summaryrefslogtreecommitdiffstats
path: root/drivers/edac
diff options
context:
space:
mode:
authorBorislav Petkov <borislav.petkov@amd.com>2010-10-07 18:29:15 +0200
committerBorislav Petkov <borislav.petkov@amd.com>2011-01-07 11:33:56 +0100
commit24f9a7fe3f19f3fd310f556364d01a22911724b3 (patch)
tree4fa8aff338bd58d42fc95b930f29a39b91bacedd /drivers/edac
parent8d5b5d9c7b86e44fda29a367db3ccd2815a52f7c (diff)
downloadlinux-24f9a7fe3f19f3fd310f556364d01a22911724b3.tar.bz2
amd64_edac: Rework printk macros
Add a macro per printk level, shorten up error messages. Add relevant information to KERN_INFO level. No functional change. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Diffstat (limited to 'drivers/edac')
-rw-r--r--drivers/edac/amd64_edac.c145
-rw-r--r--drivers/edac/amd64_edac.h29
-rw-r--r--drivers/edac/amd64_edac_inj.c13
-rw-r--r--drivers/edac/edac_core.h3
-rw-r--r--drivers/edac/edac_mc.c4
5 files changed, 87 insertions, 107 deletions
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 26fb0f962605..84c565d4f56b 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -62,7 +62,7 @@ static int ddr3_dbam[] = { [0] = -1,
[5 ... 6] = 1024,
[7 ... 8] = 2048,
[9 ... 10] = 4096,
- [11] = 8192,
+ [11] = 8192,
};
/*
@@ -148,11 +148,10 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
scrubval = scrubrates[i].scrubval;
if (scrubval)
- edac_printk(KERN_DEBUG, EDAC_MC,
- "Setting scrub rate bandwidth: %u\n",
- scrubrates[i].bandwidth);
+ amd64_info("Setting scrub rate bandwidth: %u\n",
+ scrubrates[i].bandwidth);
else
- edac_printk(KERN_DEBUG, EDAC_MC, "Turning scrubbing off.\n");
+ amd64_info("Turning scrubbing off.\n");
pci_write_bits32(ctl, K8_SCRCTRL, scrubval, 0x001F);
@@ -176,8 +175,7 @@ static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
scrubval = scrubval & 0x001F;
- edac_printk(KERN_DEBUG, EDAC_MC,
- "pci-read, sdram scrub control value: %d \n", scrubval);
+ amd64_debug("pci-read, sdram scrub control value: %d\n", scrubval);
for (i = 0; i < ARRAY_SIZE(scrubrates); i++) {
if (scrubrates[i].scrubval == scrubval) {
@@ -296,9 +294,7 @@ static struct mem_ctl_info *find_mc_by_sys_addr(struct mem_ctl_info *mci,
if (unlikely((intlv_en != 0x01) &&
(intlv_en != 0x03) &&
(intlv_en != 0x07))) {
- amd64_printk(KERN_WARNING, "junk value of 0x%x extracted from "
- "IntlvEn field of DRAM Base Register for node 0: "
- "this probably indicates a BIOS bug.\n", intlv_en);
+ amd64_warn("DRAM Base[IntlvEn] junk value: 0x%x, BIOS bug?\n", intlv_en);
return NULL;
}
@@ -314,11 +310,9 @@ static struct mem_ctl_info *find_mc_by_sys_addr(struct mem_ctl_info *mci,
/* sanity test for sys_addr */
if (unlikely(!amd64_base_limit_match(pvt, sys_addr, node_id))) {
- amd64_printk(KERN_WARNING,
- "%s(): sys_addr 0x%llx falls outside base/limit "
- "address range for node %d with node interleaving "
- "enabled.\n",
- __func__, sys_addr, node_id);
+ amd64_warn("%s: sys_addr 0x%llx falls outside base/limit address"
+ "range for node %d with node interleaving enabled.\n",
+ __func__, sys_addr, node_id);
return NULL;
}
@@ -770,9 +764,8 @@ static int sys_addr_to_csrow(struct mem_ctl_info *mci, u64 sys_addr)
csrow = input_addr_to_csrow(mci, sys_addr_to_input_addr(mci, sys_addr));
if (csrow == -1)
- amd64_mc_printk(mci, KERN_ERR,
- "Failed to translate InputAddr to csrow for "
- "address 0x%lx\n", (unsigned long)sys_addr);
+ amd64_mc_err(mci, "Failed to translate InputAddr to csrow for "
+ "address 0x%lx\n", (unsigned long)sys_addr);
return csrow;
}
@@ -860,8 +853,7 @@ 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"));
+ amd64_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))
@@ -983,7 +975,7 @@ static void amd64_read_dct_base_mask(struct amd64_pvt *pvt)
}
}
-static enum mem_type amd64_determine_memory_type(struct amd64_pvt *pvt)
+static enum mem_type amd64_determine_memory_type(struct amd64_pvt *pvt, int cs)
{
enum mem_type type;
@@ -996,7 +988,7 @@ static enum mem_type amd64_determine_memory_type(struct amd64_pvt *pvt)
type = (pvt->dclr0 & BIT(18)) ? MEM_DDR : MEM_RDDR;
}
- debugf1(" Memory type is: %s\n", edac_mem_types[type]);
+ amd64_info("CS%d: %s\n", cs, edac_mem_types[type]);
return type;
}
@@ -1087,9 +1079,8 @@ static void k8_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
* 2 DIMMs is in error. So we need to ID 'both' of them
* as suspect.
*/
- amd64_mc_printk(mci, KERN_WARNING,
- "unknown syndrome 0x%04x - possible "
- "error reporting race\n", syndrome);
+ amd64_mc_warn(mci, "unknown syndrome 0x%04x - possible "
+ "error reporting race\n", syndrome);
edac_mc_handle_ce_no_info(mci, EDAC_MOD_STR);
return;
}
@@ -1111,8 +1102,7 @@ static void k8_map_sysaddr_to_csrow(struct mem_ctl_info *mci,
*/
src_mci = find_mc_by_sys_addr(mci, sys_addr);
if (!src_mci) {
- amd64_mc_printk(mci, KERN_ERR,
- "failed to map error address 0x%lx to a node\n",
+ amd64_mc_err(mci, "failed to map error addr 0x%lx to a node\n",
(unsigned long)sys_addr);
edac_mc_handle_ce_no_info(mci, EDAC_MOD_STR);
return;
@@ -1194,7 +1184,7 @@ static int f10_early_channel_count(struct amd64_pvt *pvt)
if (channels > 2)
channels = 2;
- debugf0("MCT channel count: %d\n", channels);
+ amd64_info("MCT channel count: %d\n", channels);
return channels;
@@ -1698,9 +1688,9 @@ static void amd64_debug_display_dimm_sizes(int ctrl, struct amd64_pvt *pvt)
if (dcsb[dimm*2 + 1] & K8_DCSB_CS_ENABLE)
size1 = pvt->ops->dbam_to_cs(pvt, DBAM_DIMM(dimm, dbam));
- edac_printk(KERN_DEBUG, EDAC_MC, " %d: %5dMB %d: %5dMB\n",
- dimm * 2, size0 << factor,
- dimm * 2 + 1, size1 << factor);
+ amd64_info(EDAC_MC ": %d: %5dMB %d: %5dMB\n",
+ dimm * 2, size0 << factor,
+ dimm * 2 + 1, size1 << factor);
}
}
@@ -1906,8 +1896,7 @@ static int get_channel_from_ecc_syndrome(struct mem_ctl_info *mci, u16 syndrome)
ARRAY_SIZE(x4_vectors),
pvt->syn_type);
else {
- amd64_printk(KERN_WARNING, "%s: Illegal syndrome type: %u\n",
- __func__, pvt->syn_type);
