Re: [flashrom] [PATCH] Refactor the -p internal:mainboard handling.

[Carl-Daniel Hailfinger]

Am 13.08.2012 02:51 schrieb Stefan Tauner:
> This patch gets rid of some global variables and makes lots of bits along
> the code path that control the board enable execution more generic and
> clearer. From now on flashrom also abort on a few occasions that should be
> safer for the user. For example we abort if he specifies the mainboard (enable)
> but we can not find the enable function.
>
> Parts of the board_match_cbname refactoring were done by Carl-Daniel.
>
> FIXME: manpage
>
> Signed-off-by: Stefan Tauner 
> Signed-off-by: Carl-Daniel Hailfinger

Acked-by: Carl-Daniel Hailfinger 
with a few comments and if you fix the manpage.

BIG FAT NOTE: You do not have to change all the stuff mentioned in the
review (because that would mean I have to review the patch again), but
it would be nice to have the review comments addressed in a followup patch.
> This might be kinda unreviewable...
> i can probably split it up if need be, just tell me please.

Big patch, but still... splitting it wouldn't have helped.
> diff --git a/board_enable.c b/board_enable.c
> index 9c16905..22d4072 100644
> --- a/board_enable.c
> +++ b/board_enable.c
> @@ -25,6 +25,7 @@
>   */
>
> #include <string.h>
> +#include <stdlib.h>
>  #include "flash.h"
>  #include "programmer.h"
>  #include "hwaccess.h"
> @@ -2443,41 +2444,63 @@ const struct board_match board_matches[] = {
>    {     0,      0,      0,      0,       0,      0,      0,      0, NULL,         NULL, NULL,           P3, NULL,          NULL,                    0,   NT, NULL}, /* end marker */
>  };
>
> +/* Parse the <vendor>:<board> string specified by the user as part of -p internal:mainboard=<vendor>:<board>.
> Parameters vendor and model will be overwritten. Returns 0 on success.
> Note: strtok modifies the original string, so we work on a copy and allocate memory for the results.
> */
>
> +int board_parse_parameter(const char *boardstring, const char **vendor, const char **model)
> +{
> /* strtok may modify the original string. */
> char *tempstr = strdup(boardstring);
> char *tempstr2 = NULL;
> strtok(tempstr, ":");
> tempstr2 = strtok(NULL, ":");
> if (tempstr == NULL || tempstr2 == NULL) {
> free(tempstr);

While freeing only tempstr is correct, it's not obvious.
> msg_pinfo("Please supply the board vendor and model name with the "
> 	  "-p internal:mainboard=<vendor>:<model> option.\n");
> return 1;
> }
> *vendor = strdup(tempstr);
> *model = strdup(tempstr2);
> msg_pspew("-p internal:mainboard: vendor="%s", model="%s"\n", tempstr, tempstr2);
> free(tempstr);
> return 0;
>
> +}
>
> /*
> Match boards on coreboot table gathered vendor and part name.
> Match boards on vendor and model name.
> Hint: the parameters can come either from the coreboot table or the command line (i.e. the user).

Please add the following comment:
vendor and model must be non-NULL.
> Require main PCI IDs to match too as extra safety.
>
> */
> -static const struct board_match *board_match_cbname(const char *vendor,
> 				    const char *part)
>
> +static const struct board_match *board_match_name(const char *vendor, const char *model)
>  {
>    const struct board_match *board = board_matches;
>    const struct board_match *partmatch = NULL;
>
> for (; board->vendor_name; board++) {
> if (vendor && (!board->lb_vendor
> 	       || strcasecmp(board->lb_vendor, vendor)))
> if (!board->lb_vendor || strcasecmp(board->lb_vendor, vendor))
> continue;
>
> if (!board->lb_part || strcasecmp(board->lb_part, part))
> if (!board->lb_part || strcasecmp(board->lb_part, model))
> continue;
>
> if (!pci_dev_find(board->first_vendor, board->first_device))
> if (!pci_dev_find(board->first_vendor, board->first_device)) {
> 	msg_pdbg("Odd. Board name \"%s\":\"%s\" matches, but first PCI device %04x:%04x "
> 		 "doesn't.\n", vendor, model, board->first_vendor, board->first_device);

