Commit bfc1168d authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
Browse files

x86/cpu/AMD: Apply the Erratum 688 fix when the BIOS doesn't 



Some F14h machines have an erratum which, "under a highly specific
and detailed set of internal timing conditions" can lead to skipping
instructions and RIP corruption.

Add the fix for those machines when their BIOS doesn't apply it or
there simply isn't BIOS update for them.

Tested-by: default avatar <mirh@protonmail.ch>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Link: http://lkml.kernel.org/r/20171022104731.28249-1-bp@alien8.de
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197285


[ Added pr_info() that we activated the workaround. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ce56a86e

arch/x86/kernel/amd_nb.c

+41 −0
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ static const struct pci_device_id amd_root_ids[] = { 
	{}

};



#define PCI_DEVICE_ID_AMD_CNB17H_F4     0x1704



const struct pci_device_id amd_nb_misc_ids[] = {

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
@@ -37,6 +39,7 @@ const struct pci_device_id amd_nb_misc_ids[] = { 
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },

	{}

};

EXPORT_SYMBOL_GPL(amd_nb_misc_ids);
@@ -48,6 +51,7 @@ static const struct pci_device_id amd_nb_link_ids[] = { 
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },

	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },

	{}

};
@@ -402,11 +406,48 @@ void amd_flush_garts(void) 
}

EXPORT_SYMBOL_GPL(amd_flush_garts);



static void __fix_erratum_688(void *info)

{

#define MSR_AMD64_IC_CFG 0xC0011021



	msr_set_bit(MSR_AMD64_IC_CFG, 3);

	msr_set_bit(MSR_AMD64_IC_CFG, 14);

}



/* Apply erratum 688 fix so machines without a BIOS fix work. */

static __init void fix_erratum_688(void)

{

	struct pci_dev *F4;

	u32 val;



	if (boot_cpu_data.x86 != 0x14)

		return;



	if (!amd_northbridges.num)

		return;



	F4 = node_to_amd_nb(0)->link;

	if (!F4)

		return;



	if (pci_read_config_dword(F4, 0x164, &val))

		return;



	if (val & BIT(2))

		return;



	on_each_cpu(__fix_erratum_688, NULL, 0);



	pr_info("x86/cpu/AMD: CPU erratum 688 worked around\n");

}



static __init int init_amd_nbs(void)

{

	amd_cache_northbridges();

	amd_cache_gart();



	fix_erratum_688();



	return 0;

}

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