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Subject[PATCH v4 15/18] x86: Use IA32-specific wrappers for syscalls taking 64-bit arguments
Date
For the 32-bit syscall interface, 64-bit arguments (loff_t) are passed via
a pair of 32-bit registers. These register pairs end up in consecutive stack
slots, which matches the C ABI for 64-bit arguments. But when accessing the
registers directly from pt_regs, the wrapper needs to manually reassemble the
64-bit value. These wrappers already exist for 32-bit compat, so make them
available to 32-bit native in preparation for enabling pt_regs-based syscalls.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
arch/x86/entry/syscalls/syscall_32.tbl | 18 ++--
arch/x86/ia32/Makefile | 2 +-
arch/x86/kernel/Makefile | 2 +
arch/x86/{ia32 => kernel}/sys_ia32.c | 131 +++++++++++++------------
arch/x86/um/Makefile | 1 +
5 files changed, 79 insertions(+), 75 deletions(-)
rename arch/x86/{ia32 => kernel}/sys_ia32.c (83%)

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 0b8e24cb981d..54581ac671b4 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -191,8 +191,8 @@
177 i386 rt_sigtimedwait sys_rt_sigtimedwait_time32 compat_sys_rt_sigtimedwait_time32
178 i386 rt_sigqueueinfo sys_rt_sigqueueinfo compat_sys_rt_sigqueueinfo
179 i386 rt_sigsuspend sys_rt_sigsuspend compat_sys_rt_sigsuspend
-180 i386 pread64 sys_pread64 compat_sys_ia32_pread64
-181 i386 pwrite64 sys_pwrite64 compat_sys_ia32_pwrite64
+180 i386 pread64 sys_ia32_pread64
+181 i386 pwrite64 sys_ia32_pwrite64
182 i386 chown sys_chown16
183 i386 getcwd sys_getcwd
184 i386 capget sys_capget
@@ -204,8 +204,8 @@
190 i386 vfork sys_vfork
191 i386 ugetrlimit sys_getrlimit compat_sys_getrlimit
192 i386 mmap2 sys_mmap_pgoff
-193 i386 truncate64 sys_truncate64 compat_sys_ia32_truncate64
-194 i386 ftruncate64 sys_ftruncate64 compat_sys_ia32_ftruncate64
+193 i386 truncate64 sys_ia32_truncate64
+194 i386 ftruncate64 sys_ia32_ftruncate64
195 i386 stat64 sys_stat64 compat_sys_ia32_stat64
196 i386 lstat64 sys_lstat64 compat_sys_ia32_lstat64
197 i386 fstat64 sys_fstat64 compat_sys_ia32_fstat64
@@ -236,7 +236,7 @@
# 222 is unused
# 223 is unused
224 i386 gettid sys_gettid
-225 i386 readahead sys_readahead compat_sys_ia32_readahead
+225 i386 readahead sys_ia32_readahead
226 i386 setxattr sys_setxattr
227 i386 lsetxattr sys_lsetxattr
228 i386 fsetxattr sys_fsetxattr
@@ -261,7 +261,7 @@
247 i386 io_getevents sys_io_getevents_time32
248 i386 io_submit sys_io_submit compat_sys_io_submit
249 i386 io_cancel sys_io_cancel
-250 i386 fadvise64 sys_fadvise64 compat_sys_ia32_fadvise64
+250 i386 fadvise64 sys_ia32_fadvise64
# 251 is available for reuse (was briefly sys_set_zone_reclaim)
252 i386 exit_group sys_exit_group
253 i386 lookup_dcookie sys_lookup_dcookie compat_sys_lookup_dcookie
@@ -283,7 +283,7 @@
269 i386 fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
270 i386 tgkill sys_tgkill
271 i386 utimes sys_utimes_time32
-272 i386 fadvise64_64 sys_fadvise64_64 compat_sys_ia32_fadvise64_64
+272 i386 fadvise64_64 sys_ia32_fadvise64_64
273 i386 vserver
274 i386 mbind sys_mbind
275 i386 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
@@ -325,7 +325,7 @@
311 i386 set_robust_list sys_set_robust_list compat_sys_set_robust_list
312 i386 get_robust_list sys_get_robust_list compat_sys_get_robust_list
313 i386 splice sys_splice
-314 i386 sync_file_range sys_sync_file_range compat_sys_ia32_sync_file_range
+314 i386 sync_file_range sys_ia32_sync_file_range
315 i386 tee sys_tee
316 i386 vmsplice sys_vmsplice compat_sys_vmsplice
317 i386 move_pages sys_move_pages compat_sys_move_pages
@@ -335,7 +335,7 @@
321 i386 signalfd sys_signalfd compat_sys_signalfd
322 i386 timerfd_create sys_timerfd_create
323 i386 eventfd sys_eventfd
-324 i386 fallocate sys_fallocate compat_sys_ia32_fallocate
+324 i386 fallocate sys_ia32_fallocate
325 i386 timerfd_settime sys_timerfd_settime32
326 i386 timerfd_gettime sys_timerfd_gettime32
327 i386 signalfd4 sys_signalfd4 compat_sys_signalfd4
diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile
index d13b352b2aa7..8e4d0391ff6c 100644
--- a/arch/x86/ia32/Makefile
+++ b/arch/x86/ia32/Makefile
@@ -3,7 +3,7 @@
# Makefile for the ia32 kernel emulation subsystem.
#

