* [PATCH 1/3] x86_64: remove KERNEL_STACK_OFFSET from THREAD_INFO macro
2015-01-18 1:17 [PATCH 0/3] x86_64, entry: some cleanup and simplification Alexander van Heukelum
@ 2015-01-18 1:17 ` Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 2/3] x86_64: don't use KERNEL_STACK_OFFSET for syscall and sysenter Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 3/3] x86_64, entry: Create IRET-compatible stack frame at syscall entry Alexander van Heukelum
2 siblings, 0 replies; 4+ messages in thread
From: Alexander van Heukelum @ 2015-01-18 1:17 UTC (permalink / raw)
To: Andy Lutomirski, x86, linux-kernel
Cc: Frederic Weisbecker, Oleg Nesterov, Borislav Petkov, Rik van Riel
In the macro THREAD_INFO(reg,offset), the offset is relative to
KERNEL_STACK_OFFSET. Change the macro and all its uses so that
offset is given as the current top of stack in the pt_regs frame.
The generated code is identical.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/ia32/ia32entry.S | 30 +++++++++++++++---------------
arch/x86/include/asm/calling.h | 1 +
arch/x86/include/asm/thread_info.h | 2 +-
arch/x86/kernel/entry_64.S | 4 ++--
4 files changed, 19 insertions(+), 18 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 156ebca..1c74f39 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -135,7 +135,7 @@ ENTRY(ia32_sysenter_target)
CFI_REL_OFFSET rsp,0
pushfq_cfi
/*CFI_REL_OFFSET rflags,0*/
- movl TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d
+ movl TI_sysenter_return+THREAD_INFO(%rsp,EFLAGS),%r10d
CFI_REGISTER rip,r10
pushq_cfi $__USER32_CS
/*CFI_REL_OFFSET cs,0*/
@@ -161,8 +161,8 @@ ENTRY(ia32_sysenter_target)
jnz sysenter_fix_flags
sysenter_flags_fixed:
- orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
- testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
CFI_REMEMBER_STATE
jnz sysenter_tracesys
cmpq $(IA32_NR_syscalls-1),%rax
@@ -174,10 +174,10 @@ sysenter_dispatch:
movq %rax,RAX-ARGOFFSET(%rsp)
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
- testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz sysexit_audit
sysexit_from_sys_call:
- andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
/* clear IF, that popfq doesn't enable interrupts early */
andl $~0x200,EFLAGS-ARGOFFSET(%rsp)
movl RIP-ARGOFFSET(%rsp),%edx /* User %eip */
@@ -216,7 +216,7 @@ sysexit_from_sys_call:
.endm
.macro auditsys_exit exit
- testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz ia32_ret_from_sys_call
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
@@ -231,7 +231,7 @@ sysexit_from_sys_call:
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
- testl %edi,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl %edi,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jz \exit
CLEAR_RREGS -ARGOFFSET
jmp int_with_check
@@ -253,7 +253,7 @@ sysenter_fix_flags:
sysenter_tracesys:
#ifdef CONFIG_AUDITSYSCALL
- testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jz sysenter_auditsys
#endif
SAVE_REST
@@ -324,8 +324,8 @@ ENTRY(ia32_cstar_target)
1: movl (%r8),%r9d
_ASM_EXTABLE(1b,ia32_badarg)
ASM_CLAC
- orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
- testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
CFI_REMEMBER_STATE
jnz cstar_tracesys
cmpq $IA32_NR_syscalls-1,%rax
@@ -337,10 +337,10 @@ cstar_dispatch:
movq %rax,RAX-ARGOFFSET(%rsp)
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
- testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz sysretl_audit
sysretl_from_sys_call:
- andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
RESTORE_ARGS 0,-ARG_SKIP,0,0,0
movl RIP-ARGOFFSET(%rsp),%ecx
CFI_REGISTER rip,rcx
@@ -368,7 +368,7 @@ sysretl_audit:
cstar_tracesys:
#ifdef CONFIG_AUDITSYSCALL
- testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jz cstar_auditsys
#endif
xchgl %r9d,%ebp
@@ -434,8 +434,8 @@ ENTRY(ia32_syscall)
/* note the registers are not zero extended to the sf.
this could be a problem. */
SAVE_ARGS 0,1,0
- orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
- testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,ARGOFFSET)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz ia32_tracesys
cmpq $(IA32_NR_syscalls-1),%rax
ja ia32_badsys
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index 1f1297b..16ab13d 100644
--- a/arch/x86/include/asm/calling.h
+++ b/arch/x86/include/asm/calling.h
@@ -81,6 +81,7 @@ For 32-bit we have the following conventions - kernel is built with
#define EFLAGS 144
#define RSP 152
#define SS 160
+#define PTREGS_SIZE 168
#define ARGOFFSET R11
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index e82e95a..471037d 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -190,7 +190,7 @@ static inline unsigned long current_stack_pointer(void)
* Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
* a certain register (to be used in assembler memory operands).
