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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Ingo Molnar54ad7262015-06-05 13:02:28 +02002 * Compatibility mode system call entry point for x86-64.
3 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * Copyright 2000-2002 Andi Kleen, SuSE Labs.
Ingo Molnar54ad7262015-06-05 13:02:28 +02005 */
Ingo Molnard36f9472015-06-03 18:29:26 +02006#include "calling.h"
Sam Ravnborge2d5df92005-09-09 21:28:48 +02007#include <asm/asm-offsets.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <asm/current.h>
9#include <asm/errno.h>
Ingo Molnar54ad7262015-06-05 13:02:28 +020010#include <asm/ia32_unistd.h>
11#include <asm/thread_info.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <asm/segment.h>
Ingo Molnar2601e642006-07-03 00:24:45 -070013#include <asm/irqflags.h>
H. Peter Anvin1ce6f862012-04-20 12:19:50 -070014#include <asm/asm.h>
H. Peter Anvin63bcff22012-09-21 12:43:12 -070015#include <asm/smap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/linkage.h>
Eric Parisd7e75282012-01-03 14:23:06 -050017#include <linux/err.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Roland McGrath5cbf1562008-06-24 01:13:31 -070019/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
20#include <linux/elf-em.h>
21#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
Ingo Molnar54ad7262015-06-05 13:02:28 +020022#define __AUDIT_ARCH_LE 0x40000000
Roland McGrath5cbf1562008-06-24 01:13:31 -070023
24#ifndef CONFIG_AUDITSYSCALL
Ingo Molnar54ad7262015-06-05 13:02:28 +020025# define sysexit_audit ia32_ret_from_sys_call
26# define sysretl_audit ia32_ret_from_sys_call
Roland McGrath5cbf1562008-06-24 01:13:31 -070027#endif
28
Jiri Olsaea714542011-03-07 19:10:39 +010029 .section .entry.text, "ax"
30
Jeremy Fitzhardinge2be29982008-06-25 00:19:28 -040031#ifdef CONFIG_PARAVIRT
32ENTRY(native_usergs_sysret32)
33 swapgs
34 sysretl
35ENDPROC(native_usergs_sysret32)
Jeremy Fitzhardinge2be29982008-06-25 00:19:28 -040036#endif
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038/*
Ingo Molnar54ad7262015-06-05 13:02:28 +020039 * 32-bit SYSENTER instruction entry.
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 *
Denys Vlasenkob87cf632015-02-26 14:40:32 -080041 * SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
42 * IF and VM in rflags are cleared (IOW: interrupts are off).
43 * SYSENTER does not save anything on the stack,
44 * and does not save old rip (!!!) and rflags.
45 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 * Arguments:
Denys Vlasenkob87cf632015-02-26 14:40:32 -080047 * eax system call number
48 * ebx arg1
49 * ecx arg2
50 * edx arg3
51 * esi arg4
52 * edi arg5
53 * ebp user stack
54 * 0(%ebp) arg6
55 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 * This is purely a fast path. For anything complicated we use the int 0x80
Denys Vlasenkob87cf632015-02-26 14:40:32 -080057 * path below. We set up a complete hardware stack frame to share code
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 * with the int 0x80 path.
Denys Vlasenkob87cf632015-02-26 14:40:32 -080059 */
Ingo Molnar4c8cd0c2015-06-08 08:33:56 +020060ENTRY(entry_SYSENTER_compat)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +010061 /*
62 * Interrupts are off on entry.
63 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
64 * it is too small to ever cause noticeable irq latency.