-obj-$(CONFIG_IA32_EMULATION) := sys_ia32.o ia32_signal.o
+obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o

obj-$(CONFIG_IA32_AOUT) += ia32_aout.o

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 70615591a265..3f6d611fce08 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -57,6 +57,8 @@ obj-y += setup.o x86_init.o i8259.o irqinit.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-y += probe_roms.o
+obj-$(CONFIG_X86_32) += sys_ia32.o
+obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o
obj-$(CONFIG_X86_64) += sys_x86_64.o
obj-$(CONFIG_X86_ESPFIX64) += espfix_64.o
obj-$(CONFIG_SYSFS) += ksysfs.o
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/kernel/sys_ia32.c
similarity index 83%
rename from arch/x86/ia32/sys_ia32.c
rename to arch/x86/kernel/sys_ia32.c
index a189dc6f98dc..ab03fede1422 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/kernel/sys_ia32.c
@@ -51,20 +51,80 @@

#define AA(__x) ((unsigned long)(__x))

-
-COMPAT_SYSCALL_DEFINE3(ia32_truncate64, const char __user *, filename,
- unsigned long, offset_low, unsigned long, offset_high)
+SYSCALL_DEFINE3(ia32_truncate64, const char __user *, filename,
+ unsigned long, offset_low, unsigned long, offset_high)
{
return ksys_truncate(filename,
((loff_t) offset_high << 32) | offset_low);
}

-COMPAT_SYSCALL_DEFINE3(ia32_ftruncate64, unsigned int, fd,
- unsigned long, offset_low, unsigned long, offset_high)
+SYSCALL_DEFINE3(ia32_ftruncate64, unsigned int, fd,
+ unsigned long, offset_low, unsigned long, offset_high)
{
return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
}

+/* warning: next two assume little endian */
+SYSCALL_DEFINE5(ia32_pread64, unsigned int, fd, char __user *, ubuf,
+ u32, count, u32, poslo, u32, poshi)
+{
+ return ksys_pread64(fd, ubuf, count,
+ ((loff_t)AA(poshi) << 32) | AA(poslo));
+}
+
+SYSCALL_DEFINE5(ia32_pwrite64, unsigned int, fd, const char __user *, ubuf,
+ u32, count, u32, poslo, u32, poshi)
+{
+ return ksys_pwrite64(fd, ubuf, count,
+ ((loff_t)AA(poshi) << 32) | AA(poslo));
+}
+
+
+/*
+ * Some system calls that need sign extended arguments. This could be
+ * done by a generic wrapper.
+ */
+SYSCALL_DEFINE6(ia32_fadvise64_64, int, fd, __u32, offset_low,
+ __u32, offset_high, __u32, len_low, __u32, len_high,
+ int, advice)
+{
+ return ksys_fadvise64_64(fd,
+ (((u64)offset_high)<<32) | offset_low,
+ (((u64)len_high)<<32) | len_low,
+ advice);
+}
+
+SYSCALL_DEFINE4(ia32_readahead, int, fd, unsigned int, off_lo,
+ unsigned int, off_hi, size_t, count)
+{
+ return ksys_readahead(fd, ((u64)off_hi << 32) | off_lo, count);
+}
+
+SYSCALL_DEFINE6(ia32_sync_file_range, int, fd, unsigned int, off_low,
+ unsigned int, off_hi, unsigned int, n_low,
+ unsigned int, n_hi, int, flags)
+{
+ return ksys_sync_file_range(fd,
+ ((u64)off_hi << 32) | off_low,
+ ((u64)n_hi << 32) | n_low, flags);
+}
+
+SYSCALL_DEFINE5(ia32_fadvise64, int, fd, unsigned int, offset_lo,
+ unsigned int, offset_hi, size_t, len, int, advice)
+{
+ return ksys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo,
+ len, advice);
+}
+
+SYSCALL_DEFINE6(ia32_fallocate, int, fd, int, mode,
+ unsigned int, offset_lo, unsigned int, offset_hi,
+ unsigned int, len_lo, unsigned int, len_hi)
+{
+ return ksys_fallocate(fd, mode, ((u64)offset_hi << 32) | offset_lo,
+ ((u64)len_hi << 32) | len_lo);
+}
+
+#ifdef CONFIG_IA32_EMULATION
/*
* Another set for IA32/LFS -- x86_64 struct stat is different due to
* support for 64bit inode numbers.
@@ -170,66 +230,6 @@ COMPAT_SYSCALL_DEFINE1(ia32_mmap, struct mmap_arg_struct32 __user *, arg)
a.offset>>PAGE_SHIFT);
}