*/
-#define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)
+#define THREAD_INFO(reg, off) PTREGS_SIZE-(off)-THREAD_SIZE(reg)
#endif
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index db13655..9f9ca20 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -343,7 +343,7 @@ GLOBAL(system_call_after_swapgs)
movq_cfi rax,(ORIG_RAX-ARGOFFSET)
movq %rcx,RIP-ARGOFFSET(%rsp)
CFI_REL_OFFSET rip,RIP-ARGOFFSET
- testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz tracesys
system_call_fastpath:
#if __SYSCALL_MASK == ~0
@@ -361,7 +361,7 @@ system_call_fastpath:
* Has incomplete stack frame and undefined top of stack.
*/
ret_from_sys_call:
- testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
+ testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz int_ret_from_sys_call_fixup /* Go the the slow path */
LOCKDEP_SYS_EXIT
--
2.1.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/3] x86_64: don't use KERNEL_STACK_OFFSET for syscall and sysenter
2015-01-18 1:17 [PATCH 0/3] x86_64, entry: some cleanup and simplification Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 1/3] x86_64: remove KERNEL_STACK_OFFSET from THREAD_INFO macro Alexander van Heukelum
@ 2015-01-18 1:17 ` Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 3/3] x86_64, entry: Create IRET-compatible stack frame at syscall entry Alexander van Heukelum
2 siblings, 0 replies; 4+ messages in thread
From: Alexander van Heukelum @ 2015-01-18 1:17 UTC (permalink / raw)
To: Andy Lutomirski, x86, linux-kernel
Cc: Frederic Weisbecker, Oleg Nesterov, Borislav Petkov, Rik van Riel
The syscall and sysenter code use KERNEL_STACK_OFFSET to set the
initial stack pointer a bit below the top of the kernel stack page.
Stop doing that.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/ia32/ia32entry.S | 4 ++--
arch/x86/include/asm/thread_info.h | 6 ++----
arch/x86/kernel/cpu/common.c | 2 +-
arch/x86/kernel/entry_64.S | 3 ++-
arch/x86/kernel/process_64.c | 3 +--
arch/x86/kernel/smpboot.c | 3 +--
arch/x86/xen/smp.c | 3 +--
7 files changed, 10 insertions(+), 14 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 1c74f39..93b30a1 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -122,7 +122,6 @@ ENTRY(ia32_sysenter_target)
CFI_REGISTER rsp,rbp
SWAPGS_UNSAFE_STACK
movq PER_CPU_VAR(kernel_stack), %rsp
- addq $(KERNEL_STACK_OFFSET),%rsp
/*
* No need to follow this irqs on/off section: the syscall
* disabled irqs, here we enable it straight after entry:
@@ -292,13 +291,14 @@ ENDPROC(ia32_sysenter_target)
ENTRY(ia32_cstar_target)
CFI_STARTPROC32 simple
CFI_SIGNAL_FRAME
- CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
+ CFI_DEF_CFA rsp,0
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
movq PER_CPU_VAR(kernel_stack),%rsp
+ sub $(PTREGS_SIZE-RIP),%rsp
/*
* No need to follow this irqs on/off section: the syscall
* disabled irqs and here we enable it straight after entry:
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 471037d..2caaaf2 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -149,7 +149,6 @@ struct thread_info {
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
#define STACK_WARN (THREAD_SIZE/8)
-#define KERNEL_STACK_OFFSET (5*(BITS_PER_LONG/8))
/*
* macros/functions for gaining access to the thread information structure
@@ -163,8 +162,7 @@ DECLARE_PER_CPU(unsigned long, kernel_stack);
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- ti = (void *)(this_cpu_read_stable(kernel_stack) +
- KERNEL_STACK_OFFSET - THREAD_SIZE);
+ ti = (void *)(this_cpu_read_stable(kernel_stack) - THREAD_SIZE);
return ti;
}
@@ -184,7 +182,7 @@ static inline unsigned long current_stack_pointer(void)
/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
_ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
- _ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ;
+ _ASM_SUB $THREAD_SIZE,reg ;
/*
* Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c604965..aa76c69 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1116,7 +1116,7 @@ static __init int setup_disablecpuid(char *arg)
__setup("clearcpuid=", setup_disablecpuid);
DEFINE_PER_CPU(unsigned long, kernel_stack) =
- (unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
+ (unsigned long)&init_thread_union + THREAD_SIZE;
EXPORT_PER_CPU_SYMBOL(kernel_stack);
#ifdef CONFIG_X86_64
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 9f9ca20..7adff94 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -321,7 +321,7 @@ END(ret_from_fork)
ENTRY(system_call)
CFI_STARTPROC simple
CFI_SIGNAL_FRAME
- CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
+ CFI_DEF_CFA rsp,0
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
SWAPGS_UNSAFE_STACK
@@ -334,6 +334,7 @@ GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(old_rsp)
movq PER_CPU_VAR(kernel_stack),%rsp
+ sub $(PTREGS_SIZE-RIP),%rsp
