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 110f78ff17SBrian Gerst extern long __x64_sys_ni_syscall(const struct pt_regs *regs); 120f78ff17SBrian Gerst extern 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) \ 690f78ff17SBrian Gerst long __##abi##_##name(const struct pt_regs *regs); \ 70d2b5de49SBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 710f78ff17SBrian Gerst long __##abi##_##name(const struct pt_regs *regs) \ 72d2b5de49SBrian Gerst __alias(__do_##name); 73d2b5de49SBrian Gerst 744399e0cfSBrian Gerst #define __SYS_STUBx(abi, name, ...) \ 750f78ff17SBrian Gerst long __##abi##_##name(const struct pt_regs *regs); \ 764399e0cfSBrian Gerst ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ 770f78ff17SBrian Gerst 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) \ 830f78ff17SBrian Gerst __weak long __##abi##_##name(const struct pt_regs *__unused) \ 846cc8d2b2SBrian Gerst { \ 856cc8d2b2SBrian Gerst return sys_ni_syscall(); \ 866cc8d2b2SBrian Gerst } 876cc8d2b2SBrian Gerst 88a74d187cSBrian Gerst #define __SYS_NI(abi, name) \ 89a74d187cSBrian Gerst SYSCALL_ALIAS(__##abi##_##name, sys_ni_posix_timers) 90a74d187cSBrian Gerst 914399e0cfSBrian Gerst #ifdef CONFIG_X86_64 92d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) \ 93d2b5de49SBrian Gerst __SYS_STUB0(x64, sys_##name) 94d2b5de49SBrian Gerst 954399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) \ 964399e0cfSBrian Gerst __SYS_STUBx(x64, sys##name, \ 974399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 986cc8d2b2SBrian Gerst 996cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) \ 1006cc8d2b2SBrian Gerst __COND_SYSCALL(x64, sys_##name) 101a74d187cSBrian Gerst 102a74d187cSBrian Gerst #define __X64_SYS_NI(name) \ 103a74d187cSBrian Gerst __SYS_NI(x64, sys_##name) 1044399e0cfSBrian Gerst #else /* CONFIG_X86_64 */ 105d2b5de49SBrian Gerst #define __X64_SYS_STUB0(name) 1064399e0cfSBrian Gerst #define __X64_SYS_STUBx(x, name, ...) 1076cc8d2b2SBrian Gerst #define __X64_COND_SYSCALL(name) 108a74d187cSBrian Gerst #define __X64_SYS_NI(name) 1094399e0cfSBrian Gerst #endif /* CONFIG_X86_64 */ 1104399e0cfSBrian Gerst 11125c619e5SBrian Gerst #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) 11225c619e5SBrian Gerst #define __IA32_SYS_STUB0(name) \ 11325c619e5SBrian Gerst __SYS_STUB0(ia32, sys_##name) 11425c619e5SBrian Gerst 11525c619e5SBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) \ 11625c619e5SBrian Gerst __SYS_STUBx(ia32, sys##name, \ 11725c619e5SBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 11825c619e5SBrian Gerst 11925c619e5SBrian Gerst #define __IA32_COND_SYSCALL(name) \ 12025c619e5SBrian Gerst __COND_SYSCALL(ia32, sys_##name) 12125c619e5SBrian Gerst 12225c619e5SBrian Gerst #define __IA32_SYS_NI(name) \ 12325c619e5SBrian Gerst __SYS_NI(ia32, sys_##name) 12425c619e5SBrian Gerst #else /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ 12525c619e5SBrian Gerst #define __IA32_SYS_STUB0(name) 12625c619e5SBrian Gerst #define __IA32_SYS_STUBx(x, name, ...) 12725c619e5SBrian Gerst #define __IA32_COND_SYSCALL(name) 12825c619e5SBrian Gerst #define __IA32_SYS_NI(name) 12925c619e5SBrian Gerst #endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ 13025c619e5SBrian Gerst 131ebeb8c82SDominik Brodowski #ifdef CONFIG_IA32_EMULATION 132ebeb8c82SDominik Brodowski /* 133ebeb8c82SDominik Brodowski * For IA32 emulation, we need to handle "compat" syscalls *and* create 134e145242eSDominik Brodowski * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the 135ebeb8c82SDominik Brodowski * ia32 regs in the proper order for shared or "common" syscalls. As some 136ebeb8c82SDominik Brodowski * syscalls may not be implemented, we need to expand COND_SYSCALL in 137ebeb8c82SDominik Brodowski * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this 138ebeb8c82SDominik Brodowski * case as well. 