+ amd64_warn("Illegal syndrome type: %u\n", pvt->syn_type);
return err_sym;
}
@@ -1925,17 +1914,15 @@ static void amd64_handle_ce(struct mem_ctl_info *mci,
u64 sys_addr;
/* Ensure that the Error Address is VALID */
- if ((info->nbsh & K8_NBSH_VALID_ERROR_ADDR) == 0) {
- amd64_mc_printk(mci, KERN_ERR,
- "HW has no ERROR_ADDRESS available\n");
+ if (!(info->nbsh & K8_NBSH_VALID_ERROR_ADDR)) {
+ amd64_mc_err(mci, "HW has no ERROR_ADDRESS available\n");
edac_mc_handle_ce_no_info(mci, EDAC_MOD_STR);
return;
}
sys_addr = pvt->ops->get_error_address(mci, info);
- amd64_mc_printk(mci, KERN_ERR,
- "CE ERROR_ADDRESS= 0x%llx\n", sys_addr);
+ amd64_mc_err(mci, "CE ERROR_ADDRESS= 0x%llx\n", sys_addr);
pvt->ops->map_sysaddr_to_csrow(mci, info, sys_addr);
}
@@ -1952,9 +1939,8 @@ static void amd64_handle_ue(struct mem_ctl_info *mci,
log_mci = mci;
- if ((info->nbsh & K8_NBSH_VALID_ERROR_ADDR) == 0) {
- amd64_mc_printk(mci, KERN_CRIT,
- "HW has no ERROR_ADDRESS available\n");
+ if (!(info->nbsh & K8_NBSH_VALID_ERROR_ADDR)) {
+ amd64_mc_err(mci, "HW has no ERROR_ADDRESS available\n");
edac_mc_handle_ue_no_info(log_mci, EDAC_MOD_STR);
return;
}
@@ -1967,9 +1953,8 @@ static void amd64_handle_ue(struct mem_ctl_info *mci,
*/
src_mci = find_mc_by_sys_addr(mci, sys_addr);
if (!src_mci) {
- amd64_mc_printk(mci, KERN_CRIT,
- "ERROR ADDRESS (0x%lx) value NOT mapped to a MC\n",
- (unsigned long)sys_addr);
+ amd64_mc_err(mci, "ERROR ADDRESS (0x%lx) NOT mapped to a MC\n",
+ (unsigned long)sys_addr);
edac_mc_handle_ue_no_info(log_mci, EDAC_MOD_STR);
return;
}
@@ -1978,9 +1963,8 @@ static void amd64_handle_ue(struct mem_ctl_info *mci,
csrow = sys_addr_to_csrow(log_mci, sys_addr);
if (csrow < 0) {
- amd64_mc_printk(mci, KERN_CRIT,
- "ERROR_ADDRESS (0x%lx) value NOT mapped to 'csrow'\n",
- (unsigned long)sys_addr);
+ amd64_mc_err(mci, "ERROR_ADDRESS (0x%lx) NOT mapped to CS\n",
+ (unsigned long)sys_addr);
edac_mc_handle_ue_no_info(log_mci, EDAC_MOD_STR);
} else {
error_address_to_page_and_offset(sys_addr, &page, &offset);
@@ -2044,9 +2028,9 @@ static int amd64_reserve_mc_sibling_devices(struct amd64_pvt *pvt, u16 f1_id,
/* Reserve the ADDRESS MAP Device */
pvt->F1 = pci_get_related_function(pvt->F2->vendor, f1_id, pvt->F2);
if (!pvt->F1) {
- amd64_printk(KERN_ERR, "error address map device not found: "
- "vendor %x device 0x%x (broken BIOS?)\n",
- PCI_VENDOR_ID_AMD, f1_id);
+ amd64_err("error address map device not found: "
+ "vendor %x device 0x%x (broken BIOS?)\n",
+ PCI_VENDOR_ID_AMD, f1_id);
return -ENODEV;
}
@@ -2056,9 +2040,9 @@ static int amd64_reserve_mc_sibling_devices(struct amd64_pvt *pvt, u16 f1_id,
pci_dev_put(pvt->F1);
pvt->F1 = NULL;
- amd64_printk(KERN_ERR, "error F3 device not found: "
- "vendor %x device 0x%x (broken BIOS?)\n",
- PCI_VENDOR_ID_AMD, f3_id);
+ amd64_err("error F3 device not found: "
+ "vendor %x device 0x%x (broken BIOS?)\n",
+ PCI_VENDOR_ID_AMD, f3_id);
return -ENODEV;
}
@@ -2268,7 +2252,7 @@ static int amd64_init_csrows(struct mem_ctl_info *mci)