Should we ask for a report here? Not sure, personal preference is not to
ask. If yes, at which message level?
> 	continue;
> }
>
> if (board->second_vendor &&
>     !pci_dev_find(board->second_vendor, board->second_device))
> if (!pci_dev_find(board->second_vendor, board->second_device)) {
> 	msg_pdbg("Odd. Board name \"%s\":\"%s\" matches, but second PCI device %04x:%04x "
> 		 "doesn't.\n", vendor, model, board->second_vendor, board->second_device);
> continue;
> if (vendor)
> 	return board;
> }
>
> if (partmatch) {
> 	/* a second entry has a matching part name */
> 	msg_pinfo("AMBIGUOUS BOARD NAME: %s\n", part);
> 	msg_pinfo("At least vendors '%s' and '%s' match.\n",
> 		  partmatch->lb_vendor, board->lb_vendor);
> 	msg_perr("Please use the full -p internal:mainboard="
> 		 "vendor:part syntax.\n");
> 	/* More than one entry has a matching name. */
> 	msg_perr("Board name \"%s\":\"%s\" and PCI IDs matched more than one board enable "
> 		 "entry. Please report a bug at [e-mail]\n", vendor, model);
> return NULL;
> }
> partmatch = board;
>
> @@ -2486,15 +2509,7 @@ static const struct board_match *board_match_cbname(const char *vendor,
>    if (partmatch)
>    	return partmatch;
> if (!partvendor_from_cbtable) {
> /* Only warn if the mainboard type was not gathered from the
>  * coreboot table. If it was, the coreboot implementor is
>  * expected to fix flashrom, too.
>  */
> msg_perr("\nUnknown vendor:board from -p internal:mainboard="
> 	 " programmer parameter:\n%s:%s\n\n",
> 	 vendor, part);
> }
> msg_perr("No board enable found for vendor="%s", model="%s".\n", vendor, model);
> return NULL;
>
> }
>
> @@ -2534,9 +2549,10 @@ const static struct board_match *board_match_pci_ids(enum board_match_phase phas
> if (board->dmi_pattern) {
> 	if (!has_dmi_support) {
> 		msg_perr("WARNING: Can't autodetect %s %s,"
> 			 " DMI info unavailable.\n",
> 		msg_perr("WARNING: Can't autodetect %s %s, DMI info unavailable.\n",
> 		 board->vendor_name, board->board_name);
> 		msg_pinfo("Please supply the board vendor and model name with the "
> 			  "-p internal:mainboard=<vendor>:<model> option.\n");
> 	continue;
> } else {
> 	if (!dmi_match(board->dmi_pattern))
>
> @@ -2569,8 +2585,7 @@ static int unsafe_board_handler(const struct board_match *board)
>    	return 1;
>    }
>    msg_pinfo("NOTE: Running an untested board enable procedure.\n"
>   "Please report success/failure to [e-mail]\n"
>   "with your board name and SUCCESS or FAILURE in the subject.\n");
>   "Please report success/failure to [e-mail].\n");
> return 0;
>
> }
>
> @@ -2606,29 +2621,29 @@ void board_handle_before_laptop(void)
>    board_handle_phase(P2);
>  }
>
> -int board_flash_enable(const char *vendor, const char *part)
> +int board_flash_enable(const char *vendor, const char *model)
>  {
>    const struct board_match *board = NULL;
>    int ret = 0;
> if (part)
> board = board_match_cbname(vendor, part);
> if (!board)
> if (vendor && model) {
> board = board_match_name(vendor, model);
> if (!board) /* if a board was given it has to match, else we abort here. */
> 	return 1;
> } else {
> board = board_match_pci_ids(P3);
> if (!board) /* i.e. there is just no board enable available for this board */
> 	return 0;
> }
> if (unsafe_board_handler(board))
> board = NULL;
> if (board) {
> ret = unsafe_board_handler(board);

