diff mbox series

[v14,09/10] arch, mm: wire up memfd_secret system call were relevant

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

Commit Message

Mike Rapoport Dec. 3, 2020, 6:29 a.m. UTC
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(-)

Comments

Andrew Morton Dec. 3, 2020, 11:39 p.m. UTC | #1
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?
Mike Rapoport Dec. 6, 2020, 11:30 a.m. UTC | #2
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.
Qian Cai Dec. 7, 2020, 2:45 p.m. UTC | #3
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 */
>
Mike Rapoport Dec. 7, 2020, 4 p.m. UTC | #4
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 */
> >  
>
Andrew Morton Dec. 8, 2020, 1:34 a.m. UTC | #5
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 mbox series

Patch

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 */