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 244399e0cfSBrian Gerst #define __SYS_STUBx(abi, name, ...) \ 254399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ 264399e0cfSBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 274399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ 284399e0cfSBrian Gerst { \ 294399e0cfSBrian Gerst return __se_##name(__VA_ARGS__); \ 304399e0cfSBrian Gerst } 314399e0cfSBrian Gerst 324399e0cfSBrian Gerst #ifdef CONFIG_X86_64 334399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) \ 344399e0cfSBrian Gerst __SYS_STUBx(x64, sys##name, \ 354399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 364399e0cfSBrian Gerst #else /* CONFIG_X86_64 */ 374399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) 384399e0cfSBrian Gerst #endif /* CONFIG_X86_64 */ 394399e0cfSBrian Gerst 40ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 41ebeb8c82SDominik Brodowski /* 42ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 43e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 44ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 45ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 46ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 47ebeb8c82SDominik Brodowski * case as well. 48ebeb8c82SDominik Brodowski */ 49cf3b83e1SAndy Lutomirski #define __IA32_COMPAT_SYS_STUB0(x, name) \ 50cf3b83e1SAndy Lutomirski asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs);\ 51cf3b83e1SAndy Lutomirski ALLOW_ERROR_INJECTION(__ia32_compat_sys_##name, ERRNO); \ 52cf3b83e1SAndy Lutomirski asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs)\ 53cf3b83e1SAndy Lutomirski { \ 54cf3b83e1SAndy Lutomirski return __se_compat_sys_##name(); \ 55cf3b83e1SAndy Lutomirski } 56cf3b83e1SAndy Lutomirski 57c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 584399e0cfSBrian Gerst __SYS_STUBx(ia32, compat_sys##name, \ 594399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 60ebeb8c82SDominik Brodowski 61c76fc982SDominik Brodowski #define __IA32_SYS_STUBx(x, name, ...) \ 624399e0cfSBrian Gerst __SYS_STUBx(ia32, sys##name, \ 634399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 64ebeb8c82SDominik Brodowski 65d5a00528SDominik Brodowski /* 66d5a00528SDominik Brodowski * To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias 67d5a00528SDominik Brodowski * named __ia32_sys_*() 68d5a00528SDominik Brodowski */ 698661d769SSami Tolvanen 70d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 71d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 728661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\ 73d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 74d5a00528SDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \ 758661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused) 76d5a00528SDominik Brodowski 77ebeb8c82SDominik Brodowski #define COND_SYSCALL(name) \ 786e484764SSami Tolvanen asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \ 796e484764SSami Tolvanen { \ 806e484764SSami Tolvanen return sys_ni_syscall(); \ 816e484764SSami Tolvanen } \ 826e484764SSami Tolvanen asmlinkage __weak long __ia32_sys_##name(const struct pt_regs *__unused)\ 836e484764SSami Tolvanen { \ 846e484764SSami Tolvanen return sys_ni_syscall(); \ 856e484764SSami Tolvanen } 86ebeb8c82SDominik Brodowski 87ebeb8c82SDominik Brodowski #define SYS_NI(name) \ 88d5a00528SDominik Brodowski SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \ 89e145242eSDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers) 90ebeb8c82SDominik Brodowski 91ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 92c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 934399e0cfSBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) 94ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 95ebeb8c82SDominik Brodowski 96ebeb8c82SDominik Brodowski 97ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 98ebeb8c82SDominik Brodowski /* 99ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 100ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 101ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 102ebeb8c82SDominik Brodowski */ 103cf3b83e1SAndy Lutomirski #define __X32_COMPAT_SYS_STUB0(x, name, ...) \ 104cf3b83e1SAndy Lutomirski asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs);\ 105cf3b83e1SAndy Lutomirski ALLOW_ERROR_INJECTION(__x32_compat_sys_##name, ERRNO); \ 106cf3b83e1SAndy Lutomirski asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs)\ 107cf3b83e1SAndy Lutomirski { \ 108cf3b83e1SAndy Lutomirski return __se_compat_sys_##name();\ 109cf3b83e1SAndy Lutomirski } 110cf3b83e1SAndy Lutomirski 111c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 1124399e0cfSBrian Gerst __SYS_STUBx(x32, compat_sys##name, \ 1134399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 114ebeb8c82SDominik Brodowski 115ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 116cf3b83e1SAndy Lutomirski #define __X32_COMPAT_SYS_STUB0(x, name) 117c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 118ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 119ebeb8c82SDominik Brodowski 120ebeb8c82SDominik Brodowski 121ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 122ebeb8c82SDominik Brodowski /* 123ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 124ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 125d5a00528SDominik Brodowski * of them. 126ebeb8c82SDominik Brodowski */ 127cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 128cf3b83e1SAndy Lutomirski static long __se_compat_sys_##name(void); \ 129cf3b83e1SAndy Lutomirski static inline long __do_compat_sys_##name(void); \ 130cf3b83e1SAndy Lutomirski __IA32_COMPAT_SYS_STUB0(x, name) \ 131cf3b83e1SAndy Lutomirski __X32_COMPAT_SYS_STUB0(x, name) \ 132cf3b83e1SAndy Lutomirski static long __se_compat_sys_##name(void) \ 133cf3b83e1SAndy Lutomirski { \ 134cf3b83e1SAndy Lutomirski return __do_compat_sys_##name(); \ 135cf3b83e1SAndy Lutomirski } \ 136cf3b83e1SAndy Lutomirski static inline long __do_compat_sys_##name(void) 137cf3b83e1SAndy Lutomirski 138ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 1395ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 