2 * Compatibility mode system call entry point for x86-64.
4 * Copyright 2000-2002 Andi Kleen, SuSE Labs.
7 #include <asm/dwarf2.h>
8 #include <asm/calling.h>
9 #include <asm/asm-offsets.h>
10 #include <asm/current.h>
11 #include <asm/errno.h>
12 #include <asm/ia32_unistd.h>
13 #include <asm/thread_info.h>
14 #include <asm/segment.h>
15 #include <asm/irqflags.h>
18 #include <linux/linkage.h>
19 #include <linux/err.h>
21 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
22 #include <linux/elf-em.h>
23 #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
24 #define __AUDIT_ARCH_LE 0x40000000
26 #ifndef CONFIG_AUDITSYSCALL
27 #define sysexit_audit ia32_ret_from_sys_call
28 #define sysretl_audit ia32_ret_from_sys_call
31 .section .entry.text, "ax"
34 .macro CLEAR_RREGS _r9=rax
43 * Reload arg registers from stack in case ptrace changed them.
44 * We don't reload %eax because syscall_trace_enter() returned
45 * the %rax value we should see. Instead, we just truncate that
46 * value to 32 bits again as we did on entry from user mode.
47 * If it's a new value set by user_regset during entry tracing,
48 * this matches the normal truncation of the user-mode value.
49 * If it's -1 to make us punt the syscall, then (u32)-1 is still
50 * an appropriately invalid value.
52 .macro LOAD_ARGS32 _r9=0
60 movl %eax,%eax /* zero extension */
63 .macro CFI_STARTPROC32 simple
75 #ifdef CONFIG_PARAVIRT
76 ENTRY(native_usergs_sysret32)
79 ENDPROC(native_usergs_sysret32)
81 ENTRY(native_irq_enable_sysexit)
85 ENDPROC(native_irq_enable_sysexit)
89 * 32bit SYSENTER instruction entry.
91 * SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
92 * IF and VM in rflags are cleared (IOW: interrupts are off).
93 * SYSENTER does not save anything on the stack,
94 * and does not save old rip (!!!) and rflags.
97 * eax system call number
106 * This is purely a fast path. For anything complicated we use the int 0x80
107 * path below. We set up a complete hardware stack frame to share code
108 * with the int 0x80 path.
110 ENTRY(ia32_sysenter_target)
111 CFI_STARTPROC32 simple
116 movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
118 * No need to follow this irqs on/off section: the syscall
119 * disabled irqs, here we enable it straight after entry:
121 ENABLE_INTERRUPTS(CLBR_NONE)
122 /* Construct iret frame (ss,rsp,rflags,cs,rip) */
123 movl %ebp,%ebp /* zero extension */
124 pushq_cfi $__USER32_DS
125 /*CFI_REL_OFFSET ss,0*/
129 /*CFI_REL_OFFSET rflags,0*/
130 movl TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d
132 pushq_cfi $__USER32_CS
133 /*CFI_REL_OFFSET cs,0*/
135 /* Store thread_info->sysenter_return in rip stack slot */
140 /* Construct the rest of "struct pt_regs" */
142 ALLOC_PT_GPREGS_ON_STACK
143 SAVE_C_REGS_EXCEPT_R891011
145 * no need to do an access_ok check here because rbp has been
146 * 32bit zero extended
150 _ASM_EXTABLE(1b,ia32_badarg)
154 * Sysenter doesn't filter flags, so we need to clear NT
155 * ourselves. To save a few cycles, we can check whether
156 * NT was set instead of doing an unconditional popfq.
158 testl $X86_EFLAGS_NT,EFLAGS(%rsp)
159 jnz sysenter_fix_flags
160 sysenter_flags_fixed:
162 orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP)
163 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP)
165 jnz sysenter_tracesys
166 cmpq $(IA32_NR_syscalls-1),%rax
169 /* 32bit syscall -> 64bit C ABI argument conversion */
170 movl %edi,%r8d /* arg5 */
171 movl %ebp,%r9d /* arg6 */
172 xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
173 movl %ebx,%edi /* arg1 */
174 movl %edx,%edx /* arg3 (zero extension) */
176 call *ia32_sys_call_table(,%rax,8)
178 DISABLE_INTERRUPTS(CLBR_NONE)
180 testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP)
182 sysexit_from_sys_call:
183 andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP)
184 /* clear IF, that popfq doesn't enable interrupts early */
185 andl $~0x200,EFLAGS(%rsp)
186 movl RIP(%rsp),%edx /* User %eip */
189 /* pop everything except ss,rsp,rflags slots */
190 REMOVE_PT_GPREGS_FROM_STACK 3*8
196 /*CFI_RESTORE rflags*/
197 popq_cfi %rcx /* User %esp */
201 * 32bit SYSEXIT restores eip from edx, esp from ecx.
202 * cs and ss are loaded from MSRs.
