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authorLeah Rowe <leah@libreboot.org>2023-04-06 20:48:28 +0100
committerLeah Rowe <leah@libreboot.org>2023-04-06 20:48:28 +0100
commit2356f89f27bd8429dbf7aa6a221415189035fc5b (patch)
tree8200e4d4aa2aad39345b4def3d3a1c1237773e81 /util
parent8771551162844731cc843391ed645f387dfd0eb0 (diff)
util/nvmutil: less annoying comments
added a few that were more useful deleted a few obnoxious ones
Diffstat (limited to 'util')
-rw-r--r--util/nvmutil/nvmutil.c53
1 files changed, 16 insertions, 37 deletions
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c
index 508f76ee..4303337e 100644
--- a/util/nvmutil/nvmutil.c
+++ b/util/nvmutil/nvmutil.c
@@ -91,13 +91,13 @@ main(int argc, char *argv[])
gbe[1] = (gbe[0] = (size_t) buf) + SIZE_4KB;
test = 1;
- big_endian = ((uint8_t *) &test)[0] ^ 1; /* check host endianness */
+ big_endian = ((uint8_t *) &test)[0] ^ 1;
if (argc == 3) {
if (strcmp(COMMAND, "dump") == 0) {
#ifdef HAVE_PLEDGE
- if (pledge("stdio rpath", NULL) == -1)
- err(errno, "pledge"); /* not very puffy */
+ if (pledge("stdio rpath", NULL) == -1) /* openbsd */
+ err(errno, "pledge");
#endif
flags = O_RDONLY;
cmd = &cmd_dump;
@@ -126,19 +126,18 @@ main(int argc, char *argv[])
nr = SIZE_4KB; /* copy/swap commands need everything to be read */
if ((cmd != &cmd_copy) && (cmd != &cmd_swap))
- nr = 128; /* read only the nvm part */
+ nr = 128; /* speedhack: read only the nvm part */
if ((cmd == &cmd_copy) || (cmd == &cmd_setchecksum) ||
(cmd == &cmd_brick))
- skipread[part ^ 1] = 1; /* skip reading the unused part */
+ skipread[part ^ 1] = 1; /* speedhack: don't read unused part */
readGbeFile(&fd, FILENAME, flags, nr);
- /* perform operation specified by the user */
if (strMac != NULL)
- cmd_setmac(strMac);
+ cmd_setmac(strMac); /* nvm gbe.bin setmac */
else if (cmd != NULL)
- (*cmd)();
+ (*cmd)(); /* all other commands except setmac */
if (gbeFileModified)
writeGbeFile(&fd, FILENAME);
@@ -151,7 +150,6 @@ nvmutil_exit:
return errno;
}
-/* load the gbe file into memory */
void
readGbeFile(int *fd, const char *path, int flags, size_t nr)
{
@@ -181,7 +179,6 @@ readGbeFile(int *fd, const char *path, int flags, size_t nr)
}
}
-/* set mac address on valid nvm parts, per user input */
void
cmd_setmac(const char *strMac)
{
@@ -193,20 +190,18 @@ cmd_setmac(const char *strMac)
if (!validChecksum(partnum))
continue;
for (int w = 0; w < 3; w++)
- setWord(w, partnum, mac[w]); /* do not use memcpy! */
+ setWord(w, partnum, mac[w]);
byteswap(6, partnum); /* mac words are stored big-endian */
part = partnum;
cmd_setchecksum();
}
}
-/* read mac address from user input */
int
parseMacAddress(const char *strMac, uint16_t *mac)
{
uint8_t h;
uint64_t total = 0;
-
if (strnlen(strMac, 20) != 17)
return -1;
@@ -226,10 +221,8 @@ parseMacAddress(const char *strMac, uint16_t *mac)
<< ((8 * ((byte % 2) ^ 1)) + (4 * (nib ^ 1)));
}
}
-
- /* Disallow multicast and all-zero MAC addresses */
return ((total == 0) || (mac[0] & 0x100))
- ? -1 : 0;
+ ? -1 : 0; /* disallow multicast/zero mac addresses */
}
uint8_t
@@ -247,7 +240,6 @@ hextonum(char ch)
return 16;
}
