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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-07 09:40:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-07 09:40:47 -0800
commite24f9c5f6e3127a0679d5ba5575a181b80f219c9 (patch)
tree9ba80bb06adaf56f7e6d63ce37d1dc5fddbf6008
parent2db138bb9fa10f5652f55d3c3f427af54626a086 (diff)
parent816ef8d7a2c4182e19bc06ab65751cb9e3951e94 (diff)
Merge tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov: "I hope this is the last batch of x86/urgent updates for this round: - Remove superfluous EFI PGD range checks which lead to those assertions failing with certain kernel configs and LLVM. - Disable setting breakpoints on facilities involved in #DB exception handling to avoid infinite loops. - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE and x2 APIC MSRs) to adhere to SDM's recommendation and avoid any theoretical issues. - Re-add the EPB MSR reading on turbostat so that it works on older kernels which don't have the corresponding EPB sysfs file. - Add Alder Lake to the list of CPUs which support split lock. - Fix %dr6 register handling in order to be able to set watchpoints with gdb again. - Disable CET instrumentation in the kernel so that gcc doesn't add ENDBR64 to kernel code and thus confuse tracing" * tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/efi: Remove EFI PGD build time checks x86/debug: Prevent data breakpoints on cpu_dr7 x86/debug: Prevent data breakpoints on __per_cpu_offset x86/apic: Add extra serialization for non-serializing MSRs tools/power/turbostat: Fallback to an MSR read for EPB x86/split_lock: Enable the split lock feature on another Alder Lake CPU x86/debug: Fix DR6 handling x86/build: Disable CET instrumentation in the kernel
-rw-r--r--Makefile6
-rw-r--r--arch/x86/Makefile3
-rw-r--r--arch/x86/include/asm/apic.h10
-rw-r--r--arch/x86/include/asm/barrier.h18
-rw-r--r--arch/x86/kernel/apic/apic.c4
-rw-r--r--arch/x86/kernel/apic/x2apic_cluster.c6
-rw-r--r--arch/x86/kernel/apic/x2apic_phys.c9
-rw-r--r--arch/x86/kernel/cpu/intel.c1
-rw-r--r--arch/x86/kernel/hw_breakpoint.c61
-rw-r--r--arch/x86/platform/efi/efi_64.c19
-rw-r--r--tools/power/x86/turbostat/turbostat.c10
11 files changed, 85 insertions, 62 deletions
diff --git a/Makefile b/Makefile
index 01c36d209ab4..70035c522bd3 100644
--- a/Makefile
+++ b/Makefile
@@ -949,12 +949,6 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init)
# change __FILE__ to the relative path from the srctree
KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
-# ensure -fcf-protection is disabled when using retpoline as it is
-# incompatible with -mindirect-branch=thunk-extern
-ifdef CONFIG_RETPOLINE
-KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
-endif
-
# include additional Makefiles when needed
include-y := scripts/Makefile.extrawarn
include-$(CONFIG_KASAN) += scripts/Makefile.kasan
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 7116da3980be..5857917f83ee 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -120,6 +120,9 @@ else
KBUILD_CFLAGS += -mno-red-zone
KBUILD_CFLAGS += -mcmodel=kernel
+
+ # Intel CET isn't enabled in the kernel
+ KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
endif
ifdef CONFIG_X86_X32
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 34cb3c159481..412b51e059c8 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -197,16 +197,6 @@ static inline bool apic_needs_pit(void) { return true; }
#endif /* !CONFIG_X86_LOCAL_APIC */
#ifdef CONFIG_X86_X2APIC
-/*
- * Make previous memory operations globally visible before
- * sending the IPI through x2apic wrmsr. We need a serializing instruction or
- * mfence for this.
- */
-static inline void x2apic_wrmsr_fence(void)
-{
- asm volatile("mfence" : : : "memory");
-}
-
static inline void native_apic_msr_write(u32 reg, u32 v)
{
if (reg == APIC_DFR || reg == APIC_ID || reg == APIC_LDR ||
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 7f828fe49797..4819d5e5a335 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -84,4 +84,22 @@ do { \
#include <asm-generic/barrier.h>
+/*
+ * Make previous memory operations globally visible before
+ * a WRMSR.
+ *
+ * MFENCE makes writes visible, but only affects load/store
+ * instructions. WRMSR is unfortunately not a load/store
+ * instruction and is unaffected by MFENCE. The LFENCE ensures
+ * that the WRMSR is not reordered.
