Remove __end_entry_SYSENTER_compat?

From: Borislav Petkov
Date: Wed Jul 12 2017 - 00:13:44 EST


Anyone think this is an OK-ish idea?

It saves us the global symbol but requires the two functions to remained
glued together. :-\

---
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index e1721dafbcb1..262519da8661 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -131,7 +131,6 @@ ENTRY(entry_SYSENTER_compat)
pushq $X86_EFLAGS_FIXED
popfq
jmp .Lsysenter_flags_fixed
-GLOBAL(__end_entry_SYSENTER_compat)
ENDPROC(entry_SYSENTER_compat)

/*
@@ -180,6 +179,9 @@ ENDPROC(entry_SYSENTER_compat)
* edi arg5
* esp user stack
* 0(%esp) arg6
+ *
+ * DO NOT! move this function and the above before adjusting
+ * is_sysenter_singlestep().
*/
ENTRY(entry_SYSCALL_compat)
/* Interrupts are off on entry. */
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 8d3964fc5f91..afdef9f3f0f0 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -21,7 +21,6 @@ void __end_SYSENTER_singlestep_region(void);

#ifdef CONFIG_IA32_EMULATION
void entry_SYSENTER_compat(void);
-void __end_entry_SYSENTER_compat(void);
void entry_SYSCALL_compat(void);
void entry_INT80_compat(void);
#endif
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index bf54309b85da..143902ffe9ff 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -668,7 +668,7 @@ static bool is_sysenter_singlestep(struct pt_regs *regs)
(unsigned long)__begin_SYSENTER_singlestep_region;
#elif defined(CONFIG_IA32_EMULATION)
return (regs->ip - (unsigned long)entry_SYSENTER_compat) <
- (unsigned long)__end_entry_SYSENTER_compat -
+ (unsigned long)entry_SYSCALL_compat -
(unsigned long)entry_SYSENTER_compat;
#else
return false;

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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