From 319cbbf633ae60d7b4b89fcbb11a734f4d7d22f0 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Tue, 29 Aug 2017 18:31:08 +0100 Subject: MIPS/o32: Fix internal_syscall5/6/7 Fix a commit cc25c8b4c119 ("New pthread rwlock that is more scalable.") regression and prevent uncontrolled stack space usage from happening when a 5-, 6- or 7-argument syscall wrapper is placed in a loop. The cause of the problem is the use of `alloca' in regular MIPS/Linux wrappers to force the use of the frame pointer register in any function using one or more of these wrappers. Using the frame pointer register is required so as not to break frame unwinding as the the stack pointer is lowered within the inline asm used by these wrappers to make room for the stack arguments, which 5-, 6- and 7-argument syscalls use with the o32 ABI. The regular MIPS/Linux wrappers are macros however, expanded inline, and stack allocations made with `alloca' are not discarded until the return of the function they are made in. Consequently if called in a loop, then virtual memory is wasted, and if the loop goes through enough iterations, then ultimately available memory can get exhausted causing the program to crash. Address the issue by replacing the inline code with standalone assembly functions, which rely on the compiler arranging syscall arguments according to the o32 function calling convention, which MIPS/Linux syscalls also use, except for the syscall number passed and the error flag returned. This way there is no need to fiddle with the stack pointer anymore and all that has to be handled in the new standalone functions is the special handling of the syscall number and the error flag. Redirect 5-, 6- or 7-argument MIPS16/Linux syscall wrappers to these new functions as well, so as to avoid an unnecessary double call the existing wrappers would cause with the new arrangement. [BZ #21956] * sysdeps/unix/sysv/linux/mips/mips32/mips16/Makefile [subdir = misc] (sysdep_routines): Remove `mips16-syscall5', `mips16-syscall6' and `mips16-syscall7'. (CFLAGS-mips16-syscall5.c, CFLAGS-mips16-syscall6.c) (CFLAGS-mips16-syscall7.c): Remove. * sysdeps/unix/sysv/linux/mips/mips32/mips16/Versions (libc): Remove `__mips16_syscall5', `__mips16_syscall6' and `__mips16_syscall7'. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall0.c (__mips16_syscall0): Rename `__mips16_syscall_return' to `__mips_syscall_return'. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall1.c (__mips16_syscall1): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall2.c (__mips16_syscall2): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c (__mips16_syscall3): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall4.c (__mips16_syscall4): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall5.c: Remove. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall6.c: Remove. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall7.c: Remove. * sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall.h (__mips16_syscall5): Expand to `__mips_syscall5' rather than `__mips16_syscall5'. Remove prototype. (__mips16_syscall6): Expand to `__mips_syscall6' rather than `__mips16_syscall6'. Remove prototype. (__mips16_syscall7): Expand to `__mips_syscall7' rather than `__mips16_syscall7'. Remove prototype. (__nomips16, __mips16_syscall_return): Move to... * sysdeps/unix/sysv/linux/mips/mips32/sysdep.h (__nomips16, __mips_syscall_return): ... here. [__mips16] (INTERNAL_SYSCALL_NCS): Rename `__mips16_syscall_return' to `__mips_syscall_return'. [__mips16] (INTERNAL_SYSCALL_MIPS16): Pass `number' to `internal_syscall##nr'. [!__mips16] (INTERNAL_SYSCALL): Pass `SYS_ify (name)' to `internal_syscall##nr'. (FORCE_FRAME_POINTER): Remove. (__mips_syscall5): New prototype. (internal_syscall5): Rewrite to call `__mips_syscall5'. (__mips_syscall6): New prototype. (internal_syscall6): Rewrite to call `__mips_syscall6'. (__mips_syscall7): New prototype. (internal_syscall7): Rewrite to call `__mips_syscall7'. * sysdeps/unix/sysv/linux/mips/mips32/mips-syscall5.S: New file. * sysdeps/unix/sysv/linux/mips/mips32/mips-syscall6.S: New file. * sysdeps/unix/sysv/linux/mips/mips32/mips-syscall7.S: New file. * sysdeps/unix/sysv/linux/mips/mips32/Makefile [subdir = misc] (sysdep_routines): Add libc-do-syscall. * sysdeps/unix/sysv/linux/mips/mips32/Versions (libc): Add `__mips_syscall5', `__mips_syscall6' and `__mips_syscall7'. --- sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c') diff --git a/sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c b/sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c index c3f83fc1f6..6bd6b8222b 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c +++ b/sysdeps/unix/sysv/linux/mips/mips32/mips16/mips16-syscall3.c @@ -17,7 +17,6 @@ . */ #include -#include #undef __mips16_syscall3 @@ -25,7 +24,7 @@ long long __nomips16 __mips16_syscall3 (long a0, long a1, long a2, long number) { - union __mips16_syscall_return ret; + union __mips_syscall_return ret; ret.reg.v0 = INTERNAL_SYSCALL_MIPS16 (number, ret.reg.v1, 3, a0, a1, a2); return ret.val; -- cgit 1.4.1