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1da177e4 LT |
1 | /* |
2 | * linux/arch/x86_64/entry.S | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs | |
6 | * Copyright (C) 2000 Pavel Machek <pavel@suse.cz> | |
1da177e4 LT |
7 | */ |
8 | ||
9 | /* | |
10 | * entry.S contains the system-call and fault low-level handling routines. | |
11 | * | |
12 | * NOTE: This code handles signal-recognition, which happens every time | |
13 | * after an interrupt and after each system call. | |
14 | * | |
15 | * Normal syscalls and interrupts don't save a full stack frame, this is | |
16 | * only done for syscall tracing, signals or fork/exec et.al. | |
17 | * | |
18 | * A note on terminology: | |
19 | * - top of stack: Architecture defined interrupt frame from SS to RIP | |
20 | * at the top of the kernel process stack. | |
21 | * - partial stack frame: partially saved registers upto R11. | |
22 | * - full stack frame: Like partial stack frame, but all register saved. | |
2e91a17b AK |
23 | * |
24 | * Some macro usage: | |
25 | * - CFI macros are used to generate dwarf2 unwind information for better | |
26 | * backtraces. They don't change any code. | |
27 | * - SAVE_ALL/RESTORE_ALL - Save/restore all registers | |
28 | * - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify. | |
29 | * There are unfortunately lots of special cases where some registers | |
30 | * not touched. The macro is a big mess that should be cleaned up. | |
31 | * - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS. | |
32 | * Gives a full stack frame. | |
33 | * - ENTRY/END Define functions in the symbol table. | |
34 | * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack | |
35 | * frame that is otherwise undefined after a SYSCALL | |
36 | * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging. | |
37 | * - errorentry/paranoidentry/zeroentry - Define exception entry points. | |
1da177e4 LT |
38 | */ |
39 | ||
1da177e4 LT |
40 | #include <linux/linkage.h> |
41 | #include <asm/segment.h> | |
1da177e4 LT |
42 | #include <asm/cache.h> |
43 | #include <asm/errno.h> | |
44 | #include <asm/dwarf2.h> | |
45 | #include <asm/calling.h> | |
e2d5df93 | 46 | #include <asm/asm-offsets.h> |
1da177e4 LT |
47 | #include <asm/msr.h> |
48 | #include <asm/unistd.h> | |
49 | #include <asm/thread_info.h> | |
50 | #include <asm/hw_irq.h> | |
5f8efbb9 | 51 | #include <asm/page.h> |
2601e64d | 52 | #include <asm/irqflags.h> |
72fe4858 | 53 | #include <asm/paravirt.h> |
395a59d0 | 54 | #include <asm/ftrace.h> |
1da177e4 | 55 | |
86a1c34a RM |
56 | /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ |
57 | #include <linux/elf-em.h> | |
58 | #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE) | |
59 | #define __AUDIT_ARCH_64BIT 0x80000000 | |
60 | #define __AUDIT_ARCH_LE 0x40000000 | |
61 | ||
1da177e4 LT |
62 | .code64 |
63 | ||
16444a8a | 64 | #ifdef CONFIG_FTRACE |
d61f82d0 SR |
65 | #ifdef CONFIG_DYNAMIC_FTRACE |
66 | ENTRY(mcount) | |
67 | ||
68 | subq $0x38, %rsp | |
69 | movq %rax, (%rsp) | |
70 | movq %rcx, 8(%rsp) | |
71 | movq %rdx, 16(%rsp) | |
72 | movq %rsi, 24(%rsp) | |
73 | movq %rdi, 32(%rsp) | |
74 | movq %r8, 40(%rsp) | |
75 | movq %r9, 48(%rsp) | |
76 | ||
77 | movq 0x38(%rsp), %rdi | |
395a59d0 | 78 | subq $MCOUNT_INSN_SIZE, %rdi |
d61f82d0 SR |
79 | |
80 | .globl mcount_call | |
81 | mcount_call: | |
82 | call ftrace_stub | |
83 | ||
84 | movq 48(%rsp), %r9 | |
85 | movq 40(%rsp), %r8 | |
86 | movq 32(%rsp), %rdi | |
87 | movq 24(%rsp), %rsi | |
88 | movq 16(%rsp), %rdx | |
89 | movq 8(%rsp), %rcx | |
90 | movq (%rsp), %rax | |
91 | addq $0x38, %rsp | |
92 | ||
93 | retq | |
94 | END(mcount) | |
95 | ||
96 | ENTRY(ftrace_caller) | |
97 | ||
98 | /* taken from glibc */ | |
99 | subq $0x38, %rsp | |
100 | movq %rax, (%rsp) | |
101 | movq %rcx, 8(%rsp) | |
102 | movq %rdx, 16(%rsp) | |
103 | movq %rsi, 24(%rsp) | |
104 | movq %rdi, 32(%rsp) | |
105 | movq %r8, 40(%rsp) | |
106 | movq %r9, 48(%rsp) | |
107 | ||
108 | movq 0x38(%rsp), %rdi | |
109 | movq 8(%rbp), %rsi | |
395a59d0 | 110 | subq $MCOUNT_INSN_SIZE, %rdi |
d61f82d0 SR |
111 | |
112 | .globl ftrace_call | |
113 | ftrace_call: | |
114 | call ftrace_stub | |
115 | ||
116 | movq 48(%rsp), %r9 | |
117 | movq 40(%rsp), %r8 | |
118 | movq 32(%rsp), %rdi | |
119 | movq 24(%rsp), %rsi | |
120 | movq 16(%rsp), %rdx | |
121 | movq 8(%rsp), %rcx | |
122 | movq (%rsp), %rax | |
123 | addq $0x38, %rsp | |
124 | ||
125 | .globl ftrace_stub | |
126 | ftrace_stub: | |
127 | retq | |
128 | END(ftrace_caller) | |
129 | ||
130 | #else /* ! CONFIG_DYNAMIC_FTRACE */ | |
16444a8a ACM |
131 | ENTRY(mcount) |
132 | cmpq $ftrace_stub, ftrace_trace_function | |
133 | jnz trace | |
134 | .globl ftrace_stub | |
135 | ftrace_stub: | |
136 | retq | |
137 | ||
138 | trace: | |
139 | /* taken from glibc */ | |
140 | subq $0x38, %rsp | |
141 | movq %rax, (%rsp) | |
142 | movq %rcx, 8(%rsp) | |
143 | movq %rdx, 16(%rsp) | |
144 | movq %rsi, 24(%rsp) | |
145 | movq %rdi, 32(%rsp) | |
146 | movq %r8, 40(%rsp) | |
147 | movq %r9, 48(%rsp) | |
148 | ||
149 | movq 0x38(%rsp), %rdi | |
150 | movq 8(%rbp), %rsi | |
395a59d0 | 151 | subq $MCOUNT_INSN_SIZE, %rdi |
16444a8a ACM |
152 | |
153 | call *ftrace_trace_function | |
154 | ||
155 | movq 48(%rsp), %r9 | |
156 | movq 40(%rsp), %r8 | |
157 | movq 32(%rsp), %rdi | |
158 | movq 24(%rsp), %rsi | |
159 | movq 16(%rsp), %rdx | |
160 | movq 8(%rsp), %rcx | |
161 | movq (%rsp), %rax | |
162 | addq $0x38, %rsp | |
163 | ||
164 | jmp ftrace_stub | |
165 | END(mcount) | |
d61f82d0 SR |
166 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
167 | #endif /* CONFIG_FTRACE */ | |
16444a8a | 168 | |
dc37db4d | 169 | #ifndef CONFIG_PREEMPT |
1da177e4 LT |
170 | #define retint_kernel retint_restore_args |
171 | #endif | |
2601e64d | 172 | |
72fe4858 | 173 | #ifdef CONFIG_PARAVIRT |
2be29982 | 174 | ENTRY(native_usergs_sysret64) |
72fe4858 GOC |
175 | swapgs |
176 | sysretq | |
177 | #endif /* CONFIG_PARAVIRT */ | |
178 | ||
2601e64d IM |
179 | |
180 | .macro TRACE_IRQS_IRETQ offset=ARGOFFSET | |
181 | #ifdef CONFIG_TRACE_IRQFLAGS | |
182 | bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */ | |
183 | jnc 1f | |
184 | TRACE_IRQS_ON | |
185 | 1: | |
186 | #endif | |
187 | .endm | |
188 | ||
1da177e4 LT |
189 | /* |
190 | * C code is not supposed to know about undefined top of stack. Every time | |
191 | * a C function with an pt_regs argument is called from the SYSCALL based | |
192 | * fast path FIXUP_TOP_OF_STACK is needed. | |
193 | * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs | |
194 | * manipulation. | |
195 | */ | |
196 | ||
197 | /* %rsp:at FRAMEEND */ | |
198 | .macro FIXUP_TOP_OF_STACK tmp | |
199 | movq %gs:pda_oldrsp,\tmp | |
200 | movq \tmp,RSP(%rsp) | |
201 | movq $__USER_DS,SS(%rsp) | |
202 | movq $__USER_CS,CS(%rsp) | |
