On Fri, 27 Feb 2015 14:39:42 +0100 Artur Paszkiewicz
<artur.paszkiewicz@xxxxxxxxx> wrote:
> On 02/25/2015 06:15 PM, Jes Sorensen wrote:
> > Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx> writes:
> >> On 02/25/2015 01:29 PM, Jes Sorensen wrote:
> >>> Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx> writes:
> >>>> On 02/24/2015 10:00 PM, Jes.Sorensen@xxxxxxxxxx wrote:
> >>>>> From: Jes Sorensen <Jes.Sorensen@xxxxxxxxxx>
> >>>>>
> >>>>> This avoids adding the same orom entry to the oroms list multiple
> >>>>> times, as the comparison of pointers is never going to succeed, in
> >>>>> particular when '*orom' points to a local stack variable in the
> >>>>> calling function.
> >>>>>
> >>>>> Signed-off-by: Jes Sorensen <Jes.Sorensen@xxxxxxxxxx>
> >>>>> ---
> >>>>> platform-intel.c | 4 ++--
> >>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>>
> >>>>> diff --git a/platform-intel.c b/platform-intel.c
> >>>>> index 37274da..a4ffa9f 100644
> >>>>> --- a/platform-intel.c
> >>>>> +++ b/platform-intel.c
> >>>>> @@ -255,8 +255,8 @@ static const struct imsm_orom *add_orom(const struct imsm_orom *orom)
> >>>>> int i;
> >>>>>
> >>>>> for (i = 0; i < SYS_DEV_MAX; i++) {
> >>>>> - if (&oroms[i].orom == orom)
> >>>>> - return orom;
> >>>>> + if (!memcmp(&oroms[i].orom, orom, sizeof(struct imsm_orom)))
> >>>>> + return &oroms[i].orom;
> >>>>> if (oroms[i].orom.signature[0] == 0) {
> >>>>> oroms[i].orom = *orom;
> >>>>> return &oroms[i].orom;
> >>>>>
> >>>>
> >>>> Hi Jes,
> >>>>
> >>>> You are right that this can add the same entry multiple times, but this
> >>>> is how it is supposed to work. The oroms list should contain all the
> >>>> platform's oroms and they can be the same, this is why memcmp() should
> >>>> not be used here. We don't want to compare the contents of the
> >>>> structure, just its address. Sorry if it's not clear.
> >>>
> >>> Artur,
> >>>
> >>> Then the code is fundamentally broken, since you end up comparing a
> >>> stack variable against the oroms array when you call it from
> >>> find_imsm_efi(). Worse you can end up returning the local stack variable
> >>> declared in find_imsm_efi() to the calling function - there is no way
> >>> that can be correct.
> >>>
> >>> Look at this:
> >>>
> >>> static const struct imsm_orom *add_orom(const struct imsm_orom *orom)
> >>> {
> >>> int i;
> >>>
> >>> for (i = 0; i < SYS_DEV_MAX; i++) {
> >>> if (&oroms[i].orom == orom)
> >>> return orom;
> >>> if (oroms[i].orom.signature[0] == 0) {
> >>> oroms[i].orom = *orom;
> >>> return &oroms[i].orom;
> >>> }
> >>> }
> >>> return NULL;
> >>> }
> >>>
> >>> const struct imsm_orom *find_imsm_efi(struct sys_dev *hba)
> >>> {
> >>> struct imsm_orom orom;
> >>> const struct imsm_orom *ret;
> >>> int err;
> >>>
> >>> ....
> >>>
> >>> ret = add_orom(&orom);
> >>> add_orom_device_id(ret, hba->dev_id);
> >>>
> >>> return ret;
> >>> }
> >>
> >> I can't see how this can lead to returning a stack variable. The oroms
> >> array is global and add_orom() will always return a pointer to a struct
> >> in this array. This comparison will always fail when we pass a pointer
> >> to a stack variable to add_orom():
> >>
> >> if (&oroms[i].orom == orom)
> >> return orom;
> >>
> >> This was meant to prevent adding an orom again like this:
> >>
> >> ret = add_orom(&orom);
> >> add_orom(ret);
> >>
> >> Maybe it would be more appropriate to return NULL to indicate that
> >> nothing was added instead of returning back the same pointer. I can do a
> >> patch for this. What do you think?
> >
> > It will fail because we know we're comparing a stack pointer, but it
> > raises red flags with tools like coverity and it is really bad coding
> > practice to rely on hacks like this.
> >
> > I also don't understand why you want to keep a table of identical
> > entries in the orom structure if multiple identical entries are found.
> > Each entry ought to match onto a specific physical controller, unless I
> > get something wrong?
> >
>
> OK, you're right, it is a hack. I thought it over and redesigned those
> orom functions. This should make it simpler and more consistent.
