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libsa: smbios: Use 64-bit entry point if table below 4GB on non-EFI boot

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On amd64, boot blocks and the non-EFI loader are 32-bit compiled as
clients of BTX, so cannot access addresses beyond 4GB.  However, the
64-bit entry point may refer to a structure table below 4GB, which we
want to use if the BIOS does not provide a 32-bit entry point.  The
situation is similar for powerpc64.

Consequently, always compile-in support for the 64-bit entry point, but
ensure that it is not selected on 32-bit-compiled boot loaders if the
structure table it points to grows beyond 4GB (as it is then not
accessible).

PR:             284460
Reviewed by:    markj
MFC after:      2 weeks
Relnotes:       yes
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D49288
This commit is contained in:
Olivier Certner 2025-03-03 22:10:25 +01:00
parent 3f744fb8b2
commit 7f005c6699
No known key found for this signature in database
GPG key ID: 8CA13040971E2627
1 changed files with 14 additions and 23 deletions
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37
stand/libsa/smbios.c
View file

@ -29,11 +29,6 @@
#define PTOV(x) ptov(x)
/* Only enable 64-bit entry point if it makes sense */
#if __SIZEOF_POINTER__ > 4
#define SMBIOS_64BIT_EP 1
#endif
/*
* Detect SMBIOS and export information about the SMBIOS into the
* environment.
@ -145,9 +140,7 @@ SMBIOS_GET64(const caddr_t base, int off)
struct smbios_attr {
int probed;
#ifdef SMBIOS_64BIT_EP
int is_64bit_ep;
#endif
caddr_t addr;
size_t length;
size_t count;
@ -184,7 +177,6 @@ smbios_sigsearch(const caddr_t addr, const uint32_t len)
/* Search on 16-byte boundaries. */
for (cp = addr; cp < addr + len; cp += SMBIOS_STEP) {
#ifdef SMBIOS_64BIT_EP
/* v3.0, 64-bit Entry point */
if (strncmp(cp, SMBIOS3_SIG, sizeof(SMBIOS3_SIG) - 1) == 0 &&
/*
@ -195,10 +187,19 @@ smbios_sigsearch(const caddr_t addr, const uint32_t len)
*/
SMBIOS_GET8(cp, 0x0a) != 0 &&
smbios_checksum(cp, SMBIOS_GET8(cp, 0x06)) == 0) {
#ifdef __ILP32__
uint64_t end_addr;
end_addr = SMBIOS_GET64(cp, 0x10) + /* Start address. */
SMBIOS_GET32(cp, 0x0c); /* Maximum size. */
/* Is the table (or part of it) located above 4G? */
if (end_addr >= (uint64_t)1 << 32)
/* Can't access it with 32-bit addressing. */
continue;
#endif
smbios.is_64bit_ep = 1;
return (cp);
}
#endif
/* v2.1, 32-bit Entry point */
if (strncmp(cp, SMBIOS_SIG, sizeof(SMBIOS_SIG) - 1) == 0 &&
@ -207,13 +208,9 @@ smbios_sigsearch(const caddr_t addr, const uint32_t len)
smbios_checksum(cp + 0x10, 0x0f) == 0) {
/*
* Note that we saw this entry point, but don't return
* it right now on SMBIOS_64BIT_EP as we favor the 64-bit
* one if present.
* it right now as we favor the 64-bit one if present.
*/
v2_p = cp;
#ifndef SMBIOS_64BIT_EP
break;
#endif
}
}
return (v2_p);
@ -586,7 +583,6 @@ smbios_probe(const caddr_t addr)
if (saddr == NULL)
return;
#ifdef SMBIOS_64BIT_EP
if (smbios.is_64bit_ep) {
/* Structure Table Length */
smbios.length = SMBIOS_GET32(saddr, 0x0c);
@ -601,9 +597,7 @@ smbios_probe(const caddr_t addr)
smbios.ver = 0;
maj_off = 0x07;
min_off = 0x08;
} else
#endif
{
} else {
/* Structure Table Length */
smbios.length = SMBIOS_GET16(saddr, 0x16);
/* Structure Table Address */
@ -661,11 +655,8 @@ smbios_detect(const caddr_t addr)
dmi < smbios.addr + smbios.length && i < smbios.count; i++)
dmi = smbios_parse_table(dmi);
setenv("smbios.entry_point_type",
#ifdef SMBIOS_64BIT_EP
smbios.is_64bit_ep ? "v3 (64-bit)" :
#endif
"v2.1 (32-bit)", 1);
setenv("smbios.entry_point_type", smbios.is_64bit_ep ?
"v3 (64-bit)" : "v2.1 (32-bit)", 1);
sprintf(buf, "%d.%d", smbios.major, smbios.minor);
setenv("smbios.version", buf, 1);
if (smbios.enabled_memory > 0 || smbios.old_enabled_memory > 0) {