65 */
Jeremy Fitzhardinge457da702008-06-26 07:28:51 -070066 SWAPGS_UNSAFE_STACK
Denys Vlasenko3a232082015-04-24 17:31:35 +020067 movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -040068 ENABLE_INTERRUPTS(CLBR_NONE)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +010069
Denys Vlasenko4ee8ec12015-03-27 11:36:21 +010070 /* Zero-extending 32-bit regs, do not remove */
71 movl %ebp, %ebp
72 movl %eax, %eax
73
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +020074 movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +020075
76 /* Construct struct pt_regs on stack */
Ingo Molnar131484c2015-05-28 12:21:47 +020077 pushq $__USER32_DS /* pt_regs->ss */
78 pushq %rbp /* pt_regs->sp */
79 pushfq /* pt_regs->flags */
80 pushq $__USER32_CS /* pt_regs->cs */
Ingo Molnar54ad7262015-06-05 13:02:28 +020081 pushq %r10 /* pt_regs->ip = thread_info->sysenter_return */
Ingo Molnar131484c2015-05-28 12:21:47 +020082 pushq %rax /* pt_regs->orig_ax */
83 pushq %rdi /* pt_regs->di */
84 pushq %rsi /* pt_regs->si */
85 pushq %rdx /* pt_regs->dx */
86 pushq %rcx /* pt_regs->cx */
87 pushq $-ENOSYS /* pt_regs->ax */
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 cld
Ingo Molnar54ad7262015-06-05 13:02:28 +020089 sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +020090
Denys Vlasenkob87cf632015-02-26 14:40:32 -080091 /*
92 * no need to do an access_ok check here because rbp has been
Ingo Molnar54ad7262015-06-05 13:02:28 +020093 * 32-bit zero extended
Denys Vlasenkob87cf632015-02-26 14:40:32 -080094 */
H. Peter Anvin63bcff22012-09-21 12:43:12 -070095 ASM_STAC
Ingo Molnar54ad7262015-06-05 13:02:28 +0200961: movl (%rbp), %ebp
97 _ASM_EXTABLE(1b, ia32_badarg)
H. Peter Anvin63bcff22012-09-21 12:43:12 -070098 ASM_CLAC
Andy Lutomirski8c7aa692014-10-01 11:49:04 -070099
100 /*
101 * Sysenter doesn't filter flags, so we need to clear NT
102 * ourselves. To save a few cycles, we can check whether
103 * NT was set instead of doing an unconditional popfq.
104 */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200105 testl $X86_EFLAGS_NT, EFLAGS(%rsp)
106 jnz sysenter_fix_flags
Andy Lutomirski8c7aa692014-10-01 11:49:04 -0700107sysenter_flags_fixed:
108
Denys Vlasenko9b47feb2015-06-08 22:35:33 +0200109 orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
110 testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200111 jnz sysenter_tracesys
Ingo Molnar131484c2015-05-28 12:21:47 +0200112
Roland McGrathd4d67152008-07-09 02:38:07 -0700113sysenter_do_call:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200114 /* 32-bit syscall -> 64-bit C ABI argument conversion */
115 movl %edi, %r8d /* arg5 */
116 movl %ebp, %r9d /* arg6 */
117 xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
118 movl %ebx, %edi /* arg1 */
119 movl %edx, %edx /* arg3 (zero extension) */
Roland McGrath5cbf1562008-06-24 01:13:31 -0700120sysenter_dispatch:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200121 cmpq $(IA32_NR_syscalls-1), %rax
Denys Vlasenko3f5159a2015-04-21 18:03:14 +0200122 ja 1f
Ingo Molnar54ad7262015-06-05 13:02:28 +0200123 call *ia32_sys_call_table(, %rax, 8)
124 movq %rax, RAX(%rsp)
Denys Vlasenko3f5159a2015-04-21 18:03:14 +02001251:
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -0400126 DISABLE_INTERRUPTS(CLBR_NONE)
Ingo Molnar2601e642006-07-03 00:24:45 -0700127 TRACE_IRQS_OFF
Ingo Molnardca5b522015-03-24 19:44:42 +0100128 testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
Roland McGrath5cbf1562008-06-24 01:13:31 -0700129 jnz sysexit_audit
130sysexit_from_sys_call:
Andy Lutomirski4214a162015-04-02 17:12:12 -0700131 /*
132 * NB: SYSEXIT is not obviously safe for 64-bit kernels -- an
133 * NMI between STI and SYSEXIT has poorly specified behavior,
134 * and and NMI followed by an IRQ with usergs is fatal. So
135 * we just pretend we're using SYSEXIT but we really use
136 * SYSRETL instead.
137 *
138 * This code path is still called 'sysexit' because it pairs
139 * with 'sysenter' and it uses the SYSENTER calling convention.
