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authorRoland McGrath <roland@redhat.com>2008-06-24 04:13:31 -0400
committerRoland McGrath <roland@redhat.com>2008-07-23 20:55:22 -0400
commit5cbf1565f29eb57a86a305b08836613508e294d7 (patch)
tree70806175e0868b543860d7d123cceb230d5d5e71 /arch
parent86a1c34a929f30fde8ad01ea8245df61ddcf58b7 (diff)
x86_64 ia32 syscall audit fast-path
This adds fast paths for 32-bit syscall entry and exit when TIF_SYSCALL_AUDIT is set, but no other kind of syscall tracing. These paths does not need to save and restore all registers as the general case of tracing does. Avoiding the iret return path when syscall audit is enabled helps performance a lot. Signed-off-by: Roland McGrath <roland@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/ia32/ia32entry.S91
-rw-r--r--arch/x86/kernel/entry_64.S1
2 files changed, 88 insertions, 4 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 23d146ce676b..021d71bc69b5 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -15,6 +15,16 @@
15#include <asm/irqflags.h> 15#include <asm/irqflags.h>
16#include <linux/linkage.h> 16#include <linux/linkage.h>
17 17
18/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
19#include <linux/elf-em.h>
20#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
21#define __AUDIT_ARCH_LE 0x40000000
22
23#ifndef CONFIG_AUDITSYSCALL
24#define sysexit_audit int_ret_from_sys_call
25#define sysretl_audit int_ret_from_sys_call
26#endif
27
18#define IA32_NR_syscalls ((ia32_syscall_end - ia32_sys_call_table)/8) 28#define IA32_NR_syscalls ((ia32_syscall_end - ia32_sys_call_table)/8)
19 29
20 .macro IA32_ARG_FIXUP noebp=0 30 .macro IA32_ARG_FIXUP noebp=0
@@ -148,13 +158,15 @@ ENTRY(ia32_sysenter_target)
148 ja ia32_badsys 158 ja ia32_badsys
149sysenter_do_call: 159sysenter_do_call:
150 IA32_ARG_FIXUP 1 160 IA32_ARG_FIXUP 1
161sysenter_dispatch:
151 call *ia32_sys_call_table(,%rax,8) 162 call *ia32_sys_call_table(,%rax,8)
152 movq %rax,RAX-ARGOFFSET(%rsp) 163 movq %rax,RAX-ARGOFFSET(%rsp)
153 GET_THREAD_INFO(%r10) 164 GET_THREAD_INFO(%r10)
154 DISABLE_INTERRUPTS(CLBR_NONE) 165 DISABLE_INTERRUPTS(CLBR_NONE)
155 TRACE_IRQS_OFF 166 TRACE_IRQS_OFF
156 testl $_TIF_ALLWORK_MASK,TI_flags(%r10) 167 testl $_TIF_ALLWORK_MASK,TI_flags(%r10)
157 jnz int_ret_from_sys_call 168 jnz sysexit_audit
169sysexit_from_sys_call:
158 andl $~TS_COMPAT,TI_status(%r10) 170 andl $~TS_COMPAT,TI_status(%r10)
159 /* clear IF, that popfq doesn't enable interrupts early */ 171 /* clear IF, that popfq doesn't enable interrupts early */
160 andl $~0x200,EFLAGS-R11(%rsp) 172 andl $~0x200,EFLAGS-R11(%rsp)
@@ -170,9 +182,63 @@ sysenter_do_call:
170 TRACE_IRQS_ON 182 TRACE_IRQS_ON
171 ENABLE_INTERRUPTS_SYSEXIT32 183 ENABLE_INTERRUPTS_SYSEXIT32
172 184
173sysenter_tracesys: 185#ifdef CONFIG_AUDITSYSCALL
186 .macro auditsys_entry_common
187 movl %esi,%r9d /* 6th arg: 4th syscall arg */
188 movl %edx,%r8d /* 5th arg: 3rd syscall arg */
189 /* (already in %ecx) 4th arg: 2nd syscall arg */
190 movl %ebx,%edx /* 3rd arg: 1st syscall arg */
191 movl %eax,%esi /* 2nd arg: syscall number */
192 movl $AUDIT_ARCH_I386,%edi /* 1st arg: audit arch */
193 call audit_syscall_entry
194 movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall number */
195 cmpl $(IA32_NR_syscalls-1),%eax
196 ja ia32_badsys
197 movl %ebx,%edi /* reload 1st syscall arg */
198 movl RCX-ARGOFFSET(%rsp),%esi /* reload 2nd syscall arg */
199 movl RDX-ARGOFFSET(%rsp),%edx /* reload 3rd syscall arg */
200 movl RSI-ARGOFFSET(%rsp),%ecx /* reload 4th syscall arg */