Side note: unsafe_board_handler is a pretty dumb name. Yes, it's my
fault. Still... check_unsafe_board_enable() or something similar would
be a better name.
> if (!ret) {
> if (board->max_rom_decode_parallel)
> 	max_rom_decode.parallel =
> 		board->max_rom_decode_parallel * 1024;
> 	max_rom_decode.parallel = board->max_rom_decode_parallel * 1024;
>
> if (board->enable != NULL) {
> 	msg_pinfo("Disabling flash write protection for "
> 		  "board \"%s %s\"... ", board->vendor_name,
> 		  board->board_name);
> 	msg_pinfo("Enabling full flash access for board \"%s %s\"... ",
> 		  board->vendor_name, board->board_name);
>
> ret = board->enable();
> if (ret)
>
> diff --git a/cbtable.c b/cbtable.c
> index dde12ac..1f8b1c3 100644
> --- a/cbtable.c
> +++ b/cbtable.c
> @@ -24,57 +24,33 @@
>
> #include <unistd.h>
>  #include <stdio.h>
> -#include <stdlib.h>
>  #include <ctype.h>
>  #include <string.h>
>  #include "flash.h"
>  #include "programmer.h"
>  #include "coreboot_tables.h"
>
> -char *lb_part = NULL, *lb_vendor = NULL;
> -int partvendor_from_cbtable = 0;
> -static char *def_name = "DEFAULT";
> -static char *mainboard_vendor = NULL;
> -static char *mainboard_part = NULL;
>
> -/* Parse the [<vendor>:]<board> string specified by the user as part of
> -p internal:mainboard=[<vendor>:]<board> and set lb_vendor and lb_part
> to the extracted values.
> Note: strtok modifies the original string, so we work on a copy and allocate
> memory for lb_vendor and lb_part with strdup.
> */
>
> -void lb_vendor_dev_from_string(const char *boardstring)
> -{
> /* strtok may modify the original string. */
> char *tempstr = strdup(boardstring);
> char *tempstr2 = NULL;
> strtok(tempstr, ":");
> tempstr2 = strtok(NULL, ":");
> if (tempstr2) {
> lb_vendor = strdup(tempstr);
> lb_part = strdup(tempstr2);
> } else {
> lb_vendor = NULL;
> lb_part = strdup(tempstr);
> }
> free(tempstr);
>
> -}
> +static char *cb_vendor = NULL, *cb_model = NULL;
>
> -int show_id(uint8_t *bios, int size)
> +/* Tries to find coreboot IDs in the supplied image and compares them to the current IDs.
> Returns...
> -1	if IDs in the image do not match the IDs embedded in the current firmware,
> 0	if the IDs could not be found in the image or if they match correctly.
> */
>
> +int cb_check_image(uint8_t *image, int size)

cb_check_image_matches_board would be a better name IMHO.
> {
> const char *image_vendor = NULL;
> const char *image_model = NULL;
> unsigned int *walk;
> unsigned int mb_part_offset, mb_vendor_offset;
> char *mb_part, *mb_vendor;
> mainboard_vendor = def_name;
> mainboard_part = def_name;
> walk = (unsigned int *)(bios + size - 0x10);
> walk = (unsigned int *)(image + size - 0x10);
> walk--;

The two lines above made me scream WTF?!?
Since you're already fixing that code, can you please merge them into one?
walk = (unsigned int *)(image + size - 0x14);
> if ((*walk) == 0 || ((*walk) & 0x3ff) != 0) {
> /* We might have an NVIDIA chipset BIOS which stores the ID information somewhere else. */
> walk = (unsigned int *)(bios + size - 0x80);
> /* We might have an NVIDIA chipset which stores the ID information somewhere else. */

Actually, "BIOS" wasn't that wrong... let me rephrase the comment so
that others may have a chance to understand the reason:

/* Some NVIDIA chipsets store chipset soft straps (IIRC Hypertransport
init info etc.) in flash at exactly the location where coreboot image
size, coreboot vendor name pointer and coreboot board name pointer are
usually stored. In this case coreboot uses an alternate location for the
coreboot image data. */
> walk = (unsigned int *)(image + size - 0x80);
> walk--;

And the two lines above need to be
walk = (unsigned int *)(image + size - 0x84);
> }
>
> @@ -88,49 +64,37 @@ int show_id(uint8_t *bios, int size)
>    mb_vendor_offset = *(walk - 2);
>    if ((*walk) == 0 || ((*walk) & 0x3ff) != 0 || (*walk) > size ||
>        mb_part_offset > size || mb_vendor_offset > size) {
> msg_pinfo("Flash image seems to be a legacy BIOS. Disabling coreboot-related checks.\n");
> msg_pdbg("Flash image seems to be a legacy BIOS. Disabling coreboot-related checks.\n");
> return 0;
> }
> mb_part = (char *)(bios + size - mb_part_offset);
> mb_vendor = (char *)(bios + size - mb_vendor_offset);
> mb_part = (char *)(image + size - mb_part_offset);
> mb_vendor = (char *)(image + size - mb_vendor_offset);
> if (!isprint((unsigned char)*mb_part) ||
>   !isprint((unsigned char)*mb_vendor)) {
> msg_pinfo("Flash image seems to have garbage in the ID location. Disabling checks.\n");
> msg_pdbg("Flash image seems to have garbage in the ID location. Disabling checks.\n");

...garbage in the coreboot ID location. Disabling coreboot-related checks.
> return 0;
>
> }
>
> msg_pdbg("coreboot last image size (not ROM size) is %d bytes.\n", *walk);
> mainboard_part = strdup(mb_part);
> mainboard_vendor = strdup(mb_vendor);
> msg_pdbg("Manufacturer: %s\n", mainboard_vendor);
> msg_pdbg("Mainboard ID: %s\n", mainboard_part);
> image_vendor = strdup(mb_vendor);
> image_model = strdup(mb_part);