140 */
Denys Vlasenko9b47feb2015-06-08 22:35:33 +0200141 andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200142 movl RIP(%rsp), %ecx /* User %eip */
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800143 RESTORE_RSI_RDI
Ingo Molnar54ad7262015-06-05 13:02:28 +0200144 xorl %edx, %edx /* Do not leak kernel information */
145 xorq %r8, %r8
146 xorq %r9, %r9
147 xorq %r10, %r10
148 movl EFLAGS(%rsp), %r11d /* User eflags */
Ingo Molnar2601e642006-07-03 00:24:45 -0700149 TRACE_IRQS_ON
Andy Lutomirski4214a162015-04-02 17:12:12 -0700150
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800151 /*
Andy Lutomirski4214a162015-04-02 17:12:12 -0700152 * SYSRETL works even on Intel CPUs. Use it in preference to SYSEXIT,
153 * since it avoids a dicey window with interrupts enabled.
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800154 */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200155 movl RSP(%rsp), %esp
Andy Lutomirski4214a162015-04-02 17:12:12 -0700156
157 /*
158 * USERGS_SYSRET32 does:
159 * gsbase = user's gs base
160 * eip = ecx
161 * rflags = r11
162 * cs = __USER32_CS
163 * ss = __USER_DS
164 *
165 * The prologue set RIP(%rsp) to VDSO32_SYSENTER_RETURN, which does:
166 *
167 * pop %ebp
168 * pop %edx
169 * pop %ecx
170 *
171 * Therefore, we invoke SYSRETL with EDX and R8-R10 zeroed to
172 * avoid info leaks. R11 ends up with VDSO32_SYSENTER_RETURN's
173 * address (already known to user code), and R12-R15 are
174 * callee-saved and therefore don't contain any interesting
175 * kernel data.
176 */
177 USERGS_SYSRET32
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Roland McGrath5cbf1562008-06-24 01:13:31 -0700179#ifdef CONFIG_AUDITSYSCALL
180 .macro auditsys_entry_common
Denys Vlasenko1536bb42015-06-09 20:54:08 +0200181 /*
Denys Vlasenkoa92fde22015-06-09 20:54:09 +0200182 * At this point, registers hold syscall args in the 32-bit syscall ABI:
183 * EAX is syscall number, the 6 args are in EBX,ECX,EDX,ESI,EDI,EBP.
184 *
185 * We want to pass them to __audit_syscall_entry(), which is a 64-bit
186 * C function with 5 parameters, so shuffle them to match what
187 * the function expects: RDI,RSI,RDX,RCX,R8.
188 */
189 movl %esi, %r8d /* arg5 (R8 ) <= 4th syscall arg (ESI) */
190 xchg %ecx, %edx /* arg4 (RCX) <= 3rd syscall arg (EDX) */
191 /* arg3 (RDX) <= 2nd syscall arg (ECX) */
192 movl %ebx, %esi /* arg2 (RSI) <= 1st syscall arg (EBX) */
193 movl %eax, %edi /* arg1 (RDI) <= syscall number (EAX) */
194 call __audit_syscall_entry
195
196 /*
197 * We are going to jump back to the syscall dispatch code.
198 * Prepare syscall args as required by the 64-bit C ABI.
