diff mbox series

[V4,08/17] riscv: compat: syscall: Add compat_sys_call_table implementation

Message ID 20220129121728.1079364-9-guoren@kernel.org (mailing list archive)
State New, archived
Headers show
Series riscv: compat: Add COMPAT mode support for rv64 | expand

Commit Message

Guo Ren Jan. 29, 2022, 12:17 p.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

Implement compat sys_call_table and some system call functions:
truncate64, ftruncate64, fallocate, pread64, pwrite64,
sync_file_range, readahead, fadvise64_64 which need argument
translation.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/riscv/include/asm/syscall.h         |  1 +
 arch/riscv/include/asm/unistd.h          | 11 +++++++
 arch/riscv/include/uapi/asm/unistd.h     |  2 +-
 arch/riscv/kernel/Makefile               |  1 +
 arch/riscv/kernel/compat_syscall_table.c | 19 ++++++++++++
 arch/riscv/kernel/sys_riscv.c            |  6 ++--
 fs/open.c                                | 24 +++++++++++++++
 fs/read_write.c                          | 16 ++++++++++
 fs/sync.c                                |  9 ++++++
 include/asm-generic/compat.h             |  7 +++++
 include/linux/compat.h                   | 37 ++++++++++++++++++++++++
 mm/fadvise.c                             | 11 +++++++
 mm/readahead.c                           |  7 +++++
 13 files changed, 148 insertions(+), 3 deletions(-)
 create mode 100644 arch/riscv/kernel/compat_syscall_table.c

Comments

Arnd Bergmann Jan. 29, 2022, 10:12 p.m. UTC | #1 
> Implement compat sys_call_table and some system call functions:
> truncate64, ftruncate64, fallocate, pread64, pwrite64,
> sync_file_range, readahead, fadvise64_64 which need argument
> translation.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>

This all looks really good, but I would change one detail:

> +#ifndef compat_arg_u64
> +#define compat_arg_u64(name)           u32  name##_lo, u32  name##_hi
> +#define compat_arg_u64_dual(name)      u32, name##_lo, u32, name##_hi
> +#define compat_arg_u64_glue(name)      (((u64)name##_hi << 32) | \
> +                                        ((u64)name##_lo & 0xffffffffUL))
> +#endif

I would make these endian-specific, and reverse them on big-endian
architectures. That way it
should be possible to share them across all compat architectures
without needing the override
option.

        Arnd
Guo Ren Jan. 30, 2022, 5:54 a.m. UTC | #2 
On Sun, Jan 30, 2022 at 6:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> > Implement compat sys_call_table and some system call functions:
> > truncate64, ftruncate64, fallocate, pread64, pwrite64,
> > sync_file_range, readahead, fadvise64_64 which need argument
> > translation.
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren@kernel.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
>
> This all looks really good, but I would change one detail:
>
> > +#ifndef compat_arg_u64
> > +#define compat_arg_u64(name)           u32  name##_lo, u32  name##_hi
> > +#define compat_arg_u64_dual(name)      u32, name##_lo, u32, name##_hi
> > +#define compat_arg_u64_glue(name)      (((u64)name##_hi << 32) | \
> > +                                        ((u64)name##_lo & 0xffffffffUL))
> > +#endif
>
> I would make these endian-specific, and reverse them on big-endian
> architectures. That way it
> should be possible to share them across all compat architectures
> without needing the override
> option.
I hope it could be another patch. Because it's not clear to
_LITTLE_ENDIAN definition in archs.

eg: Names could be __ORDER_LITTLE_ENDIAN__ CPU_LITTLE_ENDIAN
SYS_SUPPORTS_LITTLE_ENDIAN __LITTLE_ENDIAN

riscv is little-endian, but no any LITTLE_ENDIAN definition.