139ebeb8c82SDominik Brodowski */ 140d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) \ 141d2b5de49SBrian Gerst __SYS_STUB0(ia32, compat_sys_##name) 142cf3b83e1SAndy Lutomirski 143c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ 1444399e0cfSBrian Gerst __SYS_STUBx(ia32, compat_sys##name, \ 1454399e0cfSBrian Gerst SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) 146ebeb8c82SDominik Brodowski 1476cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) \ 1486cc8d2b2SBrian Gerst __COND_SYSCALL(ia32, compat_sys_##name) 1496cc8d2b2SBrian Gerst 150a74d187cSBrian Gerst #define __IA32_COMPAT_SYS_NI(name) \ 151a74d187cSBrian Gerst __SYS_NI(ia32, compat_sys_##name) 152a74d187cSBrian Gerst 153ebeb8c82SDominik Brodowski #else /* CONFIG_IA32_EMULATION */ 154d2b5de49SBrian Gerst #define __IA32_COMPAT_SYS_STUB0(name) 155c76fc982SDominik Brodowski #define __IA32_COMPAT_SYS_STUBx(x, name, ...) 1566cc8d2b2SBrian Gerst #define __IA32_COMPAT_COND_SYSCALL(name) 157a74d187cSBrian Gerst #define __IA32_COMPAT_SYS_NI(name) 158ebeb8c82SDominik Brodowski #endif /* CONFIG_IA32_EMULATION */ 159ebeb8c82SDominik Brodowski 160ebeb8c82SDominik Brodowski 161ebeb8c82SDominik Brodowski #ifdef CONFIG_X86_X32 162ebeb8c82SDominik Brodowski /* 163ebeb8c82SDominik Brodowski * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware 164ebeb8c82SDominik Brodowski * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common 165ebeb8c82SDominik Brodowski * with x86_64 obviously do not need such care. 166ebeb8c82SDominik Brodowski */ 167d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) \ 168d2b5de49SBrian Gerst __SYS_STUB0(x32, compat_sys_##name) 169cf3b83e1SAndy Lutomirski 170c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) \ 1714399e0cfSBrian Gerst __SYS_STUBx(x32, compat_sys##name, \ 1724399e0cfSBrian Gerst SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) 173ebeb8c82SDominik Brodowski 1746cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) \ 1756cc8d2b2SBrian Gerst __COND_SYSCALL(x32, compat_sys_##name) 176a74d187cSBrian Gerst 177a74d187cSBrian Gerst #define __X32_COMPAT_SYS_NI(name) \ 178a74d187cSBrian Gerst __SYS_NI(x32, compat_sys_##name) 179ebeb8c82SDominik Brodowski #else /* CONFIG_X86_X32 */ 180d2b5de49SBrian Gerst #define __X32_COMPAT_SYS_STUB0(name) 181c76fc982SDominik Brodowski #define __X32_COMPAT_SYS_STUBx(x, name, ...) 1826cc8d2b2SBrian Gerst #define __X32_COMPAT_COND_SYSCALL(name) 183a74d187cSBrian Gerst #define __X32_COMPAT_SYS_NI(name) 184ebeb8c82SDominik Brodowski #endif /* CONFIG_X86_X32 */ 185ebeb8c82SDominik Brodowski 186ebeb8c82SDominik Brodowski 187ebeb8c82SDominik Brodowski #ifdef CONFIG_COMPAT 188ebeb8c82SDominik Brodowski /* 189ebeb8c82SDominik Brodowski * Compat means IA32_EMULATION and/or X86_X32. As they use a different 190ebeb8c82SDominik Brodowski * mapping of registers to parameters, we need to generate stubs for each 191d5a00528SDominik Brodowski * of them. 192ebeb8c82SDominik Brodowski */ 193cf3b83e1SAndy Lutomirski #define COMPAT_SYSCALL_DEFINE0(name) \ 1940f78ff17SBrian Gerst static long \ 195d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused); \ 196d2b5de49SBrian Gerst __IA32_COMPAT_SYS_STUB0(name) \ 197d2b5de49SBrian Gerst __X32_COMPAT_SYS_STUB0(name) \ 1980f78ff17SBrian Gerst static long \ 199d2b5de49SBrian Gerst __do_compat_sys_##name(const struct pt_regs *__unused) 200cf3b83e1SAndy Lutomirski 201ebeb8c82SDominik Brodowski #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ 2025ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 2035ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 204c76fc982SDominik Brodowski __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 205c76fc982SDominik Brodowski __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ 2065ac9efa3SDominik Brodowski static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 