203 | movq $-1,RCX(%rsp) | |
204 | movq R11(%rsp),\tmp /* get eflags */ | |
205 | movq \tmp,EFLAGS(%rsp) | |
206 | .endm | |
207 | ||
208 | .macro RESTORE_TOP_OF_STACK tmp,offset=0 | |
209 | movq RSP-\offset(%rsp),\tmp | |
210 | movq \tmp,%gs:pda_oldrsp | |
211 | movq EFLAGS-\offset(%rsp),\tmp | |
212 | movq \tmp,R11-\offset(%rsp) | |
213 | .endm | |
214 | ||
215 | .macro FAKE_STACK_FRAME child_rip | |
216 | /* push in order ss, rsp, eflags, cs, rip */ | |
3829ee6b | 217 | xorl %eax, %eax |
e04e0a63 | 218 | pushq $__KERNEL_DS /* ss */ |
1da177e4 | 219 | CFI_ADJUST_CFA_OFFSET 8 |
7effaa88 | 220 | /*CFI_REL_OFFSET ss,0*/ |
1da177e4 LT |
221 | pushq %rax /* rsp */ |
222 | CFI_ADJUST_CFA_OFFSET 8 | |
7effaa88 | 223 | CFI_REL_OFFSET rsp,0 |
1da177e4 LT |
224 | pushq $(1<<9) /* eflags - interrupts on */ |
225 | CFI_ADJUST_CFA_OFFSET 8 | |
7effaa88 | 226 | /*CFI_REL_OFFSET rflags,0*/ |
1da177e4 LT |
227 | pushq $__KERNEL_CS /* cs */ |
228 | CFI_ADJUST_CFA_OFFSET 8 | |
7effaa88 | 229 | /*CFI_REL_OFFSET cs,0*/ |
1da177e4 LT |
230 | pushq \child_rip /* rip */ |
231 | CFI_ADJUST_CFA_OFFSET 8 | |
7effaa88 | 232 | CFI_REL_OFFSET rip,0 |
1da177e4 LT |
233 | pushq %rax /* orig rax */ |
234 | CFI_ADJUST_CFA_OFFSET 8 | |
235 | .endm | |
236 | ||
237 | .macro UNFAKE_STACK_FRAME | |
238 | addq $8*6, %rsp | |
239 | CFI_ADJUST_CFA_OFFSET -(6*8) | |
240 | .endm | |
241 | ||
7effaa88 JB |
242 | .macro CFI_DEFAULT_STACK start=1 |
243 | .if \start | |
244 | CFI_STARTPROC simple | |
adf14236 | 245 | CFI_SIGNAL_FRAME |
7effaa88 JB |
246 | CFI_DEF_CFA rsp,SS+8 |
247 | .else | |
248 | CFI_DEF_CFA_OFFSET SS+8 | |
249 | .endif | |
250 | CFI_REL_OFFSET r15,R15 | |
251 | CFI_REL_OFFSET r14,R14 | |
252 | CFI_REL_OFFSET r13,R13 | |
253 | CFI_REL_OFFSET r12,R12 | |
254 | CFI_REL_OFFSET rbp,RBP | |
255 | CFI_REL_OFFSET rbx,RBX | |
256 | CFI_REL_OFFSET r11,R11 | |
257 | CFI_REL_OFFSET r10,R10 | |
258 | CFI_REL_OFFSET r9,R9 | |
259 | CFI_REL_OFFSET r8,R8 | |
260 | CFI_REL_OFFSET rax,RAX | |
261 | CFI_REL_OFFSET rcx,RCX | |
262 | CFI_REL_OFFSET rdx,RDX | |
263 | CFI_REL_OFFSET rsi,RSI | |
264 | CFI_REL_OFFSET rdi,RDI | |
265 | CFI_REL_OFFSET rip,RIP | |
266 | /*CFI_REL_OFFSET cs,CS*/ | |
267 | /*CFI_REL_OFFSET rflags,EFLAGS*/ | |
268 | CFI_REL_OFFSET rsp,RSP | |
269 | /*CFI_REL_OFFSET ss,SS*/ | |
1da177e4 LT |
270 | .endm |
271 | /* | |
272 | * A newly forked process directly context switches into this. | |
273 | */ | |
274 | /* rdi: prev */ | |
275 | ENTRY(ret_from_fork) | |
1da177e4 | 276 | CFI_DEFAULT_STACK |
658fdbef | 277 | push kernel_eflags(%rip) |
e0a5a5d9 | 278 | CFI_ADJUST_CFA_OFFSET 8 |
658fdbef | 279 | popf # reset kernel eflags |
e0a5a5d9 | 280 | CFI_ADJUST_CFA_OFFSET -8 |
1da177e4 LT |
281 | call schedule_tail |
282 | GET_THREAD_INFO(%rcx) | |
26ccb8a7 | 283 | testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%rcx) |
1da177e4 LT |
284 | jnz rff_trace |
285 | rff_action: | |
286 | RESTORE_REST | |
287 | testl $3,CS-ARGOFFSET(%rsp) # from kernel_thread? | |
288 | je int_ret_from_sys_call | |
26ccb8a7 | 289 | testl $_TIF_IA32,TI_flags(%rcx) |
1da177e4 LT |
290 | jnz int_ret_from_sys_call |
291 | RESTORE_TOP_OF_STACK %rdi,ARGOFFSET | |
292 | jmp ret_from_sys_call | |
293 | rff_trace: | |
294 | movq %rsp,%rdi | |
295 | call syscall_trace_leave | |
296 | GET_THREAD_INFO(%rcx) | |
297 | jmp rff_action | |
298 | CFI_ENDPROC | |
4b787e0b | 299 | END(ret_from_fork) |
1da177e4 LT |
300 | |
301 | /* | |
302 | * System call entry. Upto 6 arguments in registers are supported. | |
303 | * | |
304 | * SYSCALL does not save anything on the stack and does not change the | |
305 | * stack pointer. | |
306 | */ | |
307 | ||
308 | /* | |
309 | * Register setup: | |
310 | * rax system call number | |
311 | * rdi arg0 | |
312 | * rcx return address for syscall/sysret, C arg3 | |
313 | * rsi arg1 | |
314 | * rdx arg2 | |
315 | * r10 arg3 (--> moved to rcx for C) | |
316 | * r8 arg4 | |
317 | * r9 arg5 | |
318 | * r11 eflags for syscall/sysret, temporary for C | |
319 | * r12-r15,rbp,rbx saved by C code, not touched. | |
320 | * | |
321 | * Interrupts are off on entry. | |
322 | * Only called from user space. | |
323 | * | |
324 | * XXX if we had a free scratch register we could save the RSP into the stack frame | |
325 | * and report it properly in ps. Unfortunately we haven't. | |
7bf36bbc AK |
326 | * |
327 | * When user can change the frames always force IRET. That is because | |
328 | * it deals with uncanonical addresses better. SYSRET has trouble | |
329 | * with them due to bugs in both AMD and Intel CPUs. | |
1da177e4 LT |
330 | */ |
331 | ||
332 | ENTRY(system_call) | |
7effaa88 | 333 | CFI_STARTPROC simple |
adf14236 | 334 | CFI_SIGNAL_FRAME |
dffead4e | 335 | CFI_DEF_CFA rsp,PDA_STACKOFFSET |
7effaa88 JB |
336 | CFI_REGISTER rip,rcx |
337 | /*CFI_REGISTER rflags,r11*/ | |
72fe4858 GOC |
338 | SWAPGS_UNSAFE_STACK |
339 | /* | |
340 | * A hypervisor implementation might want to use a label | |
341 | * after the swapgs, so that it can do the swapgs | |
342 | * for the guest and jump here on syscall. | |
343 | */ | |
344 | ENTRY(system_call_after_swapgs) | |
345 | ||
1da177e4 LT |
346 | movq %rsp,%gs:pda_oldrsp |
347 | movq %gs:pda_kernelstack,%rsp | |
2601e64d IM |
348 | /* |
349 | * No need to follow this irqs off/on section - it's straight | |
350 | * and short: | |
351 | */ | |
72fe4858 | 352 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 LT |
353 | SAVE_ARGS 8,1 |
354 | movq %rax,ORIG_RAX-ARGOFFSET(%rsp) | |
7effaa88 JB |
355 | movq %rcx,RIP-ARGOFFSET(%rsp) |
356 | CFI_REL_OFFSET rip,RIP-ARGOFFSET | |
1da177e4 | 357 | GET_THREAD_INFO(%rcx) |
d4d67150 | 358 | testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx) |
1da177e4 | 359 | jnz tracesys |
86a1c34a | 360 | system_call_fastpath: |
1da177e4 LT |
361 | cmpq $__NR_syscall_max,%rax |
362 | ja badsys | |
363 | movq %r10,%rcx | |
364 | call *sys_call_table(,%rax,8) # XXX: rip relative | |
365 | movq %rax,RAX-ARGOFFSET(%rsp) | |
366 | /* | |
367 | * Syscall return path ending with SYSRET (fast path) | |
368 | * Has incomplete stack frame and undefined top of stack. | |
369 | */ | |
1da177e4 | 370 | ret_from_sys_call: |
11b854b2 | 371 | movl $_TIF_ALLWORK_MASK,%edi |
1da177e4 LT |
372 | /* edi: flagmask */ |
373 | sysret_check: | |
10cd706d | 374 | LOCKDEP_SYS_EXIT |
1da177e4 | 375 | GET_THREAD_INFO(%rcx) |
72fe4858 | 376 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 377 | TRACE_IRQS_OFF |
26ccb8a7 | 378 | movl TI_flags(%rcx),%edx |
1da177e4 LT |
379 | andl %edi,%edx |
380 | jnz sysret_careful | |
bcddc015 | 381 | CFI_REMEMBER_STATE |
2601e64d IM |
382 | /* |
383 | * sysretq will re-enable interrupts: | |
384 | */ | |
385 | TRACE_IRQS_ON | |
1da177e4 | 386 | movq RIP-ARGOFFSET(%rsp),%rcx |
7effaa88 | 387 | CFI_REGISTER rip,rcx |
