diff options
Diffstat (limited to 'arch/x86/include/asm/syscall_wrapper.h')
| -rw-r--r-- | arch/x86/include/asm/syscall_wrapper.h | 117 |
1 files changed, 113 insertions, 4 deletions
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h index 702bdee377af..49d7e4970110 100644 --- a/arch/x86/include/asm/syscall_wrapper.h +++ b/arch/x86/include/asm/syscall_wrapper.h @@ -6,6 +6,111 @@ #ifndef _ASM_X86_SYSCALL_WRAPPER_H #define _ASM_X86_SYSCALL_WRAPPER_H +/* 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) + +#ifdef CONFIG_IA32_EMULATION +/* + * For IA32 emulation, we need to handle "compat" syscalls *and* create + * additional wrappers (aptly named __sys_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 COMPAT_SC_IA32_STUBx(x, name, ...) \ + asmlinkage long __compat_sys_ia32##name(const struct pt_regs *regs);\ + ALLOW_ERROR_INJECTION(__compat_sys_ia32##name, ERRNO); \ + asmlinkage long __compat_sys_ia32##name(const struct pt_regs *regs)\ + { \ + return c_SyS##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\ + } \ + +#define SC_IA32_WRAPPERx(x, name, ...) \ + asmlinkage long __sys_ia32##name(const struct pt_regs *regs); \ + ALLOW_ERROR_INJECTION(__sys_ia32##name, ERRNO); \ + asmlinkage long __sys_ia32##name(const struct pt_regs *regs) \ + { \ + return SyS##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__)); \ + } + +#define COND_SYSCALL(name) \ + cond_syscall(sys_##name); \ + cond_syscall(__sys_ia32_##name) + +#define SYS_NI(name) \ + SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers); \ + SYSCALL_ALIAS(__sys_ia32_##name, sys_ni_posix_timers) + +#else /* CONFIG_IA32_EMULATION */ +#define COMPAT_SC_IA32_STUBx(x, name, ...) +#define SC_IA32_WRAPPERx(x, fullname, 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 COMPAT_SC_X32_STUBx(x, name, ...) \ + asmlinkage long __compat_sys_x32##name(const struct pt_regs *regs);\ + ALLOW_ERROR_INJECTION(__compat_sys_x32##name, ERRNO); \ + asmlinkage long __compat_sys_x32##name(const struct pt_regs *regs)\ + { \ + return c_SyS##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ + } \ + +#else /* CONFIG_X86_X32 */ +#define COMPAT_SC_X32_STUBx(x, 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. There is no need to implement COMPAT_SYSCALL_DEFINE0, as it is + * unused on x86. + */ +#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ + static long c_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \ + static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ + COMPAT_SC_IA32_STUBx(x, name, __VA_ARGS__) \ + COMPAT_SC_X32_STUBx(x, name, __VA_ARGS__) \ + static long c_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ + { \ + return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ + } \ + static inline long C_SYSC##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) \ + cond_syscall(__compat_sys_ia32_##name); \ + cond_syscall(__compat_sys_x32_##name) + +#define COMPAT_SYS_NI(name) \ + SYSCALL_ALIAS(__compat_sys_ia32_##name, sys_ni_posix_timers); \ + SYSCALL_ALIAS(__compat_sys_x32_##name, sys_ni_posix_timers) + +#endif /* CONFIG_COMPAT */ + + /* * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes * struct pt_regs *regs as the only argument of the syscall stub named @@ -34,9 +139,14 @@ * This approach avoids leaking random user-provided register content down * the call chain. * + * If IA32_EMULATION is enabled, this macro generates an additional wrapper + * named __sys_ia32_*() which decodes the struct pt_regs *regs according + * to the i386 calling convention (bx, cx, dx, si, di, bp). + * * 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, there is no need to override it. + * hurt, there is no need to override it, or to define it differently for + * IA32_EMULATION. */ #define __SYSCALL_DEFINEx(x, name, ...) \ asmlinkage long sys##name(const struct pt_regs *regs); \ @@ -45,10 +155,9 @@ static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \ asmlinkage long sys##name(const struct pt_regs *regs) \ { \ - return SyS##name(__MAP(x,__SC_ARGS \ - ,,regs->di,,regs->si,,regs->dx \ - ,,regs->r10,,regs->r8,,regs->r9)); \ + return SyS##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\ } \ + SC_IA32_WRAPPERx(x, name, __VA_ARGS__) \ static long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ { \ long ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \ |