[PATCH 15/23] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers

Rohan McLure rmclure at linux.ibm.com
Fri Sep 16 15:48:40 AEST 2022



> On 16 Sep 2022, at 3:32 pm, Rohan McLure <rmclure at linux.ibm.com> wrote:
> 
> Arch-specific implementations of syscall handlers are currently used
> over generic implementations for the following reasons:
> 
> 1. Semantics unique to powerpc
> 2. Compatibility syscalls require 'argument padding' to comply with
>   64-bit argument convention in ELF32 abi.
> 3. Parameter types or order is different in other architectures.
> 
> These syscall handlers have been defined prior to this patch series
> without invoking the SYSCALL_DEFINE or COMPAT_SYSCALL_DEFINE macros with
> custom input and output types. We remove every such direct definition in
> favour of the aforementioned macros.
> 
> Also update syscalls.tbl in order to refer to the symbol names generated
> by each of these macros. Since ppc64_personality can be called by both
> 64 bit and 32 bit binaries through compatibility, we must generate both
> both compat_sys_ and sys_ symbols for this handler.
> 
> As an aside:
> A number of architectures including arm and powerpc agree on an
> alternative argument order and numbering for most of these arch-specific
> handlers. A future patch series may allow for asm/unistd.h to signal
> through its defines that a generic implementation of these syscall
> handlers with the correct calling convention be emitted, through the
> __ARCH_WANT_COMPAT_SYS_... convention.
> 
> Signed-off-by: Rohan McLure <rmclure at linux.ibm.com>
> ---
> V1 -> V2: All syscall handlers wrapped by this macro.
> V2 -> V3: Move creation of do_ppc64_personality helper to prior patch.
> V3 -> V4: Fix parenthesis alignment. Don't emit sys_*** symbols.
> V4 -> V5: Use 'aside' in the asm-generic rant in commit message.
> ---
> arch/powerpc/include/asm/syscalls.h          | 10 ++---
> arch/powerpc/kernel/sys_ppc32.c              | 38 +++++++++++-------
> arch/powerpc/kernel/syscalls.c               | 17 ++++++--
> arch/powerpc/kernel/syscalls/syscall.tbl     | 22 +++++-----
> .../arch/powerpc/entry/syscalls/syscall.tbl  | 22 +++++-----
> 5 files changed, 64 insertions(+), 45 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/syscalls.h b/arch/powerpc/include/asm/syscalls.h
> index 20cbd29b1228..525d2aa0c8ca 100644
> --- a/arch/powerpc/include/asm/syscalls.h
> +++ b/arch/powerpc/include/asm/syscalls.h
> @@ -28,10 +28,10 @@ long sys_mmap(unsigned long addr, size_t len,
> long sys_mmap2(unsigned long addr, size_t len,
> 	       unsigned long prot, unsigned long flags,
> 	       unsigned long fd, unsigned long pgoff);
> -long ppc64_personality(unsigned long personality);
> +long sys_ppc64_personality(unsigned long personality);
> long sys_rtas(struct rtas_args __user *uargs);
> -long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
> -		      u32 len_high, u32 len_low);
> +long sys_ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
> +			  u32 len_high, u32 len_low);
> 
> #ifdef CONFIG_COMPAT
> unsigned long compat_sys_mmap2(unsigned long addr, size_t len,
> @@ -52,8 +52,8 @@ int compat_sys_truncate64(const char __user *path, u32 reg4,
> int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long len1,
> 			   unsigned long len2);
> 
> -long ppc32_fadvise64(int fd, u32 unused, u32 offset1, u32 offset2,
> -		     size_t len, int advice);
> +long compat_sys_ppc32_fadvise64(int fd, u32 unused, u32 offset1, u32 offset2,
> +				size_t len, int advice);
> 
> long compat_sys_sync_file_range2(int fd, unsigned int flags,