So let's keep them in the patch, first, Thx

>
>         Arnd
Arnd Bergmann Jan. 30, 2022, 11:32 a.m. UTC | #3 
On Sun, Jan 30, 2022 at 6:54 AM Guo Ren <guoren@kernel.org> wrote:
> On Sun, Jan 30, 2022 at 6:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > I would make these endian-specific, and reverse them on big-endian
> > architectures. That way it
> > should be possible to share them across all compat architectures
> > without needing the override
> > option.
> I hope it could be another patch. Because it's not clear to
> _LITTLE_ENDIAN definition in archs.
>
> eg: Names could be __ORDER_LITTLE_ENDIAN__ CPU_LITTLE_ENDIAN
> SYS_SUPPORTS_LITTLE_ENDIAN __LITTLE_ENDIAN
>
> riscv is little-endian, but no any LITTLE_ENDIAN definition.
>
> So let's keep them in the patch, first, Thx

The correct way to do it is to check for CONFIG_CPU_BIG_ENDIAN,
which works on all architectures. Since nothing else selects the
__ARCH_WANT_COMPAT_* symbols, there is also no risk for
regressions, so just use this and leave the #ifndef compat_arg_u64
check in place.

      Arnd
Guo Ren Jan. 30, 2022, 2:57 p.m. UTC | #4 
On Sun, Jan 30, 2022 at 7:32 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Sun, Jan 30, 2022 at 6:54 AM Guo Ren <guoren@kernel.org> wrote:
> > On Sun, Jan 30, 2022 at 6:41 AM Arnd Bergmann <arnd@arndb.de> wrote:
> > >
> > > I would make these endian-specific, and reverse them on big-endian
> > > architectures. That way it
> > > should be possible to share them across all compat architectures
> > > without needing the override
> > > option.
> > I hope it could be another patch. Because it's not clear to
> > _LITTLE_ENDIAN definition in archs.
> >
> > eg: Names could be __ORDER_LITTLE_ENDIAN__ CPU_LITTLE_ENDIAN
> > SYS_SUPPORTS_LITTLE_ENDIAN __LITTLE_ENDIAN
> >
> > riscv is little-endian, but no any LITTLE_ENDIAN definition.
> >
> > So let's keep them in the patch, first, Thx
>
> The correct way to do it is to check for CONFIG_CPU_BIG_ENDIAN,
> which works on all architectures. Since nothing else selects the
> __ARCH_WANT_COMPAT_* symbols, there is also no risk for
> regressions, so just use this and leave the #ifndef compat_arg_u64
> check in place.
Okay, got it.

>
>       Arnd
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 7ac6a0e275f2..384a63b86420 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -16,6 +16,7 @@ 
 
 /* The array of function pointers for syscalls. */
 extern void * const sys_call_table[];
+extern void * const compat_sys_call_table[];
 
 /*
  * Only the low 32 bits of orig_r0 are meaningful, so we return int.
diff --git a/arch/riscv/include/asm/unistd.h b/arch/riscv/include/asm/unistd.h
index 6c316093a1e5..5ddac412b578 100644
--- a/arch/riscv/include/asm/unistd.h
+++ b/arch/riscv/include/asm/unistd.h
@@ -11,6 +11,17 @@ 
 #define __ARCH_WANT_SYS_CLONE
 #define __ARCH_WANT_MEMFD_SECRET
 
+#ifdef CONFIG_COMPAT
+#define __ARCH_WANT_COMPAT_TRUNCATE64
+#define __ARCH_WANT_COMPAT_FTRUNCATE64
+#define __ARCH_WANT_COMPAT_FALLOCATE
+#define __ARCH_WANT_COMPAT_PREAD64
+#define __ARCH_WANT_COMPAT_PWRITE64
+#define __ARCH_WANT_COMPAT_SYNC_FILE_RANGE
+#define __ARCH_WANT_COMPAT_READAHEAD
+#define __ARCH_WANT_COMPAT_FADVISE64_64
+#endif
+
 #include <uapi/asm/unistd.h>
 