+ *
+ * Most WRMSRs are full serializing instructions themselves and
+ * do not require this barrier. This is only required for the
+ * IA32_TSC_DEADLINE and X2APIC MSRs.
+ */
+static inline void weak_wrmsr_fence(void)
+{
+ asm volatile("mfence; lfence" : : : "memory");
+}
+
#endif /* _ASM_X86_BARRIER_H */
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 6bd20c0de8bc..7f4c081f59f0 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -41,6 +41,7 @@
#include <asm/perf_event.h>
#include <asm/x86_init.h>
#include <linux/atomic.h>
+#include <asm/barrier.h>
#include <asm/mpspec.h>
#include <asm/i8259.h>
#include <asm/proto.h>
@@ -477,6 +478,9 @@ static int lapic_next_deadline(unsigned long delta,
{
u64 tsc;
+ /* This MSR is special and need a special fence: */
+ weak_wrmsr_fence();
+
tsc = rdtsc();
wrmsrl(MSR_IA32_TSC_DEADLINE, tsc + (((u64) delta) * TSC_DIVISOR));
return 0;
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index df6adc5674c9..f4da9bb69a88 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -29,7 +29,8 @@ static void x2apic_send_IPI(int cpu, int vector)
{
u32 dest = per_cpu(x86_cpu_to_logical_apicid, cpu);
- x2apic_wrmsr_fence();
+ /* x2apic MSRs are special and need a special fence: */
+ weak_wrmsr_fence();
__x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
}
@@ -41,7 +42,8 @@ __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
unsigned long flags;
u32 dest;
- x2apic_wrmsr_fence();
+ /* x2apic MSRs are special and need a special fence: */
+ weak_wrmsr_fence();
local_irq_save(flags);
tmpmsk = this_cpu_cpumask_var_ptr(ipi_mask);
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 0e4e81971567..6bde05a86b4e 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -43,7 +43,8 @@ static void x2apic_send_IPI(int cpu, int vector)
{
u32 dest = per_cpu(x86_cpu_to_apicid, cpu);
- x2apic_wrmsr_fence();
+ /* x2apic MSRs are special and need a special fence: */
+ weak_wrmsr_fence();
__x2apic_send_IPI_dest(dest, vector, APIC_DEST_PHYSICAL);
}
@@ -54,7 +55,8 @@ __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
unsigned long this_cpu;
unsigned long flags;
- x2apic_wrmsr_fence();
+ /* x2apic MSRs are special and need a special fence: */
+ weak_wrmsr_fence();
local_irq_save(flags);
@@ -125,7 +127,8 @@ void __x2apic_send_IPI_shorthand(int vector, u32 which)
{
unsigned long cfg = __prepare_ICR(which, vector, 0);
- x2apic_wrmsr_fence();
+ /* x2apic MSRs are special and need a special fence: */
+ weak_wrmsr_fence();
native_x2apic_icr_write(cfg, 0);
}
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 59a1e3ce3f14..816fdbec795a 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1159,6 +1159,7 @@ static const struct x86_cpu_id split_lock_cpu_ids[] __initconst = {
X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE, 1),
X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, 1),
X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE, 1),
+ X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L, 1),
{}
};
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index 03aa33b58165..668a4a6533d9 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -269,6 +269,20 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end)
CPU_ENTRY_AREA_TOTAL_SIZE))
return true;
+ /*
+ * When FSGSBASE is enabled, paranoid_entry() fetches the per-CPU
+ * GSBASE value via __per_cpu_offset or pcpu_unit_offsets.
+ */
+#ifdef CONFIG_SMP
+ if (within_area(addr, end, (unsigned long)__per_cpu_offset,
+ sizeof(unsigned long) * nr_cpu_ids))
+ return true;
+#else
+ if (within_area(addr, end, (unsigned long)&pcpu_unit_offsets,
+ sizeof(pcpu_unit_offsets)))
+ return true;
+#endif
+
for_each_possible_cpu(cpu) {
/* The original rw GDT is being used after load_direct_gdt() */
if (within_area(addr, end, (unsigned long)get_cpu_gdt_rw(cpu),
@@ -293,6 +307,14 @@ static inline bool within_cpu_entry(unsigned long addr, unsigned long end)
(unsigned long)&per_cpu(cpu_tlbstate, cpu),
sizeof(struct tlb_state)))
return true;
+
+ /*
+ * When in guest (X86_FEATURE_HYPERVISOR), local_db_save()
+ * will read per-cpu cpu_dr7 before clear dr7 register.
