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 11cc42c045SBrian Gerst extern asmlinkage long __x64_sys_ni_syscall(const struct pt_regs *regs); 12cc42c045SBrian Gerst extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs); 13cc42c045SBrian Gerst 1425c619e5SBrian Gerst /* 1525c619e5SBrian Gerst * Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes 1625c619e5SBrian Gerst * struct pt_regs *regs as the only argument of the syscall stub(s) named as: 1725c619e5SBrian Gerst * __x64_sys_*() - 64-bit native syscall 1825c619e5SBrian Gerst * __ia32_sys_*() - 32-bit native syscall or common compat syscall 1925c619e5SBrian Gerst * __ia32_compat_sys_*() - 32-bit compat syscall 2025c619e5SBrian Gerst * __x32_compat_sys_*() - 64-bit X32 compat syscall 2125c619e5SBrian Gerst * 2225c619e5SBrian Gerst * The registers are decoded according to the ABI: 2325c619e5SBrian Gerst * 64-bit: RDI, RSI, RDX, R10, R8, R9 2425c619e5SBrian Gerst * 32-bit: EBX, ECX, EDX, ESI, EDI, EBP 2525c619e5SBrian Gerst * 2625c619e5SBrian Gerst * The stub then passes the decoded arguments to the __se_sys_*() wrapper to 2725c619e5SBrian Gerst * perform sign-extension (omitted for zero-argument syscalls). Finally the 2825c619e5SBrian Gerst * arguments are passed to the __do_sys_*() function which is the actual 2925c619e5SBrian Gerst * syscall. These wrappers are marked as inline so the compiler can optimize 3025c619e5SBrian Gerst * the functions where appropriate. 3125c619e5SBrian Gerst * 3225c619e5SBrian Gerst * Example assembly (slightly re-ordered for better readability): 3325c619e5SBrian Gerst * 3425c619e5SBrian Gerst * <__x64_sys_recv>: <-- syscall with 4 parameters 3525c619e5SBrian Gerst * callq <__fentry__> 3625c619e5SBrian Gerst * 3725c619e5SBrian Gerst * mov 0x70(%rdi),%rdi <-- decode regs->di 3825c619e5SBrian Gerst * mov 0x68(%rdi),%rsi <-- decode regs->si 3925c619e5SBrian Gerst * mov 0x60(%rdi),%rdx <-- decode regs->dx 4025c619e5SBrian Gerst * mov 0x38(%rdi),%rcx <-- decode regs->r10 4125c619e5SBrian Gerst * 4225c619e5SBrian Gerst * xor %r9d,%r9d <-- clear %r9 4325c619e5SBrian Gerst * xor %r8d,%r8d <-- clear %r8 4425c619e5SBrian Gerst * 4525c619e5SBrian Gerst * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() 4625c619e5SBrian Gerst * which takes 6 arguments 4725c619e5SBrian Gerst * 4825c619e5SBrian Gerst * cltq <-- extend return value to 64-bit 4925c619e5SBrian Gerst * retq <-- return 5025c619e5SBrian Gerst * 5125c619e5SBrian Gerst * This approach avoids leaking random user-provided register content down 5225c619e5SBrian Gerst * the call chain. 5325c619e5SBrian Gerst */ 5425c619e5SBrian Gerst 55ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on x86-64 and x32 */ 56ebeb8c82SDominik Brodowski #define SC_X86_64_REGS_TO_ARGS(x, ...) \ 57ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 58ebeb8c82SDominik Brodowski ,,regs->di,,regs->si,,regs->dx \ 59ebeb8c82SDominik Brodowski ,,regs->r10,,regs->r8,,regs->r9) \ 60ebeb8c82SDominik Brodowski 61ebeb8c82SDominik Brodowski /* Mapping of registers to parameters for syscalls on i386 */ 62ebeb8c82SDominik Brodowski #define SC_IA32_REGS_TO_ARGS(x, ...) \ 63ebeb8c82SDominik Brodowski __MAP(x,__SC_ARGS \ 64ebeb8c82SDominik Brodowski ,,(unsigned int)regs->bx,,(unsigned int)regs->cx \ 65ebeb8c82SDominik Brodowski ,,(unsigned int)regs->dx,,(unsigned int)regs->si \ 66ebeb8c82SDominik Brodowski ,,(unsigned int)regs->di,,(unsigned int)regs->bp) 67ebeb8c82SDominik Brodowski 68d2b5de49SBrian Gerst #define __SYS_STUB0(abi, name) \ 69d2b5de49SBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ 70d2b5de49SBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 71d2b5de49SBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ 72d2b5de49SBrian Gerst __alias(__do_##name); 73d2b5de49SBrian Gerst 744399e0cfSBrian Gerst #define __SYS_STUBx(abi, name, ...) \ 754399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ 764399e0cfSBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 774399e0cfSBrian Gerst asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ 784399e0cfSBrian Gerst { \ 794399e0cfSBrian Gerst return __se_##name(__VA_ARGS__); \ 804399e0cfSBrian Gerst } 814399e0cfSBrian Gerst 826cc8d2b2SBrian Gerst #define __COND_SYSCALL(abi, name) \ 836cc8d2b2SBrian Gerst asmlinkage __weak long \ 846cc8d2b2SBrian Gerst __##abi##_##name(const struct pt_regs *__unused) \ 856cc8d2b2SBrian Gerst { \ 866cc8d2b2SBrian Gerst return sys_ni_syscall(); \ 876cc8d2b2SBrian Gerst } 886cc8d2b2SBrian Gerst 89a74d187cSBrian Gerst #define __SYS_NI(abi, name) \ 90a74d187cSBrian Gerst SYSCALL_ALIAS(__##abi##_##name, sys_ni_posix_timers) 91a74d187cSBrian Gerst 924399e0cfSBrian Gerst #ifdef CONFIG_X86_64 