1fa697140SDominik Brodowski /* SPDX-License-Identifier: GPL-2.0 */ 2fa697140SDominik Brodowski /* 3fa697140SDominik Brodowski * syscall_wrapper.h - x86 specific wrappers to syscall definitions 4fa697140SDominik Brodowski */ 5fa697140SDominik Brodowski 6fa697140SDominik Brodowski #ifndef _ASM_X86_SYSCALL_WRAPPER_H 7fa697140SDominik Brodowski #define _ASM_X86_SYSCALL_WRAPPER_H 8fa697140SDominik Brodowski 9ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on x86-64 and x32 */ 10ebeb8c82SDominik Brodowski #define SC_X86_64_REGS_TO_ARGS(x, ...) \ 11ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 12ebeb8c82SDominik Brodowski ,,regs->di,,regs->si,,regs->dx \ 13ebeb8c82SDominik Brodowski ,,regs->r10,,regs->r8,,regs->r9) \ 14ebeb8c82SDominik Brodowski 15ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on i386 */ 16ebeb8c82SDominik Brodowski #define SC_IA32_REGS_TO_ARGS(x, ...) \ 17ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 18ebeb8c82SDominik Brodowski ,,(unsigned int)regs->bx,,(unsigned int)regs->cx \ 19ebeb8c82SDominik Brodowski ,,(unsigned int)regs->dx,,(unsigned int)regs->si \ 20ebeb8c82SDominik Brodowski ,,(unsigned int)regs->di,,(unsigned int)regs->bp) 21ebeb8c82SDominik Brodowski 22ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 23ebeb8c82SDominik Brodowski /* 24ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 25e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 26ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 27ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 28ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 29ebeb8c82SDominik Brodowski * case as well. 30ebeb8c82SDominik Brodowski */ 31cf3b83e1SAndy Lutomirski #define __IA32_COMPAT_SYS_STUB0(x, name) \ 32cf3b83e1SAndy Lutomirski asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs);\ 33cf3b83e1SAndy Lutomirski ALLOW_ERROR_INJECTION(__ia32_compat_sys_##name, ERRNO); \ 34cf3b83e1SAndy Lutomirski asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs)\ 35cf3b83e1SAndy Lutomirski { \ 36cf3b83e1SAndy Lutomirski return __se_compat_sys_##name(); \ 37cf3b83e1SAndy Lutomirski } 38cf3b83e1SAndy Lutomirski 39c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 405ac9efa3SDominik Brodowski asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs);\ 415ac9efa3SDominik Brodowski ALLOW_ERROR_INJECTION(__ia32_compat_sys##name, ERRNO); \ 425ac9efa3SDominik Brodowski asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs)\ 43ebeb8c82SDominik Brodowski { \ 445ac9efa3SDominik Brodowski return __se_compat_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\ 45cf3b83e1SAndy Lutomirski } 46ebeb8c82SDominik Brodowski 47c76fc982SDominik Brodowski #define __IA32_SYS_STUBx(x, name, ...) \ 48e145242eSDominik Brodowski asmlinkage long __ia32_sys##name(const struct pt_regs *regs); \ 49e145242eSDominik Brodowski ALLOW_ERROR_INJECTION(__ia32_sys##name, ERRNO); \ 50e145242eSDominik Brodowski asmlinkage long __ia32_sys##name(const struct pt_regs *regs) \ 51ebeb8c82SDominik Brodowski { \ 52e145242eSDominik Brodowski return __se_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\ 53ebeb8c82SDominik Brodowski } 54ebeb8c82SDominik Brodowski 55d5a00528SDominik Brodowski /* 56d5a00528SDominik Brodowski * To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias 57d5a00528SDominik Brodowski * named __ia32_sys_*() 58d5a00528SDominik Brodowski */ 598661d769SSami Tolvanen 60d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 61d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 628661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\ 63d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 64d5a00528SDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \ 658661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused) 66d5a00528SDominik Brodowski 67ebeb8c82SDominik Brodowski #define COND_SYSCALL(name) \ 68d5a00528SDominik Brodowski cond_syscall(__x64_sys_##name); \ 69e145242eSDominik Brodowski cond_syscall(__ia32_sys_##name) 70ebeb8c82SDominik Brodowski 71ebeb8c82SDominik Brodowski #define SYS_NI(name) \ 72d5a00528SDominik Brodowski SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \ 73e145242eSDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers) 74ebeb8c82SDominik Brodowski 75ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 76c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 77c76fc982SDominik Brodowski #define __IA32_SYS_STUBx(x, fullname, name, ...) 78ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 79ebeb8c82SDominik Brodowski 80ebeb8c82SDominik Brodowski 81ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 82ebeb8c82SDominik Brodowski /* 83ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 84ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 85ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 86ebeb8c82SDominik Brodowski */ 87cf3b83e1SAndy Lutomirski #define __X32_COMPAT_SYS_STUB0(x, name, ...) \ 88cf3b83e1SAndy Lutomirski asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs);\ 89cf3b83e1SAndy Lutomirski ALLOW_ERROR_INJECTION(__x32_compat_sys_##name, ERRNO); \ 90cf3b83e1SAndy Lutomirski asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs)\ 91cf3b83e1SAndy Lutomirski { \ 92cf3b83e1SAndy Lutomirski return __se_compat_sys_##name();\ 93cf3b83e1SAndy Lutomirski } 94cf3b83e1SAndy Lutomirski 95c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 965ac9efa3SDominik Brodowski asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs);\ 975ac9efa3SDominik Brodowski ALLOW_ERROR_INJECTION(__x32_compat_sys##name, ERRNO); \ 985ac9efa3SDominik Brodowski asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs)\ 99ebeb8c82SDominik Brodowski { \ 1005ac9efa3SDominik Brodowski return __se_compat_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ 101cf3b83e1SAndy Lutomirski } 102ebeb8c82SDominik Brodowski 103ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 104cf3b83e1SAndy Lutomirski #define __X32_COMPAT_SYS_STUB0(x, name) 105c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 106ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 107ebeb8c82SDominik Brodowski 108ebeb8c82SDominik Brodowski 109ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 110ebeb8c82SDominik Brodowski /* 111ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 112ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 113d5a00528SDominik Brodowski * of them. 114ebeb8c82SDominik Brodowski */ 115cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 116cf3b83e1SAndy Lutomirski static long __se_compat_sys_##name(void); \ 117cf3b83e1SAndy Lutomirski static inline long __do_compat_sys_##name(void); \ 118cf3b83e1SAndy Lutomirski __IA32_COMPAT_SYS_STUB0(x, name) \ 119cf3b83e1SAndy Lutomirski __X32_COMPAT_SYS_STUB0(x, name) \ 120cf3b83e1SAndy Lutomirski static long __se_compat_sys_##name(void) \ 121cf3b83e1SAndy Lutomirski { \ 122cf3b83e1SAndy Lutomirski return __do_compat_sys_##name(); \ 123cf3b83e1SAndy Lutomirski } \ 124cf3b83e1SAndy Lutomirski static inline long __do_compat_sys_##name(void) 125cf3b83e1SAndy Lutomirski 126ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 1275ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 1285ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 129c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 130c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 1315ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 132ebeb8c82SDominik Brodowski { \ 1335ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 134ebeb8c82SDominik Brodowski } \ 1355ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 136ebeb8c82SDominik Brodowski 137ebeb8c82SDominik Brodowski /* 138ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 139ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 140ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 141ebeb8c82SDominik Brodowski */ 142ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 1435ac9efa3SDominik Brodowski cond_syscall(__ia32_compat_sys_##name); \ 1445ac9efa3SDominik Brodowski cond_syscall(__x32_compat_sys_##name) 145ebeb8c82SDominik Brodowski 146ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 1475ac9efa3SDominik Brodowski SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \ 1485ac9efa3SDominik Brodowski SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers) 149ebeb8c82SDominik Brodowski 150ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 151ebeb8c82SDominik Brodowski 152ebeb8c82SDominik Brodowski 153fa697140SDominik Brodowski /* 154fa697140SDominik Brodowski * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes 155fa697140SDominik Brodowski * struct pt_regs *regs as the only argument of the syscall stub named 156d5a00528SDominik Brodowski * __x64_sys_*(). It decodes just the registers it needs and passes them on to 157e145242eSDominik Brodowski * the __se_sys_*() wrapper performing sign extension and then to the 158e145242eSDominik Brodowski * __do_sys_*() function doing the actual job. These wrappers and functions 