1da177e4 | 388 | RESTORE_ARGS 0,-ARG_SKIP,1 |
7effaa88 | 389 | /*CFI_REGISTER rflags,r11*/ |
c7245da6 | 390 | movq %gs:pda_oldrsp, %rsp |
2be29982 | 391 | USERGS_SYSRET64 |
1da177e4 | 392 | |
bcddc015 | 393 | CFI_RESTORE_STATE |
1da177e4 LT |
394 | /* Handle reschedules */ |
395 | /* edx: work, edi: workmask */ | |
396 | sysret_careful: | |
397 | bt $TIF_NEED_RESCHED,%edx | |
398 | jnc sysret_signal | |
2601e64d | 399 | TRACE_IRQS_ON |
72fe4858 | 400 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 | 401 | pushq %rdi |
7effaa88 | 402 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 LT |
403 | call schedule |
404 | popq %rdi | |
7effaa88 | 405 | CFI_ADJUST_CFA_OFFSET -8 |
1da177e4 LT |
406 | jmp sysret_check |
407 | ||
408 | /* Handle a signal */ | |
409 | sysret_signal: | |
2601e64d | 410 | TRACE_IRQS_ON |
72fe4858 | 411 | ENABLE_INTERRUPTS(CLBR_NONE) |
86a1c34a RM |
412 | #ifdef CONFIG_AUDITSYSCALL |
413 | bt $TIF_SYSCALL_AUDIT,%edx | |
414 | jc sysret_audit | |
415 | #endif | |
10ffdbb8 | 416 | /* edx: work flags (arg3) */ |
1da177e4 LT |
417 | leaq do_notify_resume(%rip),%rax |
418 | leaq -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1 | |
419 | xorl %esi,%esi # oldset -> arg2 | |
420 | call ptregscall_common | |
15e8f348 | 421 | movl $_TIF_WORK_MASK,%edi |
7bf36bbc AK |
422 | /* Use IRET because user could have changed frame. This |
423 | works because ptregscall_common has called FIXUP_TOP_OF_STACK. */ | |
72fe4858 | 424 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 425 | TRACE_IRQS_OFF |
7bf36bbc | 426 | jmp int_with_check |
1da177e4 | 427 | |
7effaa88 JB |
428 | badsys: |
429 | movq $-ENOSYS,RAX-ARGOFFSET(%rsp) | |
430 | jmp ret_from_sys_call | |
431 | ||
86a1c34a RM |
432 | #ifdef CONFIG_AUDITSYSCALL |
433 | /* | |
434 | * Fast path for syscall audit without full syscall trace. | |
435 | * We just call audit_syscall_entry() directly, and then | |
436 | * jump back to the normal fast path. | |
437 | */ | |
438 | auditsys: | |
439 | movq %r10,%r9 /* 6th arg: 4th syscall arg */ | |
440 | movq %rdx,%r8 /* 5th arg: 3rd syscall arg */ | |
441 | movq %rsi,%rcx /* 4th arg: 2nd syscall arg */ | |
442 | movq %rdi,%rdx /* 3rd arg: 1st syscall arg */ | |
443 | movq %rax,%rsi /* 2nd arg: syscall number */ | |
444 | movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */ | |
445 | call audit_syscall_entry | |
446 | LOAD_ARGS 0 /* reload call-clobbered registers */ | |
447 | jmp system_call_fastpath | |
448 | ||
449 | /* | |
450 | * Return fast path for syscall audit. Call audit_syscall_exit() | |
451 | * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT | |
452 | * masked off. | |
453 | */ | |
454 | sysret_audit: | |
455 | movq %rax,%rsi /* second arg, syscall return value */ | |
456 | cmpq $0,%rax /* is it < 0? */ | |
457 | setl %al /* 1 if so, 0 if not */ | |
458 | movzbl %al,%edi /* zero-extend that into %edi */ | |
459 | inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */ | |
460 | call audit_syscall_exit | |
461 | movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi | |
462 | jmp sysret_check | |
463 | #endif /* CONFIG_AUDITSYSCALL */ | |
464 | ||
1da177e4 LT |
465 | /* Do syscall tracing */ |
466 | tracesys: | |
86a1c34a RM |
467 | #ifdef CONFIG_AUDITSYSCALL |
468 | testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx) | |
469 | jz auditsys | |
470 | #endif | |
1da177e4 | 471 | SAVE_REST |
a31f8dd7 | 472 | movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ |
1da177e4 LT |
473 | FIXUP_TOP_OF_STACK %rdi |
474 | movq %rsp,%rdi | |
475 | call syscall_trace_enter | |
d4d67150 RM |
476 | /* |
477 | * Reload arg registers from stack in case ptrace changed them. | |
478 | * We don't reload %rax because syscall_trace_enter() returned | |
479 | * the value it wants us to use in the table lookup. | |
480 | */ | |
481 | LOAD_ARGS ARGOFFSET, 1 | |
1da177e4 LT |
482 | RESTORE_REST |
483 | cmpq $__NR_syscall_max,%rax | |
a31f8dd7 | 484 | ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */ |
1da177e4 LT |
485 | movq %r10,%rcx /* fixup for C */ |
486 | call *sys_call_table(,%rax,8) | |
a31f8dd7 | 487 | movq %rax,RAX-ARGOFFSET(%rsp) |
7bf36bbc | 488 | /* Use IRET because user could have changed frame */ |
1da177e4 | 489 | |
1da177e4 LT |
490 | /* |
491 | * Syscall return path ending with IRET. | |
492 | * Has correct top of stack, but partial stack frame. | |
bcddc015 JB |
493 | */ |
494 | .globl int_ret_from_sys_call | |
5cbf1565 | 495 | .globl int_with_check |
bcddc015 | 496 | int_ret_from_sys_call: |
72fe4858 | 497 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 498 | TRACE_IRQS_OFF |
1da177e4 LT |
499 | testl $3,CS-ARGOFFSET(%rsp) |
500 | je retint_restore_args | |
501 | movl $_TIF_ALLWORK_MASK,%edi | |
502 | /* edi: mask to check */ | |
503 | int_with_check: | |
10cd706d | 504 | LOCKDEP_SYS_EXIT_IRQ |
1da177e4 | 505 | GET_THREAD_INFO(%rcx) |
26ccb8a7 | 506 | movl TI_flags(%rcx),%edx |
1da177e4 LT |
507 | andl %edi,%edx |
508 | jnz int_careful | |
26ccb8a7 | 509 | andl $~TS_COMPAT,TI_status(%rcx) |
1da177e4 LT |
510 | jmp retint_swapgs |
511 | ||
512 | /* Either reschedule or signal or syscall exit tracking needed. */ | |
513 | /* First do a reschedule test. */ | |
514 | /* edx: work, edi: workmask */ | |
515 | int_careful: | |
516 | bt $TIF_NEED_RESCHED,%edx | |
517 | jnc int_very_careful | |
2601e64d | 518 | TRACE_IRQS_ON |
72fe4858 | 519 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 | 520 | pushq %rdi |
7effaa88 | 521 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 LT |
522 | call schedule |
523 | popq %rdi | |
7effaa88 | 524 | CFI_ADJUST_CFA_OFFSET -8 |
72fe4858 | 525 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 526 | TRACE_IRQS_OFF |
1da177e4 LT |
527 | jmp int_with_check |
528 | ||
529 | /* handle signals and tracing -- both require a full stack frame */ | |
530 | int_very_careful: | |
2601e64d | 531 | TRACE_IRQS_ON |
72fe4858 | 532 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 LT |
533 | SAVE_REST |
534 | /* Check for syscall exit trace */ | |
d4d67150 | 535 | testl $_TIF_WORK_SYSCALL_EXIT,%edx |
1da177e4 LT |
536 | jz int_signal |
537 | pushq %rdi | |
7effaa88 | 538 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 LT |
539 | leaq 8(%rsp),%rdi # &ptregs -> arg1 |
540 | call syscall_trace_leave | |
541 | popq %rdi | |
7effaa88 | 542 | CFI_ADJUST_CFA_OFFSET -8 |
d4d67150 | 543 | andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi |
1da177e4 LT |
544 | jmp int_restore_rest |
545 | ||
546 | int_signal: | |
8f4d37ec | 547 | testl $_TIF_DO_NOTIFY_MASK,%edx |
1da177e4 LT |
548 | jz 1f |
549 | movq %rsp,%rdi # &ptregs -> arg1 | |
550 | xorl %esi,%esi # oldset -> arg2 | |
551 | call do_notify_resume | |
eca91e78 | 552 | 1: movl $_TIF_WORK_MASK,%edi |
1da177e4 LT |
553 | int_restore_rest: |
554 | RESTORE_REST | |