If the image looks like a coreboot image according to our checks, but
it's malformed (or not a coreboot image), checking string length with
if (strnlen(mb_vendor, mb_vendor_offset) < mb_vendor_offset)
and aborting otherwise may be a good idea to avoid segfaults. Can be
done in a followup patch, though.
> msg_pdbg("Manufacturer: %s\n", image_vendor);
>
> msg_pdbg("Mainboard ID: %s\n", image_model);
>
> /* If these are not set, the coreboot table was not found. */
> if (!lb_vendor || !lb_part) {
> msg_pinfo("Note: If the following flash access fails, try "
> 	  "-p internal:mainboard=<vendor>:<mainboard>.\n");
> if (!cb_vendor || !cb_model)
> return 0;
>
> }
>
> /* These comparisons are case insensitive to make things a little less user^Werror prone. */
>
> if (!strcasecmp(mainboard_vendor, lb_vendor) &&
>    !strcasecmp(mainboard_part, lb_part)) {
> msg_pdbg("This firmware image matches this mainboard.\n");
> if (!strcasecmp(image_vendor, cb_vendor) && !strcasecmp(image_model, cb_model)) {
> msg_pdbg2("This coreboot image matches this mainboard.\n");
> } else {
> if (force_boardmismatch) {
> 	msg_pinfo("WARNING: This firmware image does not "
> 	       "seem to fit to this machine - forcing it.\n");
> } else {
> 	msg_pinfo("ERROR: Your firmware image (%s:%s) does not appear to\n"
> 		  "       be correct for the detected mainboard (%s:%s)\n\n"
> 		  "Override with -p internal:boardmismatch=force to ignore the board name\n"
> 		  "in the firmware image or override the detected mainboard with\n"
> 		  "-p internal:mainboard=<vendor>:<mainboard>.\n\n",
> 		  mainboard_vendor, mainboard_part, lb_vendor, lb_part);
> 	return 1;
> }
> msg_pinfo("WARNING: This coreboot image (%s:%s) does not appear to\n"
> 	  "         be correct for the detected mainboard (%s:%s).\n",
> 	  image_vendor, image_model, cb_vendor, cb_model);
> return -1;
>
> }
>
> return 0;
>
> @@ -242,22 +206,15 @@ static void find_mainboard(struct lb_record *ptr, unsigned long addr)

find_mainboard is a misnomer... it should be
get_mainboard_from_cb_record or something like that, and the addr
parameter was never used since the code was first committed. Followup
patch, no need to complicate this one.
> rec = (struct lb_mainboard *)ptr;
>    max_size = rec->size - sizeof(*rec);
>    msg_pdbg("Vendor ID: %.*s, part ID: %.*s\n",
>       max_size - rec->vendor_idx,
>       rec->strings + rec->vendor_idx,
>       max_size - rec->part_number_idx,
>       rec->strings + rec->part_number_idx);
> snprintf(vendor, 255, "%.*s", max_size - rec->vendor_idx,
>  rec->strings + rec->vendor_idx);
> snprintf(part, 255, "%.*s", max_size - rec->part_number_idx,
>  rec->strings + rec->part_number_idx);
> if (lb_part) {
> msg_pdbg("Overwritten by command line, vendor ID: %s, part ID: %s.\n", lb_vendor, lb_part);
> } else {
> partvendor_from_cbtable = 1;
> lb_part = strdup(part);
> lb_vendor = strdup(vendor);
> }
>         max_size - rec->vendor_idx,
>         rec->strings + rec->vendor_idx,
>         max_size - rec->part_number_idx,
>         rec->strings + rec->part_number_idx);
> snprintf(vendor, 255, "%.*s", max_size - rec->vendor_idx, rec->strings + rec->vendor_idx);
> snprintf(part, 255, "%.*s", max_size - rec->part_number_idx, rec->strings + rec->part_number_idx);
> cb_vendor = strdup(vendor);
> cb_model = strdup(part);
>
> }
>
> static struct lb_record *next_record(struct lb_record *rec)
> @@ -265,8 +222,7 @@ static struct lb_record *next_record(struct lb_record *rec)
>    return (struct lb_record *)(((char *)rec) + rec->size);
>  }
>
> -static void search_lb_records(struct lb_record *rec, struct lb_record *last,
> 	      unsigned long addr)
>
> +static void search_lb_records(struct lb_record *rec, struct lb_record *last, unsigned long addr)
>  {
>    struct lb_record *next;
>    int count;
> @@ -284,7 +240,8 @@ static void search_lb_records(struct lb_record *rec, struct lb_record *last,
>  }
>
> #define BYTES_TO_MAP (1024*1024)
> -int coreboot_init(void)
> +/* returns 0 if the table was parsed successfully and cb_vendor/cb_model have been set. */
> +int cb_parse_table(const char **vendor, const char **model)
>  {
>    uint8_t *table_area;
>    unsigned long addr, start;
> @@ -317,8 +274,7 @@ int coreboot_init(void)
>    		physunmap(table_area, BYTES_TO_MAP);
>    		table_area = physmap_try_ro("high tables", start, BYTES_TO_MAP);
>    		if (ERROR_PTR == table_area) {
> 		msg_perr("Failed getting access to coreboot "
> 			 "high tables.\n");
> 		msg_perr("Failed getting access to coreboot high tables.\n");
> 	return -1;
> }
> lb_table = find_lb_table(table_area, 0x00000, 0x1000);
>
> @@ -340,6 +296,7 @@ int coreboot_init(void)
>         lb_table->table_bytes, lb_table->table_checksum,
>         lb_table->table_entries);
>    search_lb_records(rec, last, addr + lb_table->header_bytes);
> *vendor = cb_vendor;
> *model = cb_model;