 #define NR_syscalls (__NR_syscalls)
diff --git a/arch/riscv/include/uapi/asm/unistd.h b/arch/riscv/include/uapi/asm/unistd.h
index 8062996c2dfd..c9e50eed14aa 100644
--- a/arch/riscv/include/uapi/asm/unistd.h
+++ b/arch/riscv/include/uapi/asm/unistd.h
@@ -15,7 +15,7 @@ 
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifdef __LP64__
+#if defined(__LP64__) && !defined(__SYSCALL_COMPAT)
 #define __ARCH_WANT_NEW_STAT
 #define __ARCH_WANT_SET_GET_RLIMIT
 #endif /* __LP64__ */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 612556faa527..954dc7043ad2 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -66,3 +66,4 @@  obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 
 obj-$(CONFIG_EFI)		+= efi.o
+obj-$(CONFIG_COMPAT)		+= compat_syscall_table.o
diff --git a/arch/riscv/kernel/compat_syscall_table.c b/arch/riscv/kernel/compat_syscall_table.c
new file mode 100644
index 000000000000..651f2b009c28
--- /dev/null
+++ b/arch/riscv/kernel/compat_syscall_table.c
@@ -0,0 +1,19 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define __SYSCALL_COMPAT
+
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <asm-generic/mman-common.h>
+#include <asm-generic/syscalls.h>
+#include <asm/syscall.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call)      [nr] = (call),
+
+asmlinkage long compat_sys_rt_sigreturn(void);
+
+void * const compat_sys_call_table[__NR_syscalls] = {
+	[0 ... __NR_syscalls - 1] = sys_ni_syscall,
+#include <asm/unistd.h>
+};
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 12f8a7fce78b..9c0194f176fc 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -33,7 +33,9 @@  SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 {
 	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
 }
-#else
+#endif
+
+#if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT)
 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags,
 	unsigned long, fd, off_t, offset)
@@ -44,7 +46,7 @@  SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	 */
 	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
 }
-#endif /* !CONFIG_64BIT */
+#endif
 
 /*
  * Allows the instruction cache to be flushed from userspace.  Despite RISC-V
diff --git a/fs/open.c b/fs/open.c
index 9ff2f621b760..b25613f7c0a7 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -224,6 +224,21 @@  SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
 }
 #endif /* BITS_PER_LONG == 32 */
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64)
+COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
+		       compat_arg_u64_dual(length))
+{
+	return ksys_truncate(pathname, compat_arg_u64_glue(length));
+}
+#endif
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64)
+COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd,
+		       compat_arg_u64_dual(length))
+{
+	return ksys_ftruncate(fd, compat_arg_u64_glue(length));
+}
+#endif
 
 int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
@@ -339,6 +354,15 @@  SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
 	return ksys_fallocate(fd, mode, offset, len);
 }
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE)
+COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode, compat_arg_u64_dual(offset),
+		       compat_arg_u64_dual(len))
+{
+	return ksys_fallocate(fd, mode, compat_arg_u64_glue(offset),
+			      compat_arg_u64_glue(len));
+}
+#endif
+
 /*
  * access() needs to use the real uid/gid, not the effective uid/gid.
  * We do this by temporarily clearing all FS-related capabilities and
diff --git a/fs/read_write.c b/fs/read_write.c
index 0074afa7ecb3..548657c462e8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -681,6 +681,14 @@  SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
 	return ksys_pread64(fd, buf, count, pos);
 }
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PREAD64)
+COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf,
+		       size_t, count, compat_arg_u64_dual(pos))
+{
+	return ksys_pread64(fd, buf, count, compat_arg_u64_glue(pos));
+}
+#endif
+
 ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,
 		      size_t count, loff_t pos)
 {
@@ -707,6 +715,14 @@  SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
 	return ksys_pwrite64(fd, buf, count, pos);
 }
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PWRITE64)
+COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd, const char __user *, buf,
+		       size_t, count, compat_arg_u64_dual(pos))
+{
+	return ksys_pwrite64(fd, buf, count, compat_arg_u64_glue(pos));
+}
+#endif
+
 static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 		loff_t *ppos, int type, rwf_t flags)
 {
diff --git a/fs/sync.c b/fs/sync.c
index 3ce8e2137f31..75edb7a664e5 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -367,6 +367,15 @@  SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
 	return ksys_sync_file_range(fd, offset, nbytes, flags);
 }
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_SYNC_FILE_RANGE)
+COMPAT_SYSCALL_DEFINE6(sync_file_range, int, fd, compat_arg_u64_dual(offset),
+		       compat_arg_u64_dual(nbytes), unsigned int, flags)
+{
+	return ksys_sync_file_range(fd, compat_arg_u64_glue(offset),
+				    compat_arg_u64_glue(nbytes), flags);
+}
+#endif
+
 /* It would be nice if people remember that not all the world's an i386
    when they introduce new system calls */
 SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags,
diff --git a/include/asm-generic/compat.h b/include/asm-generic/compat.h
index 32269059058a..cdf1124a4883 100644
--- a/include/asm-generic/compat.h
+++ b/include/asm-generic/compat.h
@@ -14,6 +14,13 @@ 
 #define COMPAT_OFF_T_MAX	0x7fffffff
 #endif
 