-/* warning: next two assume little endian */
-COMPAT_SYSCALL_DEFINE5(ia32_pread64, unsigned int, fd, char __user *, ubuf,
- u32, count, u32, poslo, u32, poshi)
-{
- return ksys_pread64(fd, ubuf, count,
- ((loff_t)AA(poshi) << 32) | AA(poslo));
-}
-
-COMPAT_SYSCALL_DEFINE5(ia32_pwrite64, unsigned int, fd, const char __user *, ubuf,
- u32, count, u32, poslo, u32, poshi)
-{
- return ksys_pwrite64(fd, ubuf, count,
- ((loff_t)AA(poshi) << 32) | AA(poslo));
-}
-
-
-/*
- * Some system calls that need sign extended arguments. This could be
- * done by a generic wrapper.
- */
-COMPAT_SYSCALL_DEFINE6(ia32_fadvise64_64, int, fd, __u32, offset_low,
- __u32, offset_high, __u32, len_low, __u32, len_high,
- int, advice)
-{
- return ksys_fadvise64_64(fd,
- (((u64)offset_high)<<32) | offset_low,
- (((u64)len_high)<<32) | len_low,
- advice);
-}
-
-COMPAT_SYSCALL_DEFINE4(ia32_readahead, int, fd, unsigned int, off_lo,
- unsigned int, off_hi, size_t, count)
-{
- return ksys_readahead(fd, ((u64)off_hi << 32) | off_lo, count);
-}
-
-COMPAT_SYSCALL_DEFINE6(ia32_sync_file_range, int, fd, unsigned int, off_low,
- unsigned int, off_hi, unsigned int, n_low,
- unsigned int, n_hi, int, flags)
-{
- return ksys_sync_file_range(fd,
- ((u64)off_hi << 32) | off_low,
- ((u64)n_hi << 32) | n_low, flags);
-}
-
-COMPAT_SYSCALL_DEFINE5(ia32_fadvise64, int, fd, unsigned int, offset_lo,
- unsigned int, offset_hi, size_t, len, int, advice)
-{
- return ksys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo,
- len, advice);
-}
-
-COMPAT_SYSCALL_DEFINE6(ia32_fallocate, int, fd, int, mode,
- unsigned int, offset_lo, unsigned int, offset_hi,
- unsigned int, len_lo, unsigned int, len_hi)
-{
- return ksys_fallocate(fd, mode, ((u64)offset_hi << 32) | offset_lo,
- ((u64)len_hi << 32) | len_lo);
-}
-
/*
* The 32-bit clone ABI is CONFIG_CLONE_BACKWARDS
*/
@@ -252,3 +252,4 @@ COMPAT_SYSCALL_DEFINE5(ia32_clone, unsigned long, clone_flags,

return _do_fork(&args);
}
+#endif /* CONFIG_IA32_EMULATION */
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index 33c51c064c77..77f70b969d14 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -21,6 +21,7 @@ obj-y += checksum_32.o syscalls_32.o
obj-$(CONFIG_ELF_CORE) += elfcore.o

subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o
+subarch-y += ../kernel/sys_ia32.o

else

--
2.24.1
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