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x86/MCE/AMD: Cache SMCA MISC block addresses 

... into a global, two-dimensional array and service subsequent reads from
that cache to avoid rdmsr_on_cpu() calls during CPU hotplug (IPIs with IRQs
disabled).

In addition, this fixes a KASAN slab-out-of-bounds read due to wrong usage
of the bank->blocks pointer.

Fixes: 27bd595027 ("x86/mce/AMD: Get address from already initialized block")
Reported-by: Johannes Hirte <johannes.hirte@datenkhaos.de>
Tested-by: Johannes Hirte <johannes.hirte@datenkhaos.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
Link: http://lkml.kernel.org/r/20180414004230.GA2033@probook
This commit is contained in:
Borislav Petkov 2018-05-17 10:46:26 +02:00 committed by Thomas Gleixner
parent 73fcb1a370
commit 78ce241099
1 changed files with 14 additions and 15 deletions
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29
arch/x86/kernel/cpu/mcheck/mce_amd.c
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@ -94,6 +94,11 @@ static struct smca_bank_name smca_names[] = {
[SMCA_SMU] = { "smu", "System Management Unit" },
};
static u32 smca_bank_addrs[MAX_NR_BANKS][NR_BLOCKS] __ro_after_init =
{
[0 ... MAX_NR_BANKS - 1] = { [0 ... NR_BLOCKS - 1] = -1 }
};
const char *smca_get_name(enum smca_bank_types t)
{
if (t >= N_SMCA_BANK_TYPES)
@ -443,20 +448,26 @@ static u32 smca_get_block_address(unsigned int cpu, unsigned int bank,
if (!block)
return MSR_AMD64_SMCA_MCx_MISC(bank);
/* Check our cache first: */
if (smca_bank_addrs[bank][block] != -1)
return smca_bank_addrs[bank][block];
/*
* For SMCA enabled processors, BLKPTR field of the first MISC register
* (MCx_MISC0) indicates presence of additional MISC regs set (MISC1-4).
*/
if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_CONFIG(bank), &low, &high))
return addr;
goto out;
if (!(low & MCI_CONFIG_MCAX))
return addr;
goto out;
if (!rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_MISC(bank), &low, &high) &&
(low & MASK_BLKPTR_LO))
return MSR_AMD64_SMCA_MCx_MISCy(bank, block - 1);
addr = MSR_AMD64_SMCA_MCx_MISCy(bank, block - 1);
out:
smca_bank_addrs[bank][block] = addr;
return addr;
}
@ -468,18 +479,6 @@ static u32 get_block_address(unsigned int cpu, u32 current_addr, u32 low, u32 hi
if ((bank >= mca_cfg.banks) || (block >= NR_BLOCKS))
return addr;
/* Get address from already initialized block. */
if (per_cpu(threshold_banks, cpu)) {
struct threshold_bank *bankp = per_cpu(threshold_banks, cpu)[bank];
if (bankp && bankp->blocks) {
struct threshold_block *blockp = &bankp->blocks[block];
if (blockp)
return blockp->address;
}
}
if (mce_flags.smca)
return smca_get_block_address(cpu, bank, block);