4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov bp@suse.de
commit 78ce241099bb363b19dbd0245442e66c8de8f567 upstream.
... 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: 27bd59502702 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/mcheck/mce_amd.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-)
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -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(unsign 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 in 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);