* [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V)
@ 2020-02-10 20:20 Georg Sauthoff
2020-02-10 20:20 ` [PATCH 1/1] Only pass the minimum number of syscall arguments Georg Sauthoff
2020-02-11 8:43 ` [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Corinna Vinschen
0 siblings, 2 replies; 4+ messages in thread
From: Georg Sauthoff @ 2020-02-10 20:20 UTC (permalink / raw)
To: newlib; +Cc: Georg Sauthoff
As is, the RISC-V syscall code unconditionally sets all possible syscall
arguments even if the syscall requires fewer.
For example, the instruction sequence for a exit syscall looked like
this:
li a0, 1 # in ther caller of exit()
# ... # in newlib:
li a1, 0 # unused arguments
li a2, 0
li a3, 0
li a4, 0
li a5, 0
li a7, 93 # exit syscall number
(i.e. the binary contains then 5 superfluous instructions for this
one argument syscall)
This patch changes the RISC-V syscall code such that only the required
syscall argument registers are set.
Georg Sauthoff (1):
Only pass the minimum number of syscall arguments
libgloss/riscv/internal_syscall.h | 41 ++++++++++++++++++++++---------
libgloss/riscv/sys_access.c | 2 +-
libgloss/riscv/sys_close.c | 2 +-
libgloss/riscv/sys_exit.c | 2 +-
libgloss/riscv/sys_faccessat.c | 2 +-
libgloss/riscv/sys_fstat.c | 2 +-
libgloss/riscv/sys_fstatat.c | 2 +-
libgloss/riscv/sys_gettimeofday.c | 2 +-
libgloss/riscv/sys_link.c | 2 +-
libgloss/riscv/sys_lseek.c | 2 +-
libgloss/riscv/sys_lstat.c | 2 +-
libgloss/riscv/sys_open.c | 2 +-
libgloss/riscv/sys_openat.c | 2 +-
libgloss/riscv/sys_read.c | 2 +-
libgloss/riscv/sys_sbrk.c | 4 +--
libgloss/riscv/sys_stat.c | 2 +-
libgloss/riscv/sys_unlink.c | 2 +-
libgloss/riscv/sys_write.c | 2 +-
18 files changed, 48 insertions(+), 29 deletions(-)
--
2.24.1
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 1/1] Only pass the minimum number of syscall arguments 2020-02-10 20:20 [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Georg Sauthoff @ 2020-02-10 20:20 ` Georg Sauthoff 2020-02-11 6:55 ` Kito Cheng 2020-02-11 8:43 ` [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Corinna Vinschen 1 sibling, 1 reply; 4+ messages in thread From: Georg Sauthoff @ 2020-02-10 20:20 UTC (permalink / raw) To: newlib; +Cc: Georg Sauthoff Previously, __internal_syscall() compiled into asm-code that unconditionally sets the syscall argument registers a0 to a5. For example, the instruction sequence for a exit syscall looked like this: li a0, 1 # in ther caller of exit() # ... # in newlib: li a1, 0 # unused arguments li a2, 0 li a3, 0 li a4, 0 li a5, 0 li a7, 93 # exit syscall number (i.e. the binary contains then 5 superfluous instructions for this one argument syscall) This commit changes the RISC-V syscall code such that only the required syscall argument registers are set. GCC detects that argc is known at compile time and thus evaluates all the if-statements where argc is used at compile time (tested with -O2 and -Os). --- libgloss/riscv/internal_syscall.h | 41 ++++++++++++++++++++++--------- libgloss/riscv/sys_access.c | 2 +- libgloss/riscv/sys_close.c | 2 +- libgloss/riscv/sys_exit.c | 2 +- libgloss/riscv/sys_faccessat.c | 2 +- libgloss/riscv/sys_fstat.c | 2 +- libgloss/riscv/sys_fstatat.c | 2 +- libgloss/riscv/sys_gettimeofday.c | 2 +- libgloss/riscv/sys_link.c | 2 +- libgloss/riscv/sys_lseek.c | 2 +- libgloss/riscv/sys_lstat.c | 2 +- libgloss/riscv/sys_open.c | 2 +- libgloss/riscv/sys_openat.c | 2 +- libgloss/riscv/sys_read.c | 2 +- libgloss/riscv/sys_sbrk.c | 4 +-- libgloss/riscv/sys_stat.c | 2 +- libgloss/riscv/sys_unlink.c | 2 +- libgloss/riscv/sys_write.c | 2 +- 18 files changed, 48 insertions(+), 29 deletions(-) diff --git a/libgloss/riscv/internal_syscall.h b/libgloss/riscv/internal_syscall.h index e5d5594..1f1f42f 100644 --- a/libgloss/riscv/internal_syscall.h +++ b/libgloss/riscv/internal_syscall.h @@ -22,31 +22,50 @@ __syscall_error(long a0) } static inline long -__internal_syscall(long n, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) +__internal_syscall(long n, int argc, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) { +#ifdef __riscv_32e + register long syscall_id asm("t0") = n; +#else + register long syscall_id asm("a7") = n; +#endif + register long a0 asm("a0") = _a0; + if (argc < 2) { + asm volatile ("ecall" : "+r"(a0) : "r"(syscall_id)); + return a0; + } register long a1 asm("a1") = _a1; + if (argc == 2) { + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(syscall_id)); + return a0; + } register long a2 asm("a2") = _a2; + if (argc == 3) { + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(syscall_id)); + return a0; + } register long a3 asm("a3") = _a3; + if (argc == 4) { + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(syscall_id)); + return a0; + } register long a4 asm("a4") = _a4; + if (argc == 5) { + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(syscall_id)); + return a0; + } register long a5 asm("a5") = _a5; -#ifdef __riscv_32e - register long syscall_id asm("t0") = n; -#else - register long syscall_id asm("a7") = n; -#endif - - asm volatile ("scall" - : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5), "r"(syscall_id)); + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5), "r"(syscall_id)); return a0; } static inline long -syscall_errno(long n, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) +syscall_errno(long n, int argc, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) { - long a0 = __internal_syscall (n, _a0, _a1, _a2, _a3, _a4, _a5); + long a0 = __internal_syscall (n, argc, _a0, _a1, _a2, _a3, _a4, _a5); if (a0 < 0) return __syscall_error (a0); diff --git a/libgloss/riscv/sys_access.c b/libgloss/riscv/sys_access.c index ef446d2..45bedb3 100644 --- a/libgloss/riscv/sys_access.c +++ b/libgloss/riscv/sys_access.c @@ -5,5 +5,5 @@ int _access(const char *file, int mode) { - return syscall_errno (SYS_access, file, mode, 0, 0, 0, 0); + return syscall_errno (SYS_access, 2, file, mode, 0, 0, 0, 0); } diff --git a/libgloss/riscv/sys_close.c b/libgloss/riscv/sys_close.c index 80b10c6..c1691d8 100644 --- a/libgloss/riscv/sys_close.c +++ b/libgloss/riscv/sys_close.c @@ -5,5 +5,5 @@ int _close(int file) { - return syscall_errno (SYS_close, file, 0, 0, 0, 0, 0); + return syscall_errno (SYS_close, 1, file, 0, 0, 0, 0, 0); } diff --git a/libgloss/riscv/sys_exit.c b/libgloss/riscv/sys_exit.c index 03e1c34..995dd65 100644 --- a/libgloss/riscv/sys_exit.c +++ b/libgloss/riscv/sys_exit.c @@ -5,6 +5,6 @@ void _exit(int exit_status) { - syscall_errno (SYS_exit, exit_status, 0, 0, 0, 0, 0); + syscall_errno (SYS_exit, 1, exit_status, 0, 0, 0, 0, 0); while (1); } diff --git