199 * Registers clobbered by __audit_syscall_entry() are
200 * loaded from pt_regs on stack:
Denys Vlasenko1536bb42015-06-09 20:54:08 +0200201 */
202 movl ORIG_RAX(%rsp), %eax /* syscall number */
203 movl %ebx, %edi /* arg1 */
204 movl RCX(%rsp), %esi /* arg2 */
205 movl RDX(%rsp), %edx /* arg3 */
206 movl RSI(%rsp), %ecx /* arg4 */
207 movl RDI(%rsp), %r8d /* arg5 */
208 movl %ebp, %r9d /* arg6 */
Roland McGrath5cbf1562008-06-24 01:13:31 -0700209 .endm
210
Jan Beulich81766742009-10-26 15:20:29 +0000211 .macro auditsys_exit exit
Ingo Molnar54ad7262015-06-05 13:02:28 +0200212 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
213 jnz ia32_ret_from_sys_call
Roland McGrath5cbf1562008-06-24 01:13:31 -0700214 TRACE_IRQS_ON
Jan Beulich40a1ef92013-01-30 07:55:53 +0000215 ENABLE_INTERRUPTS(CLBR_NONE)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200216 movl %eax, %esi /* second arg, syscall return value */
217 cmpl $-MAX_ERRNO, %eax /* is it an error ? */
218 jbe 1f
219 movslq %eax, %rsi /* if error sign extend to 64 bits */
2201: setbe %al /* 1 if error, 0 if not */
221 movzbl %al, %edi /* zero-extend that into %edi */
222 call __audit_syscall_exit
223 movq RAX(%rsp), %rax /* reload syscall return value */
224 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %edi
Jan Beulich40a1ef92013-01-30 07:55:53 +0000225 DISABLE_INTERRUPTS(CLBR_NONE)
Roland McGrath5cbf1562008-06-24 01:13:31 -0700226 TRACE_IRQS_OFF
Ingo Molnar54ad7262015-06-05 13:02:28 +0200227 testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
228 jz \exit
229 xorl %eax, %eax /* Do not leak kernel information */
Denys Vlasenkoef0cd5d2015-06-02 21:04:01 +0200230 movq %rax, R11(%rsp)
231 movq %rax, R10(%rsp)
232 movq %rax, R9(%rsp)
233 movq %rax, R8(%rsp)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200234 jmp int_with_check
Roland McGrath5cbf1562008-06-24 01:13:31 -0700235 .endm
236
237sysenter_auditsys:
Roland McGrath5cbf1562008-06-24 01:13:31 -0700238 auditsys_entry_common
Ingo Molnar54ad7262015-06-05 13:02:28 +0200239 jmp sysenter_dispatch
Roland McGrath5cbf1562008-06-24 01:13:31 -0700240
241sysexit_audit:
242 auditsys_exit sysexit_from_sys_call
243#endif
244
Andy Lutomirski8c7aa692014-10-01 11:49:04 -0700245sysenter_fix_flags:
Denys Vlasenko9b47feb2015-06-08 22:35:33 +0200246 pushq $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
Ingo Molnar131484c2015-05-28 12:21:47 +0200247 popfq
Ingo Molnar54ad7262015-06-05 13:02:28 +0200248 jmp sysenter_flags_fixed
Andy Lutomirski8c7aa692014-10-01 11:49:04 -0700249
Roland McGrath5cbf1562008-06-24 01:13:31 -0700250sysenter_tracesys:
Roland McGrath5cbf1562008-06-24 01:13:31 -0700251#ifdef CONFIG_AUDITSYSCALL
Ingo Molnardca5b522015-03-24 19:44:42 +0100252 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
Roland McGrath5cbf1562008-06-24 01:13:31 -0700253 jz sysenter_auditsys
254#endif
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800255 SAVE_EXTRA_REGS
Ingo Molnar54ad7262015-06-05 13:02:28 +0200256 xorl %eax, %eax /* Do not leak kernel information */
Denys Vlasenkoef0cd5d2015-06-02 21:04:01 +0200257 movq %rax, R11(%rsp)
258 movq %rax, R10(%rsp)
259 movq %rax, R9(%rsp)
260 movq %rax, R8(%rsp)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200261 movq %rsp, %rdi /* &pt_regs -> arg1 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 call syscall_trace_enter
Denys Vlasenko73cbf682015-06-02 21:04:02 +0200263
264 /* Reload arg registers from stack. (see sysenter_tracesys) */
265 movl RCX(%rsp), %ecx
266 movl RDX(%rsp), %edx
267 movl RSI(%rsp), %esi
268 movl RDI(%rsp), %edi
Ingo Molnar54ad7262015-06-05 13:02:28 +0200269 movl %eax, %eax /* zero extension */
Denys Vlasenko73cbf682015-06-02 21:04:02 +0200270
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800271 RESTORE_EXTRA_REGS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 jmp sysenter_do_call
Ingo Molnar4c8cd0c2015-06-08 08:33:56 +0200273ENDPROC(entry_SYSENTER_compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275/*
Ingo Molnar54ad7262015-06-05 13:02:28 +0200276 * 32-bit SYSCALL instruction entry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 *
Ingo Molnar54ad7262015-06-05 13:02:28 +0200278 * 32-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800279 * then loads new ss, cs, and rip from previously programmed MSRs.
280 * rflags gets masked by a value from another MSR (so CLD and CLAC
281 * are not needed). SYSCALL does not save anything on the stack
282 * and does not change rsp.
283 *
284 * Note: rflags saving+masking-with-MSR happens only in Long mode
Ingo Molnar54ad7262015-06-05 13:02:28 +0200285 * (in legacy 32-bit mode, IF, RF and VM bits are cleared and that's it).
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800286 * Don't get confused: rflags saving+masking depends on Long Mode Active bit
287 * (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
288 * or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
289 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 * Arguments:
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800291 * eax system call number
292 * ecx return address
293 * ebx arg1
294 * ebp arg2 (note: not saved in the stack frame, should not be touched)
295 * edx arg3
296 * esi arg4
297 * edi arg5
298 * esp user stack
299 * 0(%esp) arg6
300 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 * This is purely a fast path. For anything complicated we use the int 0x80
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800302 * path below. We set up a complete hardware stack frame to share code
303 * with the int 0x80 path.
304 */
Ingo Molnar2cd23552015-06-08 08:28:07 +0200305ENTRY(entry_SYSCALL_compat)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +0100306 /*
307 * Interrupts are off on entry.
308 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
309 * it is too small to ever cause noticeable irq latency.
310 */
Jeremy Fitzhardinge457da702008-06-26 07:28:51 -0700311 SWAPGS_UNSAFE_STACK
Ingo Molnar54ad7262015-06-05 13:02:28 +0200312 movl %esp, %r8d
313 movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -0400314 ENABLE_INTERRUPTS(CLBR_NONE)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +0100315
Denys Vlasenko4ee8ec12015-03-27 11:36:21 +0100316 /* Zero-extending 32-bit regs, do not remove */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200317 movl %eax, %eax
Denys Vlasenko4ee8ec12015-03-27 11:36:21 +0100318
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +0200319 /* Construct struct pt_regs on stack */
Ingo Molnar131484c2015-05-28 12:21:47 +0200320 pushq $__USER32_DS /* pt_regs->ss */
321 pushq %r8 /* pt_regs->sp */
322 pushq %r11 /* pt_regs->flags */
323 pushq $__USER32_CS /* pt_regs->cs */
324 pushq %rcx /* pt_regs->ip */
325 pushq %rax /* pt_regs->orig_ax */
326 pushq %rdi /* pt_regs->di */
327 pushq %rsi /* pt_regs->si */
328 pushq %rdx /* pt_regs->dx */
329 pushq %rbp /* pt_regs->cx */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200330 movl %ebp, %ecx
Ingo Molnar131484c2015-05-28 12:21:47 +0200331 pushq $-ENOSYS /* pt_regs->ax */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200332 sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +0200333
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800334 /*
Ingo Molnar54ad7262015-06-05 13:02:28 +0200335 * No need to do an access_ok check here because r8 has been
336 * 32-bit zero extended:
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800337 */
H. Peter Anvin63bcff22012-09-21 12:43:12 -0700338 ASM_STAC
Ingo Molnar54ad7262015-06-05 13:02:28 +02003391: movl (%r8), %ebp
340 _ASM_EXTABLE(1b, ia32_badarg)
H. Peter Anvin63bcff22012-09-21 12:43:12 -0700341 ASM_CLAC
Denys Vlasenko9b47feb2015-06-08 22:35:33 +0200342 orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
343 testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
344 jnz cstar_tracesys
Ingo Molnar131484c2015-05-28 12:21:47 +0200345
Jan Beulich295286a2008-08-29 13:21:11 +0100346cstar_do_call:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200347 /* 32-bit syscall -> 64-bit C ABI argument conversion */
348 movl %edi, %r8d /* arg5 */
349 movl %ebp, %r9d /* arg6 */
350 xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
351 movl %ebx, %edi /* arg1 */
352 movl %edx, %edx /* arg3 (zero extension) */