> 				 unsigned int offset1, unsigned int offset2,
> diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
> index 776ae7565fc5..dcc3c9fd4cfd 100644
> --- a/arch/powerpc/kernel/sys_ppc32.c
> +++ b/arch/powerpc/kernel/sys_ppc32.c
> @@ -47,45 +47,55 @@
> #include <asm/syscalls.h>
> #include <asm/switch_to.h>
> 
> -compat_ssize_t compat_sys_pread64(unsigned int fd, char __user *ubuf, compat_size_t count,
> -			     u32 reg6, u32 pos1, u32 pos2)
> +COMPAT_SYSCALL_DEFINE6(ppc_pread64,
> +		       unsigned int, fd,
> +		       char __user *, ubuf, compat_size_t, count,
> +		       u32, reg6, u32, pos1, u32, pos2)
> {
> 	return ksys_pread64(fd, ubuf, count, merge_64(pos1, pos2));
> }
> 
> -compat_ssize_t compat_sys_pwrite64(unsigned int fd, const char __user *ubuf, compat_size_t count,
> -			      u32 reg6, u32 pos1, u32 pos2)
> +COMPAT_SYSCALL_DEFINE6(ppc_pwrite64,
> +		       unsigned int, fd,
> +		       const char __user *, ubuf, compat_size_t, count,
> +		       u32, reg6, u32, pos1, u32, pos2)
> {
> 	return ksys_pwrite64(fd, ubuf, count, merge_64(pos1, pos2));
> }
> 
> -compat_ssize_t compat_sys_readahead(int fd, u32 r4, u32 offset1, u32 offset2, u32 count)
> +COMPAT_SYSCALL_DEFINE5(ppc_readahead,
> +		       int, fd, u32, r4,
> +		       u32, offset1, u32, offset2, u32, count)
> {
> 	return ksys_readahead(fd, merge_64(offset1, offset2), count);
> }
> 
> -int compat_sys_truncate64(const char __user * path, u32 reg4,
> -				unsigned long len1, unsigned long len2)
> +COMPAT_SYSCALL_DEFINE4(ppc_truncate64,
> +		       const char __user *, path, u32, reg4,
> +		       unsigned long, len1, unsigned long, len2)
> {
> 	return ksys_truncate(path, merge_64(len1, len2));
> }
> 
> -int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long len1,
> -				 unsigned long len2)
> +COMPAT_SYSCALL_DEFINE4(ppc_ftruncate64,
> +		       unsigned int, fd, u32, reg4,
> +		       unsigned long, len1, unsigned long, len2)
> {
> 	return ksys_ftruncate(fd, merge_64(len1, len2));
> }
> 
> -long ppc32_fadvise64(int fd, u32 unused, u32 offset1, u32 offset2,
> -		     size_t len, int advice)
> +COMPAT_SYSCALL_DEFINE6(ppc32_fadvise64,
> +		       int, fd, u32, unused, u32, offset1, u32, offset2,
> +		       size_t, len, int, advice)
> {
> 	return ksys_fadvise64_64(fd, merge_64(offset1, offset2), len,
> 				 advice);
> }
> 
> -long compat_sys_sync_file_range2(int fd, unsigned int flags,
> -				   unsigned offset1, unsigned offset2,
> -				   unsigned nbytes1, unsigned nbytes2)
> +COMPAT_SYSCALL_DEFINE6(ppc_sync_file_range2,
> +		       int, fd, unsigned int, flags,
> +		       unsigned int, offset1, unsigned int, offset2,
> +		       unsigned int, nbytes1, unsigned int, nbytes2)
> {
> 	loff_t offset = merge_64(offset1, offset2);
> 	loff_t nbytes = merge_64(nbytes1, nbytes2);
> diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
> index 135a0b9108d5..3a35c690150b 100644
> --- a/arch/powerpc/kernel/syscalls.c
> +++ b/arch/powerpc/kernel/syscalls.c
> @@ -87,14 +87,23 @@ static long do_ppc64_personality(unsigned long personality)
> 		ret = (ret & ~PER_MASK) | PER_LINUX;
> 	return ret;
> }
> -long ppc64_personality(unsigned long personality)
> +
> +SYSCALL_DEFINE1(ppc64_personality, unsigned long, personality)
> {
> 	return do_ppc64_personality(personality);
> }
> -#endif
> 
> -long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
> -		      u32 len_high, u32 len_low)
> +#ifdef CONFIG_COMPAT
> +COMPAT_SYSCALL_DEFINE1(ppc64_personality, unsigned long, personality)
> +{
> +	return do_ppc64_personality(personality);
