Merge tag 'x86_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Fix a couple of SWAPGS fencing issues in the x86 entry code
- Use the proper operand types in __{get,put}_user() to prevent
truncation in SEV-ES string io
- Make sure the kernel mappings are present in trampoline_pgd in order
to prevent any potential accesses to unmapped memory after switching
to it
- Fix a trivial list corruption in objtool's pv_ops validation
- Disable the clocksource watchdog for TSC on platforms which claim
that the TSC is constant, doesn't stop in sleep states, CPU has TSC
adjust and the number of sockets of the platform are max 2, to
prevent erroneous markings of the TSC as unstable.
- Make sure TSC adjust is always checked not only when going idle
- Prevent a stack leak by initializing struct _fpx_sw_bytes properly in
the FPU code
- Fix INTEL_FAM6_RAPTORLAKE define naming to adhere to the convention
* tag 'x86_urgent_for_v5.16_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/xen: Add xenpv_restore_regs_and_return_to_usermode()
x86/entry: Use the correct fence macro after swapgs in kernel CR3
x86/entry: Add a fence for kernel entry SWAPGS in paranoid_entry()
x86/sev: Fix SEV-ES INS/OUTS instructions for word, dword, and qword
x86/64/mm: Map all kernel memory into trampoline_pgd
objtool: Fix pv_ops noinstr validation
x86/tsc: Disable clocksource watchdog for TSC on qualified platorms
x86/tsc: Add a timer to make sure TSC_adjust is always checked
x86/fpu/signal: Initialize sw_bytes in save_xstate_epilog()
x86/cpu: Drop spurious underscore from RAPTOR_LAKE #define
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index e38a4cf..97b1f84 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -574,6 +574,10 @@
ud2
1:
#endif
+#ifdef CONFIG_XEN_PV
+ ALTERNATIVE "", "jmp xenpv_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV
+#endif
+
POP_REGS pop_rdi=0
/*
@@ -890,6 +894,7 @@
.Lparanoid_entry_checkgs:
/* EBX = 1 -> kernel GSBASE active, no restore required */
movl $1, %ebx
+
/*
* The kernel-enforced convention is a negative GSBASE indicates
* a kernel value. No SWAPGS needed on entry and exit.
@@ -897,21 +902,14 @@
movl $MSR_GS_BASE, %ecx
rdmsr
testl %edx, %edx
- jns .Lparanoid_entry_swapgs
- ret
-
-.Lparanoid_entry_swapgs:
- swapgs
-
- /*
- * The above SAVE_AND_SWITCH_TO_KERNEL_CR3 macro doesn't do an
- * unconditional CR3 write, even in the PTI case. So do an lfence
- * to prevent GS speculation, regardless of whether PTI is enabled.
- */
- FENCE_SWAPGS_KERNEL_ENTRY
+ js .Lparanoid_kernel_gsbase
/* EBX = 0 -> SWAPGS required on exit */
xorl %ebx, %ebx
+ swapgs
+.Lparanoid_kernel_gsbase:
+
+ FENCE_SWAPGS_KERNEL_ENTRY
ret
SYM_CODE_END(paranoid_entry)
@@ -993,11 +991,6 @@
pushq %r12
ret
-.Lerror_entry_done_lfence:
- FENCE_SWAPGS_KERNEL_ENTRY
-.Lerror_entry_done:
- ret
-
/*
* There are two places in the kernel that can potentially fault with
* usergs. Handle them here. B stepping K8s sometimes report a
@@ -1020,8 +1013,14 @@
* .Lgs_change's error handler with kernel gsbase.
*/
SWAPGS
- FENCE_SWAPGS_USER_ENTRY
- jmp .Lerror_entry_done
+
+ /*
+ * Issue an LFENCE to prevent GS speculation, regardless of whether it is a
+ * kernel or user gsbase.
+ */
+.Lerror_entry_done_lfence:
+ FENCE_SWAPGS_KERNEL_ENTRY
+ ret
.Lbstep_iret:
/* Fix truncated RIP */
diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
index 5a0bcf8..048b6d5 100644
--- a/arch/x86/include/asm/intel-family.h
+++ b/arch/x86/include/asm/intel-family.h
@@ -108,7 +108,7 @@
#define INTEL_FAM6_ALDERLAKE 0x97 /* Golden Cove / Gracemont */
#define INTEL_FAM6_ALDERLAKE_L 0x9A /* Golden Cove / Gracemont */
-#define INTEL_FAM6_RAPTOR_LAKE 0xB7
+#define INTEL_FAM6_RAPTORLAKE 0xB7
/* "Small Core" Processors (Atom) */
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index d595827..91d4b6d 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -118,7 +118,7 @@
struct fpstate *fpstate)
{
struct xregs_state __user *x = buf;
- struct _fpx_sw_bytes sw_bytes;
+ struct _fpx_sw_bytes sw_bytes = {};
u32 xfeatures;
int err;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 74f0ec9..a9fc2ac 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -294,11 +294,6 @@
char *dst, char *buf, size_t size)
{
unsigned long error_code = X86_PF_PROT | X86_PF_WRITE;
- char __user *target = (char __user *)dst;
- u64 d8;
- u32 d4;
- u16 d2;
- u8 d1;
/*
* This function uses __put_user() independent of whether kernel or user
@@ -320,26 +315,42 @@
* instructions here would cause infinite nesting.
