mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
272 lines
9.1 KiB
272 lines
9.1 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
|
/* |
|
* syscall_wrapper.h - x86 specific wrappers to syscall definitions |
|
*/ |
|
|
|
#ifndef _ASM_X86_SYSCALL_WRAPPER_H |
|
#define _ASM_X86_SYSCALL_WRAPPER_H |
|
|
|
struct pt_regs; |
|
|
|
extern long __x64_sys_ni_syscall(const struct pt_regs *regs); |
|
extern long __ia32_sys_ni_syscall(const struct pt_regs *regs); |
|
|
|
/* |
|
* Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes |
|
* struct pt_regs *regs as the only argument of the syscall stub(s) named as: |
|
* __x64_sys_*() - 64-bit native syscall |
|
* __ia32_sys_*() - 32-bit native syscall or common compat syscall |
|
* __ia32_compat_sys_*() - 32-bit compat syscall |
|
* __x32_compat_sys_*() - 64-bit X32 compat syscall |
|
* |
|
* The registers are decoded according to the ABI: |
|
* 64-bit: RDI, RSI, RDX, R10, R8, R9 |
|
* 32-bit: EBX, ECX, EDX, ESI, EDI, EBP |
|
* |
|
* The stub then passes the decoded arguments to the __se_sys_*() wrapper to |
|
* perform sign-extension (omitted for zero-argument syscalls). Finally the |
|
* arguments are passed to the __do_sys_*() function which is the actual |
|
* syscall. These wrappers are marked as inline so the compiler can optimize |
|
* the functions where appropriate. |
|
* |
|
* Example assembly (slightly re-ordered for better readability): |
|
* |
|
* <__x64_sys_recv>: <-- syscall with 4 parameters |
|
* callq <__fentry__> |
|
* |
|
* mov 0x70(%rdi),%rdi <-- decode regs->di |
|
* mov 0x68(%rdi),%rsi <-- decode regs->si |
|
* mov 0x60(%rdi),%rdx <-- decode regs->dx |
|
* mov 0x38(%rdi),%rcx <-- decode regs->r10 |
|
* |
|
* xor %r9d,%r9d <-- clear %r9 |
|
* xor %r8d,%r8d <-- clear %r8 |
|
* |
|
* callq __sys_recvfrom <-- do the actual work in __sys_recvfrom() |
|
* which takes 6 arguments |
|
* |
|
* cltq <-- extend return value to 64-bit |
|
* retq <-- return |
|
* |
|
* This approach avoids leaking random user-provided register content down |
|
* the call chain. |
|
*/ |
|
|
|
/* Mapping of registers to parameters for syscalls on x86-64 and x32 */ |
|
#define SC_X86_64_REGS_TO_ARGS(x, ...) \ |
|
__MAP(x,__SC_ARGS \ |
|
,,regs->di,,regs->si,,regs->dx \ |
|
,,regs->r10,,regs->r8,,regs->r9) \ |
|
|
|
/* Mapping of registers to parameters for syscalls on i386 */ |
|
#define SC_IA32_REGS_TO_ARGS(x, ...) \ |
|
__MAP(x,__SC_ARGS \ |
|
,,(unsigned int)regs->bx,,(unsigned int)regs->cx \ |
|
,,(unsigned int)regs->dx,,(unsigned int)regs->si \ |
|
,,(unsigned int)regs->di,,(unsigned int)regs->bp) |
|
|
|
#define __SYS_STUB0(abi, name) \ |
|
long __##abi##_##name(const struct pt_regs *regs); \ |
|
ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ |
|
long __##abi##_##name(const struct pt_regs *regs) \ |
|
__alias(__do_##name); |
|
|
|
#define __SYS_STUBx(abi, name, ...) \ |
|
long __##abi##_##name(const struct pt_regs *regs); \ |
|
ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ |
|
long __##abi##_##name(const struct pt_regs *regs) \ |
|
{ \ |
|
return __se_##name(__VA_ARGS__); \ |
|
} |
|
|
|
#define __COND_SYSCALL(abi, name) \ |
|
__weak long __##abi##_##name(const struct pt_regs *__unused) \ |
|
{ \ |
|
return sys_ni_syscall(); \ |
|
} |
|
|
|
#define __SYS_NI(abi, name) \ |
