[stable:PATCH v4.9.309 30/43] arm64: entry: Don't assume tramp_vectors is the start of the vectors

From: James Morse
Date: Wed Apr 06 2022 - 14:08:41 EST


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@xxxxxxxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
---
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