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 */ 31ebeb8c82SDominik Brodowski #define COMPAT_SC_IA32_STUBx(x, name, ...) \ 325ac9efa3SDominik Brodowski asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs);\ 335ac9efa3SDominik Brodowski ALLOW_ERROR_INJECTION(__ia32_compat_sys##name, ERRNO); \ 345ac9efa3SDominik Brodowski asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs)\ 35ebeb8c82SDominik Brodowski { \ 365ac9efa3SDominik Brodowski return __se_compat_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\ 37ebeb8c82SDominik Brodowski } \ 38ebeb8c82SDominik Brodowski 39ebeb8c82SDominik Brodowski #define SC_IA32_WRAPPERx(x, name, ...) \ 40e145242eSDominik Brodowski asmlinkage long __ia32_sys##name(const struct pt_regs *regs); \ 41e145242eSDominik Brodowski ALLOW_ERROR_INJECTION(__ia32_sys##name, ERRNO); \ 42e145242eSDominik Brodowski asmlinkage long __ia32_sys##name(const struct pt_regs *regs) \ 43ebeb8c82SDominik Brodowski { \ 44e145242eSDominik Brodowski return __se_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\ 45ebeb8c82SDominik Brodowski } 46ebeb8c82SDominik Brodowski 47d5a00528SDominik Brodowski /* 48d5a00528SDominik Brodowski * To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias 49d5a00528SDominik Brodowski * named __ia32_sys_*() 50d5a00528SDominik Brodowski */ 51d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 52d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 53d5a00528SDominik Brodowski asmlinkage long __x64_sys_##sname(void); \ 54d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 55d5a00528SDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \ 56d5a00528SDominik Brodowski asmlinkage long __x64_sys_##sname(void) 57d5a00528SDominik Brodowski 58ebeb8c82SDominik Brodowski #define COND_SYSCALL(name) \ 59d5a00528SDominik Brodowski cond_syscall(__x64_sys_##name); \ 60e145242eSDominik Brodowski cond_syscall(__ia32_sys_##name) 61ebeb8c82SDominik Brodowski 62ebeb8c82SDominik Brodowski #define SYS_NI(name) \ 63d5a00528SDominik Brodowski SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \ 64e145242eSDominik Brodowski SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers) 65ebeb8c82SDominik Brodowski 66ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 67ebeb8c82SDominik Brodowski #define COMPAT_SC_IA32_STUBx(x, name, ...) 68ebeb8c82SDominik Brodowski #define SC_IA32_WRAPPERx(x, fullname, name, ...) 69ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 70ebeb8c82SDominik Brodowski 71ebeb8c82SDominik Brodowski 72ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 73ebeb8c82SDominik Brodowski /* 74ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 75ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 76ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 77ebeb8c82SDominik Brodowski */ 78ebeb8c82SDominik Brodowski #define COMPAT_SC_X32_STUBx(x, name, ...) \ 795ac9efa3SDominik Brodowski asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs);\ 805ac9efa3SDominik Brodowski ALLOW_ERROR_INJECTION(__x32_compat_sys##name, ERRNO); \ 815ac9efa3SDominik Brodowski asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs)\ 82ebeb8c82SDominik Brodowski { \ 835ac9efa3SDominik Brodowski return __se_compat_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ 84ebeb8c82SDominik Brodowski } \ 85ebeb8c82SDominik Brodowski 86ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 87ebeb8c82SDominik Brodowski #define COMPAT_SC_X32_STUBx(x, name, ...) 88ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 89ebeb8c82SDominik Brodowski 90ebeb8c82SDominik Brodowski 91ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 92ebeb8c82SDominik Brodowski /* 93ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 94ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 95d5a00528SDominik Brodowski * of them. 96ebeb8c82SDominik Brodowski */ 97ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 985ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 995ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 100ebeb8c82SDominik Brodowski COMPAT_SC_IA32_STUBx(x, name, __VA_ARGS__) \ 101ebeb8c82SDominik Brodowski COMPAT_SC_X32_STUBx(x, name, __VA_ARGS__) \ 1025ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 103ebeb8c82SDominik Brodowski { \ 1045ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 105ebeb8c82SDominik Brodowski } \ 1065ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 107ebeb8c82SDominik Brodowski 108ebeb8c82SDominik Brodowski /* 109ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 110ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 111ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 112ebeb8c82SDominik Brodowski */ 113ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 1145ac9efa3SDominik Brodowski cond_syscall(__ia32_compat_sys_##name); \ 1155ac9efa3SDominik Brodowski cond_syscall(__x32_compat_sys_##name) 116ebeb8c82SDominik Brodowski 117ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 1185ac9efa3SDominik Brodowski SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \ 1195ac9efa3SDominik Brodowski SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers) 120ebeb8c82SDominik Brodowski 121ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 122ebeb8c82SDominik Brodowski 123ebeb8c82SDominik Brodowski 124fa697140SDominik Brodowski /* 125fa697140SDominik Brodowski * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes 126fa697140SDominik Brodowski * struct pt_regs *regs as the only argument of the syscall stub named 127d5a00528SDominik Brodowski * __x64_sys_*(). It decodes just the registers it needs and passes them on to 128e145242eSDominik Brodowski * the __se_sys_*() wrapper performing sign extension and then to the 129e145242eSDominik Brodowski * __do_sys_*() function doing the actual job. These wrappers and functions 130e145242eSDominik Brodowski * are inlined (at least in very most cases), meaning that the assembly looks 131e145242eSDominik Brodowski * as follows (slightly re-ordered for better readability): 132fa697140SDominik Brodowski * 133d5a00528SDominik Brodowski * <__x64_sys_recv>: <-- syscall with 4 parameters 134fa697140SDominik Brodowski * callq <__fentry__> 135fa697140SDominik Brodowski * 136fa697140SDominik Brodowski * mov 0x70(%rdi),%rdi <-- decode regs->di 137fa697140SDominik Brodowski * mov 0x68(%rdi),%rsi <-- decode regs->si 138fa697140SDominik Brodowski * mov 0x60(%rdi),%rdx <-- decode regs->dx 139fa697140SDominik Brodowski * mov 0x38(%rdi),%rcx <-- decode regs->r10 140fa697140SDominik Brodowski * 141fa697140SDominik Brodowski * xor %r9d,%r9d <-- clear %r9 142fa697140SDominik Brodowski * xor %r8d,%r8d <-- clear %r8 143fa697140SDominik Brodowski * 144fa697140SDominik Brodowski * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 145fa697140SDominik Brodowski * which takes 6 arguments 146fa697140SDominik Brodowski * 147fa697140SDominik Brodowski * cltq <-- extend return value to 64-bit 148fa697140SDominik Brodowski * retq <-- return 149fa697140SDominik Brodowski * 150fa697140SDominik Brodowski * This approach avoids leaking random user-provided register content down 151fa697140SDominik Brodowski * the call chain. 152fa697140SDominik Brodowski * 153ebeb8c82SDominik Brodowski * If IA32_EMULATION is enabled, this macro generates an additional wrapper 154e145242eSDominik Brodowski * named __ia32_sys_*() which decodes the struct pt_regs *regs according 155ebeb8c82SDominik Brodowski * to the i386 calling convention (bx, cx, dx, si, di, bp). 156fa697140SDominik Brodowski */ 157fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 158d5a00528SDominik Brodowski asmlinkage long __x64_sys##name(const struct pt_regs *regs); \ 159d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys##name, ERRNO); \ 160e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 161e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 162d5a00528SDominik Brodowski asmlinkage long __x64_sys##name(const struct pt_regs *regs) \ 163fa697140SDominik Brodowski { \ 164e145242eSDominik Brodowski return __se_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ 165fa697140SDominik Brodowski } \ 166ebeb8c82SDominik Brodowski SC_IA32_WRAPPERx(x, name, __VA_ARGS__) \ 167e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 168fa697140SDominik Brodowski { \ 169e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 170fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 171fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 172fa697140SDominik Brodowski return ret; \ 173fa697140SDominik Brodowski } \ 174e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 175fa697140SDominik Brodowski 176fa697140SDominik Brodowski /* 177d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 178d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 179d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 180d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 181d5a00528SDominik Brodowski * macros to work correctly. 182d5a00528SDominik Brodowski */ 183d5a00528SDominik Brodowski #ifndef SYSCALL_DEFINE0 184d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 185d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 186d5a00528SDominik Brodowski asmlinkage long __x64_sys_##sname(void); \ 187d5a00528SDominik Brodowski ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \ 188d5a00528SDominik Brodowski asmlinkage long __x64_sys_##sname(void) 189d5a00528SDominik Brodowski #endif 190d5a00528SDominik Brodowski 191d5a00528SDominik Brodowski #ifndef COND_SYSCALL 192d5a00528SDominik Brodowski #define COND_SYSCALL(name) cond_syscall(__x64_sys_##name) 193d5a00528SDominik Brodowski #endif 194d5a00528SDominik Brodowski 195d5a00528SDominik Brodowski #ifndef SYS_NI 196d5a00528SDominik Brodowski #define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); 197d5a00528SDominik Brodowski #endif 198d5a00528SDominik Brodowski 199d5a00528SDominik Brodowski 200d5a00528SDominik Brodowski /* 201fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 202fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 203fa697140SDominik Brodowski */ 204fa697140SDominik Brodowski struct pt_regs; 205d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 206d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 207d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 208fa697140SDominik Brodowski 209fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 210