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-rw-r--r--arch/x86_64/kernel/entry.S63
1 files changed, 39 insertions, 24 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index aa8d893..2802524 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -4,8 +4,6 @@
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
* Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
- *
- * $Id$
*/
/*
@@ -22,15 +20,25 @@
* at the top of the kernel process stack.
* - partial stack frame: partially saved registers upto R11.
* - full stack frame: Like partial stack frame, but all register saved.
- *
- * TODO:
- * - schedule it carefully for the final hardware.
+ *
+ * Some macro usage:
+ * - CFI macros are used to generate dwarf2 unwind information for better
+ * backtraces. They don't change any code.
+ * - SAVE_ALL/RESTORE_ALL - Save/restore all registers
+ * - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify.
+ * There are unfortunately lots of special cases where some registers
+ * not touched. The macro is a big mess that should be cleaned up.
+ * - 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.
+ * - errorentry/paranoidentry/zeroentry - Define exception entry points.
*/
-#define ASSEMBLY 1
#include <linux/linkage.h>
#include <asm/segment.h>
-#include <asm/smp.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/dwarf2.h>
@@ -115,6 +123,7 @@
.macro CFI_DEFAULT_STACK start=1
.if \start
CFI_STARTPROC simple
+ CFI_SIGNAL_FRAME
CFI_DEF_CFA rsp,SS+8
.else
CFI_DEF_CFA_OFFSET SS+8
@@ -146,6 +155,10 @@
/* rdi: prev */
ENTRY(ret_from_fork)
CFI_DEFAULT_STACK
+ push kernel_eflags(%rip)
+ CFI_ADJUST_CFA_OFFSET 4
+ popf # reset kernel eflags
+ CFI_ADJUST_CFA_OFFSET -4
call schedule_tail
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx)
@@ -199,6 +212,7 @@ END(ret_from_fork)
ENTRY(system_call)
CFI_STARTPROC simple
+ CFI_SIGNAL_FRAME
CFI_DEF_CFA rsp,PDA_STACKOFFSET
CFI_REGISTER rip,rcx
/*CFI_REGISTER rflags,r11*/
@@ -316,6 +330,7 @@ END(system_call)
*/
ENTRY(int_ret_from_sys_call)
CFI_STARTPROC simple
+ CFI_SIGNAL_FRAME
CFI_DEF_CFA rsp,SS+8-ARGOFFSET
/*CFI_REL_OFFSET ss,SS-ARGOFFSET*/
CFI_REL_OFFSET rsp,RSP-ARGOFFSET
@@ -476,6 +491,7 @@ END(stub_rt_sigreturn)
*/
.macro _frame ref
CFI_STARTPROC simple
+ CFI_SIGNAL_FRAME
CFI_DEF_CFA rsp,SS+8-\ref
/*CFI_REL_OFFSET ss,SS-\ref*/
CFI_REL_OFFSET rsp,RSP-\ref
@@ -511,7 +527,12 @@ END(stub_rt_sigreturn)
testl $3,CS(%rdi)
je 1f
swapgs
-1: incl %gs:pda_irqcount # RED-PEN should check preempt count
+ /* irqcount is used to check if a CPU is already on an interrupt
+ stack or not. While this is essentially redundant with preempt_count
+ it is a little cheaper to use a separate counter in the PDA
+ (short of moving irq_enter into assembly, which would be too
+ much work) */
+1: incl %gs:pda_irqcount
cmoveq %gs:pda_irqstackptr,%rsp
push %rbp # backlink for old unwinder
/*
@@ -619,8 +640,7 @@ retint_signal:
#ifdef CONFIG_PREEMPT
/* Returning to kernel space. Check if we need preemption */
/* rcx: threadinfo. interrupts off. */
- .p2align
-retint_kernel:
+ENTRY(retint_kernel)
cmpl $0,threadinfo_preempt_count(%rcx)
jnz retint_restore_args
bt $TIF_NEED_RESCHED,threadinfo_flags(%rcx)
@@ -679,7 +699,6 @@ ENTRY(call_function_interrupt)
END(call_function_interrupt)
#endif
-#ifdef CONFIG_X86_LOCAL_APIC
ENTRY(apic_timer_interrupt)
apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt
END(apic_timer_interrupt)
@@ -691,7 +710,6 @@ END(error_interrupt)
ENTRY(spurious_interrupt)
apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt
END(spurious_interrupt)
-#endif
/*
* Exception entry points.
@@ -768,7 +786,9 @@ paranoid_exit\trace:
testl $3,CS(%rsp)
jnz paranoid_userspace\trace
paranoid_swapgs\trace:
+ .if \trace
TRACE_IRQS_IRETQ 0
+ .endif
swapgs
paranoid_restore\trace:
RESTORE_ALL 8
@@ -814,7 +834,7 @@ paranoid_schedule\trace:
* Exception entry point. This expects an error code/orig_rax on the stack
* and the exception handler in %rax.
*/
-ENTRY(error_entry)
+KPROBE_ENTRY(error_entry)
_frame RDI
/* rdi slot contains rax, oldrax contains error code */
cld
@@ -898,7 +918,7 @@ error_kernelspace:
cmpq $gs_change,RIP(%rsp)
je error_swapgs
jmp error_sti
-END(error_entry)
+KPROBE_END(error_entry)
/* Reload gs selector with exception handling */
/* edi: new selector */
@@ -1020,8 +1040,7 @@ ENDPROC(execve)
KPROBE_ENTRY(page_fault)
errorentry do_page_fault
-END(page_fault)
- .previous .text
+KPROBE_END(page_fault)
ENTRY(coprocessor_error)
zeroentry do_coprocessor_error
@@ -1042,8 +1061,7 @@ KPROBE_ENTRY(debug)
CFI_ADJUST_CFA_OFFSET 8
paranoidentry do_debug, DEBUG_STACK
paranoidexit
-END(debug)
- .previous .text
+KPROBE_END(debug)
/* runs on exception stack */
KPROBE_ENTRY(nmi)
@@ -1057,8 +1075,7 @@ KPROBE_ENTRY(nmi)
jmp paranoid_exit1
CFI_ENDPROC
#endif
-END(nmi)
- .previous .text
+KPROBE_END(nmi)
KPROBE_ENTRY(int3)
INTR_FRAME
@@ -1067,8 +1084,7 @@ KPROBE_ENTRY(int3)
paranoidentry do_int3, DEBUG_STACK
jmp paranoid_exit1
CFI_ENDPROC
-END(int3)
- .previous .text
+KPROBE_END(int3)
ENTRY(overflow)
zeroentry do_overflow
@@ -1116,8 +1132,7 @@ END(stack_segment)
KPROBE_ENTRY(general_protection)
errorentry do_general_protection
-END(general_protection)
- .previous .text
+KPROBE_END(general_protection)
ENTRY(alignment_check)
errorentry do_alignment_check
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