csrow->page_mask = ~mask_from_dct_mask(pvt, i);
/* 8 bytes of resolution */
- csrow->mtype = amd64_determine_memory_type(pvt);
+ csrow->mtype = amd64_determine_memory_type(pvt, i);
debugf1(" for MC node %d csrow %d:\n", pvt->mc_node_id, i);
debugf1(" input_addr_min: 0x%lx input_addr_max: 0x%lx\n",
@@ -2313,8 +2297,7 @@ static bool amd64_nb_mce_bank_enabled_on_node(int nid)
bool ret = false;
if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
- amd64_printk(KERN_WARNING, "%s: error allocating mask\n",
- __func__);
+ amd64_warn("%s: Error allocating mask\n", __func__);
return false;
}
@@ -2346,8 +2329,7 @@ static int amd64_toggle_ecc_err_reporting(struct amd64_pvt *pvt, bool on)
int cpu;
if (!zalloc_cpumask_var(&cmask, GFP_KERNEL)) {
- amd64_printk(KERN_WARNING, "%s: error allocating mask\n",
- __func__);
+ amd64_warn("%s: error allocating mask\n", __func__);
return false;
}
@@ -2394,8 +2376,7 @@ static void amd64_enable_ecc_error_reporting(struct mem_ctl_info *mci)
pci_write_config_dword(pvt->F3, K8_NBCTL, value);
if (amd64_toggle_ecc_err_reporting(pvt, ON))
- amd64_printk(KERN_WARNING, "Error enabling ECC reporting over "
- "MCGCTL!\n");
+ amd64_warn("Error enabling ECC reporting over MCGCTL!\n");
amd64_read_pci_cfg(pvt->F3, K8_NBCFG, &value);
@@ -2404,9 +2385,7 @@ static void amd64_enable_ecc_error_reporting(struct mem_ctl_info *mci)
(value & K8_NBCFG_ECC_ENABLE) ? "Enabled" : "Disabled");
if (!(value & K8_NBCFG_ECC_ENABLE)) {
- amd64_printk(KERN_WARNING,
- "This node reports that DRAM ECC is "
- "currently Disabled; ENABLING now\n");
+ amd64_warn("DRAM ECC disabled on this node, enabling...\n");
pvt->flags.nb_ecc_prev = 0;
@@ -2417,12 +2396,10 @@ static void amd64_enable_ecc_error_reporting(struct mem_ctl_info *mci)
amd64_read_pci_cfg(pvt->F3, K8_NBCFG, &value);
if (!(value & K8_NBCFG_ECC_ENABLE)) {
- amd64_printk(KERN_WARNING,
- "Hardware rejects Enabling DRAM ECC checking\n"
- "Check memory DIMM configuration\n");
+ amd64_warn("Hardware rejected DRAM ECC enable,"
+ "check memory DIMM configuration.\n");
} else {
- amd64_printk(KERN_DEBUG,
- "Hardware accepted DRAM ECC Enable\n");
+ amd64_info("Hardware accepted DRAM ECC Enable\n");
}
} else {
pvt->flags.nb_ecc_prev = 1;
@@ -2457,7 +2434,7 @@ static void amd64_restore_ecc_error_reporting(struct amd64_pvt *pvt)
/* restore the NB Enable MCGCTL bit */
if (amd64_toggle_ecc_err_reporting(pvt, OFF))
- amd64_printk(KERN_WARNING, "Error restoring NB MCGCTL settings!\n");
+ amd64_warn("Error restoring NB MCGCTL settings!\n");
}
/*
@@ -2481,25 +2458,20 @@ static int amd64_check_ecc_enabled(struct amd64_pvt *pvt)
amd64_read_pci_cfg(pvt->F3, K8_NBCFG, &value);
ecc_enabled = !!(value & K8_NBCFG_ECC_ENABLE);
- if (!ecc_enabled)
- amd64_printk(KERN_NOTICE, "This node reports that Memory ECC "
- "is currently disabled, set F3x%x[22] (%s).\n",
- K8_NBCFG, pci_name(pvt->F3));
- else
- amd64_printk(KERN_INFO, "ECC is enabled by BIOS.\n");
