[GIT PULL] x86 fixes

Ingo Molnar
2017-11-05T14:46:57Z

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: eda9cec4c9a12208a6f69fbe68f72a6311d50032 x86/module: Detect and skip invalid relocations

Two fixes:

- A PCID related revert that fixes power management and performance regressions.

- The module loader robustization and sanity check commit is rather fresh, but it
looked like a good idea to apply because of the hidden data corruption problem
such invalid modules could cause.

out-of-topic modifications in x86-urgent-for-linus:
-----------------------------------------------------
arch/ia64/include/asm/acpi.h # 675357362aeb: Revert "x86/mm: Stop calling
drivers/acpi/processor_idle.c # 675357362aeb: Revert "x86/mm: Stop calling
drivers/idle/intel_idle.c # 675357362aeb: Revert "x86/mm: Stop calling

Thanks,

Ingo

------------------>
Andy Lutomirski (1):
Revert "x86/mm: Stop calling leave_mm() in idle code"

Josh Poimboeuf (1):
x86/module: Detect and skip invalid relocations

arch/ia64/include/asm/acpi.h | 2 ++
arch/x86/include/asm/acpi.h | 2 ++
arch/x86/kernel/module.c | 13 +++++++++++++
arch/x86/mm/tlb.c | 17 ++++++++++++++---
drivers/acpi/processor_idle.c | 2 ++
drivers/idle/intel_idle.c | 9 +++++----
6 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h
index c86a947f5368..a3d0211970e9 100644
--- a/arch/ia64/include/asm/acpi.h
+++ b/arch/ia64/include/asm/acpi.h
@@ -112,6 +112,8 @@ static inline void arch_acpi_set_pdc_bits(u32 *buf)
buf[2] |= ACPI_PDC_EST_CAPABILITY_SMP;
}

+#define acpi_unlazy_tlb(x)
+
#ifdef CONFIG_ACPI_NUMA
extern cpumask_t early_cpu_possible_map;
#define for_each_possible_early_cpu(cpu) \
diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 72d867f6b518..8d0ec9df1cbe 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -150,6 +150,8 @@ static inline void disable_acpi(void) { }
extern int x86_acpi_numa_init(void);
#endif /* CONFIG_ACPI_NUMA */

+#define acpi_unlazy_tlb(x) leave_mm(x)
+
#ifdef CONFIG_ACPI_APEI
static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
{
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 62e7d70aadd5..da0c160e5589 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -172,19 +172,27 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
case R_X86_64_NONE:
break;
case R_X86_64_64:
+ if (*(u64 *)loc != 0)
+ goto invalid_relocation;
*(u64 *)loc = val;
break;
case R_X86_64_32:
+ if (*(u32 *)loc != 0)
+ goto invalid_relocation;
*(u32 *)loc = val;
if (val != *(u32 *)loc)
goto overflow;
break;
case R_X86_64_32S:
+ if (*(s32 *)loc != 0)
+ goto invalid_relocation;
*(s32 *)loc = val;
if ((s64)val != *(s32 *)loc)
goto overflow;
break;
case R_X86_64_PC32:
+ if (*(u32 *)loc != 0)
+ goto invalid_relocation;
val -= (u64)loc;
*(u32 *)loc = val;
#if 0
@@ -200,6 +208,11 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
}
return 0;

+invalid_relocation:
+ pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
+ (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
+ return -ENOEXEC;
+
overflow:
pr_err("overflow in relocation type %d val %Lx\n",
(int)ELF64_R_TYPE(rel[i].r_info), val);
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 0f3d0cea4d00..3118392cdf75 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -85,6 +85,7 @@ void leave_mm(int cpu)

switch_mm(NULL, &init_mm, NULL);
}
+EXPORT_SYMBOL_GPL(leave_mm);

void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
@@ -195,12 +196,22 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id);
this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen);
write_cr3(build_cr3(next, new_asid));
- trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH,
- TLB_FLUSH_ALL);
+
+ /*
+ * NB: This gets called via leave_mm() in the idle path
+ * where RCU functions differently. Tracing normally
+ * uses RCU, so we need to use the _rcuidle variant.
+ *
+ * (There is no good reason for this. The idle code should
+ * be rearranged to call this before rcu_idle_enter().)
+ */
+ trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
} else {
/* The new ASID is already up to date. */
write_cr3(build_cr3_noflush(next, new_asid));
- trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, 0);
+
+ /* See above wrt _rcuidle. */
+ trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);
}

this_cpu_write(cpu_tlbstate.loaded_mm, next);
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2736e25e9dc6..d50a7b6ccddd 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -710,6 +710,8 @@ static DEFINE_RAW_SPINLOCK(c3_lock);
static void acpi_idle_enter_bm(struct acpi_processor *pr,
struct acpi_processor_cx *cx, bool timer_bc)
{
+ acpi_unlazy_tlb(smp_processor_id());
+
/*
* Must be done before busmaster disable as we might need to
* access HPET !
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 5dc7ea4b6bc4..f0b06b14e782 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -913,15 +913,16 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
struct cpuidle_state *state = &drv->states[index];
unsigned long eax = flg2MWAIT(state->flags);
unsigned int cstate;
+ int cpu = smp_processor_id();

cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;

/*
- * NB: if CPUIDLE_FLAG_TLB_FLUSHED is set, this idle transition
- * will probably flush the TLB. It's not guaranteed to flush
- * the TLB, though, so it's not clear that we can do anything
- * useful with this knowledge.
+ * leave_mm() to avoid costly and often unnecessary wakeups
+ * for flushing the user TLB's associated with the active mm.
*/
+ if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED)
+ leave_mm(cpu);

if (!(lapic_timer_reliable_states & (1 << (cstate))))
tick_broadcast_enter();