|
SYSCALL_ALIAS(__##abi##_##name, sys_ni_posix_timers); |
|
|
|
#ifdef CONFIG_X86_64 |
|
#define __X64_SYS_STUB0(name) \ |
|
__SYS_STUB0(x64, sys_##name) |
|
|
|
#define __X64_SYS_STUBx(x, name, ...) \ |
|
__SYS_STUBx(x64, sys##name, \ |
|
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) |
|
|
|
#define __X64_COND_SYSCALL(name) \ |
|
__COND_SYSCALL(x64, sys_##name) |
|
|
|
#define __X64_SYS_NI(name) \ |
|
__SYS_NI(x64, sys_##name) |
|
#else /* CONFIG_X86_64 */ |
|
#define __X64_SYS_STUB0(name) |
|
#define __X64_SYS_STUBx(x, name, ...) |
|
#define __X64_COND_SYSCALL(name) |
|
#define __X64_SYS_NI(name) |
|
#endif /* CONFIG_X86_64 */ |
|
|
|
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) |
|
#define __IA32_SYS_STUB0(name) \ |
|
__SYS_STUB0(ia32, sys_##name) |
|
|
|
#define __IA32_SYS_STUBx(x, name, ...) \ |
|
__SYS_STUBx(ia32, sys##name, \ |
|
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) |
|
|
|
#define __IA32_COND_SYSCALL(name) \ |
|
__COND_SYSCALL(ia32, sys_##name) |
|
|
|
#define __IA32_SYS_NI(name) \ |
|
__SYS_NI(ia32, sys_##name) |
|
#else /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ |
|
#define __IA32_SYS_STUB0(name) |
|
#define __IA32_SYS_STUBx(x, name, ...) |
|
#define __IA32_COND_SYSCALL(name) |
|
#define __IA32_SYS_NI(name) |
|
#endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ |
|
|
|
#ifdef CONFIG_IA32_EMULATION |
|
/* |
|
* For IA32 emulation, we need to handle "compat" syscalls *and* create |
|
* additional wrappers (aptly named __ia32_sys_xyzzy) which decode the |
|
* ia32 regs in the proper order for shared or "common" syscalls. As some |
|
* syscalls may not be implemented, we need to expand COND_SYSCALL in |
|
* kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this |
|
* case as well. |
|
*/ |
|
#define __IA32_COMPAT_SYS_STUB0(name) \ |
|
__SYS_STUB0(ia32, compat_sys_##name) |
|
|
|
#define __IA32_COMPAT_SYS_STUBx(x, name, ...) \ |
|
__SYS_STUBx(ia32, compat_sys##name, \ |
|
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__)) |
|
|
|
#define __IA32_COMPAT_COND_SYSCALL(name) \ |
|
__COND_SYSCALL(ia32, compat_sys_##name) |
|
|
|
#define __IA32_COMPAT_SYS_NI(name) \ |
|
__SYS_NI(ia32, compat_sys_##name) |
|
|
|
#else /* CONFIG_IA32_EMULATION */ |
|
#define __IA32_COMPAT_SYS_STUB0(name) |
|
#define __IA32_COMPAT_SYS_STUBx(x, name, ...) |
|
#define __IA32_COMPAT_COND_SYSCALL(name) |
|
#define __IA32_COMPAT_SYS_NI(name) |
|
#endif /* CONFIG_IA32_EMULATION */ |
|
|
|
|
|
#ifdef CONFIG_X86_X32 |
|
/* |
|
* For the x32 ABI, we need to create a stub for compat_sys_*() which is aware |
|
* of the x86-64-style parameter ordering of x32 syscalls. The syscalls common |
|
* with x86_64 obviously do not need such care. |
|
*/ |
|
#define __X32_COMPAT_SYS_STUB0(name) \ |
|
__SYS_STUB0(x32, compat_sys_##name) |
|
|
|
#define __X32_COMPAT_SYS_STUBx(x, name, ...) \ |
|
__SYS_STUBx(x32, compat_sys##name, \ |
|
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__)) |
|
|
|
#define __X32_COMPAT_COND_SYSCALL(name) \ |
|
__COND_SYSCALL(x32, compat_sys_##name) |
|
|
|
#define __X32_COMPAT_SYS_NI(name) \ |
|
__SYS_NI(x32, compat_sys_##name) |
|
#else /* CONFIG_X86_X32 */ |
|
#define __X32_COMPAT_SYS_STUB0(name) |
|
#define __X32_COMPAT_SYS_STUBx(x, name, ...) |
|
#define __X32_COMPAT_COND_SYSCALL(name) |
