biosdevname/0006-Read-DMI-entries-from-sys-firmware-dmi-tables-DMI.patch

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From b3bb4ed21e8802cb38eb693952da058f52cf76b0 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 24 Aug 2020 14:41:54 +0200
Subject: [PATCH] Read DMI entries from /sys/firmware/dmi/tables/DMI
A kernel with Secure Boot lockdown may prohibit reading the contents
of /dev/mem, hence biosdevname fails. The recent kernel provides the
DMI byte contents in /sys/firmware/dmi/tables/*, and we can use this
instead of poking /dev/mem.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
CC: Thomas Renninger <trenn@suse.de>
CC: Michal Suchanek <msuchanek@suse.com>
---
src/dmidecode/dmidecode.c | 54 +++++++++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 13 deletions(-)
diff --git a/src/dmidecode/dmidecode.c b/src/dmidecode/dmidecode.c
index a01a6ce..f4c1269 100644
--- a/src/dmidecode/dmidecode.c
+++ b/src/dmidecode/dmidecode.c
@@ -229,7 +229,7 @@ static int isvalidsmbios(int mjr, int mnr)
return 0;
}
-static void dmi_table(u32 base, u16 len, u16 num, u16 ver, const char *devmem, const struct libbiosdevname_state *state)
+static int dmi_table(u32 base, u16 len, u16 num, u16 ver, const char *devmem, const struct libbiosdevname_state *state, int sysfs)
{
u8 *buf;
u8 *data;
@@ -237,14 +237,19 @@ static void dmi_table(u32 base, u16 len, u16 num, u16 ver, const char *devmem, c
/* Verify SMBIOS version */
if (!isvalidsmbios(ver >> 8, ver & 0xFF)) {
- return;
+ return 0;
}
- if((buf=mem_chunk(base, len, devmem))==NULL)
+
+ if (sysfs)
+ buf = __mem_chunk(0, len, devmem, 0);
+ else
+ buf = mem_chunk(base, len, devmem);
+ if(buf == NULL)
{
#ifndef USE_MMAP
printf("Table is unreachable, sorry. Try compiling dmidecode with -DUSE_MMAP.\n");
#endif
- return;
+ return 0;
}
data=buf;
@@ -280,18 +285,18 @@ static void dmi_table(u32 base, u16 len, u16 num, u16 ver, const char *devmem, c
i++;
}
free(buf);
+ return 1;
}
-
-static int smbios_decode(u8 *buf, const char *devmem, const struct libbiosdevname_state *state)
+static int smbios_decode(u8 *buf, const char *devmem, const struct libbiosdevname_state *state, int sysfs)
{
if(checksum(buf, buf[0x05])
&& memcmp(buf+0x10, "_DMI_", 5)==0
&& checksum(buf+0x10, 0x0F))
{
- dmi_table(DWORD(buf+0x18), WORD(buf+0x16), WORD(buf+0x1C),
- (buf[0x06]<<8)+buf[0x07], devmem, state);
- return 1;
+ return dmi_table(DWORD(buf+0x18), WORD(buf+0x16), WORD(buf+0x1C),
+ (buf[0x06]<<8)+buf[0x07], devmem, state,
+ sysfs);
}
return 0;
@@ -302,13 +307,32 @@ static int legacy_decode(u8 *buf, const char *devmem, const struct libbiosdevnam
if(checksum(buf, 0x0F))
{
dmi_table(DWORD(buf+0x08), WORD(buf+0x06), WORD(buf+0x0C),
- ((buf[0x0E]&0xF0)<<4)+(buf[0x0E]&0x0F), devmem, state);
+ ((buf[0x0E]&0xF0)<<4)+(buf[0x0E]&0x0F), devmem, state, 0);
return 1;
}
return 0;
}
+#define SYSFS_TABLE_SMBIOS "/sys/firmware/dmi/tables/smbios_entry_point"
+#define SYSFS_TABLE_DMI "/sys/firmware/dmi/tables/DMI"
+
+static int smibios_decode_from_sysfs(const struct libbiosdevname_state *state)
+{
+ FILE *fp;
+ u8 buf[0x1f];
+ int len;
+
+ fp = fopen(SYSFS_TABLE_SMBIOS, "r");
+ if (!fp)
+ return 0;
+ len = fread(buf, 1, sizeof(buf), fp);
+ fclose(fp);
+ if (len == 0x1f && memcmp(buf, "_SM_", 4) == 0)
+ return smbios_decode(buf, SYSFS_TABLE_DMI, state, 1);
+ return 0;
+}
+
/*
* Probe for EFI interface
*/
@@ -417,7 +441,11 @@ int dmidecode_main(const struct libbiosdevname_state *state)
if (dmidecode_read_file(state))
return 0;
- /* First try EFI (ia64, Intel-based Mac) */
+ /* First try sysfs entries */
+ if (smibios_decode_from_sysfs(state))
+ return 0;
+
+ /* Next try EFI (ia64, Intel-based Mac) */
efi=address_from_efi(&fp);
switch(efi)
{
@@ -434,7 +462,7 @@ int dmidecode_main(const struct libbiosdevname_state *state)
goto exit_free;
}
- if(smbios_decode(buf, devmem, state))
+ if(smbios_decode(buf, devmem, state, 0))
found++;
goto done;
@@ -450,7 +478,7 @@ memory_scan:
{
if(memcmp(buf+fp, "_SM_", 4)==0 && fp<=0xFFE0)
{
- if(smbios_decode(buf+fp, devmem, state))
+ if(smbios_decode(buf+fp, devmem, state, 0))
{
found++;
fp+=16;
--
2.44.0