Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ee08c6bd authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/entry/64/compat: Migrate the body of the syscall entry to C 



Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
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
Link: http://lkml.kernel.org/r/a2f0fce68feeba798a24339b5a7ec1ec2dd9eaf7.1444091585.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent bd2d3a3b

arch/x86/entry/entry_64.S

+1 −1
Original line number Original line Diff line number Diff line
@@ -582,7 +582,7 @@ retint_kernel: 
 * At this label, code paths which return to kernel and to user,

 * At this label, code paths which return to kernel and to user,

 * which come from interrupts/exception and from syscalls, merge.

 * which come from interrupts/exception and from syscalls, merge.

 */

 */

restore_regs_and_iret:

GLOBAL(restore_regs_and_iret)

	RESTORE_EXTRA_REGS

	RESTORE_EXTRA_REGS

restore_c_regs_and_iret:

restore_c_regs_and_iret:

	RESTORE_C_REGS

	RESTORE_C_REGS

arch/x86/entry/entry_64_compat.S

+18 −38
Original line number Original line Diff line number Diff line
@@ -202,14 +202,17 @@ END(entry_SYSCALL_compat) 
ENTRY(entry_INT80_compat)

ENTRY(entry_INT80_compat)

	/*

	/*

	 * Interrupts are off on entry.

	 * Interrupts are off on entry.

	 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,

	 * it is too small to ever cause noticeable irq latency.

	 */

	 */

	PARAVIRT_ADJUST_EXCEPTION_FRAME

	PARAVIRT_ADJUST_EXCEPTION_FRAME

	SWAPGS

	SWAPGS

	ENABLE_INTERRUPTS(CLBR_NONE)





	/* Zero-extending 32-bit regs, do not remove */

	/*

	 * User tracing code (ptrace or signal handlers) might assume that

	 * the saved RAX contains a 32-bit number when we're invoking a 32-bit

	 * syscall.  Just in case the high bits are nonzero, zero-extend

	 * the syscall number.  (This could almost certainly be deleted

	 * with no ill effects.)

	 */

	movl	%eax, %eax

	movl	%eax, %eax





	/* Construct struct pt_regs on stack (iret frame is already on stack) */

	/* Construct struct pt_regs on stack (iret frame is already on stack) */
@@ -232,42 +235,19 @@ ENTRY(entry_INT80_compat) 
	pushq   %r15                    /* pt_regs->r15 */

	pushq   %r15                    /* pt_regs->r15 */

	cld

	cld





	orl	$TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)

	testl	$_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)

	jnz	ia32_tracesys



ia32_do_call:

	/* 32-bit syscall -> 64-bit C ABI argument conversion */

	movl	%edi, %r8d		/* arg5 */

	movl	%ebp, %r9d		/* arg6 */

	xchg	%ecx, %esi		/* rsi:arg2, rcx:arg4 */

	movl	%ebx, %edi		/* arg1 */

	movl	%edx, %edx		/* arg3 (zero extension) */

	cmpq	$(IA32_NR_syscalls-1), %rax

	ja	1f



	call	*ia32_sys_call_table(, %rax, 8)

	movq	%rax, RAX(%rsp)

1:

	RESTORE_EXTRA_REGS

	jmp	int_ret_from_sys_call



ia32_tracesys:

	movq	%rsp, %rdi			/* &pt_regs -> arg1 */

	call	syscall_trace_enter

	/*

	/*

	 * Reload arg registers from stack in case ptrace changed them.

	 * User mode is traced as though IRQs are on, and the interrupt

	 * Don't reload %eax because syscall_trace_enter() returned

	 * gate turned them off.

	 * the %rax value we should see.  But do truncate it to 32 bits.

	 * If it's -1 to make us punt the syscall, then (u32)-1 is still

	 * an appropriately invalid value.

	 */

	 */

	movl	RCX(%rsp), %ecx

	TRACE_IRQS_OFF

	movl	RDX(%rsp), %edx



	movl	RSI(%rsp), %esi

	movq	%rsp, %rdi

	movl	RDI(%rsp), %edi

	call	do_int80_syscall_32

	movl	%eax, %eax		/* zero extension */



	jmp	ia32_do_call

	/* Go back to user mode. */

	TRACE_IRQS_ON

	SWAPGS

	jmp	restore_regs_and_iret

END(entry_INT80_compat)

END(entry_INT80_compat)





	ALIGN

	ALIGN