a/libgloss/riscv/sys_faccessat.c b/libgloss/riscv/sys_faccessat.c index e966a4a..6418ef4 100644 --- a/libgloss/riscv/sys_faccessat.c +++ b/libgloss/riscv/sys_faccessat.c @@ -4,5 +4,5 @@ /* Permissions of a file (by name) in a given directory. */ int _faccessat(int dirfd, const char *file, int mode, int flags) { - return syscall_errno (SYS_faccessat, dirfd, file, mode, flags, 0, 0); + return syscall_errno (SYS_faccessat, 4, dirfd, file, mode, flags, 0, 0); } diff --git a/libgloss/riscv/sys_fstat.c b/libgloss/riscv/sys_fstat.c index 13a0bca..d97ba44 100644 --- a/libgloss/riscv/sys_fstat.c +++ b/libgloss/riscv/sys_fstat.c @@ -9,7 +9,7 @@ int _fstat(int file, struct stat *st) { struct kernel_stat kst; - int rv = syscall_errno (SYS_fstat, file, &kst, 0, 0, 0, 0); + int rv = syscall_errno (SYS_fstat, 2, file, &kst, 0, 0, 0, 0); _conv_stat (st, &kst); return rv; } diff --git a/libgloss/riscv/sys_fstatat.c b/libgloss/riscv/sys_fstatat.c index 0e4ea42..bf03355 100644 --- a/libgloss/riscv/sys_fstatat.c +++ b/libgloss/riscv/sys_fstatat.c @@ -8,7 +8,7 @@ int _fstatat(int dirfd, const char *file, struct stat *st, int flags) { struct kernel_stat kst; - int rv = syscall_errno (SYS_fstatat, dirfd, file, &kst, flags, 0, 0); + int rv = syscall_errno (SYS_fstatat, 4, dirfd, file, &kst, flags, 0, 0); _conv_stat (st, &kst); return rv; } diff --git a/libgloss/riscv/sys_gettimeofday.c b/libgloss/riscv/sys_gettimeofday.c index 457dcbc..daa14e4 100644 --- a/libgloss/riscv/sys_gettimeofday.c +++ b/libgloss/riscv/sys_gettimeofday.c @@ -6,5 +6,5 @@ int _gettimeofday(struct timeval *tp, void *tzp) { - return syscall_errno (SYS_gettimeofday, tp, 0, 0, 0, 0, 0); + return syscall_errno (SYS_gettimeofday, 1, tp, 0, 0, 0, 0, 0); } diff --git a/libgloss/riscv/sys_link.c b/libgloss/riscv/sys_link.c index eaeb22b..83cd1b2 100644 --- a/libgloss/riscv/sys_link.c +++ b/libgloss/riscv/sys_link.c @@ -4,5 +4,5 @@ /* Establish a new name for an existing file. */ int _link(const char *old_name, const char *new_name) { - return syscall_errno (SYS_link, old_name, new_name, 0, 0, 0, 0); + return syscall_errno (SYS_link, 2, old_name, new_name, 0, 0, 0, 0); } diff --git a/libgloss/riscv/sys_lseek.c b/libgloss/riscv/sys_lseek.c index 7486a3a..8eb8b81 100644 --- a/libgloss/riscv/sys_lseek.c +++ b/libgloss/riscv/sys_lseek.c @@ -6,5 +6,5 @@ off_t _lseek(int file, off_t ptr, int dir) { - return syscall_errno (SYS_lseek, file, ptr, dir, 0, 0, 0); + return syscall_errno (SYS_lseek, 3, file, ptr, dir, 0, 0, 0); } diff --git a/libgloss/riscv/sys_lstat.c b/libgloss/riscv/sys_lstat.c index 2eeabcc..dd5dc52 100644 --- a/libgloss/riscv/sys_lstat.c +++ b/libgloss/riscv/sys_lstat.c @@ -7,7 +7,7 @@ int _lstat(const char *file, struct stat *st) { struct kernel_stat kst; - int rv = syscall_errno (SYS_lstat, file, &kst, 0, 0, 0, 0); + int rv = syscall_errno (SYS_lstat, 2, file, &kst, 0, 0, 0, 0); _conv_stat (st, &kst); return rv; } diff --git a/libgloss/riscv/sys_open.c b/libgloss/riscv/sys_open.c index 4fd5d67..eb1a99b 100644 --- a/libgloss/riscv/sys_open.c +++ b/libgloss/riscv/sys_open.c @@ -5,5 +5,5 @@ int _open(const char *name, int flags, int mode) { - return syscall_errno (SYS_open, name, flags, mode, 0, 0, 0); + return syscall_errno (SYS_open, 3, name, flags, mode, 0, 0, 0); } diff --git a/libgloss/riscv/sys_openat.c