93d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) \ 94d2b5de49SBrian Gerst __SYS_STUB0(x64, sys_##name) 95d2b5de49SBrian Gerst 964399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) \ 974399e0cfSBrian Gerst __SYS_STUBx(x64, sys##name, \ 984399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 996cc8d2b2SBrian Gerst 1006cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) \ 1016cc8d2b2SBrian Gerst __COND_SYSCALL(x64, sys_##name) 102a74d187cSBrian Gerst 103a74d187cSBrian Gerst #define __X64_SYS_NI(name) \ 104a74d187cSBrian Gerst __SYS_NI(x64, sys_##name) 1054399e0cfSBrian Gerst #else /* CONFIG_X86_64 */ 106d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) 1074399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) 1086cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) 109a74d187cSBrian Gerst #define __X64_SYS_NI(name) 1104399e0cfSBrian Gerst #endif /* CONFIG_X86_64 */ 1114399e0cfSBrian Gerst 11225c619e5SBrian Gerst #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) 11325c619e5SBrian Gerst #define __IA32_SYS_STUB0(name) \ 11425c619e5SBrian Gerst __SYS_STUB0(ia32, sys_##name) 11525c619e5SBrian Gerst 11625c619e5SBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) \ 11725c619e5SBrian Gerst __SYS_STUBx(ia32, sys##name, \ 11825c619e5SBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 11925c619e5SBrian Gerst 12025c619e5SBrian Gerst #define __IA32_COND_SYSCALL(name) \ 12125c619e5SBrian Gerst __COND_SYSCALL(ia32, sys_##name) 12225c619e5SBrian Gerst 12325c619e5SBrian Gerst #define __IA32_SYS_NI(name) \ 12425c619e5SBrian Gerst __SYS_NI(ia32, sys_##name) 12525c619e5SBrian Gerst #else /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ 12625c619e5SBrian Gerst #define __IA32_SYS_STUB0(name) 12725c619e5SBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) 12825c619e5SBrian Gerst #define __IA32_COND_SYSCALL(name) 12925c619e5SBrian Gerst #define __IA32_SYS_NI(name) 13025c619e5SBrian Gerst #endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ 13125c619e5SBrian Gerst 132ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 133ebeb8c82SDominik Brodowski /* 134ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 135e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 136ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 137ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 138ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 139ebeb8c82SDominik Brodowski * case as well. 140ebeb8c82SDominik Brodowski */ 141d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) \ 142d2b5de49SBrian Gerst __SYS_STUB0(ia32, compat_sys_##name) 143cf3b83e1SAndy Lutomirski 144c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 1454399e0cfSBrian Gerst __SYS_STUBx(ia32, compat_sys##name, \ 1464399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 147ebeb8c82SDominik Brodowski 1486cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) \ 1496cc8d2b2SBrian Gerst __COND_SYSCALL(ia32, compat_sys_##name) 1506cc8d2b2SBrian Gerst 151a74d187cSBrian Gerst #define __IA32_COMPAT_SYS_NI(name) \ 152a74d187cSBrian Gerst __SYS_NI(ia32, compat_sys_##name) 153a74d187cSBrian Gerst 154ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 155d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) 156c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 1576cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) 158a74d187cSBrian Gerst #define __IA32_COMPAT_SYS_NI(name) 159ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 160ebeb8c82SDominik Brodowski 161ebeb8c82SDominik Brodowski 162ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 163ebeb8c82SDominik Brodowski /* 164ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 165ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 166ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 167ebeb8c82SDominik Brodowski */ 168d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) \ 169d2b5de49SBrian Gerst __SYS_STUB0(x32, compat_sys_##name) 170cf3b83e1SAndy Lutomirski 171c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 1724399e0cfSBrian Gerst __SYS_STUBx(x32, compat_sys##name, \ 1734399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 174ebeb8c82SDominik Brodowski 1756cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) \ 1766cc8d2b2SBrian Gerst __COND_SYSCALL(x32, compat_sys_##name) 177a74d187cSBrian Gerst 178a74d187cSBrian Gerst #define __X32_COMPAT_SYS_NI(name) \ 179a74d187cSBrian Gerst __SYS_NI(x32, compat_sys_##name) 180ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 181d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) 182c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 