+#ifndef compat_arg_u64
+#define compat_arg_u64(name)		u32  name##_lo, u32  name##_hi
+#define compat_arg_u64_dual(name)	u32, name##_lo, u32, name##_hi
+#define compat_arg_u64_glue(name)	(((u64)name##_hi << 32) | \
+					 ((u64)name##_lo & 0xffffffffUL))
+#endif
+
 /* These types are common across all compat ABIs */
 typedef u32 compat_size_t;
 typedef s32 compat_ssize_t;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 1c758b0e0359..841d882c41e2 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -895,6 +895,43 @@  asmlinkage long compat_sys_sigaction(int sig,
 /* obsolete: net/socket.c */
 asmlinkage long compat_sys_socketcall(int call, u32 __user *args);
 
+#ifdef __ARCH_WANT_COMPAT_TRUNCATE64
+asmlinkage long compat_sys_truncate64(const char __user *pathname, compat_arg_u64(len));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_FTRUNCATE64
+asmlinkage long compat_sys_ftruncate64(unsigned int fd, compat_arg_u64(len));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_FALLOCATE
+asmlinkage long compat_sys_fallocate(int fd, int mode, compat_arg_u64(offset),
+				     compat_arg_u64(len));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_PREAD64
+asmlinkage long compat_sys_pread64(unsigned int fd, char __user * buf, size_t count,
+				   compat_arg_u64(pos));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_PWRITE64
+asmlinkage long compat_sys_pwrite64(unsigned int fd, const char __user * buf, size_t count,
+				    compat_arg_u64(pos));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_SYNC_FILE_RANGE
+asmlinkage long compat_sys_sync_file_range(int fd, compat_arg_u64(pos),
+					   compat_arg_u64(nbytes), unsigned int flags);
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_FADVISE64_64
+asmlinkage long compat_sys_fadvise64_64(int fd, int advice, compat_arg_u64(pos),
+					compat_arg_u64(len));
+#endif
+
+#ifdef __ARCH_WANT_COMPAT_READAHEAD
+asmlinkage long compat_sys_readahead(int fd, compat_arg_u64(offset), size_t count);
+#endif
+
 #endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
 
 /**
diff --git a/mm/fadvise.c b/mm/fadvise.c
index d6baa4f451c5..8950f7c05d20 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -215,5 +215,16 @@  SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice)
 	return ksys_fadvise64_64(fd, offset, len, advice);
 }
 
+#endif
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FADVISE64_64)
+
+COMPAT_SYSCALL_DEFINE6(fadvise64_64, int, fd, int, advice, compat_arg_u64_dual(offset),
+		       compat_arg_u64_dual(len))
+{
+	return ksys_fadvise64_64(fd, compat_arg_u64_glue(offset),
+				 compat_arg_u64_glue(len), advice);
+}
+
 #endif
 #endif
diff --git a/mm/readahead.c b/mm/readahead.c
index cf0dcf89eb69..9adf57044299 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -640,6 +640,13 @@  SYSCALL_DEFINE3(readahead, int, fd, loff_t, offset, size_t, count)
 	return ksys_readahead(fd, offset, count);
 }
 
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_READAHEAD)
+COMPAT_SYSCALL_DEFINE4(readahead, int, fd, compat_arg_u64_dual(offset), size_t, count)
+{
+	return ksys_readahead(fd, compat_arg_u64_glue(offset), count);
+}
+#endif
+
 /**
  * readahead_expand - Expand a readahead request
  * @ractl: The request to be expanded