b/libgloss/riscv/sys_openat.c index cf429b7..652ab2e 100644 --- a/libgloss/riscv/sys_openat.c +++ b/libgloss/riscv/sys_openat.c @@ -4,5 +4,5 @@ /* Open file relative to given directory. */ int _openat(int dirfd, const char *name, int flags, int mode) { - return syscall_errno (SYS_openat, dirfd, name, flags, mode, 0, 0); + return syscall_errno (SYS_openat, 4, dirfd, name, flags, mode, 0, 0); } diff --git a/libgloss/riscv/sys_read.c b/libgloss/riscv/sys_read.c index 7367e26..dd3bc33 100644 --- a/libgloss/riscv/sys_read.c +++ b/libgloss/riscv/sys_read.c @@ -5,5 +5,5 @@ /* Read from a file. */ ssize_t _read(int file, void *ptr, size_t len) { - return syscall_errno (SYS_read, file, ptr, len, 0, 0, 0); + return syscall_errno (SYS_read, 3, file, ptr, len, 0, 0, 0); } diff --git a/libgloss/riscv/sys_sbrk.c b/libgloss/riscv/sys_sbrk.c index f91c2c5..086509e 100644 --- a/libgloss/riscv/sys_sbrk.c +++ b/libgloss/riscv/sys_sbrk.c @@ -41,13 +41,13 @@ _sbrk(ptrdiff_t incr) if (heap_end == 0) { - long brk = __internal_syscall (SYS_brk, 0, 0, 0, 0, 0, 0); + long brk = __internal_syscall (SYS_brk, 1, 0, 0, 0, 0, 0, 0); if (brk == -1) return (void *)__syscall_error (-ENOMEM); heap_end = brk; } - if (__internal_syscall (SYS_brk, heap_end + incr, 0, 0, 0, 0, 0) != heap_end + incr) + if (__internal_syscall (SYS_brk, 1, heap_end + incr, 0, 0, 0, 0, 0) != heap_end + incr) return (void *)__syscall_error (-ENOMEM); heap_end += incr; diff --git a/libgloss/riscv/sys_stat.c b/libgloss/riscv/sys_stat.c index a193b10..1e03700 100644 --- a/libgloss/riscv/sys_stat.c +++ b/libgloss/riscv/sys_stat.c @@ -8,7 +8,7 @@ int _stat(const char *file, struct stat *st) { struct kernel_stat kst; - int rv = syscall_errno (SYS_stat, file, &kst, 0, 0, 0, 0); + int rv = syscall_errno (SYS_stat, 2, file, &kst, 0, 0, 0, 0); _conv_stat (st, &kst); return rv; } diff --git a/libgloss/riscv/sys_unlink.c b/libgloss/riscv/sys_unlink.c index b55fe1e..1cf6bbe 100644 --- a/libgloss/riscv/sys_unlink.c +++ b/libgloss/riscv/sys_unlink.c @@ -5,5 +5,5 @@ int _unlink(const char *name) { - return syscall_errno (SYS_unlink, name, 0, 0, 0, 0, 0); + return syscall_errno (SYS_unlink, 1, name, 0, 0, 0, 0, 0); } diff --git a/libgloss/riscv/sys_write.c b/libgloss/riscv/sys_write.c index b972734..ce2edd3 100644 --- a/libgloss/riscv/sys_write.c +++ b/libgloss/riscv/sys_write.c @@ -6,5 +6,5 @@ ssize_t _write(int file, const void *ptr, size_t len) { - return syscall_errno (SYS_write, file, ptr, len, 0, 0, 0); + return syscall_errno (SYS_write, 3, file, ptr, len, 0, 0, 0); } -- 2.24.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] Only pass the minimum number of syscall arguments 2020-02-10 20:20 ` [PATCH 1/1] Only pass the minimum number of syscall arguments Georg Sauthoff @ 2020-02-11 6:55 ` Kito Cheng 0 siblings, 0 replies; 4+ messages in thread From: Kito Cheng @ 2020-02-11 6:55 UTC (permalink / raw) To: Georg Sauthoff; +Cc: Newlib Hi Georg: LGTM, great job, it reduce the code size for libgloss. Tested rv32gc/rv64gc on qemu. Thanks :) On Tue, Feb 11, 2020 at 4:20 AM Georg Sauthoff <mail@gms.tf> wrote: > > Previously, __internal_syscall() compiled into asm-code that unconditionally > sets the syscall argument registers a0 to a5. > > For example, the instruction sequence for a exit syscall looked like > this: > > li