204 ENABLE_INTERRUPTS_SYSEXIT32
208 #ifdef CONFIG_AUDITSYSCALL
209 .macro auditsys_entry_common
210 movl %esi,%r8d /* 5th arg: 4th syscall arg */
211 movl %ecx,%r9d /*swap with edx*/
212 movl %edx,%ecx /* 4th arg: 3rd syscall arg */
213 movl %r9d,%edx /* 3rd arg: 2nd syscall arg */
214 movl %ebx,%esi /* 2nd arg: 1st syscall arg */
215 movl %eax,%edi /* 1st arg: syscall number */
216 call __audit_syscall_entry
217 movl RAX(%rsp),%eax /* reload syscall number */
218 cmpq $(IA32_NR_syscalls-1),%rax
220 movl %ebx,%edi /* reload 1st syscall arg */
221 movl RCX(%rsp),%esi /* reload 2nd syscall arg */
222 movl RDX(%rsp),%edx /* reload 3rd syscall arg */
223 movl RSI(%rsp),%ecx /* reload 4th syscall arg */
224 movl RDI(%rsp),%r8d /* reload 5th syscall arg */
227 .macro auditsys_exit exit
228 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP)
229 jnz ia32_ret_from_sys_call
231 ENABLE_INTERRUPTS(CLBR_NONE)
232 movl %eax,%esi /* second arg, syscall return value */
233 cmpl $-MAX_ERRNO,%eax /* is it an error ? */
235 movslq %eax, %rsi /* if error sign extend to 64 bits */
236 1: setbe %al /* 1 if error, 0 if not */
237 movzbl %al,%edi /* zero-extend that into %edi */
238 call __audit_syscall_exit
239 movq RAX(%rsp),%rax /* reload syscall return value */
240 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
241 DISABLE_INTERRUPTS(CLBR_NONE)
243 testl %edi,TI_flags+THREAD_INFO(%rsp,RIP)
250 auditsys_entry_common
251 movl %ebp,%r9d /* reload 6th syscall arg */
252 jmp sysenter_dispatch
255 auditsys_exit sysexit_from_sys_call
259 pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
261 jmp sysenter_flags_fixed
264 #ifdef CONFIG_AUDITSYSCALL
265 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP)
270 movq $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */
271 movq %rsp,%rdi /* &pt_regs -> arg1 */
272 call syscall_trace_enter
273 LOAD_ARGS32 /* reload args from stack in case ptrace changed it */
275 cmpq $(IA32_NR_syscalls-1),%rax
276 ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
279 ENDPROC(ia32_sysenter_target)
282 * 32bit SYSCALL instruction entry.
284 * 32bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
285 * then loads new ss, cs, and rip from previously programmed MSRs.
286 * rflags gets masked by a value from another MSR (so CLD and CLAC
287 * are not needed). SYSCALL does not save anything on the stack
288 * and does not change rsp.
290 * Note: rflags saving+masking-with-MSR happens only in Long mode
291 * (in legacy 32bit mode, IF, RF and VM bits are cleared and that's it).
292 * Don't get confused: rflags saving+masking depends on Long Mode Active bit
293 * (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
294 * or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
297 * eax system call number
300 * ebp arg2 (note: not saved in the stack frame, should not be touched)
307 * This is purely a fast path. For anything complicated we use the int 0x80
308 * path below. We set up a complete hardware stack frame to share code
309 * with the int 0x80 path.
311 ENTRY(ia32_cstar_target)
312 CFI_STARTPROC32 simple
314 CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
316 /*CFI_REGISTER rflags,r11*/
320 movq PER_CPU_VAR(kernel_stack),%rsp
322 * No need to follow this irqs on/off section: the syscall
323 * disabled irqs and here we enable it straight after entry:
325 ENABLE_INTERRUPTS(CLBR_NONE)
326 ALLOC_PT_GPREGS_ON_STACK 8 /* +8: space for orig_ax */
327 SAVE_C_REGS_EXCEPT_RCX_R891011
328 movl %eax,%eax /* zero extension */
329 movq %rax,ORIG_RAX(%rsp)
331 CFI_REL_OFFSET rip,RIP
332 movq %rbp,RCX(%rsp) /* this lies slightly to ptrace */
334 movq $__USER32_CS,CS(%rsp)
335 movq $__USER32_DS,SS(%rsp)
336 movq %r11,EFLAGS(%rsp)
337 /*CFI_REL_OFFSET rflags,EFLAGS*/
339 CFI_REL_OFFSET rsp,RSP
340 /* iret stack frame is complete now */
342 * no need to do an access_ok check here because r8 has been
343 * 32bit zero extended
347 _ASM_EXTABLE(1b,ia32_badarg)
349 orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP)
350 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP)
353 cmpq $IA32_NR_syscalls-1,%rax
356 /* 32bit syscall -> 64bit C ABI argument conversion */
357 movl %edi,%r8d /* arg5 */
358 /* r9 already loaded */ /* arg6 */
359 xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
360 movl %ebx,%edi /* arg1 */
361 movl %edx,%edx /* arg3 (zero extension) */
363 call *ia32_sys_call_table(,%rax,8)
365 DISABLE_INTERRUPTS(CLBR_NONE)
367 testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP)
369 sysretl_from_sys_call:
370 andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP)
374 movl EFLAGS(%rsp),%r11d
375 /*CFI_REGISTER rflags,r11*/
383 * 64bit->32bit SYSRET restores eip from ecx,
384 * eflags from r11 (but RF and VM bits are forced to 0),
385 * cs and ss are loaded from MSRs.