>
> Thanks,
> Artur
>
> >From 673ecf1c0539f0050cc5934203af6d79cd68234d Mon Sep 17 00:00:00 2001
> From: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> Date: Fri, 27 Feb 2015 10:34:20 +0100
> Subject: [PATCH] imsm: simplified multiple OROMs support
>
> Replaced oroms array with list, add_orom() now only appends to this list
> and add_orom_device_id() only appends devid_list node to an orom_entry.
>
> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> ---
> platform-intel.c | 96 +++++++++++++++++++++++++++-----------------------------
> platform-intel.h | 4 ++-
> super-intel.c | 18 +++++------
> 3 files changed, 57 insertions(+), 61 deletions(-)
>
> diff --git a/platform-intel.c b/platform-intel.c
> index 37274da..9c89c20 100644
> --- a/platform-intel.c
> +++ b/platform-intel.c
> @@ -229,65 +229,61 @@ struct pciExpDataStructFormat {
> __u16 devListOffset;
> } __attribute__ ((packed));
>
> -static struct orom_entry oroms[SYS_DEV_MAX];
> -
> -const struct orom_entry *get_oroms(void)
> -{
> - return (const struct orom_entry *)&oroms;
> -}
> +struct orom_entry *orom_entries;
>
> const struct imsm_orom *get_orom_by_device_id(__u16 dev_id)
> {
> - int i;
> - struct devid_list *list;
> + struct orom_entry *entry;
> + struct devid_list *devid;
>
> - for (i = 0; i < SYS_DEV_MAX; i++) {
> - for (list = oroms[i].devid_list; list; list = list->next) {
> - if (list->devid == dev_id)
> - return &oroms[i].orom;
> + for (entry = orom_entries; entry; entry = entry->next) {
> + for (devid = entry->devid_list; devid; devid = devid->next) {
> + if (devid->devid == dev_id)
> + return &entry->orom;
> }
> }
> +
> return NULL;
> }
>
> -static const struct imsm_orom *add_orom(const struct imsm_orom *orom)
> +static struct orom_entry *add_orom(const struct imsm_orom *orom)
> {
> - int i;
> -
> - for (i = 0; i < SYS_DEV_MAX; i++) {
> - if (&oroms[i].orom == orom)
> - return orom;
> - if (oroms[i].orom.signature[0] == 0) {
> - oroms[i].orom = *orom;
> - return &oroms[i].orom;
> - }
> - }
> - return NULL;
> + struct orom_entry *list;
> + struct orom_entry *prev = NULL;
> +
> + for (list = orom_entries; list; prev = list, list = list->next)
> + ;
> +
> + list = xmalloc(sizeof(struct orom_entry));
> + list->orom = *orom;
> + list->devid_list = NULL;
> + list->next = NULL;
> +
> + if (prev == NULL)
> + orom_entries = list;
> + else
> + prev->next = list;
> +
> + return list;
> }
>
> -static void add_orom_device_id(const struct imsm_orom *orom, __u16 dev_id)
> +static void add_orom_device_id(struct orom_entry *entry, __u16 dev_id)
> {
> - int i;
> struct devid_list *list;
> struct devid_list *prev = NULL;
>
> - for (i = 0; i < SYS_DEV_MAX; i++) {
> - if (&oroms[i].orom == orom) {
> - for (list = oroms[i].devid_list; list; prev = list, list = list->next) {
> - if (list->devid == dev_id)
> - return;
> - }
> - list = xmalloc(sizeof(struct devid_list));
> - list->devid = dev_id;
> - list->next = NULL;
> -
> - if (prev == NULL)
> - oroms[i].devid_list = list;
> - else
> - prev->next = list;
> + for (list = entry->devid_list; list; prev = list, list = list->next) {
> + if (list->devid == dev_id)
> return;
> - }
> }
> + list = xmalloc(sizeof(struct devid_list));
> + list->devid = dev_id;
> + list->next = NULL;
> +
> + if (prev == NULL)
> + entry->devid_list = list;
> + else
> + prev->next = list;
> }
>
> static int scan(const void *start, const void *end, const void *data)
> @@ -321,7 +317,7 @@ static int scan(const void *start, const void *end, const void *data)
> if (!imsm_mem)
> return 0;
>
> - const struct imsm_orom *orom = add_orom(imsm_mem);
> + struct orom_entry *orom = add_orom(imsm_mem);
>
> if (ptr->devListOffset) {
> const __u16 *dev_list = (void *)ptr + ptr->devListOffset;
> @@ -367,11 +363,11 @@ const struct imsm_orom *imsm_platform_test(struct sys_dev *hba)
> IMSM_OROM_RLC_RAID10;
> }
>
> - const struct imsm_orom *ret = add_orom(&orom);
> + struct orom_entry *ret = add_orom(&orom);
>
> add_orom_device_id(ret, hba->dev_id);
>
> - return ret;
> + return &ret->orom;
> }
>
> static const struct imsm_orom *find_imsm_hba_orom(struct sys_dev *hba)