a0, 1 # in ther caller of exit() > # ... # in newlib: > li a1, 0 # unused arguments > li a2, 0 > li a3, 0 > li a4, 0 > li a5, 0 > li a7, 93 # exit syscall number > > (i.e. the binary contains then 5 superfluous instructions for this > one argument syscall) > > This commit changes the RISC-V syscall code such that only the required > syscall argument registers are set. > > GCC detects that argc is known at compile time and thus evaluates all the > if-statements where argc is used at compile time (tested with -O2 and -Os). > --- > libgloss/riscv/internal_syscall.h | 41 ++++++++++++++++++++++--------- > libgloss/riscv/sys_access.c | 2 +- > libgloss/riscv/sys_close.c | 2 +- > libgloss/riscv/sys_exit.c | 2 +- > libgloss/riscv/sys_faccessat.c | 2 +- > libgloss/riscv/sys_fstat.c | 2 +- > libgloss/riscv/sys_fstatat.c | 2 +- > libgloss/riscv/sys_gettimeofday.c | 2 +- > libgloss/riscv/sys_link.c | 2 +- > libgloss/riscv/sys_lseek.c | 2 +- > libgloss/riscv/sys_lstat.c | 2 +- > libgloss/riscv/sys_open.c | 2 +- > libgloss/riscv/sys_openat.c | 2 +- > libgloss/riscv/sys_read.c | 2 +- > libgloss/riscv/sys_sbrk.c | 4 +-- > libgloss/riscv/sys_stat.c | 2 +- > libgloss/riscv/sys_unlink.c | 2 +- > libgloss/riscv/sys_write.c | 2 +- > 18 files changed, 48 insertions(+), 29 deletions(-) > > diff --git a/libgloss/riscv/internal_syscall.h b/libgloss/riscv/internal_syscall.h > index e5d5594..1f1f42f 100644 > --- a/libgloss/riscv/internal_syscall.h > +++ b/libgloss/riscv/internal_syscall.h > @@ -22,31 +22,50 @@ __syscall_error(long a0) > } > > static inline long > -__internal_syscall(long n, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) > +__internal_syscall(long n, int argc, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) > { > +#ifdef __riscv_32e > + register long syscall_id asm("t0") = n; > +#else > + register long syscall_id asm("a7") = n; > +#endif > + > register long a0 asm("a0") = _a0; > + if (argc < 2) { > + asm volatile ("ecall" : "+r"(a0) : "r"(syscall_id)); > + return a0; > + } > register long a1 asm("a1") = _a1; > + if (argc == 2) { > + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(syscall_id)); > + return a0; > + } > register long a2 asm("a2") = _a2; > + if (argc == 3) { > + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(syscall_id)); > + return a0; > + } > register long a3 asm("a3") = _a3; > + if (argc == 4) { > + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(syscall_id)); > + return a0; > + } > register long a4 asm("a4") = _a4; > + if (argc == 5) { > + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(syscall_id)); > + return a0; > + } > register long a5 asm("a5") = _a5; > > -#ifdef __riscv_32e > - register long syscall_id asm("t0") = n; > -#else > - register long syscall_id asm("a7") = n; > -#endif > - > - asm volatile ("scall" > - : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5), "r"(syscall_id)); > + asm volatile ("ecall" : "+r"(a0) : "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5), "r"(syscall_id)); > > return a0; > } > > static inline long > -syscall_errno(long n, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) > +syscall_errno(long n, int argc, long _a0, long _a1, long _a2, long _a3, long _a4, long _a5) > { > - long a0 = __internal_syscall (n, _a0, _a1, _a2, _a3, _a4, _a5); > + long a0 = __internal_syscall (n, argc, _a0, _a1, _a2, _a3, _a4, _a5); > > if (a0 < 0) > return __syscall_error (a0); > diff --git a/libgloss/riscv/sys_access.c b/libgloss/riscv/sys_access.c > index ef446d2..45bedb3 100644 > --- a/libgloss/riscv/sys_access.c > +++ b/libgloss/riscv/sys_access.c > @@ -5,5 +5,5 @@ > int > _access(const char *file, int mode) > { > - return syscall_errno (SYS_access, file, mode, 0, 0, 0, 0); > + return syscall_errno (SYS_access, 2, file, mode, 0, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_close.c b/libgloss/riscv/sys_close.c > index 80b10c6..c1691d8 100644 > --- a/libgloss/riscv/sys_close.c > +++ b/libgloss/riscv/sys_close.c > @@ -5,5 +5,5 @@ > int > _close(int file) > { > - return syscall_errno (SYS_close, file, 0, 0, 0, 0, 0); > + return syscall_errno (SYS_close, 1, file, 0, 0, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_exit.c b/libgloss/riscv/sys_exit.c > index 03e1c34..995dd65 100644 > --- a/libgloss/riscv/sys_exit.c > +++ b/libgloss/riscv/sys_exit.c > @@ -5,6 +5,6 @@ > void > _exit(int exit_status) > { > - syscall_errno (SYS_exit, exit_status, 0, 0, 0, 0, 0); > + syscall_errno (SYS_exit, 1, exit_status, 0, 0, 0, 0, 0); > while (1); > } > diff --git a/libgloss/riscv/sys_faccessat.c b/libgloss/riscv/sys_faccessat.c > index e966a4a..6418ef4 100644 > --- a/libgloss/riscv/sys_faccessat.c > +++ b/libgloss/riscv/sys_faccessat.c > @@ -4,5 +4,5 @@ > /* Permissions of a file (by name) in a given directory. */ > int _faccessat(int dirfd, const char *file, int mode, int flags) > { > - return syscall_errno (SYS_faccessat, dirfd, file, mode, flags, 0, 0); > + return syscall_errno (SYS_faccessat, 4, dirfd, file, mode, flags, 0, 0); > } > diff --git a/libgloss/riscv/sys_fstat.c b/libgloss/riscv/sys_fstat.c > index 13a0bca..d97ba44 100644 > --- a/libgloss/riscv/sys_fstat.c > +++ b/libgloss/riscv/sys_fstat.c > @@ -9,7 +9,7 @@ int > _fstat(int file, struct stat *st) > { > struct kernel_stat kst; > - int rv = syscall_errno (SYS_fstat, file, &kst, 0, 0, 0, 0); > + int rv = syscall_errno (SYS_fstat, 2, file, &kst, 0, 0, 0, 0); > _conv_stat (st, &kst); > return rv; > } > diff --git a/libgloss/riscv/sys_fstatat.c b/libgloss/riscv/sys_fstatat.c > index 0e4ea42..bf03355 100644 > --- a/libgloss/riscv/sys_fstatat.c > +++ b/libgloss/riscv/sys_fstatat.c > @@ -8,7 +8,7 @@ int > _fstatat(int dirfd, const char *file, struct stat *st, int flags) > { > struct kernel_stat kst; > - int rv = syscall_errno (SYS_fstatat, dirfd, file, &kst, flags, 0, 0); > + int rv = syscall_errno (SYS_fstatat, 4, dirfd, file, &kst, flags, 0, 0); > _conv_stat (st, &kst); > return rv; > } > diff --git a/libgloss/riscv/sys_gettimeofday.c b/libgloss/riscv/sys_gettimeofday.c > index 457dcbc..daa14e4 100644 > --- a/libgloss/riscv/sys_gettimeofday.c > +++ b/libgloss/riscv/sys_gettimeofday.c > @@ -6,5 +6,5 @@ > int > _gettimeofday(struct timeval *tp, void *tzp) > { > - return syscall_errno (SYS_gettimeofday, tp, 0, 0, 0, 0, 0); > + return syscall_errno (SYS_gettimeofday, 1, tp, 0, 0, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_link.c b/libgloss/riscv/sys_link.c > index eaeb22b..83cd1b2 100644 > --- a/libgloss/riscv/sys_link.c > +++ b/libgloss/riscv/sys_link.c > @@ -4,5 +4,5 @@ > /* Establish a new name for an existing file. */ > int _link(const char *old_name, const char *new_name) > { > - return syscall_errno (SYS_link, old_name, new_name, 0, 0, 0, 0); > + return syscall_errno (SYS_link, 2, old_name, new_name, 0, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_lseek.c b/libgloss/riscv/sys_lseek.c > index 7486a3a..8eb8b81 100644 > --- a/libgloss/riscv/sys_lseek.c > +++ b/libgloss/riscv/sys_lseek.c > @@ -6,5 +6,5 @@ > off_t > _lseek(int file, off_t ptr, int dir) > { > - return syscall_errno (SYS_lseek, file, ptr, dir, 0, 0, 0); > + return syscall_errno (SYS_lseek, 3, file, ptr, dir, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_lstat.c b/libgloss/riscv/sys_lstat.c > index 2eeabcc..dd5dc52 100644 > --- a/libgloss/riscv/sys_lstat.c > +++ b/libgloss/riscv/sys_lstat.c > @@ -7,7 +7,7 @@ > int _lstat(const char *file, struct stat *st) > { > struct kernel_stat kst; > - int rv = syscall_errno (SYS_lstat, file, &kst, 0, 0, 0, 0); > + int rv = syscall_errno (SYS_lstat, 2, file, &kst, 0, 0, 0, 0); > _conv_stat (st, &kst); > return rv; > } > diff --git a/libgloss/riscv/sys_open.c b/libgloss/riscv/sys_open.c > index 4fd5d67..eb1a99b 100644 > --- a/libgloss/riscv/sys_open.c > +++ b/libgloss/riscv/sys_open.c > @@ -5,5 +5,5 @@ > int > _open(const char *name, int flags, int mode) > { > - return syscall_errno (SYS_open, name, flags, mode, 0, 0, 0); > + return syscall_errno (SYS_open, 3, name, flags, mode, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_openat.c b/libgloss/riscv/sys_openat.c > index cf429b7..652ab2e 100644 > --- a/libgloss/riscv/sys_openat.c > +++ b/libgloss/riscv/sys_openat.c > @@ -4,5 +4,5 @@ > /* Open file relative to given directory. */ > int _openat(int dirfd, const char *name, int flags, int mode) > { > - return syscall_errno (SYS_openat, dirfd, name, flags, mode, 0, 0); > + return syscall_errno (SYS_openat, 4, dirfd, name, flags, mode, 0, 0); > } > diff --git a/libgloss/riscv/sys_read.c b/libgloss/riscv/sys_read.c > index 7367e26..dd3bc33 100644 > --- a/libgloss/riscv/sys_read.c > +++ b/libgloss/riscv/sys_read.c > @@ -5,5 +5,5 @@ > /* Read from a file. */ > ssize_t _read(int file, void *ptr, size_t len) > { > - return syscall_errno (SYS_read, file, ptr, len, 0, 0, 0); > + return syscall_errno (SYS_read, 3, file, ptr, len, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_sbrk.c b/libgloss/riscv/sys_sbrk.c > index f91c2c5..086509e 100644 > --- a/libgloss/riscv/sys_sbrk.c > +++ b/libgloss/riscv/sys_sbrk.c > @@ -41,13 +41,13 @@ _sbrk(ptrdiff_t incr) > > if (heap_end == 0) > { > - long brk = __internal_syscall (SYS_brk, 0, 0, 0, 0, 0, 0); > + long brk = __internal_syscall (SYS_brk, 1, 0, 0, 0, 0, 0, 0); > if (brk == -1) > return (void *)__syscall_error (-ENOMEM); > heap_end = brk; > } > > - if (__internal_syscall (SYS_brk, heap_end + incr, 0, 0, 0, 0, 0) != heap_end + incr) > + if (__internal_syscall (SYS_brk, 1, heap_end + incr, 0, 0, 0, 0, 0) != heap_end + incr) > return (void *)__syscall_error (-ENOMEM); > > heap_end += incr; > diff --git a/libgloss/riscv/sys_stat.c b/libgloss/riscv/sys_stat.c > index a193b10..1e03700 100644 > --- a/libgloss/riscv/sys_stat.c > +++ b/libgloss/riscv/sys_stat.c > @@ -8,7 +8,7 @@ int > _stat(const char *file, struct stat *st) > { > struct kernel_stat kst; > - int rv = syscall_errno (SYS_stat, file, &kst, 0, 0, 0, 0); > + int rv = syscall_errno (SYS_stat, 2, file, &kst, 