Differential D17257 Diff 48279 head/sys/amd64/amd64/support.S

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head/sys/amd64/amd64/support.S

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* Access user memory from inside the kernel. These routines should be		* Access user memory from inside the kernel. These routines should be
* the only places that do this.		* the only places that do this.
*		*
* These routines set curpcb->pcb_onfault for the time they execute. When a		* These routines set curpcb->pcb_onfault for the time they execute. When a
* protection violation occurs inside the functions, the trap handler		* protection violation occurs inside the functions, the trap handler
* returns to *curpcb->pcb_onfault instead of the function.		* returns to *curpcb->pcb_onfault instead of the function.
*/		*/

		.macro SMAP_DISABLE smap
		.if \smap
		stac
		.endif
		.endmacro


		.macro SMAP_ENABLE smap
		.if \smap
		clac
		.endif
		.endmacro

/*		/*
* copyout(from_kernel, to_user, len)		* copyout(from_kernel, to_user, len)
* %rdi, %rsi, %rdx		* %rdi, %rsi, %rdx
*/		*/
ENTRY(copyout_nosmap)		.macro COPYOUT smap erms
PUSH_FRAME_POINTER		PUSH_FRAME_POINTER
movq PCPU(CURPCB),%rax		movq PCPU(CURPCB),%rax
movq $copyout_fault,PCB_ONFAULT(%rax)
testq %rdx,%rdx /* anything to do? */
jz done_copyout

/*
* Check explicitly for non-user addresses. This check is essential
* because it prevents usermode from writing into the kernel. We do
* not verify anywhere else that the user did not specify a rogue
* address.
*/
/*
* First, prevent address wrapping.
*/
movq %rsi,%rax
addq %rdx,%rax
jc copyout_fault
/*
* XXX STOP USING VM_MAXUSER_ADDRESS.
* It is an end address, not a max, so every time it is used correctly it
* looks like there is an off by one error, and of course it caused an off
* by one error in several places.
*/
movq $VM_MAXUSER_ADDRESS,%rcx
cmpq %rcx,%rax
ja copyout_fault

xchgq %rdi,%rsi
/* bcopy(%rsi, %rdi, %rdx) */
movq %rdx,%rcx

shrq $3,%rcx
rep
movsq
movb %dl,%cl
andb $7,%cl
je done_copyout
rep
movsb

jmp done_copyout
END(copyout_nosmap)

ENTRY(copyout_smap)
PUSH_FRAME_POINTER
movq PCPU(CURPCB),%rax
/* Trap entry clears PSL.AC */		/* Trap entry clears PSL.AC */
movq $copyout_fault,PCB_ONFAULT(%rax)		movq $copyout_fault,PCB_ONFAULT(%rax)
testq %rdx,%rdx /* anything to do? */		testq %rdx,%rdx /* anything to do? */
jz done_copyout		jz 2f

/*		/*
* Check explicitly for non-user addresses. If 486 write protection		* Check explicitly for non-user addresses. If 486 write protection
* is being used, this check is essential because we are in kernel		* is being used, this check is essential because we are in kernel
* mode so the h/w does not provide any protection against writing		* mode so the h/w does not provide any protection against writing
* kernel addresses.		* kernel addresses.
*/		*/

Show All 12 Lines	*/
movq $VM_MAXUSER_ADDRESS,%rcx		movq $VM_MAXUSER_ADDRESS,%rcx
cmpq %rcx,%rax		cmpq %rcx,%rax
ja copyout_fault		ja copyout_fault

xchgq %rdi,%rsi		xchgq %rdi,%rsi
/* bcopy(%rsi, %rdi, %rdx) */		/* bcopy(%rsi, %rdi, %rdx) */
movq %rdx,%rcx		movq %rdx,%rcx

		SMAP_DISABLE \smap
		.if \erms == 0
shrq $3,%rcx		shrq $3,%rcx
stac
rep		rep
movsq		movsq
movb %dl,%cl		movb %dl,%cl
andb $7,%cl		andb $7,%cl
je 1f		je 1f
		.endif
rep		rep
movsb		movsb
1: clac		1:
		SMAP_ENABLE \smap
done_copyout:		2:
xorl %eax,%eax		xorl %eax,%eax
movq PCPU(CURPCB),%rdx		movq PCPU(CURPCB),%rdx
movq %rax,PCB_ONFAULT(%rdx)		movq %rax,PCB_ONFAULT(%rdx)
POP_FRAME_POINTER		POP_FRAME_POINTER
ret		ret
		.endmacro

		ENTRY(copyout_nosmap_std)
		COPYOUT smap=0 erms=0
		END(copyout_nosmap_std)

		ENTRY(copyout_smap_std)
		COPYOUT smap=1 erms=0
		END(copyout_smap_std)