353
Roland McGrath5cbf1562008-06-24 01:13:31 -0700354cstar_dispatch:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200355 cmpq $(IA32_NR_syscalls-1), %rax
Denys Vlasenko3f5159a2015-04-21 18:03:14 +0200356 ja 1f
Ingo Molnar54ad7262015-06-05 13:02:28 +0200357
358 call *ia32_sys_call_table(, %rax, 8)
359 movq %rax, RAX(%rsp)
Denys Vlasenko3f5159a2015-04-21 18:03:14 +02003601:
Denys Vlasenkoaee4b012015-06-09 20:54:07 +0200361 movl RCX(%rsp), %ebp
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -0400362 DISABLE_INTERRUPTS(CLBR_NONE)
Ingo Molnar2601e642006-07-03 00:24:45 -0700363 TRACE_IRQS_OFF
Ingo Molnar54ad7262015-06-05 13:02:28 +0200364 testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
365 jnz sysretl_audit
366
Roland McGrath5cbf1562008-06-24 01:13:31 -0700367sysretl_from_sys_call:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200368 andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800369 RESTORE_RSI_RDI_RDX
Ingo Molnar54ad7262015-06-05 13:02:28 +0200370 movl RIP(%rsp), %ecx
371 movl EFLAGS(%rsp), %r11d
372 xorq %r10, %r10
373 xorq %r9, %r9
374 xorq %r8, %r8
Ingo Molnar2601e642006-07-03 00:24:45 -0700375 TRACE_IRQS_ON
Ingo Molnar54ad7262015-06-05 13:02:28 +0200376 movl RSP(%rsp), %esp
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800377 /*
Ingo Molnar54ad7262015-06-05 13:02:28 +0200378 * 64-bit->32-bit SYSRET restores eip from ecx,
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800379 * eflags from r11 (but RF and VM bits are forced to 0),
380 * cs and ss are loaded from MSRs.
Ingo Molnar54ad7262015-06-05 13:02:28 +0200381 * (Note: 32-bit->32-bit SYSRET is different: since r11
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800382 * does not exist, it merely sets eflags.IF=1).
Andy Lutomirski61f01dd2015-04-26 16:47:59 -0700383 *
384 * NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss
385 * descriptor is not reinitialized. This means that we must
386 * avoid SYSRET with SS == NULL, which could happen if we schedule,
387 * exit the kernel, and re-enter using an interrupt vector. (All
388 * interrupt entries on x86_64 set SS to NULL.) We prevent that
389 * from happening by reloading SS in __switch_to.
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800390 */
Jeremy Fitzhardinge2be29982008-06-25 00:19:28 -0400391 USERGS_SYSRET32
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800392
Roland McGrath5cbf1562008-06-24 01:13:31 -0700393#ifdef CONFIG_AUDITSYSCALL
394cstar_auditsys:
Roland McGrath5cbf1562008-06-24 01:13:31 -0700395 auditsys_entry_common
Ingo Molnar54ad7262015-06-05 13:02:28 +0200396 jmp cstar_dispatch
Roland McGrath5cbf1562008-06-24 01:13:31 -0700397
398sysretl_audit:
Jan Beulich81766742009-10-26 15:20:29 +0000399 auditsys_exit sysretl_from_sys_call
Roland McGrath5cbf1562008-06-24 01:13:31 -0700400#endif
401
402cstar_tracesys:
403#ifdef CONFIG_AUDITSYSCALL
Ingo Molnar54ad7262015-06-05 13:02:28 +0200404 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
405 jz cstar_auditsys
Roland McGrath5cbf1562008-06-24 01:13:31 -0700406#endif
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800407 SAVE_EXTRA_REGS
Ingo Molnar54ad7262015-06-05 13:02:28 +0200408 xorl %eax, %eax /* Do not leak kernel information */
Denys Vlasenkoef0cd5d2015-06-02 21:04:01 +0200409 movq %rax, R11(%rsp)
410 movq %rax, R10(%rsp)
Denys Vlasenko53e9acc2015-06-03 14:56:09 +0200411 movq %rax, R9(%rsp)
Denys Vlasenkoef0cd5d2015-06-02 21:04:01 +0200412 movq %rax, R8(%rsp)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200413 movq %rsp, %rdi /* &pt_regs -> arg1 */
Denys Vlasenko53e9acc2015-06-03 14:56:09 +0200414 call syscall_trace_enter
Denys Vlasenko73cbf682015-06-02 21:04:02 +0200415
416 /* Reload arg registers from stack. (see sysenter_tracesys) */
417 movl RCX(%rsp), %ecx
