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Commit d8174bd7 authored by Marc Zyngier's avatar Marc Zyngier Committed by Greg Kroah-Hartman
Browse files

arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2 



commit 5cf9ce6e5ea50f805c6188c04ed0daaec7b6887d upstream.

In a heterogeneous system, we can end up with both affected and
unaffected CPUs. Let's check their status before calling into the
firmware.

Reviewed-by: default avatarJulien Grall <julien.grall@arm.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent be331630

arch/arm64/kernel/cpu_errata.c

+2 −0
Original line number Diff line number Diff line
@@ -188,6 +188,8 @@ static int enable_smccc_arch_workaround_1(void *data) 
#endif	/* CONFIG_HARDEN_BRANCH_PREDICTOR */



#ifdef CONFIG_ARM64_SSBD

DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);



void __init arm64_update_smccc_conduit(struct alt_instr *alt,

				       __le32 *origptr, __le32 *updptr,

				       int nr_inst)

arch/arm64/kernel/entry.S

+7 −4
Original line number Diff line number Diff line
@@ -98,8 +98,10 @@ alternative_else_nop_endif 


	// This macro corrupts x0-x3. It is the caller's duty

	// to save/restore them if required.

	.macro	apply_ssbd, state

	.macro	apply_ssbd, state, targ, tmp1, tmp2

#ifdef CONFIG_ARM64_SSBD

	ldr_this_cpu	\tmp2, arm64_ssbd_callback_required, \tmp1

	cbz	\tmp2, \targ

	mov	w0, #ARM_SMCCC_ARCH_WORKAROUND_2

	mov	w1, #\state

alternative_cb	arm64_update_smccc_conduit
@@ -135,12 +137,13 @@ alternative_cb_end 
	ldr	x19, [tsk, #TI_FLAGS]		// since we can unmask debug

	disable_step_tsk x19, x20		// exceptions when scheduling.



	apply_ssbd 1

	apply_ssbd 1, 1f, x22, x23



#ifdef CONFIG_ARM64_SSBD

	ldp	x0, x1, [sp, #16 * 0]

	ldp	x2, x3, [sp, #16 * 1]

#endif

1:



	mov	x29, xzr			// fp pointed to user-space

	.else
@@ -210,8 +213,8 @@ alternative_if ARM64_WORKAROUND_845719 
alternative_else_nop_endif

#endif

3:

	apply_ssbd 0



	apply_ssbd 0, 5f, x0, x1

5:

	.endif

	msr	elr_el1, x21			// set up the return data

	msr	spsr_el1, x22