amd64_edac: Sanitize syndrome extraction

Remove the two syndrome extraction macros and add a single function
which does the same thing but with proper typechecking. While at it,
make sure to cache ECC syndrome size and dump it in debug output.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

2 files changed, 55 insertions, 33 deletions

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index ac9f7985096d..e8d84f89dbcf 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -796,6 +796,11 @@ static int sys_addr_to_csrow(struct mem_ctl_info *mci, u64 sys_addr)
 
 static int get_channel_from_ecc_syndrome(struct mem_ctl_info *, u16);
 
+static u16 extract_syndrome(struct err_regs *err)
+{
+        return ((err->nbsh >> 15) & 0xff) | ((err->nbsl >> 16) & 0xff00);
+}
+
 static void amd64_cpu_display_info(struct amd64_pvt *pvt)
 {
         if (boot_cpu_data.x86 == 0x11)
@@ -888,6 +893,9 @@ static void amd64_dump_misc_regs(struct amd64_pvt *pvt)
                 return;
         }
 
+        amd64_printk(KERN_INFO, "using %s syndromes.\n",
+                     ((pvt->syn_type == 8) ? "x8" : "x4"));
+
         /* Only if NOT ganged does dclr1 have valid info */
         if (!dct_ganging_enabled(pvt))
                 amd64_dump_dramcfg_low(pvt->dclr1, 1);
@@ -1101,20 +1109,17 @@ static void k8_read_dram_base_limit(struct amd64_pvt *pvt, int dram)
 }
 
 static void k8_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
-                                        struct err_regs *info,
-                                        u64 sys_addr)
+                                    struct err_regs *err_info, u64 sys_addr)
 {
         struct mem_ctl_info *src_mci;
-        unsigned short syndrome;
         int channel, csrow;
         u32 page, offset;
+        u16 syndrome;
 
-        /* Extract the syndrome parts and form a 16-bit syndrome */
-        syndrome  = HIGH_SYNDROME(info->nbsl) << 8;
-        syndrome |= LOW_SYNDROME(info->nbsh);
+        syndrome = extract_syndrome(err_info);
 
         /* CHIPKILL enabled */
-        if (info->nbcfg & K8_NBCFG_CHIPKILL) {
+        if (err_info->nbcfg & K8_NBCFG_CHIPKILL) {
                 channel = get_channel_from_ecc_syndrome(mci, syndrome);
                 if (channel < 0) {
                         /*
@@ -1123,8 +1128,8 @@ static void k8_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
                          * as suspect.
                          */
                         amd64_mc_printk(mci, KERN_WARNING,
-                                       "unknown syndrome 0x%x - possible error "
-                                       "reporting race\n", syndrome);
+                                        "unknown syndrome 0x%04x - possible "
+                                        "error reporting race\n", syndrome);
                         edac_mc_handle_ce_no_info(mci, EDAC_MOD_STR);
                         return;
                 }
@@ -1654,13 +1659,13 @@ static int f10_translate_sysaddr_to_cs(struct amd64_pvt *pvt, u64 sys_addr,
  * (MCX_ADDR).
  */
 static void f10_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
-                                     struct err_regs *info,
+                                     struct err_regs *err_info,
                                      u64 sys_addr)
 {
         struct amd64_pvt *pvt = mci->pvt_info;
         u32 page, offset;
-        unsigned short syndrome;
         int nid, csrow, chan = 0;
+        u16 syndrome;
 
         csrow = f10_translate_sysaddr_to_cs(pvt, sys_addr, &nid, &chan);
 
@@ -1671,8 +1676,7 @@ static void f10_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
 
         error_address_to_page_and_offset(sys_addr, &page, &offset);
 
-        syndrome  = HIGH_SYNDROME(info->nbsl) << 8;
-        syndrome |= LOW_SYNDROME(info->nbsh);
+        syndrome = extract_syndrome(err_info);
 
         /*
          * We need the syndromes for channel detection only when we're
@@ -1878,7 +1882,7 @@ static u16 x8_vectors[] = {
 };
 
 static int decode_syndrome(u16 syndrome, u16 *vectors, int num_vecs,
-                                 int v_dim)
+                           int v_dim)
 {
         unsigned int i, err_sym;
 