418 movl RDX(%rsp), %edx
419 movl RSI(%rsp), %esi
420 movl RDI(%rsp), %edi
Ingo Molnar54ad7262015-06-05 13:02:28 +0200421 movl %eax, %eax /* zero extension */
Denys Vlasenko73cbf682015-06-02 21:04:02 +0200422
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800423 RESTORE_EXTRA_REGS
Denys Vlasenko53e9acc2015-06-03 14:56:09 +0200424 jmp cstar_do_call
Ingo Molnar2cd23552015-06-08 08:28:07 +0200425END(entry_SYSCALL_compat)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200426
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427ia32_badarg:
H. Peter Anvin63bcff22012-09-21 12:43:12 -0700428 ASM_CLAC
Denys Vlasenkoeb478542015-06-07 20:24:30 +0200429 movq $-EFAULT, RAX(%rsp)
Denys Vlasenko61b1e3e2015-06-02 19:35:10 +0200430ia32_ret_from_sys_call:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200431 xorl %eax, %eax /* Do not leak kernel information */
Denys Vlasenkoef0cd5d2015-06-02 21:04:01 +0200432 movq %rax, R11(%rsp)
433 movq %rax, R10(%rsp)
434 movq %rax, R9(%rsp)
435 movq %rax, R8(%rsp)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200436 jmp int_ret_from_sys_call
Denys Vlasenko61b1e3e2015-06-02 19:35:10 +0200437
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800438/*
439 * Emulated IA32 system calls via int 0x80.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 *
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800441 * Arguments:
442 * eax system call number
443 * ebx arg1
444 * ecx arg2
445 * edx arg3
446 * esi arg4
447 * edi arg5
448 * ebp arg6 (note: not saved in the stack frame, should not be touched)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 *
450 * Notes:
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800451 * Uses the same stack frame as the x86-64 version.
452 * All registers except eax must be saved (but ptrace may violate that).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 * Arguments are zero extended. For system calls that want sign extension and
454 * take long arguments a wrapper is needed. Most calls can just be called
455 * directly.
Denys Vlasenkob87cf632015-02-26 14:40:32 -0800456 * Assumes it is only called from user space and entered with interrupts off.
457 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
Ingo Molnar2cd23552015-06-08 08:28:07 +0200459ENTRY(entry_INT80_compat)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +0100460 /*
461 * Interrupts are off on entry.
462 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
463 * it is too small to ever cause noticeable irq latency.
464 */
Jeremy Fitzhardinge360c0442008-07-08 15:06:28 -0700465 PARAVIRT_ADJUST_EXCEPTION_FRAME
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -0400466 SWAPGS
Jeremy Fitzhardinge66804152008-06-25 00:19:29 -0400467 ENABLE_INTERRUPTS(CLBR_NONE)
Denys Vlasenkoa232e3d2015-03-27 11:36:20 +0100468
Denys Vlasenko4ee8ec12015-03-27 11:36:21 +0100469 /* Zero-extending 32-bit regs, do not remove */
Ingo Molnar54ad7262015-06-05 13:02:28 +0200470 movl %eax, %eax
Denys Vlasenko4ee8ec12015-03-27 11:36:21 +0100471
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +0200472 /* Construct struct pt_regs on stack (iret frame is already on stack) */
Ingo Molnar131484c2015-05-28 12:21:47 +0200473 pushq %rax /* pt_regs->orig_ax */
474 pushq %rdi /* pt_regs->di */
475 pushq %rsi /* pt_regs->si */
476 pushq %rdx /* pt_regs->dx */
477 pushq %rcx /* pt_regs->cx */
478 pushq $-ENOSYS /* pt_regs->ax */
Denys Vlasenko61b1e3e2015-06-02 19:35:10 +0200479 pushq $0 /* pt_regs->r8 */
480 pushq $0 /* pt_regs->r9 */
481 pushq $0 /* pt_regs->r10 */
482 pushq $0 /* pt_regs->r11 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 cld
Ingo Molnar54ad7262015-06-05 13:02:28 +0200484 sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
Denys Vlasenko4c9c0e92015-03-31 19:00:04 +0200485