		ENTRY(copyout_nosmap_erms)
		COPYOUT smap=0 erms=1
		END(copyout_nosmap_erms)

		ENTRY(copyout_smap_erms)
		COPYOUT smap=1 erms=1
		END(copyout_smap_erms)

ALIGN_TEXT		ALIGN_TEXT
copyout_fault:		copyout_fault:
movq PCPU(CURPCB),%rdx		movq PCPU(CURPCB),%rdx
movq $0,PCB_ONFAULT(%rdx)		movq $0,PCB_ONFAULT(%rdx)
movq $EFAULT,%rax		movq $EFAULT,%rax
POP_FRAME_POINTER		POP_FRAME_POINTER
ret		ret
END(copyout_smap)

/*		/*
* copyin(from_user, to_kernel, len)		* copyin(from_user, to_kernel, len)
* %rdi, %rsi, %rdx		* %rdi, %rsi, %rdx
*/		*/
ENTRY(copyin_nosmap)		.macro COPYIN smap erms
PUSH_FRAME_POINTER		PUSH_FRAME_POINTER
movq PCPU(CURPCB),%rax		movq PCPU(CURPCB),%rax
movq $copyin_fault,PCB_ONFAULT(%rax)		movq $copyin_fault,PCB_ONFAULT(%rax)
testq %rdx,%rdx /* anything to do? */		testq %rdx,%rdx /* anything to do? */
jz done_copyin		jz 2f

/*		/*
* make sure address is valid		* make sure address is valid
*/		*/
movq %rdi,%rax		movq %rdi,%rax
addq %rdx,%rax		addq %rdx,%rax
jc copyin_fault		jc copyin_fault
movq $VM_MAXUSER_ADDRESS,%rcx		movq $VM_MAXUSER_ADDRESS,%rcx
cmpq %rcx,%rax		cmpq %rcx,%rax
ja copyin_fault		ja copyin_fault

xchgq %rdi,%rsi		xchgq %rdi,%rsi
movq %rdx,%rcx		movq %rdx,%rcx
movb %cl,%al		movb %cl,%al
shrq $3,%rcx /* copy longword-wise */
rep
movsq
movb %al,%cl
andb $7,%cl /* copy remaining bytes */
je done_copyin
rep
movsb

jmp done_copyin		SMAP_DISABLE \smap
END(copyin_nosmap)		.if \erms == 0

ENTRY(copyin_smap)
PUSH_FRAME_POINTER
movq PCPU(CURPCB),%rax
movq $copyin_fault,PCB_ONFAULT(%rax)
testq %rdx,%rdx /* anything to do? */
jz done_copyin

/*
* make sure address is valid
*/
movq %rdi,%rax
addq %rdx,%rax
jc copyin_fault
movq $VM_MAXUSER_ADDRESS,%rcx
cmpq %rcx,%rax
ja copyin_fault

xchgq %rdi,%rsi
movq %rdx,%rcx
movb %cl,%al
shrq $3,%rcx /* copy longword-wise */		shrq $3,%rcx /* copy longword-wise */
stac
rep		rep
movsq		movsq
movb %al,%cl		movb %al,%cl
andb $7,%cl /* copy remaining bytes */		andb $7,%cl /* copy remaining bytes */
je 1f		je 1
		.endif
rep		rep
movsb		movsb
1: clac

done_copyin:		1:
		SMAP_ENABLE \smap
		2:
xorl %eax,%eax		xorl %eax,%eax
movq PCPU(CURPCB),%rdx		movq PCPU(CURPCB),%rdx
movq %rax,PCB_ONFAULT(%rdx)		movq %rax,PCB_ONFAULT(%rdx)
POP_FRAME_POINTER		POP_FRAME_POINTER
ret		ret
END(copyin_smap)		.endmacro

		ENTRY(copyin_nosmap_std)
		COPYIN smap=0 erms=0
		END(copyin_nosmap_std)

		ENTRY(copyin_smap_std)
		COPYIN smap=1 erms=0
		END(copyin_smap_std)

		ENTRY(copyin_nosmap_erms)
		COPYIN smap=0 erms=1
		END(copyin_nosmap_erms)

		ENTRY(copyin_smap_erms)
		COPYIN smap=1 erms=1
		END(copyin_smap_erms)

ALIGN_TEXT		ALIGN_TEXT
copyin_fault:		copyin_fault:
movq PCPU(CURPCB),%rdx		movq PCPU(CURPCB),%rdx
movq $0,PCB_ONFAULT(%rdx)		movq $0,PCB_ONFAULT(%rdx)
movq $EFAULT,%rax		movq $EFAULT,%rax
POP_FRAME_POINTER		POP_FRAME_POINTER
ret		ret
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