+ */
+ if (within_area(addr, end, (unsigned long)&per_cpu(cpu_dr7, cpu),
+ sizeof(cpu_dr7)))
+ return true;
}
return false;
@@ -491,15 +513,12 @@ static int hw_breakpoint_handler(struct die_args *args)
struct perf_event *bp;
unsigned long *dr6_p;
unsigned long dr6;
+ bool bpx;
/* The DR6 value is pointed by args->err */
dr6_p = (unsigned long *)ERR_PTR(args->err);
dr6 = *dr6_p;
- /* If it's a single step, TRAP bits are random */
- if (dr6 & DR_STEP)
- return NOTIFY_DONE;
-
/* Do an early return if no trap bits are set in DR6 */
if ((dr6 & DR_TRAP_BITS) == 0)
return NOTIFY_DONE;
@@ -509,28 +528,29 @@ static int hw_breakpoint_handler(struct die_args *args)
if (likely(!(dr6 & (DR_TRAP0 << i))))
continue;
+ bp = this_cpu_read(bp_per_reg[i]);
+ if (!bp)
+ continue;
+
+ bpx = bp->hw.info.type == X86_BREAKPOINT_EXECUTE;
+
/*
- * The counter may be concurrently released but that can only
- * occur from a call_rcu() path. We can then safely fetch
- * the breakpoint, use its callback, touch its counter
- * while we are in an rcu_read_lock() path.
+ * TF and data breakpoints are traps and can be merged, however
+ * instruction breakpoints are faults and will be raised
+ * separately.
+ *
+ * However DR6 can indicate both TF and instruction
+ * breakpoints. In that case take TF as that has precedence and
+ * delay the instruction breakpoint for the next exception.
*/
- rcu_read_lock();
+ if (bpx && (dr6 & DR_STEP))
+ continue;
- bp = this_cpu_read(bp_per_reg[i]);
/*
* Reset the 'i'th TRAP bit in dr6 to denote completion of
* exception handling
*/
(*dr6_p) &= ~(DR_TRAP0 << i);
- /*
- * bp can be NULL due to lazy debug register switching
- * or due to concurrent perf counter removing.
- */
- if (!bp) {
- rcu_read_unlock();
- break;
- }
perf_bp_event(bp, args->regs);
@@ -538,11 +558,10 @@ static int hw_breakpoint_handler(struct die_args *args)
* Set up resume flag to avoid breakpoint recursion when
* returning back to origin.
*/
- if (bp->hw.info.type == X86_BREAKPOINT_EXECUTE)
+ if (bpx)
args->regs->flags |= X86_EFLAGS_RF;
-
- rcu_read_unlock();
}
+
/*
* Further processing in do_debug() is needed for a) user-space
* breakpoints (to generate signals) and b) when the system has
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index e1e8d4e3a213..8efd003540ca 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -115,31 +115,12 @@ void efi_sync_low_kernel_mappings(void)
pud_t *pud_k, *pud_efi;
pgd_t *efi_pgd = efi_mm.pgd;
- /*
- * We can share all PGD entries apart from the one entry that
- * covers the EFI runtime mapping space.
- *
- * Make sure the EFI runtime region mappings are guaranteed to
- * only span a single PGD entry and that the entry also maps
- * other important kernel regions.
- */
- MAYBE_BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END));
- MAYBE_BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) !=
- (EFI_VA_END & PGDIR_MASK));
-
pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET);
pgd_k = pgd_offset_k(PAGE_OFFSET);
num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET);
memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries);
- /*
- * As with PGDs, we share all P4D entries apart from the one entry
- * that covers the EFI runtime mapping space.
- */
- BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END));
- BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK));
-
pgd_efi = efi_pgd + pgd_index(EFI_VA_END);
pgd_k = pgd_offset_k(EFI_VA_END);
p4d_efi = p4d_offset(pgd_efi, 0);
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 389ea5209a83..a7c4f0772e53 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1834,12 +1834,15 @@ int get_mp(int cpu, struct msr_counter *mp, unsigned long long *counterp)
int get_epb(int cpu)
{
char path[128 + PATH_BYTES];
+ unsigned long long msr;
int ret, epb = -1;
FILE *fp;
sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
- fp = fopen_or_die(path, "r");
+ fp = fopen(path, "r");
+ if (!fp)
+ goto msr_fallback;
ret = fscanf(fp, "%d", &epb);
if (ret != 1)
@@ -1848,6 +1851,11 @@ int get_epb(int cpu)
fclose(fp);
return epb;
+
+msr_fallback:
+ get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &msr);
+
+ return msr & 0xf;
}
void get_apic_id(struct thread_data *t)