From 1d2a6f21294f8390b683e4e097cb49210ed832d1 Mon Sep 17 00:00:00 2001 From: johannst Date: Fri, 26 Mar 2021 23:17:46 +0100 Subject: Added dyn allocator + syscall wrappers + minor fixes. --- lib/include/syscall.h | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-) (limited to 'lib/include/syscall.h') diff --git a/lib/include/syscall.h b/lib/include/syscall.h index 4947155..c9314d2 100644 --- a/lib/include/syscall.h +++ b/lib/include/syscall.h @@ -35,29 +35,44 @@ // https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html // https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html#Machine-Constraints // https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html - -// Linux syscall ABI -// x86-64 -// #syscall: rax -// ret : rax -// instr : syscall -// args : rdi rsi rdx r10 r8 r9 +// +// +// Linux syscall ABI - x86-64 +// #syscall: rax +// ret : rax +// instr : syscall +// args : rdi rsi rdx r10 r8 r9 // // Reference: // syscall(2) +// +// +// X86_64 `syscall` instruction additionally clobbers following registers: +// rcx Store return address. +// r11 Store RFLAGS. +// +// Reference: +// https://www.felixcloutier.com/x86/syscall #define argcast(A) ((long)(A)) #define syscall1(n, a1) _syscall1(n, argcast(a1)) +#define syscall2(n, a1, a2) _syscall2(n, argcast(a1), argcast(a2)) #define syscall3(n, a1, a2, a3) _syscall3(n, argcast(a1), argcast(a2), argcast(a3)) static inline long _syscall1(long n, long a1) { long ret; - asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1) : "memory"); + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1) : "rcx", "r11", "memory"); + return ret; +} + +static inline long _syscall2(long n, long a1, long a2) { + long ret; + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2) : "rcx", "r11", "memory"); return ret; } static inline long _syscall3(long n, long a1, long a2, long a3) { long ret; - asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), "d"(a3) : "memory"); + asm volatile("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), "d"(a3) : "rcx", "r11", "memory"); return ret; } -- cgit v1.2.3