[GIT PULL] x86 fixes

Ingo Molnar
2015-04-03T13:16:38Z

Linus,

Please pull the latest x86-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-for-linus

# HEAD: f59df35fc28167886a0caf9f15db2f4a1f5932da kgdb/x86: Fix reporting of 'si' in kgdb on x86_64

Misc fixes: a SYSRET single-stepping fix, a dmi-scan robustization
fix, a reboot quirk and a kgdb fixlet.

out-of-topic modifications in x86-urgent-for-linus:
-----------------------------------------------------
MAINTAINERS # ca68a525ff6b: MAINTAINERS: Change the x86
drivers/firmware/dmi_scan.c # bfbaafae8519: firmware: dmi_scan: Prevent

Thanks,

Ingo

------------------>
Andy Lutomirski (1):
x86/asm/entry/64: Disable opportunistic SYSRET if regs->flags has TF set

Borislav Petkov (1):
MAINTAINERS: Change the x86 microcode loader maintainer

Jean Delvare (1):
firmware: dmi_scan: Prevent dmi_num integer overflow

Stefan Lippers-Hollmann (1):
x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk

Steffen Liebergeld (1):
kgdb/x86: Fix reporting of 'si' in kgdb on x86_64

MAINTAINERS | 5 ++---
arch/x86/kernel/entry_64.S | 16 +++++++++++++++-
arch/x86/kernel/kgdb.c | 2 +-
arch/x86/kernel/reboot.c | 10 ++++++++++
drivers/firmware/dmi_scan.c | 22 +++++++---------------
5 files changed, 35 insertions(+), 20 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 1de6afa8ee51..e04362883ea3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -637,8 +637,7 @@ F: drivers/gpu/drm/radeon/radeon_kfd.h
F: include/uapi/linux/kfd_ioctl.h

AMD MICROCODE UPDATE SUPPORT
-M: Andreas Herrmann <herrmann.der.user@googlemail.com>
-L: amd64-microcode@amd64.org
+M: Borislav Petkov <bp@alien8.de>
S: Maintained
F: arch/x86/kernel/cpu/microcode/amd*

@@ -5095,7 +5094,7 @@ S: Supported
F: drivers/platform/x86/intel_menlow.c

INTEL IA32 MICROCODE UPDATE SUPPORT
-M: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
+M: Borislav Petkov <bp@alien8.de>
S: Maintained
F: arch/x86/kernel/cpu/microcode/core*
F: arch/x86/kernel/cpu/microcode/intel*
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 2babb393915e..f0095a76c182 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -799,7 +799,21 @@ retint_swapgs: /* return to user-space */
cmpq %r11,(EFLAGS-ARGOFFSET)(%rsp) /* R11 == RFLAGS */
jne opportunistic_sysret_failed

- testq $X86_EFLAGS_RF,%r11 /* sysret can't restore RF */
+ /*
+ * SYSRET can't restore RF. SYSRET can restore TF, but unlike IRET,
+ * restoring TF results in a trap from userspace immediately after
+ * SYSRET. This would cause an infinite loop whenever #DB happens
+ * with register state that satisfies the opportunistic SYSRET
+ * conditions. For example, single-stepping this user code:
+ *
+ * movq $stuck_here,%rcx
+ * pushfq
+ * popq %r11
+ * stuck_here:
+ *
+ * would never get past 'stuck_here'.
+ */
+ testq $(X86_EFLAGS_RF|X86_EFLAGS_TF), %r11
jnz opportunistic_sysret_failed

/* nothing to check for RSP */
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 7ec1d5f8d283..25ecd56cefa8 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -72,7 +72,7 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{ "bx", 8, offsetof(struct pt_regs, bx) },
{ "cx", 8, offsetof(struct pt_regs, cx) },
{ "dx", 8, offsetof(struct pt_regs, dx) },
- { "si", 8, offsetof(struct pt_regs, dx) },
+ { "si", 8, offsetof(struct pt_regs, si) },
{ "di", 8, offsetof(struct pt_regs, di) },
{ "bp", 8, offsetof(struct pt_regs, bp) },
{ "sp", 8, offsetof(struct pt_regs, sp) },
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index bae6c609888e..86db4bcd7ce5 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -183,6 +183,16 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
},
},

+ /* ASRock */
+ { /* Handle problems with rebooting on ASRock Q1900DC-ITX */
+ .callback = set_pci_reboot,
+ .ident = "ASRock Q1900DC-ITX",
+ .matches = {
+ DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
+ DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
+ },
+ },
+
/* ASUS */
{ /* Handle problems with rebooting on ASUS P4S800 */
.callback = set_bios_reboot,
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 69fac068669f..2eebd28b4c40 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -86,10 +86,13 @@ static void dmi_table(u8 *buf, u32 len, int num,
int i = 0;

/*
- * Stop when we see all the items the table claimed to have
- * OR we run off the end of the table (also happens)
+ * Stop when we have seen all the items the table claimed to have
+ * (SMBIOS < 3.0 only) OR we reach an end-of-table marker OR we run
+ * off the end of the table (should never happen but sometimes does
+ * on bogus implementations.)
*/
- while ((i < num) && (data - buf + sizeof(struct dmi_header)) <= len) {
+ while ((!num || i < num) &&
+ (data - buf + sizeof(struct dmi_header)) <= len) {
const struct dmi_header *dm = (const struct dmi_header *)data;

/*
@@ -529,21 +532,10 @@ static int __init dmi_smbios3_present(const u8 *buf)
if (memcmp(buf, "_SM3_", 5) == 0 &&
buf[6] < 32 && dmi_checksum(buf, buf[6])) {
dmi_ver = get_unaligned_be16(buf + 7);
+ dmi_num = 0; /* No longer specified */
dmi_len = get_unaligned_le32(buf + 12);
dmi_base = get_unaligned_le64(buf + 16);

- /*
- * The 64-bit SMBIOS 3.0 entry point no longer has a field
- * containing the number of structures present in the table.
- * Instead, it defines the table size as a maximum size, and
- * relies on the end-of-table structure type (#127) to be used
- * to signal the end of the table.
- * So let's define dmi_num as an upper bound as well: each
- * structure has a 4 byte header, so dmi_len / 4 is an upper
- * bound for the number of structures in the table.
- */
- dmi_num = dmi_len / 4;
-
if (dmi_walk_early(dmi_decode) == 0) {
pr_info("SMBIOS %d.%d present.\n",
dmi_ver >> 8, dmi_ver & 0xFF);