201 movl RDI-ARGOFFSET(%rsp),%r8d /* reload 5th syscall arg */
202 .endm
203
204 .macro auditsys_exit exit
205 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
206 jnz int_ret_from_sys_call
207 TRACE_IRQS_ON
208 sti
209 movl %eax,%esi /* second arg, syscall return value */
210 cmpl $0,%eax /* is it < 0? */
211 setl %al /* 1 if so, 0 if not */
212 movzbl %al,%edi /* zero-extend that into %edi */
213 inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
214 call audit_syscall_exit
215 GET_THREAD_INFO(%r10)
216 movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall return value */
217 movl RBP-ARGOFFSET(%rsp),%ebp /* reload user register value */
218 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
219 cli
220 TRACE_IRQS_OFF
221 testl %edi,TI_flags(%r10)
222 jnz int_with_check
223 jmp \exit
224 .endm
225
226sysenter_auditsys:
174 CFI_RESTORE_STATE 227 CFI_RESTORE_STATE
228 auditsys_entry_common
229 movl %ebp,%r9d /* reload 6th syscall arg */
230 jmp sysenter_dispatch
231
232sysexit_audit:
233 auditsys_exit sysexit_from_sys_call
234#endif
235
236sysenter_tracesys:
175 xchgl %r9d,%ebp 237 xchgl %r9d,%ebp
238#ifdef CONFIG_AUDITSYSCALL
239 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
240 jz sysenter_auditsys
241#endif
176 SAVE_REST 242 SAVE_REST
177 CLEAR_RREGS 243 CLEAR_RREGS
178 movq %r9,R9(%rsp) 244 movq %r9,R9(%rsp)
@@ -252,13 +318,15 @@ cstar_do_call:
252 cmpl $IA32_NR_syscalls-1,%eax 318 cmpl $IA32_NR_syscalls-1,%eax
253 ja ia32_badsys 319 ja ia32_badsys
254 IA32_ARG_FIXUP 1 320 IA32_ARG_FIXUP 1
321cstar_dispatch:
255 call *ia32_sys_call_table(,%rax,8) 322 call *ia32_sys_call_table(,%rax,8)
256 movq %rax,RAX-ARGOFFSET(%rsp) 323 movq %rax,RAX-ARGOFFSET(%rsp)
257 GET_THREAD_INFO(%r10) 324 GET_THREAD_INFO(%r10)
258 DISABLE_INTERRUPTS(CLBR_NONE) 325 DISABLE_INTERRUPTS(CLBR_NONE)
259 TRACE_IRQS_OFF 326 TRACE_IRQS_OFF
260 testl $_TIF_ALLWORK_MASK,TI_flags(%r10) 327 testl $_TIF_ALLWORK_MASK,TI_flags(%r10)
261 jnz int_ret_from_sys_call 328 jnz sysretl_audit
329sysretl_from_sys_call:
262 andl $~TS_COMPAT,TI_status(%r10) 330 andl $~TS_COMPAT,TI_status(%r10)
263 RESTORE_ARGS 1,-ARG_SKIP,1,1,1 331 RESTORE_ARGS 1,-ARG_SKIP,1,1,1
264 movl RIP-ARGOFFSET(%rsp),%ecx 332 movl RIP-ARGOFFSET(%rsp),%ecx
@@ -270,8 +338,23 @@ cstar_do_call:
270 CFI_RESTORE rsp 338 CFI_RESTORE rsp
271 USERGS_SYSRET32 339 USERGS_SYSRET32
272 340
273cstar_tracesys: 341#ifdef CONFIG_AUDITSYSCALL
342cstar_auditsys:
274 CFI_RESTORE_STATE 343 CFI_RESTORE_STATE
344 movl %r9d,R9-ARGOFFSET(%rsp) /* register to be clobbered by call */
345 auditsys_entry_common
346 movl R9-ARGOFFSET(%rsp),%r9d /* reload 6th syscall arg */
347 jmp cstar_dispatch
348
349sysretl_audit:
350 auditsys_exit sysretl_from_sys_call
351#endif
352
353cstar_tracesys:
354#ifdef CONFIG_AUDITSYSCALL
355 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
356 jz cstar_auditsys
357#endif
275 xchgl %r9d,%ebp 358 xchgl %r9d,%ebp
276 SAVE_REST 359 SAVE_REST
277 CLEAR_RREGS 360 CLEAR_RREGS
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index db7d34a89d2e..89434d439605 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -492,6 +492,7 @@ tracesys:
492 * Has correct top of stack, but partial stack frame. 492 * Has correct top of stack, but partial stack frame.
493 */ 493 */
494 .globl int_ret_from_sys_call 494 .globl int_ret_from_sys_call
495 .globl int_with_check
495int_ret_from_sys_call: 496int_ret_from_sys_call:
496 DISABLE_INTERRUPTS(CLBR_NONE) 497 DISABLE_INTERRUPTS(CLBR_NONE)
497 TRACE_IRQS_OFF 498 TRACE_IRQS_OFF