linux-kernel - [stable:PATCH v4.9.309 30/43] arm64: entry: Don't assume tramp

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Message-Id: <20220406164546.1888528-30-james.morse@arm.com>
Date:   Wed,  6 Apr 2022 17:45:33 +0100
From:   James Morse <james.morse@....com>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     James Morse <james.morse@....com>,
        Catalin Marinas <catalin.marinas@....com>
Subject: [stable:PATCH v4.9.309 30/43] arm64: entry: Don't assume tramp_vectors is the start of the vectors

commit ed50da7764535f1e24432ded289974f2bf2b0c5a upstream.

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) <rmk+kernel@...linux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: James Morse <james.morse@....com>
---
 arch/arm64/kernel/entry.S | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 4c4f7df5f0f3..114922c1c3e3 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -926,7 +926,7 @@ __ni_sys_trace:
 	sub	\dst, \dst, PAGE_SIZE
 	.endm
 
-	.macro tramp_ventry, regsize = 64
+	.macro tramp_ventry, vector_start, regsize
 	.align	7
 1:
 	.if	\regsize == 64
@@ -948,9 +948,9 @@ __ni_sys_trace:
 #else
 	ldr	x30, =vectors
 #endif
-	prfm	plil1strm, [x30, #(1b - tramp_vectors)]
+	prfm	plil1strm, [x30, #(1b - \vector_start)]
 	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?
@@ -968,19 +968,21 @@ __ni_sys_trace:
 	eret
 	.endm
 
-	.align	11
-ENTRY(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
+ENTRY(tramp_vectors)
+	generate_tramp_vector
 END(tramp_vectors)
 
 ENTRY(tramp_exit_native)
-- 
2.30.2