*/
switch (size) {
- case 1:
+ case 1: {
+ u8 d1;
+ u8 __user *target = (u8 __user *)dst;
+
memcpy(&d1, buf, 1);
if (__put_user(d1, target))
goto fault;
break;
- case 2:
+ }
+ case 2: {
+ u16 d2;
+ u16 __user *target = (u16 __user *)dst;
+
memcpy(&d2, buf, 2);
if (__put_user(d2, target))
goto fault;
break;
- case 4:
+ }
+ case 4: {
+ u32 d4;
+ u32 __user *target = (u32 __user *)dst;
+
memcpy(&d4, buf, 4);
if (__put_user(d4, target))
goto fault;
break;
- case 8:
+ }
+ case 8: {
+ u64 d8;
+ u64 __user *target = (u64 __user *)dst;
+
memcpy(&d8, buf, 8);
if (__put_user(d8, target))
goto fault;
break;
+ }
default:
WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
return ES_UNSUPPORTED;
@@ -362,11 +373,6 @@
char *src, char *buf, size_t size)
{
unsigned long error_code = X86_PF_PROT;
- char __user *s = (char __user *)src;
- u64 d8;
- u32 d4;
- u16 d2;
- u8 d1;
/*
* This function uses __get_user() independent of whether kernel or user
@@ -388,26 +394,41 @@
* instructions here would cause infinite nesting.
*/
switch (size) {
- case 1:
+ case 1: {
+ u8 d1;
+ u8 __user *s = (u8 __user *)src;
+
if (__get_user(d1, s))
goto fault;
memcpy(buf, &d1, 1);
break;
- case 2:
+ }
+ case 2: {
+ u16 d2;
+ u16 __user *s = (u16 __user *)src;
+
if (__get_user(d2, s))
goto fault;
memcpy(buf, &d2, 2);
break;
- case 4:
+ }
+ case 4: {
+ u32 d4;
+ u32 __user *s = (u32 __user *)src;
+
if (__get_user(d4, s))
goto fault;
memcpy(buf, &d4, 4);
break;
- case 8:
+ }
+ case 8: {
+ u64 d8;
+ u64 __user *s = (u64 __user *)src;
if (__get_user(d8, s))
goto fault;
memcpy(buf, &d8, 8);
break;
+ }
default:
WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
return ES_UNSUPPORTED;
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 2e076a4..a698196 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1180,6 +1180,12 @@
EXPORT_SYMBOL_GPL(mark_tsc_unstable);
+static void __init tsc_disable_clocksource_watchdog(void)
+{
+ clocksource_tsc_early.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
+ clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
+}
+
static void __init check_system_tsc_reliable(void)
{
#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC)
@@ -1196,6 +1202,23 @@
#endif
if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
tsc_clocksource_reliable = 1;
+
+ /*
+ * Disable the clocksource watchdog when the system has:
+ * - TSC running at constant frequency
+ * - TSC which does not stop in C-States
+ * - the TSC_ADJUST register which allows to detect even minimal
+ * modifications
+ * - not more than two sockets. As the number of sockets cannot be
+ * evaluated at the early boot stage where this has to be
+ * invoked, check the number of online memory nodes as a
+ * fallback solution which is an reasonable estimate.
+ */
+ if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
+ boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&
+ boot_cpu_has(X86_FEATURE_TSC_ADJUST) &&
+ nr_online_nodes <= 2)
+ tsc_disable_clocksource_watchdog();
}
/*
@@ -1387,9 +1410,6 @@
if (tsc_unstable)
goto unreg;
- if (tsc_clocksource_reliable || no_tsc_watchdog)
- clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
-
if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
@@ -1527,7 +1547,7 @@
}
if (tsc_clocksource_reliable || no_tsc_watchdog)
- clocksource_tsc_early.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
+ tsc_disable_clocksource_watchdog();
clocksource_register_khz(&clocksource_tsc_early, tsc_khz);
detect_art();
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index 50a4515..9452dc9 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -30,6 +30,7 @@
};
static DEFINE_PER_CPU(struct tsc_adjust, tsc_adjust);
+static struct timer_list tsc_sync_check_timer;
/*
* TSC's on different sockets may be reset asynchronously.
