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| author |   James Morse <james.morse@arm.com> | 2021-11-18 13:16:23 +0000 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2022-02-15 17:40:16 +0000 |
| commit | c47e4d04ba0f1ea17353d85d45f611277507e07a (patch) | |
| tree | 4d27a89b64dc825a3b6e359487ee437c32a60c77 /arch/arm64/kernel/entry.S | |
| parent | arm64: entry: Move trampoline macros out of ifdef'd section (diff) | |
| download | linux-dev-c47e4d04ba0f1ea17353d85d45f611277507e07a.tar.xz linux-dev-c47e4d04ba0f1ea17353d85d45f611277507e07a.zip | |
arm64: entry: Make the kpti trampoline's kpti sequence optional
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>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 2735c8941c2d..23e85c94ea36 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -646,9 +646,10 @@ 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 @@ -671,9 +672,14 @@ alternative_insn isb, nop, ARM64_WORKAROUND_QCOM_FALKOR_E1003 alternative_if_not ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM prfm plil1strm, [x30, #(1b - \vector_start)] alternative_else_nop_endif + 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 @@ -691,15 +697,15 @@ alternative_else_nop_endif sb .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 @@ -710,7 +716,7 @@ alternative_else_nop_endif .pushsection ".entry.tramp.text", "ax" .align 11 SYM_CODE_START_NOALIGN(tramp_vectors) - generate_tramp_vector + generate_tramp_vector kpti=1 SYM_CODE_END(tramp_vectors) SYM_CODE_START(tramp_exit_native) |