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 96e484764SSami Tolvanen struct pt_regs; 106e484764SSami Tolvanen 11ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on x86-64 and x32 */ 12ebeb8c82SDominik Brodowski #define SC_X86_64_REGS_TO_ARGS(x, ...) \ 13ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 14ebeb8c82SDominik Brodowski ,,regs->di,,regs->si,,regs->dx \ 15ebeb8c82SDominik Brodowski ,,regs->r10,,regs->r8,,regs->r9) \ 16ebeb8c82SDominik Brodowski 17ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on i386 */ 18ebeb8c82SDominik Brodowski #define SC_IA32_REGS_TO_ARGS(x, ...) \ 19ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 20ebeb8c82SDominik Brodowski ,,(unsigned int)regs->bx,,(unsigned int)regs->cx \ 21ebeb8c82SDominik Brodowski ,,(unsigned int)regs->dx,,(unsigned int)regs->si \ 22ebeb8c82SDominik Brodowski ,,(unsigned int)regs->di,,(unsigned int)regs->bp) 23ebeb8c82SDominik Brodowski 24d2b5de49SBrian Gerst #define __SYS_STUB0(abi, name) \ 25d2b5de49SBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ 26d2b5de49SBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 27d2b5de49SBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ 28d2b5de49SBrian Gerst __alias(__do_##name); 29d2b5de49SBrian Gerst 304399e0cfSBrian Gerst #define __SYS_STUBx(abi, name, ...) \ 314399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ 324399e0cfSBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 334399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ 344399e0cfSBrian Gerst { \ 354399e0cfSBrian Gerst return __se_##name(__VA_ARGS__); \ 364399e0cfSBrian Gerst } 374399e0cfSBrian Gerst 386cc8d2b2SBrian Gerst #define __COND_SYSCALL(abi, name) \ 396cc8d2b2SBrian Gerst asmlinkage __weak long \ 406cc8d2b2SBrian Gerst __##abi##_##name(const struct pt_regs *__unused) \ 416cc8d2b2SBrian Gerst { \ 426cc8d2b2SBrian Gerst return sys_ni_syscall(); \ 436cc8d2b2SBrian Gerst } 446cc8d2b2SBrian Gerst 454399e0cfSBrian Gerst #ifdef CONFIG_X86_64 46d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) \ 47d2b5de49SBrian Gerst __SYS_STUB0(x64, sys_##name) 48d2b5de49SBrian Gerst 494399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) \ 504399e0cfSBrian Gerst __SYS_STUBx(x64, sys##name, \ 514399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 526cc8d2b2SBrian Gerst 536cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) \ 546cc8d2b2SBrian Gerst __COND_SYSCALL(x64, sys_##name) 554399e0cfSBrian Gerst #else /* CONFIG_X86_64 */ 56d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) 574399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) 586cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) 594399e0cfSBrian Gerst #endif /* CONFIG_X86_64 */ 604399e0cfSBrian Gerst 61ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 62ebeb8c82SDominik Brodowski /* 63ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 64e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 65ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 66ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 67ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 68ebeb8c82SDominik Brodowski * case as well. 69ebeb8c82SDominik Brodowski */ 70d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) \ 71d2b5de49SBrian Gerst __SYS_STUB0(ia32, compat_sys_##name) 72cf3b83e1SAndy Lutomirski 73c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 744399e0cfSBrian Gerst __SYS_STUBx(ia32, compat_sys##name, \ 754399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 76ebeb8c82SDominik Brodowski 776cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) \ 786cc8d2b2SBrian Gerst __COND_SYSCALL(ia32, compat_sys_##name) 796cc8d2b2SBrian Gerst 80d2b5de49SBrian Gerst #define __IA32_SYS_STUB0(name) \ 81d2b5de49SBrian Gerst __SYS_STUB0(ia32, sys_##name) 82d2b5de49SBrian Gerst 83c76fc982SDominik Brodowski #define __IA32_SYS_STUBx(x, name, ...) \ 844399e0cfSBrian Gerst __SYS_STUBx(ia32, sys##name, \ 854399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 86ebeb8c82SDominik Brodowski 876cc8d2b2SBrian Gerst #define __IA32_COND_SYSCALL(name) \ 886cc8d2b2SBrian Gerst __COND_SYSCALL(ia32, sys_##name) 89ebeb8c82SDominik Brodowski 90ebeb8c82SDominik Brodowski #define SYS_NI(name) \ 91d5a00528SDominik Brodowski SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \ 92e145242eSDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers) 93ebeb8c82SDominik Brodowski 94ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 95d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) 96c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 976cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) 98d2b5de49SBrian Gerst #define __IA32_SYS_STUB0(name) 994399e0cfSBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) 1006cc8d2b2SBrian Gerst #define __IA32_COND_SYSCALL(name) 101ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 102ebeb8c82SDominik Brodowski 103ebeb8c82SDominik Brodowski 104ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 105ebeb8c82SDominik Brodowski /* 106ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 107ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 108ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 109ebeb8c82SDominik Brodowski */ 110d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) \ 111d2b5de49SBrian Gerst __SYS_STUB0(x32, compat_sys_##name) 112cf3b83e1SAndy Lutomirski 113c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 1144399e0cfSBrian Gerst __SYS_STUBx(x32, compat_sys##name, \ 1154399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 116ebeb8c82SDominik Brodowski 1176cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) \ 1186cc8d2b2SBrian Gerst __COND_SYSCALL(x32, compat_sys_##name) 119ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 120d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) 121c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 1226cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) 123ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 124ebeb8c82SDominik Brodowski 125ebeb8c82SDominik Brodowski 126ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 127ebeb8c82SDominik Brodowski /* 128ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 129ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 130d5a00528SDominik Brodowski * of them. 131ebeb8c82SDominik Brodowski */ 132cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 