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Commit b092201e authored by Marc Zyngier's avatar Marc Zyngier Committed by Catalin Marinas
Browse files

arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support 



Add the detection and runtime code for ARM_SMCCC_ARCH_WORKAROUND_1.
It is lovely. Really.

Tested-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent f2d3b2e8

arch/arm64/kernel/bpi.S

+20 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
 */



#include <linux/linkage.h>

#include <linux/arm-smccc.h>



.macro ventry target

	.rept 31
@@ -85,3 +86,22 @@ ENTRY(__qcom_hyp_sanitize_link_stack_start) 
	.endr

	ldp	x29, x30, [sp], #16

ENTRY(__qcom_hyp_sanitize_link_stack_end)



.macro smccc_workaround_1 inst

	sub	sp, sp, #(8 * 4)

	stp	x2, x3, [sp, #(8 * 0)]

	stp	x0, x1, [sp, #(8 * 2)]

	mov	w0, #ARM_SMCCC_ARCH_WORKAROUND_1

	\inst	#0

	ldp	x2, x3, [sp, #(8 * 0)]

	ldp	x0, x1, [sp, #(8 * 2)]

	add	sp, sp, #(8 * 4)

.endm



ENTRY(__smccc_workaround_1_smc_start)

	smccc_workaround_1	smc

ENTRY(__smccc_workaround_1_smc_end)



ENTRY(__smccc_workaround_1_hvc_start)

	smccc_workaround_1	hvc

ENTRY(__smccc_workaround_1_hvc_end)

arch/arm64/kernel/cpu_errata.c

+67 −1
Original line number Diff line number Diff line
@@ -70,6 +70,10 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data); 
extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[];

extern char __qcom_hyp_sanitize_link_stack_start[];

extern char __qcom_hyp_sanitize_link_stack_end[];

extern char __smccc_workaround_1_smc_start[];

extern char __smccc_workaround_1_smc_end[];

extern char __smccc_workaround_1_hvc_start[];

extern char __smccc_workaround_1_hvc_end[];



static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,

				const char *hyp_vecs_end)
@@ -116,6 +120,10 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, 
#define __psci_hyp_bp_inval_end			NULL

#define __qcom_hyp_sanitize_link_stack_start	NULL

#define __qcom_hyp_sanitize_link_stack_end	NULL

#define __smccc_workaround_1_smc_start		NULL

#define __smccc_workaround_1_smc_end		NULL

#define __smccc_workaround_1_hvc_start		NULL

#define __smccc_workaround_1_hvc_end		NULL



static void __install_bp_hardening_cb(bp_hardening_cb_t fn,

				      const char *hyp_vecs_start,
@@ -142,17 +150,75 @@ static void install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry, 
	__install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end);

}



#include <uapi/linux/psci.h>

#include <linux/arm-smccc.h>

#include <linux/psci.h>



static void call_smc_arch_workaround_1(void)

{

	arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);

}



static void call_hvc_arch_workaround_1(void)

{

	arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);

}



static bool check_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)

{

	bp_hardening_cb_t cb;

	void *smccc_start, *smccc_end;

	struct arm_smccc_res res;



	if (!entry->matches(entry, SCOPE_LOCAL_CPU))

		return false;



	if (psci_ops.smccc_version == SMCCC_VERSION_1_0)

		return false;



	switch (psci_ops.conduit) {

	case PSCI_CONDUIT_HVC:

		arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,

				  ARM_SMCCC_ARCH_WORKAROUND_1, &res);

		if (res.a0)

			return false;

		cb = call_hvc_arch_workaround_1;

		smccc_start = __smccc_workaround_1_hvc_start;

		smccc_end = __smccc_workaround_1_hvc_end;

		break;



	case PSCI_CONDUIT_SMC:

		arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,

				  ARM_SMCCC_ARCH_WORKAROUND_1, &res);

		if (res.a0)

			return false;

		cb = call_smc_arch_workaround_1;

		smccc_start = __smccc_workaround_1_smc_start;

		smccc_end = __smccc_workaround_1_smc_end;

		break;



	default:

		return false;

	}



	install_bp_hardening_cb(entry, cb, smccc_start, smccc_end);



	return true;

}



static int enable_psci_bp_hardening(void *data)

{

	const struct arm64_cpu_capabilities *entry = data;



	if (psci_ops.get_version)

	if (psci_ops.get_version) {

		if (check_smccc_arch_workaround_1(entry))

			return 0;



		install_bp_hardening_cb(entry,

				       (bp_hardening_cb_t)psci_ops.get_version,

				       __psci_hyp_bp_inval_start,

				       __psci_hyp_bp_inval_end);

	}



	return 0;

}