|
#define __X32_COMPAT_SYS_NI(name) |
|
#endif /* CONFIG_X86_X32 */ |
|
|
|
|
|
#ifdef CONFIG_COMPAT |
|
/* |
|
* Compat means IA32_EMULATION and/or X86_X32. As they use a different |
|
* mapping of registers to parameters, we need to generate stubs for each |
|
* of them. |
|
*/ |
|
#define COMPAT_SYSCALL_DEFINE0(name) \ |
|
static long \ |
|
__do_compat_sys_##name(const struct pt_regs *__unused); \ |
|
__IA32_COMPAT_SYS_STUB0(name) \ |
|
__X32_COMPAT_SYS_STUB0(name) \ |
|
static long \ |
|
__do_compat_sys_##name(const struct pt_regs *__unused) |
|
|
|
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ |
|
static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ |
|
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ |
|
__IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ |
|
__X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \ |
|
static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ |
|
{ \ |
|
return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\ |
|
} \ |
|
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) |
|
|
|
/* |
|
* As some compat syscalls may not be implemented, we need to expand |
|
* COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in |
|
* kernel/time/posix-stubs.c to cover this case as well. |
|
*/ |
|
#define COND_SYSCALL_COMPAT(name) \ |
|
__IA32_COMPAT_COND_SYSCALL(name) \ |
|
__X32_COMPAT_COND_SYSCALL(name) |
|
|
|
#define COMPAT_SYS_NI(name) \ |
|
__IA32_COMPAT_SYS_NI(name) \ |
|
__X32_COMPAT_SYS_NI(name) |
|
|
|
#endif /* CONFIG_COMPAT */ |
|
|
|
#define __SYSCALL_DEFINEx(x, name, ...) \ |
|
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ |
|
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ |
|
__X64_SYS_STUBx(x, name, __VA_ARGS__) \ |
|
__IA32_SYS_STUBx(x, name, __VA_ARGS__) \ |
|
static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ |
|
{ \ |
|
long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\ |
|
__MAP(x,__SC_TEST,__VA_ARGS__); \ |
|
__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ |
|
return ret; \ |
|
} \ |
|
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) |
|
|
|
/* |
|
* As the generic SYSCALL_DEFINE0() macro does not decode any parameters for |
|
* obvious reasons, and passing struct pt_regs *regs to it in %rdi does not |
|
* hurt, we only need to re-define it here to keep the naming congruent to |
|
* SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI() |
|
* macros to work correctly. |
|
*/ |
|
#define SYSCALL_DEFINE0(sname) \ |
|
SYSCALL_METADATA(_##sname, 0); \ |
|
static long __do_sys_##sname(const struct pt_regs *__unused); \ |
|
__X64_SYS_STUB0(sname) \ |
|
__IA32_SYS_STUB0(sname) \ |
|
static long __do_sys_##sname(const struct pt_regs *__unused) |
|
|
|
#define COND_SYSCALL(name) \ |
|
__X64_COND_SYSCALL(name) \ |
|
__IA32_COND_SYSCALL(name) |
|
|
|
#define SYS_NI(name) \ |
|
__X64_SYS_NI(name) \ |
|
__IA32_SYS_NI(name) |
|
|
|
|
|
/* |
|
* For VSYSCALLS, we need to declare these three syscalls with the new |
|
* pt_regs-based calling convention for in-kernel use. |
|
*/ |
|
long __x64_sys_getcpu(const struct pt_regs *regs); |
|
long __x64_sys_gettimeofday(const struct pt_regs *regs); |
|
long __x64_sys_time(const struct pt_regs *regs); |
|
|
|
#endif /* _ASM_X86_SYSCALL_WRAPPER_H */
|
|
|