@@ -77,6 +78,46 @@
}
}
+/*
+ * Normally the tsc_sync will be checked every time system enters idle
+ * state, but there is still caveat that a system won't enter idle,
+ * either because it's too busy or configured purposely to not enter
+ * idle.
+ *
+ * So setup a periodic timer (every 10 minutes) to make sure the check
+ * is always on.
+ */
+
+#define SYNC_CHECK_INTERVAL (HZ * 600)
+
+static void tsc_sync_check_timer_fn(struct timer_list *unused)
+{
+ int next_cpu;
+
+ tsc_verify_tsc_adjust(false);
+
+ /* Run the check for all onlined CPUs in turn */
+ next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
+ if (next_cpu >= nr_cpu_ids)
+ next_cpu = cpumask_first(cpu_online_mask);
+
+ tsc_sync_check_timer.expires += SYNC_CHECK_INTERVAL;
+ add_timer_on(&tsc_sync_check_timer, next_cpu);
+}
+
+static int __init start_sync_check_timer(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_TSC_ADJUST) || tsc_clocksource_reliable)
+ return 0;
+
+ timer_setup(&tsc_sync_check_timer, tsc_sync_check_timer_fn, 0);
+ tsc_sync_check_timer.expires = jiffies + SYNC_CHECK_INTERVAL;
+ add_timer(&tsc_sync_check_timer);
+
+ return 0;
+}
+late_initcall(start_sync_check_timer);
+
static void tsc_sanitize_first_cpu(struct tsc_adjust *cur, s64 bootval,
unsigned int cpu, bool bootcpu)
{
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 4a3da75..38d24d2 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -72,6 +72,7 @@
#ifdef CONFIG_X86_64
u64 *trampoline_pgd;
u64 efer;
+ int i;
#endif
base = (unsigned char *)real_mode_header;
@@ -128,8 +129,17 @@
trampoline_header->flags = 0;
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
+
+ /* Map the real mode stub as virtual == physical */
trampoline_pgd[0] = trampoline_pgd_entry.pgd;
- trampoline_pgd[511] = init_top_pgt[511].pgd;
+
+ /*
+ * Include the entirety of the kernel mapping into the trampoline
+ * PGD. This way, all mappings present in the normal kernel page
+ * tables are usable while running on trampoline_pgd.
+ */
+ for (i = pgd_index(__PAGE_OFFSET); i < PTRS_PER_PGD; i++)
+ trampoline_pgd[i] = init_top_pgt[i].pgd;
#endif
sme_sev_setup_real_mode(trampoline_header);
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 220dd96..444d824 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -20,6 +20,7 @@
#include <linux/init.h>
#include <linux/linkage.h>
+#include <../entry/calling.h>
.pushsection .noinstr.text, "ax"
/*
@@ -193,6 +194,25 @@
SYM_CODE_END(xen_iret)
/*
+ * XEN pv doesn't use trampoline stack, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is
+ * also the kernel stack. Reusing swapgs_restore_regs_and_return_to_usermode()
+ * in XEN pv would cause %rsp to move up to the top of the kernel stack and
+ * leave the IRET frame below %rsp, which is dangerous to be corrupted if #NMI
+ * interrupts. And swapgs_restore_regs_and_return_to_usermode() pushing the IRET
+ * frame at the same address is useless.
+ */
+SYM_CODE_START(xenpv_restore_regs_and_return_to_usermode)
+ UNWIND_HINT_REGS
+ POP_REGS
+
+ /* stackleak_erase() can work safely on the kernel stack. */
+ STACKLEAK_ERASE_NOCLOBBER
+
+ addq $8, %rsp /* skip regs->orig_ax */
+ jmp xen_iret
+SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode)
+
+/*
* Xen handles syscall callbacks much like ordinary exceptions, which
* means we have:
* - kernel gs
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 81a4c54..4b384c9 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -375,6 +375,7 @@
return -1;
}
memset(sym, 0, sizeof(*sym));
+ INIT_LIST_HEAD(&sym->pv_target);
sym->alias = sym;
sym->idx = i;
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index c90c708..bdf699f 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -153,6 +153,10 @@
!strcmp(func->name, "_paravirt_ident_64"))
return;
+ /* already added this function */
+ if (!list_empty(&func->pv_target))
+ return;
+
list_add(&func->pv_target, &f->pv_ops[idx].targets);
f->pv_ops[idx].clean = false;
}
