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x86/asm/entry: Untangle 'system_call' into two entry points: entry_SYSCALL_64 and entry_INT80_32

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The 'system_call' entry points differ starkly between native 32-bit and 64-bit
kernels: on 32-bit kernels it defines the INT 0x80 entry point, while on
64-bit it's the SYSCALL entry point.

This is pretty confusing when looking at generic code, and it also obscures
the nature of the entry point at the assembly level.

So unangle this by splitting the name into its two uses:

	system_call (32) -> entry_INT80_32
	system_call (64) -> entry_SYSCALL_64

As per the generic naming scheme for x86 system call entry points:

	entry_MNEMONIC_qualifier

where 'qualifier' is one of _32, _64 or _compat.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-06-08 08:42:03 +02:00
parent 4c8cd0c50d
commit b2502b418e
6 changed files with 14 additions and 14 deletions
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4
arch/x86/entry/entry_32.S
View File

@ -415,7 +415,7 @@ sysexit_audit:
ENDPROC(entry_SYSENTER_32)
# system call handler stub
ENTRY(system_call)
ENTRY(entry_INT80_32)
ASM_CLAC
pushl %eax # save orig_eax
SAVE_ALL
@ -508,7 +508,7 @@ ldt_ss:
lss (%esp), %esp /* switch to espfix segment */
jmp restore_nocheck
#endif
ENDPROC(system_call)
ENDPROC(entry_INT80_32)
# perform work that needs to be done immediately before resumption
ALIGN

10
arch/x86/entry/entry_64.S
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@ -137,7 +137,7 @@ ENDPROC(native_usergs_sysret64)
* with them due to bugs in both AMD and Intel CPUs.
*/
ENTRY(system_call)
ENTRY(entry_SYSCALL_64)
/*
* Interrupts are off on entry.
* We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
@ -149,7 +149,7 @@ ENTRY(system_call)
* after the swapgs, so that it can do the swapgs
* for the guest and jump here on syscall.
*/
GLOBAL(system_call_after_swapgs)
GLOBAL(entry_SYSCALL_64_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
@ -182,7 +182,7 @@ GLOBAL(system_call_after_swapgs)
testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jnz tracesys
system_call_fastpath:
entry_SYSCALL_64_fastpath:
#if __SYSCALL_MASK == ~0
cmpq $__NR_syscall_max,%rax
#else
@ -246,7 +246,7 @@ tracesys:
jnz tracesys_phase2 /* if needed, run the slow path */
RESTORE_C_REGS_EXCEPT_RAX /* else restore clobbered regs */
movq ORIG_RAX(%rsp), %rax
jmp system_call_fastpath /* and return to the fast path */
jmp entry_SYSCALL_64_fastpath /* and return to the fast path */
tracesys_phase2:
SAVE_EXTRA_REGS
@ -411,7 +411,7 @@ syscall_return_via_sysret:
opportunistic_sysret_failed:
SWAPGS
jmp restore_c_regs_and_iret
END(system_call)
END(entry_SYSCALL_64)
.macro FORK_LIKE func

5
arch/x86/include/asm/proto.h
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@ -5,11 +5,12 @@
/* misc architecture specific prototypes */
void system_call(void);
void syscall_init(void);
void entry_INT80_compat(void);
void entry_SYSCALL_64(void);
void entry_SYSCALL_compat(void);
void entry_INT80_32(void);
void entry_INT80_compat(void);
void entry_SYSENTER_32(void);
void entry_SYSENTER_compat(void);

2
arch/x86/kernel/cpu/common.c
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@ -1204,7 +1204,7 @@ void syscall_init(void)
* set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
*/
wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32);
wrmsrl(MSR_LSTAR, system_call);
wrmsrl(MSR_LSTAR, entry_SYSCALL_64);
#ifdef CONFIG_IA32_EMULATION
wrmsrl(MSR_CSTAR, entry_SYSCALL_compat);

5
arch/x86/kernel/traps.c
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@ -72,8 +72,7 @@ gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
#else
#include <asm/processor-flags.h>
#include <asm/setup.h>
asmlinkage int system_call(void);
#include <asm/proto.h>
#endif
/* Must be page-aligned because the real IDT is used in a fixmap. */
@ -997,7 +996,7 @@ void __init trap_init(void)
#endif
#ifdef CONFIG_X86_32
set_system_trap_gate(IA32_SYSCALL_VECTOR, &system_call);
set_system_trap_gate(IA32_SYSCALL_VECTOR, entry_INT80_32);
set_bit(IA32_SYSCALL_VECTOR, used_vectors);
#endif

2
arch/x86/xen/xen-asm_64.S
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@ -114,7 +114,7 @@ RELOC(xen_sysret32, 1b+1)
/* Normal 64-bit system call target */
ENTRY(xen_syscall_target)
undo_xen_syscall
jmp system_call_after_swapgs
jmp entry_SYSCALL_64_after_swapgs
ENDPROC(xen_syscall_target)
#ifdef CONFIG_IA32_EMULATION