +863,13 @@ __SYSCALL(__NR_process_madvise, sys_proc __SYSCALL(__NR_watch_mount, sys_watch_mount) #define __NR_epoll_pwait2 442 __SC_COMP(__NR_epoll_pwait2, sys_epoll_pwait2, compat_sys_epoll_pwait2) +#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/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 7236f4d9458a..b8a32954ac68 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 */