From: James Morse james.morse@arm.com
commit c47e4d04ba0f1ea17353d85d45f611277507e07a upstream.
Spectre-BHB needs to add sequences to the vectors. Having one global set of vectors is a problem for big/little systems where the sequence is costly on cpus that are not vulnerable.
Making the vectors per-cpu in the style of KVM's bh_harden_hyp_vecs requires the vectors to be generated by macros.
Make the kpti re-mapping of the kernel optional, so the macros can be used without kpti.
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 | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
--- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -970,9 +970,10 @@ alternative_else_nop_endif sub \dst, \dst, PAGE_SIZE .endm
- .macro tramp_ventry, vector_start, regsize + .macro tramp_ventry, vector_start, regsize, kpti .align 7 1: + .if \kpti == 1 .if \regsize == 64 msr tpidrro_el0, x30 // Restored in kernel_ventry .endif @@ -994,8 +995,12 @@ alternative_insn isb, nop, ARM64_WORKARO #endif prfm plil1strm, [x30, #(1b - \vector_start)] msr vbar_el1, x30 - add x30, x30, #(1b - \vector_start + 4) isb + .else + ldr x30, =vectors + .endif // \kpti == 1 + + add x30, x30, #(1b - \vector_start + 4) ret .org 1b + 128 // Did we overflow the ventry slot? .endm @@ -1012,15 +1017,15 @@ alternative_insn isb, nop, ARM64_WORKARO eret .endm
- .macro generate_tramp_vector + .macro generate_tramp_vector, kpti .Lvector_start@: .space 0x400
.rept 4 - tramp_ventry .Lvector_start@, 64 + tramp_ventry .Lvector_start@, 64, \kpti .endr .rept 4 - tramp_ventry .Lvector_start@, 32 + tramp_ventry .Lvector_start@, 32, \kpti .endr .endm
@@ -1031,7 +1036,7 @@ alternative_insn isb, nop, ARM64_WORKARO .pushsection ".entry.tramp.text", "ax" .align 11 ENTRY(tramp_vectors) - generate_tramp_vector + generate_tramp_vector kpti=1 END(tramp_vectors)
ENTRY(tramp_exit_native)