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ichspi.c: Simplify ich9_handle_{frap,pr}() to work with logical rep

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Simplify ich9_handle_frap() to do the translation to the logical
representation of the ich_access_protection enum in one place and
work from there. This removes some unnecessary branch complexity
and the possibility of out of bounds array accesses.

Change-Id: I1eda067c44a84d662713475d13902c85534a59fe
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/65189
Reviewed-by: Sam McNally <sammc@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nikolai Artemiev <nartemiev@google.com>
This commit is contained in:
Edward O'Callaghan 2022-06-17 14:43:45 +10:00 committed by Edward O'Callaghan
parent 6f610a8391
commit f56a0322f4
1 changed files with 23 additions and 28 deletions
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51
ichspi.c
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@ -1679,12 +1679,11 @@ static const enum ich_access_protection access_perms_to_protection[] = {
LOCKED, WRITE_PROT, READ_PROT, NO_PROT
};
static const char *const access_names[] = {
"locked", "read-only", "write-only", "read-write"
"read-write", "write-only", "read-only", "locked"
};
static enum ich_access_protection ich9_handle_frap(uint32_t frap, unsigned int i)
{
const int rwperms_unknown = ARRAY_SIZE(access_names);
static const char *const region_names[] = {
"Flash Descriptor", "BIOS", "Management Engine",
"Gigabit Ethernet", "Platform Data", "Device Expansion",
@ -1693,23 +1692,13 @@ static enum ich_access_protection ich9_handle_frap(uint32_t frap, unsigned int i
const char *const region_name = i < ARRAY_SIZE(region_names) ? region_names[i] : "unknown";
uint32_t base, limit;
int rwperms;
unsigned int rwperms_idx;
enum ich_access_protection rwperms;
const int offset = i < 12
? ICH9_REG_FREG0 + i * 4
: APL_REG_FREG12 + (i - 12) * 4;
uint32_t freg = mmio_readl(ich_spibar + offset);
if (i < 8) {
rwperms = (((ICH_BRWA(frap) >> i) & 1) << 1) |
(((ICH_BRRA(frap) >> i) & 1) << 0);
} else {
/* Datasheets don't define any access bits for regions > 7. We
can't rely on the actual descriptor settings either as there
are several overrides for them (those by other masters are
not even readable by us, *shrug*). */
rwperms = rwperms_unknown;
}
base = ICH_FREG_BASE(freg);
limit = ICH_FREG_LIMIT(freg);
if (base > limit || (freg == 0 && i > 0)) {
@ -1719,20 +1708,24 @@ static enum ich_access_protection ich9_handle_frap(uint32_t frap, unsigned int i
return NO_PROT;
}
msg_pdbg("0x%02X: 0x%08x ", offset, freg);
if (rwperms == 0x3) {
msg_pdbg("FREG%u: %s region (0x%08x-0x%08x) is %s.\n", i,
region_name, base, limit, access_names[rwperms]);
return NO_PROT;
}
if (rwperms == rwperms_unknown) {
msg_pdbg("FREG%u: %s region (0x%08x-0x%08x) has unknown permissions.\n",
i, region_name, base, limit);
return NO_PROT;
}
if (i < 8) {
rwperms_idx = (((ICH_BRWA(frap) >> i) & 1) << 1) |
(((ICH_BRRA(frap) >> i) & 1) << 0);
rwperms = access_perms_to_protection[rwperms_idx];
} else {
/* Datasheets don't define any access bits for regions > 7. We
can't rely on the actual descriptor settings either as there
are several overrides for them (those by other masters are
not even readable by us, *shrug*). */
msg_pdbg("FREG%u: %s region (0x%08x-0x%08x) has unknown permissions.\n",
i, region_name, base, limit);
return NO_PROT;
}
msg_pinfo("FREG%u: %s region (0x%08x-0x%08x) is %s.\n", i,
region_name, base, limit, access_names[rwperms]);
return access_perms_to_protection[rwperms];
return rwperms;
}
/* In contrast to FRAP and the master section of the descriptor the bits
@ -1748,14 +1741,15 @@ static enum ich_access_protection ich9_handle_pr(const size_t reg_pr0, unsigned
{
uint8_t off = reg_pr0 + (i * 4);
uint32_t pr = mmio_readl(ich_spibar + off);
unsigned int rwperms = ICH_PR_PERMS(pr);
unsigned int rwperms_idx = ICH_PR_PERMS(pr);
enum ich_access_protection rwperms = access_perms_to_protection[rwperms_idx];
/* From 5 on we have GPR registers and start from 0 again. */
const char *const prefix = i >= 5 ? "G" : "";
if (i >= 5)
i -= 5;
if (rwperms == 0x3) {
if (rwperms == NO_PROT) {
msg_pdbg2("0x%02X: 0x%08x (%sPR%u is unused)\n", off, pr, prefix, i);
return NO_PROT;
}
@ -1763,7 +1757,8 @@ static enum ich_access_protection ich9_handle_pr(const size_t reg_pr0, unsigned
msg_pdbg("0x%02X: 0x%08x ", off, pr);
msg_pwarn("%sPR%u: Warning: 0x%08x-0x%08x is %s.\n", prefix, i, ICH_FREG_BASE(pr),
ICH_FREG_LIMIT(pr), access_names[rwperms]);
return access_perms_to_protection[rwperms];
return rwperms;
}
/* Set/Clear the read and write protection enable bits of PR register @i