This sets up stack switching, including for SYSCALL. I think it's
in decent shape.
Known issues:
- KASAN is likely to be busted. This could be fixed either by teaching
KASAN that cpu_entry_area contains valid stacks (I have no clue how
to go about doing this) or by rigging up the IST entry code to switch
RSP to point to the direct-mapped copy of the stacks before calling
into non-KASAN-excluded C code.
- 32-bit kernels are failing the sigreturn_32 test. But they're also
failing without the patches, so I'm not sure this is a bug in the
series per se. Needs further investigation. (Off the top of my head,
this could be further fallout from Thomas's IDT rework.)
- I think we're going to want a way to turn the stack switching on and
off either at boot time or at runtime. It should be fairly straightforward
to make it work.
- I think the ORC unwinder isn't so good at dealing with stack overflows.
It bails too early (I think), resulting in lots of ? entries. This
isn't a regression with this series -- it's just something that could
be improved.
Changes:
- This is quite massively changed from last time.
- 32-bit seems to build and mostly work
- KASAN is less broken now
Andy Lutomirski (16):
x86/asm/64: Allocate and enable the SYSENTER stack
x86/dumpstack: Add get_stack_info() support for the SYSENTER stack
x86/gdt: Put per-cpu GDT remaps in ascending order
x86/fixmap: Generalize the GDT fixmap mechanism
x86/asm: Fix assumptions that the HW TSS is at the beginning of
cpu_tss
x86/dumpstack: Handle stack overflow on all stacks
x86/asm: Move SYSENTER_stack to the beginning of struct tss_struct
x86/asm: Remap the TSS into the cpu entry area
x86/asm/64: Separate cpu_current_top_of_stack from TSS.sp0
x86/espfix/64: Stop assuming that pt_regs is on the entry stack
x86/asm/64: Use a percpu trampoline stack for IDT entries
x86/asm/64: Return to userspace from the trampoline stack
x86/entry/64: Create a percpu SYSCALL entry trampoline
x86/irq: Remove an old outdated comment about context tracking races
x86/irq/64: In the stack overflow warning, print the offending IP
x86/entry/64: Move the IST stacks into cpu_entry_area
arch/x86/entry/entry_32.S | 6 +-
arch/x86/entry/entry_64.S | 177 +++++++++++++++++++++++++++++++++----
arch/x86/entry/entry_64_compat.S | 6 +-
arch/x86/include/asm/desc.h | 11 +--
arch/x86/include/asm/fixmap.h | 55 +++++++++++-
arch/x86/include/asm/processor.h | 49 ++++++----
arch/x86/include/asm/stacktrace.h | 3 +
arch/x86/include/asm/switch_to.h | 2 +-
arch/x86/include/asm/thread_info.h | 2 +-
arch/x86/include/asm/traps.h | 1 -
arch/x86/kernel/asm-offsets.c | 9 ++
arch/x86/kernel/asm-offsets_32.c | 5 --
arch/x86/kernel/asm-offsets_64.c | 1 +
arch/x86/kernel/cpu/common.c | 136 +++++++++++++++++++++-------
arch/x86/kernel/doublefault.c | 36 ++++----
arch/x86/kernel/dumpstack.c | 46 +++++++---
arch/x86/kernel/dumpstack_32.c | 6 ++
arch/x86/kernel/dumpstack_64.c | 6 ++
arch/x86/kernel/irq.c | 12 ---
arch/x86/kernel/irq_64.c | 4 +-
arch/x86/kernel/process.c | 12 ++-
arch/x86/kernel/process_64.c | 1 +
arch/x86/kernel/traps.c | 25 +++---
arch/x86/kernel/vmlinux.lds.S | 10 +++
arch/x86/power/cpu.c | 16 ++--
arch/x86/xen/mmu_pv.c | 2 +-
26 files changed, 487 insertions(+), 152 deletions(-)
--
2.13.6
