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 384399e0cfSBrian Gerst #ifdef CONFIG_X86_64 39d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) \ 40d2b5de49SBrian Gerst __SYS_STUB0(x64, sys_##name) 41d2b5de49SBrian Gerst 424399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) \ 434399e0cfSBrian Gerst __SYS_STUBx(x64, sys##name, \ 444399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 454399e0cfSBrian Gerst #else /* CONFIG_X86_64 */ 46d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) 474399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) 484399e0cfSBrian Gerst #endif /* CONFIG_X86_64 */ 494399e0cfSBrian Gerst 50ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 51ebeb8c82SDominik Brodowski /* 52ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 53e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 54ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 55ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 56ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 57ebeb8c82SDominik Brodowski * case as well. 58ebeb8c82SDominik Brodowski */ 59d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) \ 60d2b5de49SBrian Gerst __SYS_STUB0(ia32, compat_sys_##name) 61cf3b83e1SAndy Lutomirski 62c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 634399e0cfSBrian Gerst __SYS_STUBx(ia32, compat_sys##name, \ 644399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 65ebeb8c82SDominik Brodowski 66d2b5de49SBrian Gerst #define __IA32_SYS_STUB0(name) \ 67d2b5de49SBrian Gerst __SYS_STUB0(ia32, sys_##name) 68d2b5de49SBrian Gerst 69c76fc982SDominik Brodowski #define __IA32_SYS_STUBx(x, name, ...) \ 704399e0cfSBrian Gerst __SYS_STUBx(ia32, sys##name, \ 714399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 72ebeb8c82SDominik Brodowski 73ebeb8c82SDominik Brodowski #define COND_SYSCALL(name) \ 746e484764SSami Tolvanen asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \ 756e484764SSami Tolvanen { \ 766e484764SSami Tolvanen return sys_ni_syscall(); \ 776e484764SSami Tolvanen } \ 786e484764SSami Tolvanen asmlinkage __weak long __ia32_sys_##name(const struct pt_regs *__unused)\ 796e484764SSami Tolvanen { \ 806e484764SSami Tolvanen return sys_ni_syscall(); \ 816e484764SSami Tolvanen } 82ebeb8c82SDominik Brodowski 83ebeb8c82SDominik Brodowski #define SYS_NI(name) \ 84d5a00528SDominik Brodowski SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \ 85e145242eSDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers) 86ebeb8c82SDominik Brodowski 87ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 88d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) 89c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 90d2b5de49SBrian Gerst #define __IA32_SYS_STUB0(name) 914399e0cfSBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) 92ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 93ebeb8c82SDominik Brodowski 94ebeb8c82SDominik Brodowski 95ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 96ebeb8c82SDominik Brodowski /* 97ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 98ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 99ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 100ebeb8c82SDominik Brodowski */ 101d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) \ 102d2b5de49SBrian Gerst __SYS_STUB0(x32, compat_sys_##name) 103cf3b83e1SAndy Lutomirski 104c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 1054399e0cfSBrian Gerst __SYS_STUBx(x32, compat_sys##name, \ 1064399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 107ebeb8c82SDominik Brodowski 108ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 109d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) 110c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 111ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 112ebeb8c82SDominik Brodowski 113ebeb8c82SDominik Brodowski 114ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 115ebeb8c82SDominik Brodowski /* 116ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 117ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 118d5a00528SDominik Brodowski * of them. 119ebeb8c82SDominik Brodowski */ 120cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 121d2b5de49SBrian Gerst static asmlinkage long \ 122d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused); \ 123d2b5de49SBrian Gerst __IA32_COMPAT_SYS_STUB0(name) \ 124d2b5de49SBrian Gerst __X32_COMPAT_SYS_STUB0(name) \ 125d2b5de49SBrian Gerst static asmlinkage long \ 126d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused) 127cf3b83e1SAndy Lutomirski 128ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 1295ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 1305ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 131c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 132c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 1335ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 134ebeb8c82SDominik Brodowski { \ 1355ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 136ebeb8c82SDominik Brodowski } \ 1375ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 138ebeb8c82SDominik Brodowski 139ebeb8c82SDominik Brodowski /* 140ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 141ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 142ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 143ebeb8c82SDominik Brodowski */ 144ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 1455ac9efa3SDominik Brodowski cond_syscall(__ia32_compat_sys_##name); \ 1465ac9efa3SDominik Brodowski cond_syscall(__x32_compat_sys_##name) 147ebeb8c82SDominik Brodowski 148ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 1495ac9efa3SDominik Brodowski SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \ 1505ac9efa3SDominik Brodowski SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers) 151ebeb8c82SDominik Brodowski 152ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 153ebeb8c82SDominik Brodowski 154ebeb8c82SDominik Brodowski 155fa697140SDominik Brodowski /* 156fa697140SDominik Brodowski * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes 157fa697140SDominik Brodowski * struct pt_regs *regs as the only argument of the syscall stub named 158d5a00528SDominik Brodowski * __x64_sys_*(). It decodes just the registers it needs and passes them on to 159e145242eSDominik Brodowski * the __se_sys_*() wrapper performing sign extension and then to the 160e145242eSDominik Brodowski * __do_sys_*() function doing the actual job. These wrappers and functions 161e145242eSDominik Brodowski * are inlined (at least in very most cases), meaning that the assembly looks 162e145242eSDominik Brodowski * as follows (slightly re-ordered for better readability): 163fa697140SDominik Brodowski * 164d5a00528SDominik Brodowski * <__x64_sys_recv>: <-- syscall with 4 parameters 165fa697140SDominik Brodowski * callq <__fentry__> 166fa697140SDominik Brodowski * 167fa697140SDominik Brodowski * mov 0x70(%rdi),%rdi <-- decode regs->di 168fa697140SDominik Brodowski * mov 0x68(%rdi),%rsi <-- decode regs->si 169fa697140SDominik Brodowski * mov 0x60(%rdi),%rdx <-- decode regs->dx 170fa697140SDominik Brodowski * mov 0x38(%rdi),%rcx <-- decode regs->r10 171fa697140SDominik Brodowski * 172fa697140SDominik Brodowski * xor %r9d,%r9d <-- clear %r9 173fa697140SDominik Brodowski * xor %r8d,%r8d <-- clear %r8 174fa697140SDominik Brodowski * 175fa697140SDominik Brodowski * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 176fa697140SDominik Brodowski * which takes 6 arguments 177fa697140SDominik Brodowski * 178fa697140SDominik Brodowski * cltq <-- extend return value to 64-bit 179fa697140SDominik Brodowski * retq <-- return 180fa697140SDominik Brodowski * 181fa697140SDominik Brodowski * This approach avoids leaking random user-provided register content down 182fa697140SDominik Brodowski * the call chain. 183fa697140SDominik Brodowski * 184ebeb8c82SDominik Brodowski * If IA32_EMULATION is enabled, this macro generates an additional wrapper 185e145242eSDominik Brodowski * named __ia32_sys_*() which decodes the struct pt_regs *regs according 186ebeb8c82SDominik Brodowski * to the i386 calling convention (bx, cx, dx, si, di, bp). 187fa697140SDominik Brodowski */ 188fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 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__));\ 1914399e0cfSBrian Gerst __X64_SYS_STUBx(x, name, __VA_ARGS__) \ 192c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 193e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 194fa697140SDominik Brodowski { \ 195e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 196fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 197fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 198fa697140SDominik Brodowski return ret; \ 199fa697140SDominik Brodowski } \ 200e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 201fa697140SDominik Brodowski 202fa697140SDominik Brodowski /* 203d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 204d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 205d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 206d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 207d5a00528SDominik Brodowski * macros to work correctly. 208d5a00528SDominik Brodowski */ 209d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 210d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 211d2b5de49SBrian Gerst static asmlinkage long \ 212d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused); \ 213d2b5de49SBrian Gerst __X64_SYS_STUB0(sname) \ 214d2b5de49SBrian Gerst __IA32_SYS_STUB0(sname) \ 215d2b5de49SBrian Gerst static asmlinkage long \ 216d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused) 217d5a00528SDominik Brodowski 218d5a00528SDominik Brodowski #ifndef COND_SYSCALL 2196e484764SSami Tolvanen #define COND_SYSCALL(name) \ 2206e484764SSami Tolvanen asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \ 2216e484764SSami Tolvanen { \ 2226e484764SSami Tolvanen return sys_ni_syscall(); \ 2236e484764SSami Tolvanen } 224d5a00528SDominik Brodowski #endif 225d5a00528SDominik Brodowski 226d5a00528SDominik Brodowski #ifndef SYS_NI 227d5a00528SDominik Brodowski #define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); 228d5a00528SDominik Brodowski #endif 229d5a00528SDominik Brodowski 230d5a00528SDominik Brodowski 231d5a00528SDominik Brodowski /* 232fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 233fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 234fa697140SDominik Brodowski */ 235d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 236d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 237d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 238fa697140SDominik Brodowski 239fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 240