1405ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 141c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 142c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 1435ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 144ebeb8c82SDominik Brodowski { \ 1455ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 146ebeb8c82SDominik Brodowski } \ 1475ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 148ebeb8c82SDominik Brodowski 149ebeb8c82SDominik Brodowski /* 150ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 151ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 152ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 153ebeb8c82SDominik Brodowski */ 154ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 1555ac9efa3SDominik Brodowski cond_syscall(__ia32_compat_sys_##name); \ 1565ac9efa3SDominik Brodowski cond_syscall(__x32_compat_sys_##name) 157ebeb8c82SDominik Brodowski 158ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 1595ac9efa3SDominik Brodowski SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \ 1605ac9efa3SDominik Brodowski SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers) 161ebeb8c82SDominik Brodowski 162ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 163ebeb8c82SDominik Brodowski 164ebeb8c82SDominik Brodowski 165fa697140SDominik Brodowski /* 166fa697140SDominik Brodowski * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes 167fa697140SDominik Brodowski * struct pt_regs *regs as the only argument of the syscall stub named 168d5a00528SDominik Brodowski * __x64_sys_*(). It decodes just the registers it needs and passes them on to 169e145242eSDominik Brodowski * the __se_sys_*() wrapper performing sign extension and then to the 170e145242eSDominik Brodowski * __do_sys_*() function doing the actual job. These wrappers and functions 171e145242eSDominik Brodowski * are inlined (at least in very most cases), meaning that the assembly looks 172e145242eSDominik Brodowski * as follows (slightly re-ordered for better readability): 173fa697140SDominik Brodowski * 174d5a00528SDominik Brodowski * <__x64_sys_recv>: <-- syscall with 4 parameters 175fa697140SDominik Brodowski * callq <__fentry__> 176fa697140SDominik Brodowski * 177fa697140SDominik Brodowski * mov 0x70(%rdi),%rdi <-- decode regs->di 178fa697140SDominik Brodowski * mov 0x68(%rdi),%rsi <-- decode regs->si 179fa697140SDominik Brodowski * mov 0x60(%rdi),%rdx <-- decode regs->dx 180fa697140SDominik Brodowski * mov 0x38(%rdi),%rcx <-- decode regs->r10 181fa697140SDominik Brodowski * 182fa697140SDominik Brodowski * xor %r9d,%r9d <-- clear %r9 183fa697140SDominik Brodowski * xor %r8d,%r8d <-- clear %r8 184fa697140SDominik Brodowski * 185fa697140SDominik Brodowski * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 186fa697140SDominik Brodowski * which takes 6 arguments 187fa697140SDominik Brodowski * 188fa697140SDominik Brodowski * cltq <-- extend return value to 64-bit 189fa697140SDominik Brodowski * retq <-- return 190fa697140SDominik Brodowski * 191fa697140SDominik Brodowski * This approach avoids leaking random user-provided register content down 192fa697140SDominik Brodowski * the call chain. 193fa697140SDominik Brodowski * 194ebeb8c82SDominik Brodowski * If IA32_EMULATION is enabled, this macro generates an additional wrapper 195e145242eSDominik Brodowski * named __ia32_sys_*() which decodes the struct pt_regs *regs according 196ebeb8c82SDominik Brodowski * to the i386 calling convention (bx, cx, dx, si, di, bp). 197fa697140SDominik Brodowski */ 198fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 199e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 200e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 2014399e0cfSBrian Gerst __X64_SYS_STUBx(x, name, __VA_ARGS__) \ 202c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 203e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 204fa697140SDominik Brodowski { \ 205e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 206fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 207fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 208fa697140SDominik Brodowski return ret; \ 209fa697140SDominik Brodowski } \ 210e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 211fa697140SDominik Brodowski 212fa697140SDominik Brodowski /* 213d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 214d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 215d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 216d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 217d5a00528SDominik Brodowski * macros to work correctly. 218d5a00528SDominik Brodowski */ 219d5a00528SDominik Brodowski #ifndef SYSCALL_DEFINE0 220d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 221d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 2228661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\ 223d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 2248661d769SSami Tolvanen asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused) 225d5a00528SDominik Brodowski #endif 226d5a00528SDominik Brodowski 227d5a00528SDominik Brodowski #ifndef COND_SYSCALL 2286e484764SSami Tolvanen #define COND_SYSCALL(name) \ 2296e484764SSami Tolvanen asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \ 2306e484764SSami Tolvanen { \ 2316e484764SSami Tolvanen return sys_ni_syscall(); \ 2326e484764SSami Tolvanen } 233d5a00528SDominik Brodowski #endif 234d5a00528SDominik Brodowski 235d5a00528SDominik Brodowski #ifndef SYS_NI 236d5a00528SDominik Brodowski #define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); 237d5a00528SDominik Brodowski #endif 238d5a00528SDominik Brodowski 239d5a00528SDominik Brodowski 240d5a00528SDominik Brodowski /* 241fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 242fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 243fa697140SDominik Brodowski */ 244d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 245d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 246d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 247fa697140SDominik Brodowski 248fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 249