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| author | James Morse <james.morse@arm.com> | 2022-03-18 17:48:31 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-23 09:10:43 +0100 |
| commit | 9e056623dfc538909ed2a914f70a66d68ec71ec3 (patch) | |
| tree | fc952164e6f226290244d84b2d9b4bbeeee612d8 | |
| parent | f689fa53bb944873f75fe1584f446cae1aabd2c1 (diff) | |
| download | linux-stable-9e056623dfc538909ed2a914f70a66d68ec71ec3.tar.gz linux-stable-9e056623dfc538909ed2a914f70a66d68ec71ec3.tar.bz2 linux-stable-9e056623dfc538909ed2a914f70a66d68ec71ec3.zip | |
arm64: entry: Make the kpti trampoline's kpti sequence optional
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>
| -rw-r--r-- | arch/arm64/kernel/entry.S | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 03c45538a93f..50843161607e 100644 --- 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_WORKAROUND_QCOM_FALKOR_E1003 #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_WORKAROUND_QCOM_FALKOR_E1003 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_WORKAROUND_QCOM_FALKOR_E1003 .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) |