72fe4858 | 555 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 556 | TRACE_IRQS_OFF |
1da177e4 LT |
557 | jmp int_with_check |
558 | CFI_ENDPROC | |
bcddc015 | 559 | END(system_call) |
1da177e4 LT |
560 | |
561 | /* | |
562 | * Certain special system calls that need to save a complete full stack frame. | |
563 | */ | |
564 | ||
565 | .macro PTREGSCALL label,func,arg | |
566 | .globl \label | |
567 | \label: | |
568 | leaq \func(%rip),%rax | |
569 | leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */ | |
570 | jmp ptregscall_common | |
4b787e0b | 571 | END(\label) |
1da177e4 LT |
572 | .endm |
573 | ||
7effaa88 JB |
574 | CFI_STARTPROC |
575 | ||
1da177e4 LT |
576 | PTREGSCALL stub_clone, sys_clone, %r8 |
577 | PTREGSCALL stub_fork, sys_fork, %rdi | |
578 | PTREGSCALL stub_vfork, sys_vfork, %rdi | |
1da177e4 LT |
579 | PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx |
580 | PTREGSCALL stub_iopl, sys_iopl, %rsi | |
581 | ||
582 | ENTRY(ptregscall_common) | |
1da177e4 | 583 | popq %r11 |
7effaa88 JB |
584 | CFI_ADJUST_CFA_OFFSET -8 |
585 | CFI_REGISTER rip, r11 | |
1da177e4 LT |
586 | SAVE_REST |
587 | movq %r11, %r15 | |
7effaa88 | 588 | CFI_REGISTER rip, r15 |
1da177e4 LT |
589 | FIXUP_TOP_OF_STACK %r11 |
590 | call *%rax | |
591 | RESTORE_TOP_OF_STACK %r11 | |
592 | movq %r15, %r11 | |
7effaa88 | 593 | CFI_REGISTER rip, r11 |
1da177e4 LT |
594 | RESTORE_REST |
595 | pushq %r11 | |
7effaa88 JB |
596 | CFI_ADJUST_CFA_OFFSET 8 |
597 | CFI_REL_OFFSET rip, 0 | |
1da177e4 LT |
598 | ret |
599 | CFI_ENDPROC | |
4b787e0b | 600 | END(ptregscall_common) |
1da177e4 LT |
601 | |
602 | ENTRY(stub_execve) | |
603 | CFI_STARTPROC | |
604 | popq %r11 | |
7effaa88 JB |
605 | CFI_ADJUST_CFA_OFFSET -8 |
606 | CFI_REGISTER rip, r11 | |
1da177e4 | 607 | SAVE_REST |
1da177e4 | 608 | FIXUP_TOP_OF_STACK %r11 |
5d119b2c | 609 | movq %rsp, %rcx |
1da177e4 | 610 | call sys_execve |
1da177e4 | 611 | RESTORE_TOP_OF_STACK %r11 |
1da177e4 LT |
612 | movq %rax,RAX(%rsp) |
613 | RESTORE_REST | |
614 | jmp int_ret_from_sys_call | |
615 | CFI_ENDPROC | |
4b787e0b | 616 | END(stub_execve) |
1da177e4 LT |
617 | |
618 | /* | |
619 | * sigreturn is special because it needs to restore all registers on return. | |
620 | * This cannot be done with SYSRET, so use the IRET return path instead. | |
621 | */ | |
622 | ENTRY(stub_rt_sigreturn) | |
623 | CFI_STARTPROC | |
7effaa88 JB |
624 | addq $8, %rsp |
625 | CFI_ADJUST_CFA_OFFSET -8 | |
1da177e4 LT |
626 | SAVE_REST |
627 | movq %rsp,%rdi | |
628 | FIXUP_TOP_OF_STACK %r11 | |
629 | call sys_rt_sigreturn | |
630 | movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer | |
631 | RESTORE_REST | |
632 | jmp int_ret_from_sys_call | |
633 | CFI_ENDPROC | |
4b787e0b | 634 | END(stub_rt_sigreturn) |
1da177e4 | 635 | |
7effaa88 JB |
636 | /* |
637 | * initial frame state for interrupts and exceptions | |
638 | */ | |
639 | .macro _frame ref | |
640 | CFI_STARTPROC simple | |
adf14236 | 641 | CFI_SIGNAL_FRAME |
7effaa88 JB |
642 | CFI_DEF_CFA rsp,SS+8-\ref |
643 | /*CFI_REL_OFFSET ss,SS-\ref*/ | |
644 | CFI_REL_OFFSET rsp,RSP-\ref | |
645 | /*CFI_REL_OFFSET rflags,EFLAGS-\ref*/ | |
646 | /*CFI_REL_OFFSET cs,CS-\ref*/ | |
647 | CFI_REL_OFFSET rip,RIP-\ref | |
648 | .endm | |
649 | ||
650 | /* initial frame state for interrupts (and exceptions without error code) */ | |
651 | #define INTR_FRAME _frame RIP | |
652 | /* initial frame state for exceptions with error code (and interrupts with | |
653 | vector already pushed) */ | |
654 | #define XCPT_FRAME _frame ORIG_RAX | |
655 | ||
1da177e4 LT |
656 | /* |
657 | * Interrupt entry/exit. | |
658 | * | |
659 | * Interrupt entry points save only callee clobbered registers in fast path. | |
660 | * | |
661 | * Entry runs with interrupts off. | |
662 | */ | |
663 | ||
664 | /* 0(%rsp): interrupt number */ | |
665 | .macro interrupt func | |
1da177e4 | 666 | cld |
1da177e4 LT |
667 | SAVE_ARGS |
668 | leaq -ARGOFFSET(%rsp),%rdi # arg1 for handler | |
1de9c3f6 | 669 | pushq %rbp |
097a0788 GC |
670 | /* |
671 | * Save rbp twice: One is for marking the stack frame, as usual, and the | |
672 | * other, to fill pt_regs properly. This is because bx comes right | |
673 | * before the last saved register in that structure, and not bp. If the | |
674 | * base pointer were in the place bx is today, this would not be needed. | |
675 | */ | |
676 | movq %rbp, -8(%rsp) | |
1de9c3f6 JB |
677 | CFI_ADJUST_CFA_OFFSET 8 |
678 | CFI_REL_OFFSET rbp, 0 | |
679 | movq %rsp,%rbp | |
680 | CFI_DEF_CFA_REGISTER rbp | |
1da177e4 LT |
681 | testl $3,CS(%rdi) |
682 | je 1f | |
72fe4858 | 683 | SWAPGS |
96e54049 AK |
684 | /* irqcount is used to check if a CPU is already on an interrupt |
685 | stack or not. While this is essentially redundant with preempt_count | |
686 | it is a little cheaper to use a separate counter in the PDA | |
687 | (short of moving irq_enter into assembly, which would be too | |
688 | much work) */ | |
689 | 1: incl %gs:pda_irqcount | |
1de9c3f6 | 690 | cmoveq %gs:pda_irqstackptr,%rsp |
2699500b | 691 | push %rbp # backlink for old unwinder |
2601e64d IM |
692 | /* |
693 | * We entered an interrupt context - irqs are off: | |
694 | */ | |
695 | TRACE_IRQS_OFF | |
1da177e4 LT |
696 | call \func |
697 | .endm | |
698 | ||
699 | ENTRY(common_interrupt) | |
7effaa88 | 700 | XCPT_FRAME |
1da177e4 LT |
701 | interrupt do_IRQ |
702 | /* 0(%rsp): oldrsp-ARGOFFSET */ | |
7effaa88 | 703 | ret_from_intr: |
72fe4858 | 704 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 705 | TRACE_IRQS_OFF |
3829ee6b | 706 | decl %gs:pda_irqcount |
1de9c3f6 | 707 | leaveq |
7effaa88 | 708 | CFI_DEF_CFA_REGISTER rsp |
1de9c3f6 | 709 | CFI_ADJUST_CFA_OFFSET -8 |
7effaa88 | 710 | exit_intr: |
1da177e4 LT |
711 | GET_THREAD_INFO(%rcx) |
712 | testl $3,CS-ARGOFFSET(%rsp) | |
713 | je retint_kernel | |
714 | ||
715 | /* Interrupt came from user space */ | |
716 | /* | |
717 | * Has a correct top of stack, but a partial stack frame | |
718 | * %rcx: thread info. Interrupts off. | |
719 | */ | |
720 | retint_with_reschedule: | |
721 | movl $_TIF_WORK_MASK,%edi | |
7effaa88 | 722 | retint_check: |
10cd706d | 723 | LOCKDEP_SYS_EXIT_IRQ |
26ccb8a7 | 724 | movl TI_flags(%rcx),%edx |
1da177e4 | 725 | andl %edi,%edx |
7effaa88 | 726 | CFI_REMEMBER_STATE |
1da177e4 | 727 | jnz retint_careful |
10cd706d PZ |
728 | |
729 | retint_swapgs: /* return to user-space */ | |
2601e64d IM |
730 | /* |
731 | * The iretq could re-enable interrupts: | |
732 | */ | |
72fe4858 | 733 | DISABLE_INTERRUPTS(CLBR_ANY) |
2601e64d | 734 | TRACE_IRQS_IRETQ |
72fe4858 | 735 | SWAPGS |
2601e64d IM |
736 | jmp restore_args |
737 | ||
10cd706d | 738 | retint_restore_args: /* return to kernel space */ |
72fe4858 | 739 | DISABLE_INTERRUPTS(CLBR_ANY) |
2601e64d IM |
740 | /* |
741 | * The iretq could re-enable interrupts: | |
