[PATCH v10 5/7] ACPI: APEI: EINJ: Create debugfs files to enter device id and syndrome

[Zaid Alali]

From: Tony Luck <tony.l...@intel.com>

EINJv2 allows users to inject multiple errors at the same time by
specifying the device id and syndrome bits for each error in a flex
array.

Create files in the einj debugfs directory to enter data for each
device id and syndrome value. Note that the specification says these
are 128-bit little-endian values. Linux doesn't have a handy helper
to manage objects of this type.

Signed-off-by: Tony Luck <tony.l...@intel.com>
Reviewed-by: Ira Weiny <ira.we...@intel.com>
Signed-off-by: Zaid Alali <zai...@os.amperecomputing.com>
---
 drivers/acpi/apei/einj-core.c | 97 +++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/drivers/acpi/apei/einj-core.c b/drivers/acpi/apei/einj-core.c
index ea6fd4343e63..87f1b8718387 100644
--- a/drivers/acpi/apei/einj-core.c
+++ b/drivers/acpi/apei/einj-core.c
@@ -111,6 +111,7 @@ static char vendor_dev[64];
 static u32 max_nr_components;
 static u32 available_error_type;
 static u32 available_error_type_v2;
+static struct syndrome_array *syndrome_data;
 
 /*
  * Some BIOSes allow parameters to the SET_ERROR_TYPE entries in the
@@ -712,6 +713,7 @@ static u64 error_param3;
 static u64 error_param4;
 static struct dentry *einj_debug_dir;
 static char einj_buf[32];
+static bool einj_v2_enabled;
 static struct { u32 mask; const char *str; } const einj_error_type_string[] = {
        { BIT(0), "Processor Correctable" },
        { BIT(1), "Processor Uncorrectable non-fatal" },
@@ -848,6 +850,98 @@ static int einj_check_table(struct acpi_table_einj 
*einj_tab)
        return 0;
 }
 
+static ssize_t u128_read(struct file *f, char __user *buf, size_t count, 
loff_t *off)
+{
+       char output[2 * COMPONENT_LEN + 1];
+       u8 *data = f->f_inode->i_private;
+       int i;
+
+       if (*off >= sizeof(output))
+               return 0;
+
+       for (i = 0; i < COMPONENT_LEN; i++)
+               sprintf(output + 2 * i, "%.02x", data[COMPONENT_LEN - i - 1]);
+       output[2 * COMPONENT_LEN] = '\n';
+
+       return simple_read_from_buffer(buf, count, off, output, sizeof(output));
+}
+
+static ssize_t u128_write(struct file *f, const char __user *buf, size_t 
count, loff_t *off)
+{
+       char input[2 + 2 * COMPONENT_LEN + 2];
+       u8 *save = f->f_inode->i_private;
+       u8 tmp[COMPONENT_LEN];
+       char byte[3] = {};
+       char *s, *e;
+       size_t c;
+       long val;
+       int i;
+
+       /* Require that user supply whole input line in one write(2) syscall */
+       if (*off)
+               return -EINVAL;
+
+       c = simple_write_to_buffer(input, sizeof(input), off, buf, count);
+       if (c < 0)
+               return c;
+
+       if (c < 1 || input[c - 1] != '\n')
+               return -EINVAL;
+
+       /* Empty line means invalidate this entry */
+       if (c == 1) {
+               memset(save, 0xff, COMPONENT_LEN);
+               return c;
+       }
+
+       if (input[0] == '0' && (input[1] == 'x' || input[1] == 'X'))
+               s = input + 2;
+       else
+               s = input;
+       e = input + c - 1;
+
+       for (i = 0; i < COMPONENT_LEN; i++) {
+               byte[1] = *--e;
+               byte[0] = e > s ? *--e : '0';
+               if (kstrtol(byte, 16, &val))
+                       return -EINVAL;
+               tmp[i] = val;
+               if (e <= s)
+                       break;
+       }
+       while (++i < COMPONENT_LEN)
+               tmp[i] = 0;
+
+       memcpy(save, tmp, COMPONENT_LEN);
+
+       return c;
+}
+
+static const struct file_operations u128_fops = {
+       .read   = u128_read,
+       .write  = u128_write,
+};
+
+static bool setup_einjv2_component_files(void)
+{
+       char name[32];
+
+       syndrome_data = kcalloc(max_nr_components, sizeof(syndrome_data[0]), 
GFP_KERNEL);
+       if (!syndrome_data)
+               return false;
+
+       for (int i = 0; i < max_nr_components; i++) {
+               sprintf(name, "component_id%d", i);
+               debugfs_create_file(name, 0600, einj_debug_dir,
+                                   &syndrome_data[i].comp_id, &u128_fops);
+               sprintf(name, "component_syndrome%d", i);
+               debugfs_create_file(name, 0600, einj_debug_dir,
+                                   &syndrome_data[i].comp_synd, &u128_fops);
+       }
+
+       return true;
+}
+
 static int __init einj_probe(struct faux_device *fdev)
 {
        int rc;
@@ -919,6 +1013,8 @@ static int __init einj_probe(struct faux_device *fdev)
                                   &error_param4);
                debugfs_create_x32("notrigger", S_IRUSR | S_IWUSR,
                                   einj_debug_dir, &notrigger);
+               if (available_error_type & ACPI65_EINJV2_SUPP)
+                       einj_v2_enabled = setup_einjv2_component_files();
        }
 
        if (vendor_dev[0]) {
@@ -967,6 +1063,7 @@ static void __exit einj_remove(struct faux_device *fdev)
        apei_resources_release(&einj_resources);
        apei_resources_fini(&einj_resources);
        debugfs_remove_recursive(einj_debug_dir);
+       kfree(syndrome_data);
        acpi_put_table((struct acpi_table_header *)einj_tab);
 }
 
-- 
2.43.0