1836cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) 184a74d187cSBrian Gerst #define __X32_COMPAT_SYS_NI(name) 185ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 186ebeb8c82SDominik Brodowski 187ebeb8c82SDominik Brodowski 188ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 189ebeb8c82SDominik Brodowski /* 190ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 191ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 192d5a00528SDominik Brodowski * of them. 193ebeb8c82SDominik Brodowski */ 194cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 195d2b5de49SBrian Gerst static asmlinkage long \ 196d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused); \ 197d2b5de49SBrian Gerst __IA32_COMPAT_SYS_STUB0(name) \ 198d2b5de49SBrian Gerst __X32_COMPAT_SYS_STUB0(name) \ 199d2b5de49SBrian Gerst static asmlinkage long \ 200d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused) 201cf3b83e1SAndy Lutomirski 202ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 2035ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 2045ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 205c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 206c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 2075ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 208ebeb8c82SDominik Brodowski { \ 2095ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 210ebeb8c82SDominik Brodowski } \ 2115ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 212ebeb8c82SDominik Brodowski 213ebeb8c82SDominik Brodowski /* 214ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 215ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 216ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 217ebeb8c82SDominik Brodowski */ 218ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 2196cc8d2b2SBrian Gerst __IA32_COMPAT_COND_SYSCALL(name) \ 2206cc8d2b2SBrian Gerst __X32_COMPAT_COND_SYSCALL(name) 221ebeb8c82SDominik Brodowski 222ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 223a74d187cSBrian Gerst __IA32_COMPAT_SYS_NI(name) \ 224a74d187cSBrian Gerst __X32_COMPAT_SYS_NI(name) 225ebeb8c82SDominik Brodowski 226ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 227ebeb8c82SDominik Brodowski 228fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 229e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 230e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 2314399e0cfSBrian Gerst __X64_SYS_STUBx(x, name, __VA_ARGS__) \ 232c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 233e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 234fa697140SDominik Brodowski { \ 235e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 236fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 237fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 238fa697140SDominik Brodowski return ret; \ 239fa697140SDominik Brodowski } \ 240e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 241fa697140SDominik Brodowski 242fa697140SDominik Brodowski /* 243d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 244d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 245d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 246d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 247d5a00528SDominik Brodowski * macros to work correctly. 248d5a00528SDominik Brodowski */ 249d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 250d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 251d2b5de49SBrian Gerst static asmlinkage long \ 252d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused); \ 253d2b5de49SBrian Gerst __X64_SYS_STUB0(sname) \ 254d2b5de49SBrian Gerst __IA32_SYS_STUB0(sname) \ 255d2b5de49SBrian Gerst static asmlinkage long \ 256d2b5de49SBrian Gerst __do_sys_##sname(const struct pt_regs *__unused) 257d5a00528SDominik Brodowski 2586e484764SSami Tolvanen #define COND_SYSCALL(name) \ 2596cc8d2b2SBrian Gerst __X64_COND_SYSCALL(name) \ 2606cc8d2b2SBrian Gerst __IA32_COND_SYSCALL(name) 261d5a00528SDominik Brodowski 262a74d187cSBrian Gerst #define SYS_NI(name) \ 263a74d187cSBrian Gerst __X64_SYS_NI(name) \ 264a74d187cSBrian Gerst __IA32_SYS_NI(name) 265d5a00528SDominik Brodowski 266d5a00528SDominik Brodowski 267d5a00528SDominik Brodowski /* 268fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 269fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 270fa697140SDominik Brodowski */ 271d5a00528SDominik Brodowski asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); 272d5a00528SDominik Brodowski asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); 273d5a00528SDominik Brodowski asmlinkage long __x64_sys_time(const struct pt_regs *regs); 274fa697140SDominik Brodowski 275fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 276