I'm not totally happy with those static variables, but I can't offer a
better suggestion (unless we want to extend struct flashctx with
board/device matching info, but anything like that should be a separate
patch.
> return 0;
>  }
> diff --git a/flashrom.c b/flashrom.c
> index 9544155..c39c12c 100644
> --- a/flashrom.c
> +++ b/flashrom.c
> @@ -1814,11 +1814,15 @@ int doit(struct flashctx *flash, int force, const char *filename, int read_it,
>    	}
>
> #if CONFIG_INTERNAL == 1
> if (programmer == PROGRAMMER_INTERNAL)
> 	if (show_id(newcontents, size)) {
> if (programmer == PROGRAMMER_INTERNAL && cb_check_image(newcontents, size) < 0) {
> 	if (force_boardmismatch) {
> 		msg_pinfo("Proceeding anyway because user forced us to.\n");
> 	} else {
> 		msg_perr("Aborting. You can override this with -p internal:boardmismatch=force.\n");

112 column limit...
> 		ret = 1;
> 		goto out;
> 	}
> }
>
> #endif
>    }
>
> diff --git a/internal.c b/internal.c
> index 3ecc348..b1686aa 100644
> --- a/internal.c
> +++ b/internal.c
> @@ -249,10 +256,20 @@ int internal_init(void)
>    }
>
> #if defined(__i386__) || defined(__x86_64__)
> /* We look at the cbtable first to see if we need a
> * mainboard specific flash enable sequence.
> */
> coreboot_init();
> if (cb_parse_table(&cb_vendor, &cb_model) == 0) { /* coreboot IDs valid */
> /* if no -p internal:mainboard was given but there are valid coreboot IDs then use those */

Please capitalize first word and finish with full stop. Otherwise you'll
see an instant followup commit by Uwe changing it. ;-)
> if (board_vendor == NULL || board_model == NULL) {

Is it even possible that only one of board_vendor/board_model is NULL?
> 	board_vendor = cb_vendor;
> 	board_model = cb_model;
> } else if (strcasecmp(board_vendor, cb_vendor) || strcasecmp(board_model, cb_model)) {
> 	msg_pinfo("WARNING: The mainboard IDs set by -p internal:mainboard (%s:%s) do not\n"
> 		  "         match the current coreboot IDs of the mainboard (%s:%s).\n",
> 		  board_vendor, board_model, cb_vendor, cb_model);
> 	if (!force_boardmismatch)
> 		return 1;
> 	msg_pinfo("Continuing anyway.\n");
> }
>
> }
>
> dmi_init();
>
> @@ -321,12 +338,11 @@ int internal_init(void)
>    init_superio_ite();
>  #endif
> board_flash_enable(lb_vendor, lb_part);
> if (board_flash_enable(board_vendor, board_model)) {
> msg_perr("Aborting to be safe.\n");
> return 1;
> }
> /* Even if chipset init returns an error code, we don't want to abort.
> * The error code might have been a warning only.

The two lines above still make sense AFAICS.
> * Besides that, we don't check the board enable return code either.

The line above can be killed as you did.
> */
>
> #if defined(__i386__) || defined(__x86_64__) || defined (__mips)
>    register_par_programmer(&par_programmer_internal, internal_buses_supported);
>    return 0;

Thanks for cleaning up this code!

Regards,
Carl-Daniel