133d2b5de49SBrian Gerst static asmlinkage long \ 134d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused); \ 135d2b5de49SBrian Gerst __IA32_COMPAT_SYS_STUB0(name) \ 136d2b5de49SBrian Gerst __X32_COMPAT_SYS_STUB0(name) \ 137d2b5de49SBrian Gerst static asmlinkage long \ 138d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused) 139cf3b83e1SAndy Lutomirski 140ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 1415ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 1425ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 143c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 144c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 1455ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 146ebeb8c82SDominik Brodowski { \ 1475ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 148ebeb8c82SDominik Brodowski } \ 1495ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 150ebeb8c82SDominik Brodowski 151ebeb8c82SDominik Brodowski /* 152ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 153ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 154ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 155ebeb8c82SDominik Brodowski */ 156ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 1576cc8d2b2SBrian Gerst __IA32_COMPAT_COND_SYSCALL(name) \ 1586cc8d2b2SBrian Gerst __X32_COMPAT_COND_SYSCALL(name) 159ebeb8c82SDominik Brodowski 160ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 1615ac9efa3SDominik Brodowski SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \ 1625ac9efa3SDominik Brodowski SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers) 163ebeb8c82SDominik Brodowski 164ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 165ebeb8c82SDominik Brodowski 166ebeb8c82SDominik Brodowski 167fa697140SDominik Brodowski /* 168fa697140SDominik Brodowski * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes 169fa697140SDominik Brodowski * struct pt_regs *regs as the only argument of the syscall stub named 170d5a00528SDominik Brodowski * __x64_sys_*(). It decodes just the registers it needs and passes them on to 171e145242eSDominik Brodowski * the __se_sys_*() wrapper performing sign extension and then to the 172e145242eSDominik Brodowski * __do_sys_*() function doing the actual job. These wrappers and functions 173e145242eSDominik Brodowski * are inlined (at least in very most cases), meaning that the assembly looks 174e145242eSDominik Brodowski * as follows (slightly re-ordered for better readability): 175fa697140SDominik Brodowski * 176d5a00528SDominik Brodowski * <__x64_sys_recv>: <-- syscall with 4 parameters 177fa697140SDominik Brodowski * callq <__fentry__> 178fa697140SDominik Brodowski * 179fa697140SDominik Brodowski * mov 0x70(%rdi),%rdi <-- decode regs->di 180fa697140SDominik Brodowski * mov 0x68(%rdi),%rsi <-- decode regs->si 181fa697140SDominik Brodowski * mov 0x60(%rdi),%rdx <-- decode regs->dx 182fa697140SDominik Brodowski * mov 0x38(%rdi),%rcx <-- decode regs->r10 183fa697140SDominik Brodowski * 184fa697140SDominik Brodowski * xor %r9d,%r9d <-- clear %r9 185fa697140SDominik Brodowski * xor %r8d,%r8d <-- clear %r8 186fa697140SDominik Brodowski * 187fa697140SDominik Brodowski * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 188fa697140SDominik Brodowski * which takes 6 arguments 189fa697140SDominik Brodowski * 190fa697140SDominik Brodowski * cltq <-- extend return value to 64-bit 191fa697140SDominik Brodowski * retq <-- return 192fa697140SDominik Brodowski * 193fa697140SDominik Brodowski * This approach avoids leaking random user-provided register content down 194fa697140SDominik Brodowski * the call chain. 195fa697140SDominik Brodowski * 196ebeb8c82SDominik Brodowski * If IA32_EMULATION is enabled, this macro generates an additional wrapper 197e145242eSDominik Brodowski * named __ia32_sys_*() which decodes the struct pt_regs *regs according 198ebeb8c82SDominik Brodowski * to the i386 calling convention (bx, cx, dx, si, di, bp). 199fa697140SDominik Brodowski */ 200fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 201e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 202e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 2034399e0cfSBrian Gerst __X64_SYS_STUBx(x, name, __VA_ARGS__) \ 204c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 205e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 206fa697140SDominik Brodowski { \ 207e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 208fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 209fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 210fa697140SDominik Brodowski return ret; \ 211fa697140SDominik Brodowski } \ 212e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 213fa697140SDominik Brodowski 214fa697140SDominik Brodowski /* 215d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 216d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 217d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 218d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 219d5a00528SDominik Brodowski * macros to work correctly. 220d5a00528SDominik Brodowski */ 221d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 222d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 223d2b5de49SBrian Gerst static asmlinkage long \ 224d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused); \ 225d2b5de49SBrian Gerst __X64_SYS_STUB0(sname) \ 226d2b5de49SBrian Gerst __IA32_SYS_STUB0(sname) \ 227d2b5de49SBrian Gerst static asmlinkage long \ 228d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused) 229d5a00528SDominik Brodowski 2306e484764SSami Tolvanen #define COND_SYSCALL(name) \ 2316cc8d2b2SBrian Gerst __X64_COND_SYSCALL(name) \ 2326cc8d2b2SBrian Gerst __IA32_COND_SYSCALL(name) 233d5a00528SDominik Brodowski 234d5a00528SDominik Brodowski #ifndef SYS_NI 235d5a00528SDominik Brodowski #define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); 236d5a00528SDominik Brodowski #endif 237d5a00528SDominik Brodowski 238d5a00528SDominik Brodowski 239d5a00528SDominik Brodowski /* 240fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 241fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 242fa697140SDominik Brodowski */ 243d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 244d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 245d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 246fa697140SDominik Brodowski 247fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 248