> +}
> +#endif /* CONFIG_COMPAT */
> +#endif /* CONFIG_PPC64 */
> +
> +SYSCALL_DEFINE6(ppc_fadvise64_64,
> +		int, fd, int, advice, u32, offset_high, u32, offset_low,
> +		u32, len_high, u32, len_low)
> {
> 	return ksys_fadvise64_64(fd, merge_64(offset_high, offset_low),
> 				 merge_64(len_high, len_low), advice);
> diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> index 64f27cbbdd2c..2bca64f96164 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -178,9 +178,9 @@
> 133	common	fchdir				sys_fchdir
> 134	common	bdflush				sys_ni_syscall
> 135	common	sysfs				sys_sysfs
> -136	32	personality			sys_personality			ppc64_personality
> -136	64	personality			ppc64_personality
> -136	spu	personality			ppc64_personality
> +136	32	personality			sys_personality			compat_sys_ppc64_personality
> +136	64	personality			sys_ppc64_personality
> +136	spu	personality			sys_ppc64_personality
> 137	common	afs_syscall			sys_ni_syscall
> 138	common	setfsuid			sys_setfsuid
> 139	common	setfsgid			sys_setfsgid
> @@ -228,8 +228,8 @@
> 176	64	rt_sigtimedwait			sys_rt_sigtimedwait
> 177	nospu 	rt_sigqueueinfo			sys_rt_sigqueueinfo		compat_sys_rt_sigqueueinfo
> 178	nospu 	rt_sigsuspend			sys_rt_sigsuspend		compat_sys_rt_sigsuspend
> -179	common	pread64				sys_pread64			compat_sys_pread64
> -180	common	pwrite64			sys_pwrite64			compat_sys_pwrite64
> +179	common	pread64				sys_pread64			compat_sys_ppc_pread64
> +180	common	pwrite64			sys_pwrite64			compat_sys_ppc_pwrite64
> 181	common	chown				sys_chown
> 182	common	getcwd				sys_getcwd
> 183	common	capget				sys_capget
> @@ -242,10 +242,10 @@
> 188	common 	putpmsg				sys_ni_syscall
> 189	nospu	vfork				sys_vfork
> 190	common	ugetrlimit			sys_getrlimit			compat_sys_getrlimit
> -191	common	readahead			sys_readahead			compat_sys_readahead
> +191	common	readahead			sys_readahead			compat_sys_ppc_readahead
> 192	32	mmap2				sys_mmap2			compat_sys_mmap2
> -193	32	truncate64			sys_truncate64			compat_sys_truncate64
> -194	32	ftruncate64			sys_ftruncate64			compat_sys_ftruncate64
> +193	32	truncate64			sys_truncate64			compat_sys_ppc_truncate64
> +194	32	ftruncate64			sys_ftruncate64			compat_sys_ppc_ftruncate64
> 195	32	stat64				sys_stat64
> 196	32	lstat64				sys_lstat64
> 197	32	fstat64				sys_fstat64
> @@ -288,7 +288,7 @@
> 230	common	io_submit			sys_io_submit			compat_sys_io_submit
> 231	common	io_cancel			sys_io_cancel
> 232	nospu	set_tid_address			sys_set_tid_address
> -233	common	fadvise64			sys_fadvise64			ppc32_fadvise64
> +233	common	fadvise64			sys_fadvise64			compat_sys_ppc32_fadvise64
> 234	nospu	exit_group			sys_exit_group
> 235	nospu	lookup_dcookie			sys_lookup_dcookie		compat_sys_lookup_dcookie
> 236	common	epoll_create			sys_epoll_create
> @@ -323,7 +323,7 @@
> 251	spu	utimes				sys_utimes
> 252	common	statfs64			sys_statfs64			compat_sys_statfs64
> 253	common	fstatfs64			sys_fstatfs64			compat_sys_fstatfs64
> -254	32	fadvise64_64			ppc_fadvise64_64
> +254	32	fadvise64_64			sys_ppc_fadvise64_64
> 254	spu	fadvise64_64			sys_ni_syscall
> 255	common	rtas				sys_rtas
> 256	32	sys_debug_setcontext		sys_debug_setcontext		sys_ni_syscall
> @@ -390,7 +390,7 @@
> 305	common	signalfd			sys_signalfd			compat_sys_signalfd
> 306	common	timerfd_create			sys_timerfd_create
> 307	common	eventfd				sys_eventfd
> -308	common	sync_file_range2		sys_sync_file_range2		compat_sys_sync_file_range2
> +308	common	sync_file_range2		sys_sync_file_range2		compat_sys_ppc_sync_file_range2
> 309	nospu	fallocate			sys_fallocate			compat_sys_fallocate
> 310	nospu	subpage_prot			sys_subpage_prot