+ amd64_info("DRAM ECC %s.\n", (ecc_enabled ? "enabled" : "disabled"));
nb_mce_en = amd64_nb_mce_bank_enabled_on_node(pvt->mc_node_id);
if (!nb_mce_en)
- amd64_printk(KERN_NOTICE, "NB MCE bank disabled, set MSR "
- "0x%08x[4] on node %d to enable.\n",
+ amd64_notice("NB MCE bank disabled, "
+ "set MSR 0x%08x[4] on node %d to enable.\n",
MSR_IA32_MCG_CTL, pvt->mc_node_id);
if (!ecc_enabled || !nb_mce_en) {
if (!ecc_enable_override) {
- amd64_printk(KERN_NOTICE, "%s", ecc_msg);
+ amd64_notice("%s", ecc_msg);
return -ENODEV;
} else {
- amd64_printk(KERN_WARNING, "Forcing ECC checking on!\n");
+ amd64_warn("Forcing ECC on!\n");
}
}
@@ -2575,17 +2547,17 @@ static struct amd64_family_type *amd64_per_family_init(struct amd64_pvt *pvt)
break;
default:
- amd64_printk(KERN_ERR, "Unsupported family!\n");
+ amd64_err("Unsupported family!\n");
return NULL;
}
pvt->ext_model = boot_cpu_data.x86_model >> 4;
- amd64_printk(KERN_INFO, "%s %s detected.\n", pvt->ctl_name,
+ amd64_info("%s %sdetected (node %d).\n", pvt->ctl_name,
(fam == 0xf ?
- (pvt->ext_model >= K8_REV_F ? "revF or later"
- : "revE or earlier")
- : ""));
+ (pvt->ext_model >= K8_REV_F ? "revF or later "
+ : "revE or earlier ")
+ : ""), pvt->mc_node_id);
return fam_type;
}
@@ -2736,8 +2708,6 @@ static int __devinit amd64_init_one_instance(struct pci_dev *pdev,
{
int ret = 0;
- debugf0("(MC node=%d)\n", get_node_id(pdev));
-
ret = pci_enable_device(pdev);
if (ret < 0) {
debugf0("ret=%d\n", ret);
@@ -2746,8 +2716,7 @@ static int __devinit amd64_init_one_instance(struct pci_dev *pdev,
ret = amd64_probe_one_instance(pdev);
if (ret < 0)
- amd64_printk(KERN_ERR, "Error probing instance: %d\n",
- get_node_id(pdev));
+ amd64_err("Error probing instance: %d\n", get_node_id(pdev));
return ret;
}
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index 76760a8043ca..f15e2b257e72 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -74,11 +74,26 @@
#include "edac_core.h"
#include "mce_amd.h"
-#define amd64_printk(level, fmt, arg...) \
- edac_printk(level, "amd64", fmt, ##arg)
+#define amd64_debug(fmt, arg...) \
+ edac_printk(KERN_DEBUG, "amd64", fmt, ##arg)
-#define amd64_mc_printk(mci, level, fmt, arg...) \
- edac_mc_chipset_printk(mci, level, "amd64", fmt, ##arg)
+#define amd64_info(fmt, arg...) \
+ edac_printk(KERN_INFO, "amd64", fmt, ##arg)
+
+#define amd64_notice(fmt, arg...) \
+ edac_printk(KERN_NOTICE, "amd64", fmt, ##arg)
+
+#define amd64_warn(fmt, arg...) \
+ edac_printk(KERN_WARNING, "amd64", fmt, ##arg)
+
+#define amd64_err(fmt, arg...) \
+ edac_printk(KERN_ERR, "amd64", fmt, ##arg)
+
+#define amd64_mc_warn(mci, fmt, arg...) \
+ edac_mc_chipset_printk(mci, KERN_WARNING, "amd64", fmt, ##arg)
+
+#define amd64_mc_err(mci, fmt, arg...) \
+ edac_mc_chipset_printk(mci, KERN_ERR, "amd64", fmt, ##arg)
/*
* Throughout the comments in this code, the following terms are used:
@@ -129,7 +144,7 @@
* sections 3.5.4 and 3.5.5 for more information.