742 | */ | |
743 | TRACE_IRQS_IRETQ | |
744 | restore_args: | |
3701d863 IM |
745 | RESTORE_ARGS 0,8,0 |
746 | ||
f7f3d791 | 747 | irq_return: |
72fe4858 | 748 | INTERRUPT_RETURN |
3701d863 IM |
749 | |
750 | .section __ex_table, "a" | |
751 | .quad irq_return, bad_iret | |
752 | .previous | |
753 | ||
754 | #ifdef CONFIG_PARAVIRT | |
72fe4858 | 755 | ENTRY(native_iret) |
1da177e4 LT |
756 | iretq |
757 | ||
758 | .section __ex_table,"a" | |
72fe4858 | 759 | .quad native_iret, bad_iret |
1da177e4 | 760 | .previous |
3701d863 IM |
761 | #endif |
762 | ||
1da177e4 | 763 | .section .fixup,"ax" |
1da177e4 | 764 | bad_iret: |
3aa4b37d RM |
765 | /* |
766 | * The iret traps when the %cs or %ss being restored is bogus. | |
767 | * We've lost the original trap vector and error code. | |
768 | * #GPF is the most likely one to get for an invalid selector. | |
769 | * So pretend we completed the iret and took the #GPF in user mode. | |
770 | * | |
771 | * We are now running with the kernel GS after exception recovery. | |
772 | * But error_entry expects us to have user GS to match the user %cs, | |
773 | * so swap back. | |
774 | */ | |
775 | pushq $0 | |
776 | ||
777 | SWAPGS | |
778 | jmp general_protection | |
779 | ||
72fe4858 GOC |
780 | .previous |
781 | ||
7effaa88 | 782 | /* edi: workmask, edx: work */ |
1da177e4 | 783 | retint_careful: |
7effaa88 | 784 | CFI_RESTORE_STATE |
1da177e4 LT |
785 | bt $TIF_NEED_RESCHED,%edx |
786 | jnc retint_signal | |
2601e64d | 787 | TRACE_IRQS_ON |
72fe4858 | 788 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 | 789 | pushq %rdi |
7effaa88 | 790 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 LT |
791 | call schedule |
792 | popq %rdi | |
7effaa88 | 793 | CFI_ADJUST_CFA_OFFSET -8 |
1da177e4 | 794 | GET_THREAD_INFO(%rcx) |
72fe4858 | 795 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 796 | TRACE_IRQS_OFF |
1da177e4 LT |
797 | jmp retint_check |
798 | ||
799 | retint_signal: | |
8f4d37ec | 800 | testl $_TIF_DO_NOTIFY_MASK,%edx |
10ffdbb8 | 801 | jz retint_swapgs |
2601e64d | 802 | TRACE_IRQS_ON |
72fe4858 | 803 | ENABLE_INTERRUPTS(CLBR_NONE) |
1da177e4 LT |
804 | SAVE_REST |
805 | movq $-1,ORIG_RAX(%rsp) | |
3829ee6b | 806 | xorl %esi,%esi # oldset |
1da177e4 LT |
807 | movq %rsp,%rdi # &pt_regs |
808 | call do_notify_resume | |
809 | RESTORE_REST | |
72fe4858 | 810 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 811 | TRACE_IRQS_OFF |
be9e6870 | 812 | GET_THREAD_INFO(%rcx) |
eca91e78 | 813 | jmp retint_with_reschedule |
1da177e4 LT |
814 | |
815 | #ifdef CONFIG_PREEMPT | |
816 | /* Returning to kernel space. Check if we need preemption */ | |
817 | /* rcx: threadinfo. interrupts off. */ | |
b06babac | 818 | ENTRY(retint_kernel) |
26ccb8a7 | 819 | cmpl $0,TI_preempt_count(%rcx) |
1da177e4 | 820 | jnz retint_restore_args |
26ccb8a7 | 821 | bt $TIF_NEED_RESCHED,TI_flags(%rcx) |
1da177e4 LT |
822 | jnc retint_restore_args |
823 | bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */ | |
824 | jnc retint_restore_args | |
825 | call preempt_schedule_irq | |
826 | jmp exit_intr | |
827 | #endif | |
4b787e0b | 828 | |
1da177e4 | 829 | CFI_ENDPROC |
4b787e0b | 830 | END(common_interrupt) |
1da177e4 LT |
831 | |
832 | /* | |
833 | * APIC interrupts. | |
834 | */ | |
835 | .macro apicinterrupt num,func | |
7effaa88 | 836 | INTR_FRAME |
19eadf98 | 837 | pushq $~(\num) |
7effaa88 | 838 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 LT |
839 | interrupt \func |
840 | jmp ret_from_intr | |
841 | CFI_ENDPROC | |
842 | .endm | |
843 | ||
844 | ENTRY(thermal_interrupt) | |
845 | apicinterrupt THERMAL_APIC_VECTOR,smp_thermal_interrupt | |
4b787e0b | 846 | END(thermal_interrupt) |
1da177e4 | 847 | |
89b831ef JS |
848 | ENTRY(threshold_interrupt) |
849 | apicinterrupt THRESHOLD_APIC_VECTOR,mce_threshold_interrupt | |
4b787e0b | 850 | END(threshold_interrupt) |
89b831ef | 851 | |
1da177e4 LT |
852 | #ifdef CONFIG_SMP |
853 | ENTRY(reschedule_interrupt) | |
854 | apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt | |
4b787e0b | 855 | END(reschedule_interrupt) |
1da177e4 | 856 | |
e5bc8b6b AK |
857 | .macro INVALIDATE_ENTRY num |
858 | ENTRY(invalidate_interrupt\num) | |
859 | apicinterrupt INVALIDATE_TLB_VECTOR_START+\num,smp_invalidate_interrupt | |
4b787e0b | 860 | END(invalidate_interrupt\num) |
e5bc8b6b AK |
861 | .endm |
862 | ||
863 | INVALIDATE_ENTRY 0 | |
864 | INVALIDATE_ENTRY 1 | |
865 | INVALIDATE_ENTRY 2 | |
866 | INVALIDATE_ENTRY 3 | |
867 | INVALIDATE_ENTRY 4 | |
868 | INVALIDATE_ENTRY 5 | |
869 | INVALIDATE_ENTRY 6 | |
870 | INVALIDATE_ENTRY 7 | |
1da177e4 LT |
871 | |
872 | ENTRY(call_function_interrupt) | |
873 | apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt | |
4b787e0b | 874 | END(call_function_interrupt) |
3b16cf87 JA |
875 | ENTRY(call_function_single_interrupt) |
876 | apicinterrupt CALL_FUNCTION_SINGLE_VECTOR,smp_call_function_single_interrupt | |
877 | END(call_function_single_interrupt) | |
61014292 EB |
878 | ENTRY(irq_move_cleanup_interrupt) |
879 | apicinterrupt IRQ_MOVE_CLEANUP_VECTOR,smp_irq_move_cleanup_interrupt | |
880 | END(irq_move_cleanup_interrupt) | |
1da177e4 LT |
881 | #endif |
882 | ||
1da177e4 LT |
883 | ENTRY(apic_timer_interrupt) |
884 | apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt | |
4b787e0b | 885 | END(apic_timer_interrupt) |
1da177e4 | 886 | |
1812924b CW |
887 | ENTRY(uv_bau_message_intr1) |
888 | apicinterrupt 220,uv_bau_message_interrupt | |
889 | END(uv_bau_message_intr1) | |
890 | ||
1da177e4 LT |
891 | ENTRY(error_interrupt) |
892 | apicinterrupt ERROR_APIC_VECTOR,smp_error_interrupt | |
4b787e0b | 893 | END(error_interrupt) |
1da177e4 LT |
894 | |
895 | ENTRY(spurious_interrupt) | |
896 | apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt | |
4b787e0b | 897 | END(spurious_interrupt) |
1da177e4 LT |
898 | |
899 | /* | |
900 | * Exception entry points. | |
901 | */ | |
902 | .macro zeroentry sym | |
7effaa88 | 903 | INTR_FRAME |
fab58420 | 904 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 | 905 | pushq $0 /* push error code/oldrax */ |
7effaa88 | 906 | CFI_ADJUST_CFA_OFFSET 8 |
1da177e4 | 907 | pushq %rax /* push real oldrax to the rdi slot */ |
7effaa88 | 908 | CFI_ADJUST_CFA_OFFSET 8 |
37550907 | 909 | CFI_REL_OFFSET rax,0 |
1da177e4 LT |
910 | leaq \sym(%rip),%rax |
911 | jmp error_entry | |
7effaa88 | 912 | CFI_ENDPROC |
1da177e4 LT |
913 | .endm |
914 | ||
915 | .macro errorentry sym | |
7effaa88 | 916 | XCPT_FRAME |
fab58420 | 917 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 | 918 | pushq %rax |
7effaa88 | 919 | CFI_ADJUST_CFA_OFFSET 8 |
37550907 | 920 | CFI_REL_OFFSET rax,0 |
1da177e4 LT |
921 | leaq \sym(%rip),%rax |
922 | jmp error_entry | |
7effaa88 | 923 | CFI_ENDPROC |
1da177e4 LT |
924 | .endm |
925 | ||