0, 0, 0, 0); > _conv_stat (st, &kst); > return rv; > } > diff --git a/libgloss/riscv/sys_unlink.c b/libgloss/riscv/sys_unlink.c > index b55fe1e..1cf6bbe 100644 > --- a/libgloss/riscv/sys_unlink.c > +++ b/libgloss/riscv/sys_unlink.c > @@ -5,5 +5,5 @@ > int > _unlink(const char *name) > { > - return syscall_errno (SYS_unlink, name, 0, 0, 0, 0, 0); > + return syscall_errno (SYS_unlink, 1, name, 0, 0, 0, 0, 0); > } > diff --git a/libgloss/riscv/sys_write.c b/libgloss/riscv/sys_write.c > index b972734..ce2edd3 100644 > --- a/libgloss/riscv/sys_write.c > +++ b/libgloss/riscv/sys_write.c > @@ -6,5 +6,5 @@ > ssize_t > _write(int file, const void *ptr, size_t len) > { > - return syscall_errno (SYS_write, file, ptr, len, 0, 0, 0); > + return syscall_errno (SYS_write, 3, file, ptr, len, 0, 0, 0); > } > -- > 2.24.1 > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) 2020-02-10 20:20 [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Georg Sauthoff 2020-02-10 20:20 ` [PATCH 1/1] Only pass the minimum number of syscall arguments Georg Sauthoff @ 2020-02-11 8:43 ` Corinna Vinschen 1 sibling, 0 replies; 4+ messages in thread From: Corinna Vinschen @ 2020-02-11 8:43 UTC (permalink / raw) To: Georg Sauthoff; +Cc: newlib [-- Attachment #1: Type: text/plain, Size: 1818 bytes --] On Feb 10 21:19, Georg Sauthoff wrote: > As is, the RISC-V syscall code unconditionally sets all possible syscall > arguments even if the syscall requires fewer. > > For example, the instruction sequence for a exit syscall looked like > this: > > li a0, 1 # in ther caller of exit() > # ... # in newlib: > li a1, 0 # unused arguments > li a2, 0 > li a3, 0 > li a4, 0 > li a5, 0 > li a7, 93 # exit syscall number > > (i.e. the binary contains then 5 superfluous instructions for this > one argument syscall) > > This patch changes the RISC-V syscall code such that only the required > syscall argument registers are set. > > Georg Sauthoff (1): > Only pass the minimum number of syscall arguments > > libgloss/riscv/internal_syscall.h | 41 ++++++++++++++++++++++--------- > libgloss/riscv/sys_access.c | 2 +- > libgloss/riscv/sys_close.c | 2 +- > libgloss/riscv/sys_exit.c | 2 +- > libgloss/riscv/sys_faccessat.c | 2 +- > libgloss/riscv/sys_fstat.c | 2 +- > libgloss/riscv/sys_fstatat.c | 2 +- > libgloss/riscv/sys_gettimeofday.c | 2 +- > libgloss/riscv/sys_link.c | 2 +- > libgloss/riscv/sys_lseek.c | 2 +- > libgloss/riscv/sys_lstat.c | 2 +- > libgloss/riscv/sys_open.c | 2 +- > libgloss/riscv/sys_openat.c | 2 +- > libgloss/riscv/sys_read.c | 2 +- > libgloss/riscv/sys_sbrk.c | 4 +-- > libgloss/riscv/sys_stat.c | 2 +- > libgloss/riscv/sys_unlink.c | 2 +- > libgloss/riscv/sys_write.c | 2 +- > 18 files changed, 48 insertions(+), 29 deletions(-) > > -- > 2.24.1 Pushed. Thanks, Corinna -- Corinna Vinschen Cygwin Maintainer Red Hat [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-02-11 8:43 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-02-10 20:20 [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Georg Sauthoff 2020-02-10 20:20 ` [PATCH 1/1] Only pass the minimum number of syscall arguments Georg Sauthoff 2020-02-11 6:55 ` Kito Cheng 2020-02-11 8:43 ` [PATCH 0/1] Only pass the minimum number of syscall arguments (RISC-V) Corinna Vinschen
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