Popcorn Linux is a Linux kernel-based software stack
that enables applications to execute, with a shared
source base, on distributed hosts.
This Popcorn patch adds x86_64 functionality only.
Future iterations of Popcorn will support
heterogeneous architectures.
---
arch/x86/Kconfig | 3 +++
arch/x86/include/asm/pgtable.h | 11 +++++++++++
arch/x86/kernel/Makefile | 1 +
arch/x86/mm/fault.c | 18 ++++++++++++++++++
4 files changed, 33 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2bbbd4d1b..4ca75c6c3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -88,6 +88,7 @@ config X86
select ARCH_SUPPORTS_ACPI
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
+ select ARCH_SUPPORTS_POPCORN if X86_64
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS
@@ -353,6 +354,8 @@ config PGTABLE_LEVELS
default 3 if X86_PAE
default 2
+source "kernel/Kconfig.popcorn"
+
config CC_HAS_SANE_STACKPROTECTOR
bool
default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh
$(CC)) if 64BIT
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5e0509b41..7a0171c67 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -210,9 +210,13 @@ static inline u64 protnone_mask(u64 val);
static inline unsigned long pte_pfn(pte_t pte)
{
+#ifdef CONFIG_POPCORN
+ return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
+#else
phys_addr_t pfn = pte_val(pte);
pfn ^= protnone_mask(pfn);
return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT;
+#endif
}
static inline unsigned long pmd_pfn(pmd_t pmd)
@@ -602,7 +606,11 @@ static inline u64 flip_protnone_guard(u64 oldval, u64 val,
u64 mask);
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
+#ifndef CONFIG_POPCORN
pteval_t val = pte_val(pte), oldval = val;
+#else
+ pteval_t val = pte_val(pte);
+#endif
/*
* Chop off the NX bit (if present), and add the NX portion of
@@ -610,8 +618,11 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
*/
val &= _PAGE_CHG_MASK;
val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK;
+#ifndef CONFIG_POPCORN
val = flip_protnone_guard(oldval, val, PTE_PFN_MASK);
+#endif
return __pte(val);
+
}
static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index ce1b5cc36..3fb863285 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -133,6 +133,7 @@ obj-$(CONFIG_EFI) += sysfb_efi.o
obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
obj-$(CONFIG_TRACING) += tracepoint.o
+obj-$(CONFIG_POPCORN) += process_server.o
obj-$(CONFIG_SCHED_MC_PRIO) += itmt.o
obj-$(CONFIG_X86_INTEL_UMIP) += umip.o
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 46df4c6aa..14b9755f9 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -33,6 +33,11 @@
#define CREATE_TRACE_POINTS
#include <asm/trace/exceptions.h>
+#ifdef CONFIG_POPCORN
+#include <popcorn/types.h>
+#include <popcorn/vma_server.h>
+#endif
+
/*
* Returns 0 if mmiotrace is disabled, or if the fault is not
* handled by mmiotrace:
@@ -1416,6 +1421,19 @@ void do_user_addr_fault(struct pt_regs *regs,
}
vma = find_vma(mm, address);
+#ifdef CONFIG_POPCORN
+ /* vma worker should not fault */
+ BUG_ON(tsk->is_worker);
+
+ if (distributed_remote_process(tsk)) {
+ if (!vma || vma->vm_start > address) {
+ if (vma_server_fetch_vma(tsk, address) == 0) {
+ /* Replace with updated VMA */
+ vma = find_vma(mm, address);
+ }
+ }
+ }
+#endif
if (unlikely(!vma)) {
bad_area(regs, hw_error_code, address);
return;
--
2.17.1