/*
* No need to follow this irqs off/on section - it's straight
* and short:
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 5a2c029..0747dbf 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -414,8 +414,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count);
this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) +
- THREAD_SIZE - KERNEL_STACK_OFFSET);
+ (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
/*
* Now maybe reload the debug registers and handle I/O bitmaps
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6d7022c..66fd449 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -776,8 +776,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
initial_gs = per_cpu_offset(cpu);
#endif
per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) -
- KERNEL_STACK_OFFSET + THREAD_SIZE;
+ (unsigned long)task_stack_page(idle) + THREAD_SIZE;
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
initial_code = (unsigned long)start_secondary;
stack_start = idle->thread.sp;
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 4c071ae..4e71a3b 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -452,8 +452,7 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
clear_tsk_thread_flag(idle, TIF_FORK);
#endif
per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) -
- KERNEL_STACK_OFFSET + THREAD_SIZE;
+ (unsigned long)task_stack_page(idle) + THREAD_SIZE;
xen_setup_runstate_info(cpu);
xen_setup_timer(cpu);
--
2.1.0
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 3/3] x86_64, entry: Create IRET-compatible stack frame at syscall entry
2015-01-18 1:17 [PATCH 0/3] x86_64, entry: some cleanup and simplification Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 1/3] x86_64: remove KERNEL_STACK_OFFSET from THREAD_INFO macro Alexander van Heukelum
2015-01-18 1:17 ` [PATCH 2/3] x86_64: don't use KERNEL_STACK_OFFSET for syscall and sysenter Alexander van Heukelum
@ 2015-01-18 1:17 ` Alexander van Heukelum
2 siblings, 0 replies; 4+ messages in thread
From: Alexander van Heukelum @ 2015-01-18 1:17 UTC (permalink / raw)
To: Andy Lutomirski, x86, linux-kernel
Cc: Frederic Weisbecker, Oleg Nesterov, Borislav Petkov, Rik van Riel
Create an IRET-compatible top of stack at syscall entry and use this
information to return to user mode in the sysret path. This removes
the need for the FIXUP_TOP_OF_STACK and RESTORE_TOP_OF_STACK macros.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/kernel/entry_64.S | 77 +++++++++++++---------------------------------
1 file changed, 22 insertions(+), 55 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7adff94..e952839 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -33,8 +33,6 @@
* - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS.
* Gives a full stack frame.
* - ENTRY/END Define functions in the symbol table.
- * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack
- * frame that is otherwise undefined after a SYSCALL
* - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
* - idtentry - Define exception entry points.
*/
@@ -130,33 +128,6 @@ ENDPROC(native_usergs_sysret64)
#endif
/*
- * C code is not supposed to know about undefined top of stack. Every time
- * a C function with an pt_regs argument is called from the SYSCALL based
- * fast path FIXUP_TOP_OF_STACK is needed.
- * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
- * manipulation.
- */
-
- /* %rsp:at FRAMEEND */
- .macro FIXUP_TOP_OF_STACK tmp offset=0
- movq PER_CPU_VAR(old_rsp),\tmp
- movq \tmp,RSP+\offset(%rsp)
- movq $__USER_DS,SS+\offset(%rsp)
- movq $__USER_CS,CS+\offset(%rsp)
- movq RIP+\offset(%rsp),\tmp /* get rip */
- movq \tmp,RCX+\offset(%rsp) /* copy it to rcx as sysret would do */
- movq R11+\offset(%rsp),\tmp /* get eflags */
- movq \tmp,EFLAGS+\offset(%rsp)
- .endm
-
- .macro RESTORE_TOP_OF_STACK tmp offset=0
- movq RSP+\offset(%rsp),\tmp
- movq \tmp,PER_CPU_VAR(old_rsp)
- movq EFLAGS+\offset(%rsp),\tmp
- movq \tmp,R11+\offset(%rsp)
- .endm
-
-/*
* initial frame state for interrupts (and exceptions without error code)
*/
.macro EMPTY_FRAME start=1 offset=0
@@ -272,7 +243,6 @@ ENTRY(ret_from_fork)
testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
jnz int_ret_from_sys_call
- RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
jmp ret_from_sys_call # go to the SYSRET fastpath
1:
@@ -334,16 +304,30 @@ GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(old_rsp)
movq PER_CPU_VAR(kernel_stack),%rsp
- sub $(PTREGS_SIZE-RIP),%rsp
/*
* No need to follow this irqs off/on section - it's straight
* and short:
*/
ENABLE_INTERRUPTS(CLBR_NONE)
- SAVE_ARGS 8, 0, rax_enosys=1
+
+ /*
+ * Save user mode rsp (temporarily saved above in old_rsp),
+ * rflags (%r11), rip (%rcx) and segments (fixed values) on
+ * the stack as a regular interrupt frame.