> @@ -508,7 +504,7 @@ static int read_efi_variable(void *buffer, ssize_t buf_size, char *variable_name
> const struct imsm_orom *find_imsm_efi(struct sys_dev *hba)
> {
> struct imsm_orom orom;
> - const struct imsm_orom *ret;
> + struct orom_entry *ret;
> int err;
>
> if (check_env("IMSM_TEST_AHCI_EFI") || check_env("IMSM_TEST_SCU_EFI"))
> @@ -529,14 +525,14 @@ const struct imsm_orom *find_imsm_efi(struct sys_dev *hba)
>
> /* try to read variable for combined AHCI controllers */
> if (err && hba->type == SYS_DEV_SATA) {
> - static const struct imsm_orom *csata;
> + static struct orom_entry *csata;
>
> err = read_efi_variable(&orom, sizeof(orom), AHCI_CSATA_PROP, VENDOR_GUID);
> if (!err) {
> if (!csata)
> csata = add_orom(&orom);
> add_orom_device_id(csata, hba->dev_id);
> - return csata;
> + return &csata->orom;
> }
> }
>
> @@ -546,12 +542,12 @@ const struct imsm_orom *find_imsm_efi(struct sys_dev *hba)
> ret = add_orom(&orom);
> add_orom_device_id(ret, hba->dev_id);
>
> - return ret;
> + return &ret->orom;
> }
>
> const struct imsm_orom *find_imsm_nvme(struct sys_dev *hba)
> {
> - static const struct imsm_orom *nvme_orom;
> + static struct orom_entry *nvme_orom;
>
> if (hba->type != SYS_DEV_NVME)
> return NULL;
> @@ -574,7 +570,7 @@ const struct imsm_orom *find_imsm_nvme(struct sys_dev *hba)
> nvme_orom = add_orom(&nvme_orom_compat);
> }
> add_orom_device_id(nvme_orom, hba->dev_id);
> - return nvme_orom;
> + return &nvme_orom->orom;
> }
>
> const struct imsm_orom *find_imsm_capability(struct sys_dev *hba)
> diff --git a/platform-intel.h b/platform-intel.h
> index 2ead431..631fa76 100644
> --- a/platform-intel.h
> +++ b/platform-intel.h
> @@ -213,8 +213,11 @@ struct devid_list {
> struct orom_entry {
> struct imsm_orom orom;
> struct devid_list *devid_list;
> + struct orom_entry *next;
> };
>
> +extern struct orom_entry *orom_entries;
> +
> static inline char *guid_str(char *buf, struct efi_guid guid)
> {
> sprintf(buf, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
> @@ -235,6 +238,5 @@ int devt_attached_to_hba(dev_t dev, const char *hba_path);
> char *devt_to_devpath(dev_t dev);
> int path_attached_to_hba(const char *disk_path, const char *hba_path);
> const char *get_sys_dev_type(enum sys_dev_type);
> -const struct orom_entry * get_oroms(void);
> const struct imsm_orom *get_orom_by_device_id(__u16 device_id);
> struct sys_dev *device_by_id(__u16 device_id);
> diff --git a/super-intel.c b/super-intel.c
> index 819e0da..53269fd 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -1948,13 +1948,12 @@ static int detail_platform_imsm(int verbose, int enumerate_only, char *controlle
> return result;
> }
>
> - const struct orom_entry *oroms = get_oroms();
> - int i;
> + const struct orom_entry *entry;
>
> - for (i = 0; i < SYS_DEV_MAX && oroms[i].devid_list; i++) {
> - print_imsm_capability(&oroms[i].orom);
> + for (entry = orom_entries; entry; entry = entry->next) {
> + print_imsm_capability(&entry->orom);
>
> - if (imsm_orom_is_nvme(&oroms[i].orom)) {
> + if (imsm_orom_is_nvme(&entry->orom)) {
> for (hba = list; hba; hba = hba->next) {
> if (hba->type == SYS_DEV_NVME)
> printf(" NVMe Device : %s\n", hba->path);
> @@ -1963,7 +1962,7 @@ static int detail_platform_imsm(int verbose, int enumerate_only, char *controlle
> }
>
> struct devid_list *devid;
> - for (devid = oroms[i].devid_list; devid; devid = devid->next) {
> + for (devid = entry->devid_list; devid; devid = devid->next) {
> hba = device_by_id(devid->devid);
> if (!hba)
> continue;
> @@ -2007,11 +2006,10 @@ static int export_detail_platform_imsm(int verbose, char *controller_path)
> result = 0;
> }
>
> - const struct orom_entry *oroms = get_oroms();
> - int i;
> + const struct orom_entry *entry;
>
> - for (i = 0; i < SYS_DEV_MAX && oroms[i].devid_list; i++)
> - print_imsm_capability_export(&oroms[i].orom);
> + for (entry = orom_entries; entry; entry = entry->next)
> + print_imsm_capability_export(&entry->orom);
>
> return result;
> }
Applied, thanks.
NeilBrown
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