From 4221f154ff29ab0d6be1e7beaa5ea2d1731bc58e Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 15 Sep 2012 02:22:10 -0400 Subject: [PATCH] fix buggy constraints in mips inline syscall asm if same register is used for input/output, the compiler must be told. otherwise is generates random junk code that clobbers the result. in pure syscall-wrapper functions, nothing went wrong, but in more complex functions where register allocation is non-trivial, things broke badly. --- arch/mips/syscall_arch.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mips/syscall_arch.h b/arch/mips/syscall_arch.h index b1e68ffb..7c7f9a1a 100644 --- a/arch/mips/syscall_arch.h +++ b/arch/mips/syscall_arch.h @@ -11,7 +11,7 @@ register long r2 __asm__("$2"); \ __asm__ __volatile__ ( \ "addu $2,$0,%2 ; syscall" \ - : "=&r"(r2), "=r"(r7) : "ir"(n), __VA_ARGS__, "r"(r2) \ + : "=&r"(r2), "=r"(r7) : "ir"(n), __VA_ARGS__, "0"(r2), "1"(r7) \ : "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", \ "$14", "$15", "$24", "$25", "hi", "lo", "memory"); \ return r7 ? -r2 : r2; \ @@ -53,7 +53,7 @@ static inline long __syscall4(long n, long a, long b, long c, long d) register long r5 __asm__("$5") = b; register long r6 __asm__("$6") = c; register long r7 __asm__("$7") = d; - __asm_syscall("r"(r4), "r"(r5), "r"(r6), "r"(r7)); + __asm_syscall("r"(r4), "r"(r5), "r"(r6)); } #else -- 2.25.1