926 | /* error code is on the stack already */ | |
927 | /* handle NMI like exceptions that can happen everywhere */ | |
2601e64d | 928 | .macro paranoidentry sym, ist=0, irqtrace=1 |
1da177e4 LT |
929 | SAVE_ALL |
930 | cld | |
931 | movl $1,%ebx | |
932 | movl $MSR_GS_BASE,%ecx | |
933 | rdmsr | |
934 | testl %edx,%edx | |
935 | js 1f | |
72fe4858 | 936 | SWAPGS |
1da177e4 | 937 | xorl %ebx,%ebx |
b556b35e JB |
938 | 1: |
939 | .if \ist | |
940 | movq %gs:pda_data_offset, %rbp | |
941 | .endif | |
7e61a793 AH |
942 | .if \irqtrace |
943 | TRACE_IRQS_OFF | |
944 | .endif | |
b556b35e | 945 | movq %rsp,%rdi |
1da177e4 LT |
946 | movq ORIG_RAX(%rsp),%rsi |
947 | movq $-1,ORIG_RAX(%rsp) | |
b556b35e | 948 | .if \ist |
5f8efbb9 | 949 | subq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) |
b556b35e | 950 | .endif |
1da177e4 | 951 | call \sym |
b556b35e | 952 | .if \ist |
5f8efbb9 | 953 | addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) |
b556b35e | 954 | .endif |
72fe4858 | 955 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d IM |
956 | .if \irqtrace |
957 | TRACE_IRQS_OFF | |
958 | .endif | |
1da177e4 | 959 | .endm |
2601e64d IM |
960 | |
961 | /* | |
962 | * "Paranoid" exit path from exception stack. | |
963 | * Paranoid because this is used by NMIs and cannot take | |
964 | * any kernel state for granted. | |
965 | * We don't do kernel preemption checks here, because only | |
966 | * NMI should be common and it does not enable IRQs and | |
967 | * cannot get reschedule ticks. | |
968 | * | |
969 | * "trace" is 0 for the NMI handler only, because irq-tracing | |
970 | * is fundamentally NMI-unsafe. (we cannot change the soft and | |
971 | * hard flags at once, atomically) | |
972 | */ | |
973 | .macro paranoidexit trace=1 | |
974 | /* ebx: no swapgs flag */ | |
975 | paranoid_exit\trace: | |
976 | testl %ebx,%ebx /* swapgs needed? */ | |
977 | jnz paranoid_restore\trace | |
978 | testl $3,CS(%rsp) | |
979 | jnz paranoid_userspace\trace | |
980 | paranoid_swapgs\trace: | |
7a0a2dff | 981 | .if \trace |
2601e64d | 982 | TRACE_IRQS_IRETQ 0 |
7a0a2dff | 983 | .endif |
72fe4858 | 984 | SWAPGS_UNSAFE_STACK |
2601e64d IM |
985 | paranoid_restore\trace: |
986 | RESTORE_ALL 8 | |
3701d863 | 987 | jmp irq_return |
2601e64d IM |
988 | paranoid_userspace\trace: |
989 | GET_THREAD_INFO(%rcx) | |
26ccb8a7 | 990 | movl TI_flags(%rcx),%ebx |
2601e64d IM |
991 | andl $_TIF_WORK_MASK,%ebx |
992 | jz paranoid_swapgs\trace | |
993 | movq %rsp,%rdi /* &pt_regs */ | |
994 | call sync_regs | |
995 | movq %rax,%rsp /* switch stack for scheduling */ | |
996 | testl $_TIF_NEED_RESCHED,%ebx | |
997 | jnz paranoid_schedule\trace | |
998 | movl %ebx,%edx /* arg3: thread flags */ | |
999 | .if \trace | |
1000 | TRACE_IRQS_ON | |
1001 | .endif | |
72fe4858 | 1002 | ENABLE_INTERRUPTS(CLBR_NONE) |
2601e64d IM |
1003 | xorl %esi,%esi /* arg2: oldset */ |
1004 | movq %rsp,%rdi /* arg1: &pt_regs */ | |
1005 | call do_notify_resume | |
72fe4858 | 1006 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d IM |
1007 | .if \trace |
1008 | TRACE_IRQS_OFF | |
1009 | .endif | |
1010 | jmp paranoid_userspace\trace | |
1011 | paranoid_schedule\trace: | |
1012 | .if \trace | |
1013 | TRACE_IRQS_ON | |
1014 | .endif | |
72fe4858 | 1015 | ENABLE_INTERRUPTS(CLBR_ANY) |
2601e64d | 1016 | call schedule |
72fe4858 | 1017 | DISABLE_INTERRUPTS(CLBR_ANY) |
2601e64d IM |
1018 | .if \trace |
1019 | TRACE_IRQS_OFF | |
1020 | .endif | |
1021 | jmp paranoid_userspace\trace | |
1022 | CFI_ENDPROC | |
1023 | .endm | |
1024 | ||
1da177e4 LT |
1025 | /* |
1026 | * Exception entry point. This expects an error code/orig_rax on the stack | |
1027 | * and the exception handler in %rax. | |
1028 | */ | |
d28c4393 | 1029 | KPROBE_ENTRY(error_entry) |
7effaa88 | 1030 | _frame RDI |
37550907 | 1031 | CFI_REL_OFFSET rax,0 |
1da177e4 LT |
1032 | /* rdi slot contains rax, oldrax contains error code */ |
1033 | cld | |
1034 | subq $14*8,%rsp | |
1035 | CFI_ADJUST_CFA_OFFSET (14*8) | |
1036 | movq %rsi,13*8(%rsp) | |
1037 | CFI_REL_OFFSET rsi,RSI | |
1038 | movq 14*8(%rsp),%rsi /* load rax from rdi slot */ | |
37550907 | 1039 | CFI_REGISTER rax,rsi |
1da177e4 LT |
1040 | movq %rdx,12*8(%rsp) |
1041 | CFI_REL_OFFSET rdx,RDX | |
1042 | movq %rcx,11*8(%rsp) | |
1043 | CFI_REL_OFFSET rcx,RCX | |
1044 | movq %rsi,10*8(%rsp) /* store rax */ | |
1045 | CFI_REL_OFFSET rax,RAX | |
1046 | movq %r8, 9*8(%rsp) | |
1047 | CFI_REL_OFFSET r8,R8 | |
1048 | movq %r9, 8*8(%rsp) | |
1049 | CFI_REL_OFFSET r9,R9 | |
1050 | movq %r10,7*8(%rsp) | |
1051 | CFI_REL_OFFSET r10,R10 | |
1052 | movq %r11,6*8(%rsp) | |
1053 | CFI_REL_OFFSET r11,R11 | |
1054 | movq %rbx,5*8(%rsp) | |
1055 | CFI_REL_OFFSET rbx,RBX | |
1056 | movq %rbp,4*8(%rsp) | |
1057 | CFI_REL_OFFSET rbp,RBP | |
1058 | movq %r12,3*8(%rsp) | |
1059 | CFI_REL_OFFSET r12,R12 | |
1060 | movq %r13,2*8(%rsp) | |
1061 | CFI_REL_OFFSET r13,R13 | |
1062 | movq %r14,1*8(%rsp) | |
1063 | CFI_REL_OFFSET r14,R14 | |
1064 | movq %r15,(%rsp) | |
1065 | CFI_REL_OFFSET r15,R15 | |
1066 | xorl %ebx,%ebx | |
1067 | testl $3,CS(%rsp) | |
1068 | je error_kernelspace | |
1069 | error_swapgs: | |
72fe4858 | 1070 | SWAPGS |
6b11d4ef AH |
1071 | error_sti: |
1072 | TRACE_IRQS_OFF | |
1da177e4 | 1073 | movq %rdi,RDI(%rsp) |
37550907 | 1074 | CFI_REL_OFFSET rdi,RDI |
1da177e4 LT |
1075 | movq %rsp,%rdi |
1076 | movq ORIG_RAX(%rsp),%rsi /* get error code */ | |
1077 | movq $-1,ORIG_RAX(%rsp) | |
1078 | call *%rax | |
10cd706d PZ |
1079 | /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */ |
1080 | error_exit: | |
1081 | movl %ebx,%eax | |
1da177e4 | 1082 | RESTORE_REST |
72fe4858 | 1083 | DISABLE_INTERRUPTS(CLBR_NONE) |
2601e64d | 1084 | TRACE_IRQS_OFF |
1da177e4 LT |
1085 | GET_THREAD_INFO(%rcx) |
1086 | testl %eax,%eax | |
1087 | jne retint_kernel | |
10cd706d | 1088 | LOCKDEP_SYS_EXIT_IRQ |
26ccb8a7 | 1089 | movl TI_flags(%rcx),%edx |
1da177e4 LT |
1090 | movl $_TIF_WORK_MASK,%edi |
1091 | andl %edi,%edx | |
1092 | jnz retint_careful | |
10cd706d | 1093 | jmp retint_swapgs |
1da177e4 LT |
1094 | CFI_ENDPROC |
1095 | ||
1096 | error_kernelspace: | |
1097 | incl %ebx | |
1098 | /* There are two places in the kernel that can potentially fault with | |
1099 | usergs. Handle them here. The exception handlers after | |
1100 | iret run with kernel gs again, so don't set the user space flag. | |
1101 | B stepping K8s sometimes report an truncated RIP for IRET | |
1102 | exceptions returning to compat mode. Check for these here too. */ | |
9d8ad5d6 VN |
1103 | leaq irq_return(%rip),%rcx |
1104 | cmpq %rcx,RIP(%rsp) | |
1da177e4 | 1105 | je error_swapgs |
9d8ad5d6 VN |
1106 | movl %ecx,%ecx /* zero extend */ |
1107 | cmpq %rcx,RIP(%rsp) | |
1da177e4 LT |
1108 | je error_swapgs |
1109 | cmpq $gs_change,RIP(%rsp) | |
1110 | je error_swapgs | |
