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Commit 5bd92949 authored by Marc Zyngier's avatar Marc Zyngier Committed by Isaac J. Manjarres
Browse files

arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2 



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

Change-Id: Ie938e9c0ec0ae85e070c3a80d9b6043208471edb
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>
Git-commit: 5cf9ce6e5ea50f805c6188c04ed0daaec7b6887d
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[isaacm@codeaurora.org: define per cpu var only when ssbd
 config option is set.]
Signed-off-by: default avatarIsaac J. Manjarres <isaacm@codeaurora.org>
parent f045269b

arch/arm64/kernel/cpu_errata.c

+4 −0
Original line number Diff line number Diff line
@@ -228,6 +228,10 @@ static int qcom_enable_link_stack_sanitization(void *data) 
}

#endif	/* CONFIG_HARDEN_BRANCH_PREDICTOR */



#ifdef CONFIG_ARM64_SSBD

DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);

#endif /* CONFIG_ARM64_SSBD */



#define MIDR_RANGE(model, min, max) \

	.def_scope = SCOPE_LOCAL_CPU, \

	.matches = is_affected_midr_range, \

arch/arm64/kernel/entry.S

+7 −4
Original line number Diff line number Diff line
@@ -140,8 +140,10 @@ 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

	smc	#0
@@ -174,12 +176,13 @@ alternative_else_nop_endif 
	ldr	x19, [tsk, #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
@@ -319,8 +322,8 @@ 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