386 * (Note: 32bit->32bit SYSRET is different: since r11
387 * does not exist, it merely sets eflags.IF=1).
391 #ifdef CONFIG_AUDITSYSCALL
394 movl %r9d,R9(%rsp) /* register to be clobbered by call */
395 auditsys_entry_common
396 movl R9(%rsp),%r9d /* reload 6th syscall arg */
400 auditsys_exit sysretl_from_sys_call
404 #ifdef CONFIG_AUDITSYSCALL
405 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP)
411 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
412 movq %rsp,%rdi /* &pt_regs -> arg1 */
413 call syscall_trace_enter
414 LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */
417 cmpq $(IA32_NR_syscalls-1),%rax
418 ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
420 END(ia32_cstar_target)
429 * Emulated IA32 system calls via int 0x80.
432 * eax system call number
438 * ebp arg6 (note: not saved in the stack frame, should not be touched)
441 * Uses the same stack frame as the x86-64 version.
442 * All registers except eax must be saved (but ptrace may violate that).
443 * Arguments are zero extended. For system calls that want sign extension and
444 * take long arguments a wrapper is needed. Most calls can just be called
446 * Assumes it is only called from user space and entered with interrupts off.
450 CFI_STARTPROC32 simple
452 CFI_DEF_CFA rsp,SS+8-RIP
453 /*CFI_REL_OFFSET ss,SS-RIP*/
454 CFI_REL_OFFSET rsp,RSP-RIP
455 /*CFI_REL_OFFSET rflags,EFLAGS-RIP*/
456 /*CFI_REL_OFFSET cs,CS-RIP*/
457 CFI_REL_OFFSET rip,RIP-RIP
458 PARAVIRT_ADJUST_EXCEPTION_FRAME
461 * No need to follow this irqs on/off section: the syscall
462 * disabled irqs and here we enable it straight after entry:
464 ENABLE_INTERRUPTS(CLBR_NONE)
466 pushq_cfi %rax /* store orig_ax */
468 /* note the registers are not zero extended to the sf.
469 this could be a problem. */
470 ALLOC_PT_GPREGS_ON_STACK
471 SAVE_C_REGS_EXCEPT_R891011
472 orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP)
473 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP)
475 cmpq $(IA32_NR_syscalls-1),%rax
478 /* 32bit syscall -> 64bit C ABI argument conversion */
479 movl %edi,%r8d /* arg5 */
480 movl %ebp,%r9d /* arg6 */
481 xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */
482 movl %ebx,%edi /* arg1 */
483 movl %edx,%edx /* arg3 (zero extension) */
484 call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
487 ia32_ret_from_sys_call:
489 jmp int_ret_from_sys_call
494 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
495 movq %rsp,%rdi /* &pt_regs -> arg1 */
496 call syscall_trace_enter
497 LOAD_ARGS32 /* reload args from stack in case ptrace changed it */
499 cmpq $(IA32_NR_syscalls-1),%rax
500 ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
505 movq $0,ORIG_RAX(%rsp)
511 .macro PTREGSCALL label, func
514 leaq \func(%rip),%rax
515 jmp ia32_ptregs_common
520 PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
521 PTREGSCALL stub32_sigreturn, sys32_sigreturn
522 PTREGSCALL stub32_execve, compat_sys_execve
523 PTREGSCALL stub32_execveat, compat_sys_execveat
524 PTREGSCALL stub32_fork, sys_fork
525 PTREGSCALL stub32_vfork, sys_vfork
529 leaq sys_clone(%rip),%rax
531 jmp ia32_ptregs_common
536 CFI_STARTPROC32 simple
538 CFI_DEF_CFA rsp,SIZEOF_PTREGS
539 CFI_REL_OFFSET rax,RAX
540 CFI_REL_OFFSET rcx,RCX
541 CFI_REL_OFFSET rdx,RDX
542 CFI_REL_OFFSET rsi,RSI
543 CFI_REL_OFFSET rdi,RDI
544 CFI_REL_OFFSET rip,RIP
545 /* CFI_REL_OFFSET cs,CS*/
546 /* CFI_REL_OFFSET rflags,EFLAGS*/
547 CFI_REL_OFFSET rsp,RSP
548 /* CFI_REL_OFFSET ss,SS*/
554 END(ia32_ptregs_common)