207ebeb8c82SDominik Brodowski { \ 2085ac9efa3SDominik Brodowski return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ 209ebeb8c82SDominik Brodowski } \ 2105ac9efa3SDominik Brodowski static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 211ebeb8c82SDominik Brodowski 212ebeb8c82SDominik Brodowski /* 213ebeb8c82SDominik Brodowski * As some compat syscalls may not be implemented, we need to expand 214ebeb8c82SDominik Brodowski * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in 215ebeb8c82SDominik Brodowski * kernel/time/posix-stubs.c to cover this case as well. 216ebeb8c82SDominik Brodowski */ 217ebeb8c82SDominik Brodowski #define COND_SYSCALL_COMPAT(name) \ 2186cc8d2b2SBrian Gerst __IA32_COMPAT_COND_SYSCALL(name) \ 2196cc8d2b2SBrian Gerst __X32_COMPAT_COND_SYSCALL(name) 220ebeb8c82SDominik Brodowski 221ebeb8c82SDominik Brodowski #define COMPAT_SYS_NI(name) \ 222a74d187cSBrian Gerst __IA32_COMPAT_SYS_NI(name) \ 223a74d187cSBrian Gerst __X32_COMPAT_SYS_NI(name) 224ebeb8c82SDominik Brodowski 225ebeb8c82SDominik Brodowski #endif /* CONFIG_COMPAT */ 226ebeb8c82SDominik Brodowski 227fa697140SDominik Brodowski #define __SYSCALL_DEFINEx(x, name, ...) \ 228e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ 229e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ 2304399e0cfSBrian Gerst __X64_SYS_STUBx(x, name, __VA_ARGS__) \ 231c76fc982SDominik Brodowski __IA32_SYS_STUBx(x, name, __VA_ARGS__) \ 232e145242eSDominik Brodowski static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ 233fa697140SDominik Brodowski { \ 234e145242eSDominik Brodowski long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ 235fa697140SDominik Brodowski __MAP(x,__SC_TEST,__VA_ARGS__); \ 236fa697140SDominik Brodowski __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ 237fa697140SDominik Brodowski return ret; \ 238fa697140SDominik Brodowski } \ 239e145242eSDominik Brodowski static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) 240fa697140SDominik Brodowski 241fa697140SDominik Brodowski /* 242d5a00528SDominik Brodowski * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for 243d5a00528SDominik Brodowski * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not 244d5a00528SDominik Brodowski * hurt, we only need to re-define it here to keep the naming congruent to 245d5a00528SDominik Brodowski * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() 246d5a00528SDominik Brodowski * macros to work correctly. 247d5a00528SDominik Brodowski */ 248d5a00528SDominik Brodowski #define SYSCALL_DEFINE0(sname) \ 249d5a00528SDominik Brodowski SYSCALL_METADATA(_##sname, 0); \ 2500f78ff17SBrian Gerst static long __do_sys_##sname(const struct pt_regs *__unused); \ 251d2b5de49SBrian Gerst __X64_SYS_STUB0(sname) \ 252d2b5de49SBrian Gerst __IA32_SYS_STUB0(sname) \ 2530f78ff17SBrian Gerst static long __do_sys_##sname(const struct pt_regs *__unused) 254d5a00528SDominik Brodowski 2556e484764SSami Tolvanen #define COND_SYSCALL(name) \ 2566cc8d2b2SBrian Gerst __X64_COND_SYSCALL(name) \ 2576cc8d2b2SBrian Gerst __IA32_COND_SYSCALL(name) 258d5a00528SDominik Brodowski 259a74d187cSBrian Gerst #define SYS_NI(name) \ 260a74d187cSBrian Gerst __X64_SYS_NI(name) \ 261a74d187cSBrian Gerst __IA32_SYS_NI(name) 262d5a00528SDominik Brodowski 263d5a00528SDominik Brodowski 264d5a00528SDominik Brodowski /* 265fa697140SDominik Brodowski * For VSYSCALLS, we need to declare these three syscalls with the new 266fa697140SDominik Brodowski * pt_regs-based calling convention for in-kernel use. 267fa697140SDominik Brodowski */ 2680f78ff17SBrian Gerst long __x64_sys_getcpu(const struct pt_regs *regs); 2690f78ff17SBrian Gerst long __x64_sys_gettimeofday(const struct pt_regs *regs); 2700f78ff17SBrian Gerst long __x64_sys_time(const struct pt_regs *regs); 271fa697140SDominik Brodowski 272fa697140SDominik Brodowski #endif /* _ASM_X86_SYSCALL_WRAPPER_H */ 273