Messages in this thread Patch in this message | | | Date | Fri, 29 May 2015 15:49:43 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 3/6] edac, mce_amd_inj: Modify flags attrigute to use string arguments |
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On Wed, May 27, 2015 at 02:03:35PM -0500, Aravind Gopalakrishnan wrote: > Use char values such as "hw" or "sw" to indicate the type of error > injection to be performed. > > Current flags attribute derives the meanings of values that can be > programmed into it from asm/mce.h. Moving to defined strings for the > atribute allows this module to be self sufficient and removes the > dependency. Also, we can introduce new flags as and when needed without > having to worry about conflicting with the flags already defined > in asm/mce.h > > Also, modify do_inject() to use the newly defined injection_type enum > to figure out the injection mechanism we need to use > > Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com> > --- > drivers/edac/mce_amd_inj.c | 85 +++++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 76 insertions(+), 9 deletions(-) > > diff --git a/drivers/edac/mce_amd_inj.c b/drivers/edac/mce_amd_inj.c > index 15f6aa1..daec4af 100644 > --- a/drivers/edac/mce_amd_inj.c > +++ b/drivers/edac/mce_amd_inj.c > @@ -15,6 +15,8 @@ > #include <linux/device.h> > #include <linux/module.h> > #include <linux/cpu.h> > +#include <linux/string.h> > +#include <linux/uaccess.h> > #include <asm/mce.h> > > #include "mce_amd.h" > @@ -27,6 +29,23 @@ static struct dentry *dfs_inj; > > static u8 n_banks; > > +#define MAX_FLAG_OPT_SIZE 10
Why 10?
This should be 2 and increased when another, longer injection type string gets introduced.
> + > +enum injection_type { > + SW_INJ = 0, /* SW injection, simply decode the error */ > + HW_INJ, /* Trigger a #MC */ > + N_INJ_TYPES, > +}; > + > +static const char * const flags_options[] = { > + [SW_INJ] = "sw", > + [HW_INJ] = "hw", > + NULL > +};
> + > +/* Set default injection to SW_INJ */ > +enum injection_type inj_type = SW_INJ; > + > #define MCE_INJECT_SET(reg) \ > static int inj_##reg##_set(void *data, u64 val) \ > { \ > @@ -81,24 +100,72 @@ static int toggle_hw_mce_inject(unsigned int cpu, bool enable) > return err; > } > > -static int flags_get(void *data, u64 *val) > +static int __set_inj(const char *buf, size_t cnt) > { > - struct mce *m = (struct mce *)data; > + int i; > + const char *inj_op = NULL; > > - *val = m->inject_flags; > + for (i = 0; i <= N_INJ_TYPES; i++) { > + inj_op = flags_options[i]; > + if (inj_op && strncmp(inj_op, buf, cnt) == 0) > + break; > + }
What's wrong with:
for (i = 0; i < N_INJ_TYPES; i++) { if (!strncmp(flags_options[i], buf, strlen(flags_options[i]))) { inj_type = i; return 0; } }
return -EINVAL;
> + > + if (!inj_op) > + return -EINVAL; > + > + inj_type = i; > > return 0; > } > > -static int flags_set(void *data, u64 val) > +static ssize_t flags_read(struct file *filp, char __user *ubuf, > + size_t cnt, loff_t *ppos) > { > - struct mce *m = (struct mce *)data; > + char buf[MAX_FLAG_OPT_SIZE + 1]; > + int n; > > - m->inject_flags = (u8)val; > - return 0; > + n = sprintf(buf, "%s\n", flags_options[inj_type]); > + > + return simple_read_from_buffer(ubuf, cnt, ppos, buf, n); > } > > -DEFINE_SIMPLE_ATTRIBUTE(flags_fops, flags_get, flags_set, "%llu\n"); > +static ssize_t flags_write(struct file *filp, const char __user *ubuf, > + size_t cnt, loff_t *ppos) > +{ > + char buf[MAX_FLAG_OPT_SIZE + 1]; > + int err; > + size_t ret; > + > + ret = cnt;
You're assigning cnt to ret here...
> + > + if (cnt > MAX_FLAG_OPT_SIZE) > + cnt = MAX_FLAG_OPT_SIZE;
... but correcting cnt afterwards. The assignment should be *after* that correction.
> + > + if (copy_from_user(&buf, ubuf, cnt)) > + return -EFAULT; > + > + buf[cnt] = 0; > + > + /* strip whitespaces.. */ > + strstrip(buf); > + > + err = __set_inj(buf, cnt - 1); > + if (err) { > + pr_err("%s: Invalid flags value: %s\n", __func__, buf); > + return err; > + } > + > + *ppos += ret; > + > + return ret; > +} > + > +static const struct file_operations flags_fops = { > + .read = flags_read, > + .write = flags_write, > + .llseek = generic_file_llseek, > +}; > > /* > * On which CPU to inject? > @@ -130,7 +197,7 @@ static void do_inject(void) > unsigned int cpu = i_mce.extcpu; > u8 b = i_mce.bank; > > - if (!(i_mce.inject_flags & MCJ_EXCEPTION)) { > + if (inj_type == SW_INJ) { > amd_decode_mce(NULL, 0, &i_mce); > return; > } > -- > 2.4.0 > >
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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