1111 | jmp error_sti | |
d28c4393 | 1112 | KPROBE_END(error_entry) |
1da177e4 LT |
1113 | |
1114 | /* Reload gs selector with exception handling */ | |
1115 | /* edi: new selector */ | |
9f9d489a | 1116 | ENTRY(native_load_gs_index) |
7effaa88 | 1117 | CFI_STARTPROC |
1da177e4 | 1118 | pushf |
7effaa88 | 1119 | CFI_ADJUST_CFA_OFFSET 8 |
72fe4858 GOC |
1120 | DISABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI)) |
1121 | SWAPGS | |
1da177e4 LT |
1122 | gs_change: |
1123 | movl %edi,%gs | |
1124 | 2: mfence /* workaround */ | |
72fe4858 | 1125 | SWAPGS |
1da177e4 | 1126 | popf |
7effaa88 | 1127 | CFI_ADJUST_CFA_OFFSET -8 |
1da177e4 | 1128 | ret |
7effaa88 | 1129 | CFI_ENDPROC |
9f9d489a | 1130 | ENDPROC(native_load_gs_index) |
1da177e4 LT |
1131 | |
1132 | .section __ex_table,"a" | |
1133 | .align 8 | |
1134 | .quad gs_change,bad_gs | |
1135 | .previous | |
1136 | .section .fixup,"ax" | |
1137 | /* running with kernelgs */ | |
1138 | bad_gs: | |
72fe4858 | 1139 | SWAPGS /* switch back to user gs */ |
1da177e4 LT |
1140 | xorl %eax,%eax |
1141 | movl %eax,%gs | |
1142 | jmp 2b | |
1143 | .previous | |
1144 | ||
1145 | /* | |
1146 | * Create a kernel thread. | |
1147 | * | |
1148 | * C extern interface: | |
1149 | * extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) | |
1150 | * | |
1151 | * asm input arguments: | |
1152 | * rdi: fn, rsi: arg, rdx: flags | |
1153 | */ | |
1154 | ENTRY(kernel_thread) | |
1155 | CFI_STARTPROC | |
1156 | FAKE_STACK_FRAME $child_rip | |
1157 | SAVE_ALL | |
1158 | ||
1159 | # rdi: flags, rsi: usp, rdx: will be &pt_regs | |
1160 | movq %rdx,%rdi | |
1161 | orq kernel_thread_flags(%rip),%rdi | |
1162 | movq $-1, %rsi | |
1163 | movq %rsp, %rdx | |
1164 | ||
1165 | xorl %r8d,%r8d | |
1166 | xorl %r9d,%r9d | |
1167 | ||
1168 | # clone now | |
1169 | call do_fork | |
1170 | movq %rax,RAX(%rsp) | |
1171 | xorl %edi,%edi | |
1172 | ||
1173 | /* | |
1174 | * It isn't worth to check for reschedule here, | |
1175 | * so internally to the x86_64 port you can rely on kernel_thread() | |
1176 | * not to reschedule the child before returning, this avoids the need | |
1177 | * of hacks for example to fork off the per-CPU idle tasks. | |
1178 | * [Hopefully no generic code relies on the reschedule -AK] | |
1179 | */ | |
1180 | RESTORE_ALL | |
1181 | UNFAKE_STACK_FRAME | |
1182 | ret | |
1183 | CFI_ENDPROC | |
4b787e0b | 1184 | ENDPROC(kernel_thread) |
1da177e4 LT |
1185 | |
1186 | child_rip: | |
c05991ed AK |
1187 | pushq $0 # fake return address |
1188 | CFI_STARTPROC | |
1da177e4 LT |
1189 | /* |
1190 | * Here we are in the child and the registers are set as they were | |
1191 | * at kernel_thread() invocation in the parent. | |
1192 | */ | |
1193 | movq %rdi, %rax | |
1194 | movq %rsi, %rdi | |
1195 | call *%rax | |
1196 | # exit | |
1c5b5cfd | 1197 | mov %eax, %edi |
1da177e4 | 1198 | call do_exit |
c05991ed | 1199 | CFI_ENDPROC |
4b787e0b | 1200 | ENDPROC(child_rip) |
1da177e4 LT |
1201 | |
1202 | /* | |
1203 | * execve(). This function needs to use IRET, not SYSRET, to set up all state properly. | |
1204 | * | |
1205 | * C extern interface: | |
1206 | * extern long execve(char *name, char **argv, char **envp) | |
1207 | * | |
1208 | * asm input arguments: | |
1209 | * rdi: name, rsi: argv, rdx: envp | |
1210 | * | |
1211 | * We want to fallback into: | |
5d119b2c | 1212 | * extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs *regs) |
1da177e4 LT |
1213 | * |
1214 | * do_sys_execve asm fallback arguments: | |
5d119b2c | 1215 | * rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack |
1da177e4 | 1216 | */ |
3db03b4a | 1217 | ENTRY(kernel_execve) |
1da177e4 LT |
1218 | CFI_STARTPROC |
1219 | FAKE_STACK_FRAME $0 | |
1220 | SAVE_ALL | |
5d119b2c | 1221 | movq %rsp,%rcx |
1da177e4 LT |
1222 | call sys_execve |
1223 | movq %rax, RAX(%rsp) | |
1224 | RESTORE_REST | |
1225 | testq %rax,%rax | |
1226 | je int_ret_from_sys_call | |
1227 | RESTORE_ARGS | |
1228 | UNFAKE_STACK_FRAME | |
1229 | ret | |
1230 | CFI_ENDPROC | |
3db03b4a | 1231 | ENDPROC(kernel_execve) |
1da177e4 | 1232 | |
0f2fbdcb | 1233 | KPROBE_ENTRY(page_fault) |
1da177e4 | 1234 | errorentry do_page_fault |
d28c4393 | 1235 | KPROBE_END(page_fault) |
1da177e4 LT |
1236 | |
1237 | ENTRY(coprocessor_error) | |
1238 | zeroentry do_coprocessor_error | |
4b787e0b | 1239 | END(coprocessor_error) |
1da177e4 LT |
1240 | |
1241 | ENTRY(simd_coprocessor_error) | |
1242 | zeroentry do_simd_coprocessor_error | |
4b787e0b | 1243 | END(simd_coprocessor_error) |
1da177e4 LT |
1244 | |
1245 | ENTRY(device_not_available) | |
1246 | zeroentry math_state_restore | |
4b787e0b | 1247 | END(device_not_available) |
1da177e4 LT |
1248 | |
1249 | /* runs on exception stack */ | |
0f2fbdcb | 1250 | KPROBE_ENTRY(debug) |
7effaa88 | 1251 | INTR_FRAME |
09402947 | 1252 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 LT |
1253 | pushq $0 |
1254 | CFI_ADJUST_CFA_OFFSET 8 | |
5f8efbb9 | 1255 | paranoidentry do_debug, DEBUG_STACK |
2601e64d | 1256 | paranoidexit |
d28c4393 | 1257 | KPROBE_END(debug) |
1da177e4 LT |
1258 | |
1259 | /* runs on exception stack */ | |
eddb6fb9 | 1260 | KPROBE_ENTRY(nmi) |
7effaa88 | 1261 | INTR_FRAME |
09402947 | 1262 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 | 1263 | pushq $-1 |
7effaa88 | 1264 | CFI_ADJUST_CFA_OFFSET 8 |
2601e64d IM |
1265 | paranoidentry do_nmi, 0, 0 |
1266 | #ifdef CONFIG_TRACE_IRQFLAGS | |
1267 | paranoidexit 0 | |
1268 | #else | |
1269 | jmp paranoid_exit1 | |
1270 | CFI_ENDPROC | |
1271 | #endif | |
d28c4393 | 1272 | KPROBE_END(nmi) |
6fefb0d1 | 1273 | |
0f2fbdcb | 1274 | KPROBE_ENTRY(int3) |
b556b35e | 1275 | INTR_FRAME |
09402947 | 1276 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
b556b35e JB |
1277 | pushq $0 |
1278 | CFI_ADJUST_CFA_OFFSET 8 | |
5f8efbb9 | 1279 | paranoidentry do_int3, DEBUG_STACK |
2601e64d | 1280 | jmp paranoid_exit1 |
b556b35e | 1281 | CFI_ENDPROC |
d28c4393 | 1282 | KPROBE_END(int3) |
1da177e4 LT |
1283 | |
1284 | ENTRY(overflow) | |
1285 | zeroentry do_overflow | |
4b787e0b | 1286 | END(overflow) |
1da177e4 LT |
1287 | |
1288 | ENTRY(bounds) | |
1289 | zeroentry do_bounds | |
4b787e0b | 1290 | END(bounds) |
1da177e4 LT |
1291 | |
1292 | ENTRY(invalid_op) | |
1293 | zeroentry do_invalid_op | |
4b787e0b | 1294 | END(invalid_op) |
1da177e4 LT |
1295 | |
1296 | ENTRY(coprocessor_segment_overrun) | |
1297 | zeroentry do_coprocessor_segment_overrun | |
4b787e0b | 1298 | END(coprocessor_segment_overrun) |
1da177e4 | 1299 | |
1da177e4 LT |
1300 | /* runs on exception stack */ |
1301 | ENTRY(double_fault) | |
7effaa88 | 1302 | XCPT_FRAME |
09402947 | 1303 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 | 1304 | paranoidentry do_double_fault |
2601e64d | 1305 | jmp paranoid_exit1 |
1da177e4 | 1306 | CFI_ENDPROC |
4b787e0b | 1307 | END(double_fault) |