Ingo Molnar54ad7262015-06-05 13:02:28 +0200486 orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
487 testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
488 jnz ia32_tracesys
489
Roland McGrathc09249f2009-02-06 18:15:18 -0800490ia32_do_call:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200491 /* 32-bit syscall -> 64-bit C ABI argument conversion */
492 movl %edi, %r8d /* arg5 */
493 movl %ebp, %r9d /* arg6 */
494 xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
495 movl %ebx, %edi /* arg1 */
496 movl %edx, %edx /* arg3 (zero extension) */
497 cmpq $(IA32_NR_syscalls-1), %rax
Denys Vlasenko3f5159a2015-04-21 18:03:14 +0200498 ja 1f
Ingo Molnar54ad7262015-06-05 13:02:28 +0200499
Denys Vlasenkoeb478542015-06-07 20:24:30 +0200500 call *ia32_sys_call_table(, %rax, 8)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200501 movq %rax, RAX(%rsp)
Denys Vlasenko3f5159a2015-04-21 18:03:14 +02005021:
Ingo Molnar54ad7262015-06-05 13:02:28 +0200503 jmp int_ret_from_sys_call
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800505ia32_tracesys:
506 SAVE_EXTRA_REGS
Ingo Molnar54ad7262015-06-05 13:02:28 +0200507 movq %rsp, %rdi /* &pt_regs -> arg1 */
508 call syscall_trace_enter
Denys Vlasenko73cbf682015-06-02 21:04:02 +0200509 /*
510 * Reload arg registers from stack in case ptrace changed them.
511 * Don't reload %eax because syscall_trace_enter() returned
512 * the %rax value we should see. But do truncate it to 32 bits.
513 * If it's -1 to make us punt the syscall, then (u32)-1 is still
514 * an appropriately invalid value.
515 */
516 movl RCX(%rsp), %ecx
517 movl RDX(%rsp), %edx
518 movl RSI(%rsp), %esi
519 movl RDI(%rsp), %edi
Ingo Molnar54ad7262015-06-05 13:02:28 +0200520 movl %eax, %eax /* zero extension */
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800521 RESTORE_EXTRA_REGS
Ingo Molnar54ad7262015-06-05 13:02:28 +0200522 jmp ia32_do_call
Ingo Molnar2cd23552015-06-08 08:28:07 +0200523END(entry_INT80_compat)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
Ramkumar Ramachandrad2475b82013-07-10 23:34:28 +0530525 .macro PTREGSCALL label, func
Jan Beulichf6b2bc82011-11-29 11:24:10 +0000526 ALIGN
527GLOBAL(\label)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200528 leaq \func(%rip), %rax
529 jmp ia32_ptregs_common
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 .endm
531
Ingo Molnar54ad7262015-06-05 13:02:28 +0200532 PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
533 PTREGSCALL stub32_sigreturn, sys32_sigreturn
534 PTREGSCALL stub32_fork, sys_fork
535 PTREGSCALL stub32_vfork, sys_vfork
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
Jan Beulichf6b2bc82011-11-29 11:24:10 +0000537 ALIGN
Al Viro1d4b4b22012-10-22 22:34:11 -0400538GLOBAL(stub32_clone)
Ingo Molnar54ad7262015-06-05 13:02:28 +0200539 leaq sys_clone(%rip), %rax
Denys Vlasenko5cdc6832015-06-03 15:58:49 +0200540 /*
Denys Vlasenko7a5a9822015-06-03 15:58:50 +0200541 * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr).
542 * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val).
543 *
544 * The native 64-bit kernel's sys_clone() implements the latter,
545 * so we need to swap arguments here before calling it:
Denys Vlasenko5cdc6832015-06-03 15:58:49 +0200546 */
Denys Vlasenko7a5a9822015-06-03 15:58:50 +0200547 xchg %r8, %rcx
Ingo Molnar54ad7262015-06-05 13:02:28 +0200548 jmp ia32_ptregs_common
Al Viro1d4b4b22012-10-22 22:34:11 -0400549
550 ALIGN
Jan Beulichf6b2bc82011-11-29 11:24:10 +0000551ia32_ptregs_common:
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800552 SAVE_EXTRA_REGS 8
Ingo Molnar54ad7262015-06-05 13:02:28 +0200553 call *%rax
Denys Vlasenko76f5df42015-02-26 14:40:27 -0800554 RESTORE_EXTRA_REGS 8
555 ret
Jan Beulich4b787e02006-06-26 13:56:55 +0200556END(ia32_ptregs_common)