@@ -1955,23 +1959,23 @@ static int map_err_sym_to_channel(int err_sym, int sym_size)
 static int get_channel_from_ecc_syndrome(struct mem_ctl_info *mci, u16 syndrome)
 {
         struct amd64_pvt *pvt = mci->pvt_info;
-        u32 value = 0;
-        int err_sym = 0;
-
-        if (boot_cpu_data.x86 == 0x10) {
-
-                amd64_read_pci_cfg(pvt->misc_f3_ctl, 0x180, &value);
-
-                /* F3x180[EccSymbolSize]=1 => x8 symbols */
-                if (boot_cpu_data.x86_model > 7 &&
-                    value & BIT(25)) {
-                        err_sym = decode_syndrome(syndrome, x8_vectors,
-                                                  ARRAY_SIZE(x8_vectors), 8);
-                        return map_err_sym_to_channel(err_sym, 8);
-                }
+        int err_sym = -1;
+
+        if (pvt->syn_type == 8)
+                err_sym = decode_syndrome(syndrome, x8_vectors,
+                                          ARRAY_SIZE(x8_vectors),
+                                          pvt->syn_type);
+        else if (pvt->syn_type == 4)
+                err_sym = decode_syndrome(syndrome, x4_vectors,
+                                          ARRAY_SIZE(x4_vectors),
+                                          pvt->syn_type);
+        else {
+                amd64_printk(KERN_WARNING, "%s: Illegal syndrome type: %u\n",
+                                           __func__, pvt->syn_type);
+                return err_sym;
         }
-        err_sym = decode_syndrome(syndrome, x4_vectors, ARRAY_SIZE(x4_vectors), 4);
-        return map_err_sym_to_channel(err_sym, 4);
+
+        return map_err_sym_to_channel(err_sym, pvt->syn_type);
 }
 
 /*
@@ -2284,6 +2288,7 @@ static void amd64_free_mc_sibling_devices(struct amd64_pvt *pvt)
 static void amd64_read_mc_registers(struct amd64_pvt *pvt)
 {
         u64 msr_val;
+        u32 tmp;
         int dram;
 
         /*
@@ -2349,10 +2354,22 @@ static void amd64_read_mc_registers(struct amd64_pvt *pvt)
         amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCLR_0, &pvt->dclr0);
         amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCHR_0, &pvt->dchr0);
 
-        if (!dct_ganging_enabled(pvt) && boot_cpu_data.x86 >= 0x10) {
-                amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCLR_1, &pvt->dclr1);
-                amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCHR_1, &pvt->dchr1);
+        if (boot_cpu_data.x86 >= 0x10) {
+                if (!dct_ganging_enabled(pvt)) {
+                        amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCLR_1, &pvt->dclr1);
+                        amd64_read_pci_cfg(pvt->dram_f2_ctl, F10_DCHR_1, &pvt->dchr1);
+                }
+                amd64_read_pci_cfg(pvt->misc_f3_ctl, EXT_NB_MCA_CFG, &tmp);
         }
+
+        if (boot_cpu_data.x86 == 0x10 &&
+            boot_cpu_data.x86_model > 7 &&
+            /* F3x180[EccSymbolSize]=1 => x8 symbols */
+            tmp & BIT(25))
+                pvt->syn_type = 8;
+        else
+                pvt->syn_type = 4;
+
         amd64_dump_misc_regs(pvt);
 }
 
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index 0d4bf5638243..707745b36733 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -382,6 +382,8 @@ enum {
 #define K8_NBCAP_SECDED                 BIT(3)
 #define K8_NBCAP_DCT_DUAL               BIT(0)
 
+#define EXT_NB_MCA_CFG                  0x180
+
 /* MSRs */
 #define K8_MSR_MCGCTL_NBE               BIT(4)
 
@@ -471,6 +473,9 @@ struct amd64_pvt {
         u32 dram_ctl_select_high;       /* DRAM Controller Select High Reg */
         u32 online_spare;               /* On-Line spare Reg */
 
+        /* x4 or x8 syndromes in use */
+        u8 syn_type;
+
         /* temp storage for when input is received from sysfs */
         struct err_regs ctl_error_info;