*/
-#define EDAC_AMD64_VERSION " Ver: 3.3.0 " __DATE__
+#define EDAC_AMD64_VERSION "v3.3.0"
#define EDAC_MOD_STR "amd64_edac"
#define EDAC_MAX_NUMNODES 8
@@ -527,8 +542,8 @@ static inline int amd64_read_pci_cfg_dword(struct pci_dev *pdev, int offset,
err = pci_read_config_dword(pdev, offset, val);
if (err)
- amd64_printk(KERN_WARNING, "%s: error reading F%dx%x.\n",
- func, PCI_FUNC(pdev->devfn), offset);
+ amd64_warn("%s: error reading F%dx%x.\n",
+ func, PCI_FUNC(pdev->devfn), offset);
return err;
}
diff --git a/drivers/edac/amd64_edac_inj.c b/drivers/edac/amd64_edac_inj.c
index 523ce4a6edc6..688478de1cbd 100644
--- a/drivers/edac/amd64_edac_inj.c
+++ b/drivers/edac/amd64_edac_inj.c
@@ -23,9 +23,7 @@ static ssize_t amd64_inject_section_store(struct mem_ctl_info *mci,
if (ret != -EINVAL) {
if (value > 3) {
- amd64_printk(KERN_WARNING,
- "%s: invalid section 0x%lx\n",
- __func__, value);
+ amd64_warn("%s: invalid section 0x%lx\n", __func__, value);
return -EINVAL;
}
@@ -58,9 +56,7 @@ static ssize_t amd64_inject_word_store(struct mem_ctl_info *mci,
if (ret != -EINVAL) {
if (value > 8) {
- amd64_printk(KERN_WARNING,
- "%s: invalid word 0x%lx\n",
- __func__, value);
+ amd64_warn("%s: invalid word 0x%lx\n", __func__, value);
return -EINVAL;
}
@@ -92,9 +88,8 @@ static ssize_t amd64_inject_ecc_vector_store(struct mem_ctl_info *mci,
if (ret != -EINVAL) {
if (value & 0xFFFF0000) {
- amd64_printk(KERN_WARNING,
- "%s: invalid EccVector: 0x%lx\n",
- __func__, value);
+ amd64_warn("%s: invalid EccVector: 0x%lx\n",
+ __func__, value);
return -EINVAL;
}
diff --git a/drivers/edac/edac_core.h b/drivers/edac/edac_core.h
index 251440cd50a3..e8d3dd0b5e9c 100644
--- a/drivers/edac/edac_core.h
+++ b/drivers/edac/edac_core.h
@@ -68,9 +68,10 @@
#define EDAC_PCI "PCI"
#define EDAC_DEBUG "DEBUG"
+extern const char *edac_mem_types[];
+
#ifdef CONFIG_EDAC_DEBUG
extern int edac_debug_level;
-extern const char *edac_mem_types[];
#define edac_debug_printk(level, fmt, arg...) \
do { \
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 795ea69c4d8f..a4e9db2d6524 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -76,6 +76,8 @@ static void edac_mc_dump_mci(struct mem_ctl_info *mci)
debugf3("\tpvt_info = %p\n\n", mci->pvt_info);
}
+#endif /* CONFIG_EDAC_DEBUG */
+
/*
* keep those in sync with the enum mem_type
*/
@@ -100,8 +102,6 @@ const char *edac_mem_types[] = {
};
EXPORT_SYMBOL_GPL(edac_mem_types);
-#endif /* CONFIG_EDAC_DEBUG */
-
/* 'ptr' points to a possibly unaligned item X such that sizeof(X) is 'size'.
* Adjust 'ptr' so that its alignment is at least as stringent as what the
* compiler would provide for X and return the aligned result.