-/* generate a random number from 0 to 15, the unix way */
uint8_t
rhex(void)
{
@@ -265,7 +257,6 @@ rhex(void)
return rval;
}
-/* show mac address and hexdump of each nvm part */
void
cmd_dump(void)
{
@@ -281,7 +272,6 @@ cmd_dump(void)
errno = 0;
}
-/* show formatted mac address contained within the nvm part */
void
showmac(int partnum)
{
@@ -296,7 +286,6 @@ showmac(int partnum)
}
}
-/* output a hexdump of both nvm parts, bytes reversed to big-endian order */
void
hexdump(int partnum)
{
@@ -311,7 +300,6 @@ hexdump(int partnum)
}
}
-/* set a valid checksum on a given part */
void
cmd_setchecksum(void)
{
@@ -321,7 +309,6 @@ cmd_setchecksum(void)
setWord(0x3F, part, 0xBABA - val16);
}
-/* set invalid checksum, intentionally */
void
cmd_brick(void)
{
@@ -329,12 +316,11 @@ cmd_brick(void)
setWord(0x3F, part, (word(0x3F, part)) ^ 0xFF);
}
-/* swap the words of each part with each other */
void
cmd_swap(void)
{
if (validChecksum(1) || validChecksum(0)) {
- gbe[0] ^= gbe[1]; /* speed hack: xorswap pointers, not words */
+ gbe[0] ^= gbe[1]; /* speedhack: xorswap pointers, not words */
gbe[1] ^= gbe[0];
gbe[0] ^= gbe[1];
gbeFileModified = 1; /* not using setWord, so must set these */
@@ -344,12 +330,11 @@ cmd_swap(void)
}
}
-/* overwrite one part with the other */
void
cmd_copy(void)
{
if (validChecksum(part)) {
- gbe[part ^ 1] = gbe[part]; /* pointer-based speed hack */
+ gbe[part ^ 1] = gbe[part]; /* speedhack: copy ptr, not words */
gbeFileModified = 1; /* not using setWord, so must set these */
nvmPartModified[part ^ 1] = 1;
}
@@ -369,14 +354,12 @@ validChecksum(int partnum)
return 0;
}
-/* fetch a word from gbe buffer */
uint16_t
word(int pos16, int partnum)
{
return buf16[pos16 + (partnum << 11)];
}
-/* write a word to gbe buffer, and record that a write has occured */
void
setWord(int pos16, int partnum, uint16_t val16)
{
@@ -388,7 +371,6 @@ setWord(int pos16, int partnum, uint16_t val16)
nvmPartModified[partnum] = 1;
}
-/* big-endian host compatibility: called post-read and again pre-write */
void
byteswap(int n, int partnum)
{
@@ -396,28 +378,25 @@ byteswap(int n, int partnum)
uint8_t *nbuf = (uint8_t *) gbe[partnum];
for (int w = 0; w < wcount; w++) {
b1 = b2 = w << 1;
-
- /* xor-based swap method */
- nbuf[b1] ^= nbuf[++b2];
+ nbuf[b1] ^= nbuf[++b2]; /* xor swap */
nbuf[b2] ^= nbuf[b1];
nbuf[b1] ^= nbuf[b2];
}
}
-/* called after all operations are done, if gbe was modified */
void
writeGbeFile(int *fd, const char *filename)
{
int p, nw;
errno = 0;
if ((gbe[0] != gbe[1]) && (gbe[0] < gbe[1]))
- nw = 128; /* write only the nvm part */
+ nw = 128; /* speedhack: write only the nvm part */
else
nw = SIZE_4KB; /* copy/swap, so only write everything */
for (p = 0; p < 2; p++) {
- if (gbe[0] > gbe[1]) /* write sequentially on-disk */
- p ^= 1;
+ if (gbe[0] > gbe[1])
+ p ^= 1; /* speedhack: write sequentially on-disk */
if (!nvmPartModified[p])
goto next_part;
if (big_endian)
@@ -426,7 +405,7 @@ writeGbeFile(int *fd, const char *filename)
err(errno, "%s", filename);
next_part:
if (gbe[0] > gbe[1])
- p ^= 1;
+ p ^= 1; /* speedhack: write sequentially on-disk */
}
if (close((*fd)))
err(errno, "%s", filename);