159e145242eSDominik Brodowski * are inlined (at least in very most cases), meaning that the assembly looks 160e145242eSDominik Brodowski * as follows (slightly re-ordered for better readability): 161fa697140SDominik Brodowski * 162d5a00528SDominik Brodowski * <__x64_sys_recv>: <-- syscall with 4 parameters 163fa697140SDominik Brodowski * callq <__fentry__> 164fa697140SDominik Brodowski * 165fa697140SDominik Brodowski * mov 0x70(%rdi),%rdi <-- decode regs->di 166fa697140SDominik Brodowski * mov 0x68(%rdi),%rsi <-- decode regs->si 167fa697140SDominik Brodowski * mov 0x60(%rdi),%rdx <-- decode regs->dx 168fa697140SDominik Brodowski * mov 0x38(%rdi),%rcx <-- decode regs->r10 169fa697140SDominik Brodowski * 170fa697140SDominik Brodowski * xor %r9d,%r9d <-- clear %r9 171fa697140SDominik Brodowski * xor %r8d,%r8d <-- clear %r8 172fa697140SDominik Brodowski * 173fa697140SDominik Brodowski * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 174fa697140SDominik Brodowski * which takes 6 arguments 175fa697140SDominik Brodowski * 176fa697140SDominik Brodowski * cltq <-- extend return value to 64-bit 177fa697140SDominik Brodowski * retq <-- return 178fa697140SDominik Brodowski * 179fa697140SDominik Brodowski * This approach avoids leaking random user-provided register content down 180fa697140SDominik Brodowski * the call chain. 181fa697140SDominik Brodowski * 182ebeb8c82SDominik Brodowski * If IA32_EMULATION is enabled, this macro generates an additional wrapper 183e145242eSDominik Brodowski * named __ia32_sys_*() which decodes the struct pt_regs *regs according 184ebeb8c82SDominik Brodowski * to the i386 calling convention (bx, cx, dx, si, di, bp). 185fa697140SDominik Brodowski */ 186fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 187d5a00528SDominik Brodowski asmlinkage long __x64_sys##name(const struct pt_regs *regs); \ 188d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys##name, ERRNO); \ 189e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 190e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 191d5a00528SDominik Brodowski asmlinkage long __x64_sys##name(const struct pt_regs *regs) \ 192fa697140SDominik Brodowski { \ 193e145242eSDominik Brodowski return __se_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ 194fa697140SDominik Brodowski } \ 195c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 196e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 197fa697140SDominik Brodowski { \ 198e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 199fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 200fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 201fa697140SDominik Brodowski return ret; \ 202fa697140SDominik Brodowski } \ 203e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 204fa697140SDominik Brodowski 205fa697140SDominik Brodowski /* 206d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 207d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 208d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 209d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 210d5a00528SDominik Brodowski * macros to work correctly. 211d5a00528SDominik Brodowski */ 212d5a00528SDominik Brodowski #ifndef SYSCALL_DEFINE0 213d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 214d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 2158661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\ 216d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 2178661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused) 218d5a00528SDominik Brodowski #endif 219d5a00528SDominik Brodowski 220d5a00528SDominik Brodowski #ifndef COND_SYSCALL 221d5a00528SDominik Brodowski #define COND_SYSCALL(name) cond_syscall(__x64_sys_##name) 222d5a00528SDominik Brodowski #endif 223d5a00528SDominik Brodowski 224d5a00528SDominik Brodowski #ifndef SYS_NI 225d5a00528SDominik Brodowski #define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); 226d5a00528SDominik Brodowski #endif 227d5a00528SDominik Brodowski 228d5a00528SDominik Brodowski 229d5a00528SDominik Brodowski /* 230fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 231fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 232fa697140SDominik Brodowski */ 233fa697140SDominik Brodowski struct pt_regs; 234d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 235d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 236d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 237fa697140SDominik Brodowski 238fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 239