arm64: entry: Don't assume tramp_vectors is the start of the vectors

The tramp_ventry macro uses tramp_vectors as the address of the vectors
when calculating which ventry in the 'full fat' vectors to branch to.

While there is one set of tramp_vectors, this will be true.
Adding multiple sets of vectors will break this assumption.

Move the generation of the vectors to a macro, and pass the start
of the vectors as an argument to tramp_ventry.

Reviewed-by: Russell King (Oracle) <[e-mail]>
Reviewed-by: Catalin Marinas <[e-mail]>
Signed-off-by: James Morse <[e-mail]>

arch/arm64/kernel/entry.S

···
 	sub	\dst, \dst, PAGE_SIZE
 	.endm
 
-	.macro tramp_ventry, regsize = 64
+	.macro tramp_ventry, vector_start, regsize
 	.align	7
 1:
 	.if	\regsize == 64
···
 	ldr	x30, =vectors
 #endif
 alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM
-	prfm	plil1strm, [x30, #(1b - tramp_vectors)]
+	prfm	plil1strm, [x30, #(1b - \vector_start)]
 alternative_else_nop_endif
 	msr	vbar_el1, x30
-	add	x30, x30, #(1b - tramp_vectors + 4)
+	add	x30, x30, #(1b - \vector_start + 4)
 	isb
 	ret
 .org 1b + 128	// Did we overflow the ventry slot?
···
 	sb
 	.endm
 
-	.align	11
-SYM_CODE_START_NOALIGN(tramp_vectors)
+	.macro	generate_tramp_vector
+.Lvector_start\@:
 	.space	0x400
 
-	tramp_ventry
-	tramp_ventry
-	tramp_ventry
-	tramp_ventry
+	.rept	4
+	tramp_ventry	.Lvector_start\@, 64
+	.endr
+	.rept	4
+	tramp_ventry	.Lvector_start\@, 32
+	.endr
+	.endm
 
-	tramp_ventry	32
-	tramp_ventry	32
-	tramp_ventry	32
-	tramp_ventry	32
+	.align	11
+SYM_CODE_START_NOALIGN(tramp_vectors)
+	generate_tramp_vector
 SYM_CODE_END(tramp_vectors)
 
 SYM_CODE_START(tramp_exit_native)