1da177e4 LT |
1308 | |
1309 | ENTRY(invalid_TSS) | |
1310 | errorentry do_invalid_TSS | |
4b787e0b | 1311 | END(invalid_TSS) |
1da177e4 LT |
1312 | |
1313 | ENTRY(segment_not_present) | |
1314 | errorentry do_segment_not_present | |
4b787e0b | 1315 | END(segment_not_present) |
1da177e4 LT |
1316 | |
1317 | /* runs on exception stack */ | |
1318 | ENTRY(stack_segment) | |
7effaa88 | 1319 | XCPT_FRAME |
09402947 | 1320 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 | 1321 | paranoidentry do_stack_segment |
2601e64d | 1322 | jmp paranoid_exit1 |
1da177e4 | 1323 | CFI_ENDPROC |
4b787e0b | 1324 | END(stack_segment) |
1da177e4 | 1325 | |
0f2fbdcb | 1326 | KPROBE_ENTRY(general_protection) |
1da177e4 | 1327 | errorentry do_general_protection |
d28c4393 | 1328 | KPROBE_END(general_protection) |
1da177e4 LT |
1329 | |
1330 | ENTRY(alignment_check) | |
1331 | errorentry do_alignment_check | |
4b787e0b | 1332 | END(alignment_check) |
1da177e4 LT |
1333 | |
1334 | ENTRY(divide_error) | |
1335 | zeroentry do_divide_error | |
4b787e0b | 1336 | END(divide_error) |
1da177e4 LT |
1337 | |
1338 | ENTRY(spurious_interrupt_bug) | |
1339 | zeroentry do_spurious_interrupt_bug | |
4b787e0b | 1340 | END(spurious_interrupt_bug) |
1da177e4 LT |
1341 | |
1342 | #ifdef CONFIG_X86_MCE | |
1343 | /* runs on exception stack */ | |
1344 | ENTRY(machine_check) | |
7effaa88 | 1345 | INTR_FRAME |
09402947 | 1346 | PARAVIRT_ADJUST_EXCEPTION_FRAME |
1da177e4 LT |
1347 | pushq $0 |
1348 | CFI_ADJUST_CFA_OFFSET 8 | |
1349 | paranoidentry do_machine_check | |
2601e64d | 1350 | jmp paranoid_exit1 |
1da177e4 | 1351 | CFI_ENDPROC |
4b787e0b | 1352 | END(machine_check) |
1da177e4 LT |
1353 | #endif |
1354 | ||
2699500b | 1355 | /* Call softirq on interrupt stack. Interrupts are off. */ |
ed6b676c | 1356 | ENTRY(call_softirq) |
7effaa88 | 1357 | CFI_STARTPROC |
2699500b AK |
1358 | push %rbp |
1359 | CFI_ADJUST_CFA_OFFSET 8 | |
1360 | CFI_REL_OFFSET rbp,0 | |
1361 | mov %rsp,%rbp | |
1362 | CFI_DEF_CFA_REGISTER rbp | |
ed6b676c | 1363 | incl %gs:pda_irqcount |
2699500b AK |
1364 | cmove %gs:pda_irqstackptr,%rsp |
1365 | push %rbp # backlink for old unwinder | |
ed6b676c | 1366 | call __do_softirq |
2699500b | 1367 | leaveq |
7effaa88 | 1368 | CFI_DEF_CFA_REGISTER rsp |
2699500b | 1369 | CFI_ADJUST_CFA_OFFSET -8 |
ed6b676c | 1370 | decl %gs:pda_irqcount |
ed6b676c | 1371 | ret |
7effaa88 | 1372 | CFI_ENDPROC |
4b787e0b | 1373 | ENDPROC(call_softirq) |
75154f40 AK |
1374 | |
1375 | KPROBE_ENTRY(ignore_sysret) | |
1376 | CFI_STARTPROC | |
1377 | mov $-ENOSYS,%eax | |
1378 | sysret | |
1379 | CFI_ENDPROC | |
1380 | ENDPROC(ignore_sysret) | |
3d75e1b8 JF |
1381 | |
1382 | #ifdef CONFIG_XEN | |
1383 | ENTRY(xen_hypervisor_callback) | |
1384 | zeroentry xen_do_hypervisor_callback | |
1385 | END(xen_hypervisor_callback) | |
1386 | ||
1387 | /* | |
1388 | # A note on the "critical region" in our callback handler. | |
1389 | # We want to avoid stacking callback handlers due to events occurring | |
1390 | # during handling of the last event. To do this, we keep events disabled | |
1391 | # until we've done all processing. HOWEVER, we must enable events before | |
1392 | # popping the stack frame (can't be done atomically) and so it would still | |
1393 | # be possible to get enough handler activations to overflow the stack. | |
1394 | # Although unlikely, bugs of that kind are hard to track down, so we'd | |
1395 | # like to avoid the possibility. | |
1396 | # So, on entry to the handler we detect whether we interrupted an | |
1397 | # existing activation in its critical region -- if so, we pop the current | |
1398 | # activation and restart the handler using the previous one. | |
1399 | */ | |
1400 | ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs) | |
1401 | CFI_STARTPROC | |
1402 | /* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will | |
1403 | see the correct pointer to the pt_regs */ | |
1404 | movq %rdi, %rsp # we don't return, adjust the stack frame | |
1405 | CFI_ENDPROC | |
1406 | CFI_DEFAULT_STACK | |
1407 | 11: incl %gs:pda_irqcount | |
1408 | movq %rsp,%rbp | |
1409 | CFI_DEF_CFA_REGISTER rbp | |
1410 | cmovzq %gs:pda_irqstackptr,%rsp | |
1411 | pushq %rbp # backlink for old unwinder | |
1412 | call xen_evtchn_do_upcall | |
1413 | popq %rsp | |
1414 | CFI_DEF_CFA_REGISTER rsp | |
1415 | decl %gs:pda_irqcount | |
1416 | jmp error_exit | |
1417 | CFI_ENDPROC | |
1418 | END(do_hypervisor_callback) | |
1419 | ||
1420 | /* | |
1421 | # Hypervisor uses this for application faults while it executes. | |
1422 | # We get here for two reasons: | |
1423 | # 1. Fault while reloading DS, ES, FS or GS | |
1424 | # 2. Fault while executing IRET | |
1425 | # Category 1 we do not need to fix up as Xen has already reloaded all segment | |
1426 | # registers that could be reloaded and zeroed the others. | |
1427 | # Category 2 we fix up by killing the current process. We cannot use the | |
1428 | # normal Linux return path in this case because if we use the IRET hypercall | |
1429 | # to pop the stack frame we end up in an infinite loop of failsafe callbacks. | |
1430 | # We distinguish between categories by comparing each saved segment register | |
1431 | # with its current contents: any discrepancy means we in category 1. | |
1432 | */ | |
1433 | ENTRY(xen_failsafe_callback) | |
4a5c3e77 JF |
1434 | framesz = (RIP-0x30) /* workaround buggy gas */ |
1435 | _frame framesz | |
3d75e1b8 JF |
1436 | CFI_REL_OFFSET rcx, 0 |
1437 | CFI_REL_OFFSET r11, 8 | |
1438 | movw %ds,%cx | |
1439 | cmpw %cx,0x10(%rsp) | |
1440 | CFI_REMEMBER_STATE | |
1441 | jne 1f | |
1442 | movw %es,%cx | |
1443 | cmpw %cx,0x18(%rsp) | |
1444 | jne 1f | |
1445 | movw %fs,%cx | |
1446 | cmpw %cx,0x20(%rsp) | |
1447 | jne 1f | |
1448 | movw %gs,%cx | |
1449 | cmpw %cx,0x28(%rsp) | |
1450 | jne 1f | |
1451 | /* All segments match their saved values => Category 2 (Bad IRET). */ | |
1452 | movq (%rsp),%rcx | |
1453 | CFI_RESTORE rcx | |
1454 | movq 8(%rsp),%r11 | |
1455 | CFI_RESTORE r11 | |
1456 | addq $0x30,%rsp | |
1457 | CFI_ADJUST_CFA_OFFSET -0x30 | |
4a5c3e77 JF |
1458 | pushq $0 |
1459 | CFI_ADJUST_CFA_OFFSET 8 | |
1460 | pushq %r11 | |
1461 | CFI_ADJUST_CFA_OFFSET 8 | |
1462 | pushq %rcx | |
1463 | CFI_ADJUST_CFA_OFFSET 8 | |
1464 | jmp general_protection | |
3d75e1b8 JF |
1465 | CFI_RESTORE_STATE |
1466 | 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ | |
1467 | movq (%rsp),%rcx | |
1468 | CFI_RESTORE rcx | |
1469 | movq 8(%rsp),%r11 | |
1470 | CFI_RESTORE r11 | |
1471 | addq $0x30,%rsp | |
1472 | CFI_ADJUST_CFA_OFFSET -0x30 | |
1473 | pushq $0 | |
1474 | CFI_ADJUST_CFA_OFFSET 8 | |
1475 | SAVE_ALL | |
1476 | jmp error_exit | |
1477 | CFI_ENDPROC | |
3d75e1b8 JF |
1478 | END(xen_failsafe_callback) |
1479 | ||
1480 | #endif /* CONFIG_XEN */ |