+ */
+ pushq_cfi $__USER_DS
+ /* CFI_REL_OFFSET ss, 0 */
+ pushq_cfi PER_CPU_VAR(old_rsp)
+ CFI_REL_OFFSET rsp, 0
+ pushq_cfi %r11 /* %r11 clobbered (userspace %rflags) */
+ /* CFI_REL_OFFSET rflags, 0 */
+ pushq_cfi $__USER_CS
+ /* CFI_REL_OFFSET cs, 0 */
+ pushq_cfi %rcx /* %rcx clobbered (userspace %rip) */
+ CFI_REL_OFFSET rip, 0
+
+ SAVE_ARGS 8, rax_enosys=1
movq_cfi rax,(ORIG_RAX-ARGOFFSET)
- movq %rcx,RIP-ARGOFFSET(%rsp)
- CFI_REL_OFFSET rip,RIP-ARGOFFSET
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
jnz tracesys
system_call_fastpath:
@@ -363,7 +347,7 @@ system_call_fastpath:
*/
ret_from_sys_call:
testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,ARGOFFSET)
- jnz int_ret_from_sys_call_fixup /* Go the the slow path */
+ jnz int_ret_from_sys_call /* Go the the slow path */
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_NONE)
@@ -373,19 +357,16 @@ ret_from_sys_call:
* sysretq will re-enable interrupts:
*/
TRACE_IRQS_ON
+ RESTORE_ARGS addskip=-ARG_SKIP, rstor_rcx=0, rstor_r11=0
movq RIP-ARGOFFSET(%rsp),%rcx
CFI_REGISTER rip,rcx
- RESTORE_ARGS 1,-ARG_SKIP,0
+ mov EFLAGS-ARGOFFSET(%rsp), %r11
/*CFI_REGISTER rflags,r11*/
- movq PER_CPU_VAR(old_rsp), %rsp
+ mov RSP-ARGOFFSET(%rsp), %rsp
USERGS_SYSRET64
CFI_RESTORE_STATE
-int_ret_from_sys_call_fixup:
- FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
- jmp int_ret_from_sys_call
-
/* Do syscall tracing */
tracesys:
leaq -REST_SKIP(%rsp), %rdi
@@ -398,7 +379,6 @@ tracesys:
tracesys_phase2:
SAVE_REST
- FIXUP_TOP_OF_STACK %rdi
movq %rsp, %rdi
movq $AUDIT_ARCH_X86_64, %rsi
movq %rax,%rdx
@@ -494,10 +474,8 @@ ENTRY(stub_\func)
PARTIAL_FRAME 0
SAVE_REST
pushq %r11 /* put it back on stack */
- FIXUP_TOP_OF_STACK %r11, 8
DEFAULT_FRAME 0 8 /* offset 8: return address */
call sys_\func
- RESTORE_TOP_OF_STACK %r11, 8
ret $REST_SKIP /* pop extended registers */
CFI_ENDPROC
END(stub_\func)
@@ -507,9 +485,7 @@ END(stub_\func)
ENTRY(\label)
CFI_STARTPROC
PARTIAL_FRAME 0 8 /* offset 8: return address */
- FIXUP_TOP_OF_STACK %r11, 8-ARGOFFSET
call \func
- RESTORE_TOP_OF_STACK %r11, 8-ARGOFFSET
ret
CFI_ENDPROC
END(\label)
@@ -525,7 +501,6 @@ ENTRY(stub_execve)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call sys_execve
movq %rax,RAX(%rsp)
RESTORE_REST
@@ -538,9 +513,7 @@ ENTRY(stub_execveat)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call sys_execveat
- RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
@@ -556,7 +529,6 @@ ENTRY(stub_rt_sigreturn)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call sys_rt_sigreturn
movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
RESTORE_REST
@@ -570,7 +542,6 @@ ENTRY(stub_x32_rt_sigreturn)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call sys32_x32_rt_sigreturn
movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
RESTORE_REST
@@ -583,9 +554,7 @@ ENTRY(stub_x32_execve)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call compat_sys_execve
- RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
@@ -597,9 +566,7 @@ ENTRY(stub_x32_execveat)
addq $8, %rsp
PARTIAL_FRAME 0
SAVE_REST
- FIXUP_TOP_OF_STACK %r11
call compat_sys_execveat
- RESTORE_TOP_OF_STACK %r11
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
--
2.1.0
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