[PATCH 5.10 29/58] arm64: entry: Dont assume tramp_vectors is the start of the vectors

Greg Kroah-Hartman
2022-03-10T14:35:04Z

From: James Morse <james.morse@arm.com>

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@armlinux.org.uk>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/kernel/entry.S | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -822,7 +822,7 @@ alternative_else_nop_endif
sub \dst, \dst, PAGE_SIZE
.endm

- .macro tramp_ventry, regsize = 64
+ .macro tramp_ventry, vector_start, regsize
.align 7
1:
.if \regsize == 64
@@ -845,10 +845,10 @@ alternative_insn isb, nop, ARM64_WORKARO
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?
@@ -867,19 +867,21 @@ alternative_else_nop_endif
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
-
- tramp_ventry 32
- tramp_ventry 32
- tramp_ventry 32
- tramp_ventry 32
+ .rept 4
+ tramp_ventry .Lvector_start\@, 64
+ .endr
+ .rept 4
+ tramp_ventry .Lvector_start\@, 32
+ .endr
+ .endm
+
+ .align 11
+SYM_CODE_START_NOALIGN(tramp_vectors)
+ generate_tramp_vector
SYM_CODE_END(tramp_vectors)

SYM_CODE_START(tramp_exit_native)