> 311	32	timerfd_settime			sys_timerfd_settime32
> diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
> index 64f27cbbdd2c..2bca64f96164 100644
> --- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
> +++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
> @@ -178,9 +178,9 @@
> 133	common	fchdir				sys_fchdir
> 134	common	bdflush				sys_ni_syscall
> 135	common	sysfs				sys_sysfs
> -136	32	personality			sys_personality			ppc64_personality
> -136	64	personality			ppc64_personality
> -136	spu	personality			ppc64_personality
> +136	32	personality			sys_personality			compat_sys_ppc64_personality
> +136	64	personality			sys_ppc64_personality
> +136	spu	personality			sys_ppc64_personality
> 137	common	afs_syscall			sys_ni_syscall
> 138	common	setfsuid			sys_setfsuid
> 139	common	setfsgid			sys_setfsgid
> @@ -228,8 +228,8 @@
> 176	64	rt_sigtimedwait			sys_rt_sigtimedwait
> 177	nospu 	rt_sigqueueinfo			sys_rt_sigqueueinfo		compat_sys_rt_sigqueueinfo
> 178	nospu 	rt_sigsuspend			sys_rt_sigsuspend		compat_sys_rt_sigsuspend
> -179	common	pread64				sys_pread64			compat_sys_pread64
> -180	common	pwrite64			sys_pwrite64			compat_sys_pwrite64
> +179	common	pread64				sys_pread64			compat_sys_ppc_pread64
> +180	common	pwrite64			sys_pwrite64			compat_sys_ppc_pwrite64
> 181	common	chown				sys_chown
> 182	common	getcwd				sys_getcwd
> 183	common	capget				sys_capget
> @@ -242,10 +242,10 @@
> 188	common 	putpmsg				sys_ni_syscall
> 189	nospu	vfork				sys_vfork
> 190	common	ugetrlimit			sys_getrlimit			compat_sys_getrlimit
> -191	common	readahead			sys_readahead			compat_sys_readahead
> +191	common	readahead			sys_readahead			compat_sys_ppc_readahead
> 192	32	mmap2				sys_mmap2			compat_sys_mmap2
> -193	32	truncate64			sys_truncate64			compat_sys_truncate64
> -194	32	ftruncate64			sys_ftruncate64			compat_sys_ftruncate64
> +193	32	truncate64			sys_truncate64			compat_sys_ppc_truncate64
> +194	32	ftruncate64			sys_ftruncate64			compat_sys_ppc_ftruncate64
> 195	32	stat64				sys_stat64
> 196	32	lstat64				sys_lstat64
> 197	32	fstat64				sys_fstat64
> @@ -288,7 +288,7 @@
> 230	common	io_submit			sys_io_submit			compat_sys_io_submit
> 231	common	io_cancel			sys_io_cancel
> 232	nospu	set_tid_address			sys_set_tid_address
> -233	common	fadvise64			sys_fadvise64			ppc32_fadvise64
> +233	common	fadvise64			sys_fadvise64			compat_sys_ppc32_fadvise64
> 234	nospu	exit_group			sys_exit_group
> 235	nospu	lookup_dcookie			sys_lookup_dcookie		compat_sys_lookup_dcookie
> 236	common	epoll_create			sys_epoll_create
> @@ -323,7 +323,7 @@
> 251	spu	utimes				sys_utimes
> 252	common	statfs64			sys_statfs64			compat_sys_statfs64
> 253	common	fstatfs64			sys_fstatfs64			compat_sys_fstatfs64
> -254	32	fadvise64_64			ppc_fadvise64_64
> +254	32	fadvise64_64			sys_ppc_fadvise64_64
> 254	spu	fadvise64_64			sys_ni_syscall
> 255	common	rtas				sys_rtas
> 256	32	sys_debug_setcontext		sys_debug_setcontext		sys_ni_syscall
> @@ -390,7 +390,7 @@
> 305	common	signalfd			sys_signalfd			compat_sys_signalfd
> 306	common	timerfd_create			sys_timerfd_create
> 307	common	eventfd				sys_eventfd
> -308	common	sync_file_range2		sys_sync_file_range2		compat_sys_sync_file_range2
> +308	common	sync_file_range2		sys_sync_file_range2		compat_sys_ppc_sync_file_range2
> 309	nospu	fallocate			sys_fallocate			compat_sys_fallocate
> 310	nospu	subpage_prot			sys_subpage_prot
> 311	32	timerfd_settime			sys_timerfd_settime32
> -- 
> 2.34.1
> 

Apologies. This is in fact V5. I can resend if anyone needs me to.

Rohan



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