linux-stable/arch/x86/kernel/Makefile
Michael Roth 469693d8f6 x86/head/64: Re-enable stack protection
Due to

  103a4908ad ("x86/head/64: Disable stack protection for head$(BITS).o")

kernel/head{32,64}.c are compiled with -fno-stack-protector to allow
a call to set_bringup_idt_handler(), which would otherwise have stack
protection enabled with CONFIG_STACKPROTECTOR_STRONG.

While sufficient for that case, there may still be issues with calls to
any external functions that were compiled with stack protection enabled
that in-turn make stack-protected calls, or if the exception handlers
set up by set_bringup_idt_handler() make calls to stack-protected
functions.

Subsequent patches for SEV-SNP CPUID validation support will introduce
both such cases. Attempting to disable stack protection for everything
in scope to address that is prohibitive since much of the code, like the
SEV-ES #VC handler, is shared code that remains in use after boot and
could benefit from having stack protection enabled. Attempting to inline
calls is brittle and can quickly balloon out to library/helper code
where that's not really an option.

Instead, re-enable stack protection for head32.c/head64.c, and make the
appropriate changes to ensure the segment used for the stack canary is
initialized in advance of any stack-protected C calls.

For head64.c:

- The BSP will enter from startup_64() and call into C code
  (startup_64_setup_env()) shortly after setting up the stack, which
  may result in calls to stack-protected code. Set up %gs early to allow
  for this safely.
- APs will enter from secondary_startup_64*(), and %gs will be set up
  soon after. There is one call to C code prior to %gs being setup
  (__startup_secondary_64()), but it is only to fetch 'sme_me_mask'
  global, so just load 'sme_me_mask' directly instead, and remove the
  now-unused __startup_secondary_64() function.

For head32.c:

- BSPs/APs will set %fs to __BOOT_DS prior to any C calls. In recent
  kernels, the compiler is configured to access the stack canary at
  %fs:__stack_chk_guard [1], which overlaps with the initial per-cpu
  '__stack_chk_guard' variable in the initial/"master" .data..percpu
  area. This is sufficient to allow access to the canary for use
  during initial startup, so no changes are needed there.

[1] 3fb0fdb3bb ("x86/stackprotector/32: Make the canary into a regular percpu variable")

  [ bp: Massage commit message. ]

Suggested-by: Joerg Roedel <jroedel@suse.de> #for 64-bit %gs set up
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-24-brijesh.singh@amd.com
2022-04-06 17:06:55 +02:00

159 lines
4.8 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the linux kernel.
#
extra-y := head_$(BITS).o
extra-y += head$(BITS).o
extra-y += ebda.o
extra-y += platform-quirks.o
extra-y += vmlinux.lds
CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
ifdef CONFIG_FUNCTION_TRACER
# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc.o = -pg
CFLAGS_REMOVE_paravirt-spinlocks.o = -pg
CFLAGS_REMOVE_pvclock.o = -pg
CFLAGS_REMOVE_kvmclock.o = -pg
CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_early_printk.o = -pg
CFLAGS_REMOVE_head64.o = -pg
CFLAGS_REMOVE_sev.o = -pg
endif
KASAN_SANITIZE_head$(BITS).o := n
KASAN_SANITIZE_dumpstack.o := n
KASAN_SANITIZE_dumpstack_$(BITS).o := n
KASAN_SANITIZE_stacktrace.o := n
KASAN_SANITIZE_paravirt.o := n
KASAN_SANITIZE_sev.o := n
# With some compiler versions the generated code results in boot hangs, caused
# by several compilation units. To be safe, disable all instrumentation.
KCSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD_test_nx.o := y
ifdef CONFIG_FRAME_POINTER
OBJECT_FILES_NON_STANDARD_ftrace_$(BITS).o := y
endif
# If instrumentation of this dir is enabled, boot hangs during first second.
# Probably could be more selective here, but note that files related to irqs,
# boot, dumpstack/stacktrace, etc are either non-interesting or can lead to
# non-deterministic coverage.
KCOV_INSTRUMENT := n
CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
obj-y := process_$(BITS).o signal.o
obj-$(CONFIG_COMPAT) += signal_compat.o
obj-y += traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
obj-y += time.o ioport.o dumpstack.o nmi.o
obj-$(CONFIG_MODIFY_LDT_SYSCALL) += ldt.o
obj-y += setup.o x86_init.o i8259.o irqinit.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-y += probe_roms.o
obj-$(CONFIG_X86_32) += sys_ia32.o
obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o
obj-$(CONFIG_X86_64) += sys_x86_64.o
obj-$(CONFIG_X86_ESPFIX64) += espfix_64.o
obj-$(CONFIG_SYSFS) += ksysfs.o
obj-y += bootflag.o e820.o
obj-y += pci-dma.o quirks.o topology.o kdebugfs.o
obj-y += alternative.o i8253.o hw_breakpoint.o
obj-y += tsc.o tsc_msr.o io_delay.o rtc.o
obj-y += pci-iommu_table.o
obj-y += resource.o
obj-y += irqflags.o
obj-y += static_call.o
obj-y += process.o
obj-y += fpu/
obj-y += ptrace.o
obj-$(CONFIG_X86_32) += tls.o
obj-$(CONFIG_IA32_EMULATION) += tls.o
obj-y += step.o
obj-$(CONFIG_INTEL_TXT) += tboot.o
obj-$(CONFIG_ISA_DMA_API) += i8237.o
obj-y += stacktrace.o
obj-y += cpu/
obj-y += acpi/
obj-y += reboot.o
obj-$(CONFIG_X86_MSR) += msr.o
obj-$(CONFIG_X86_CPUID) += cpuid.o
obj-$(CONFIG_PCI) += early-quirks.o
apm-y := apm_32.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SMP) += smpboot.o
obj-$(CONFIG_X86_TSC) += tsc_sync.o
obj-$(CONFIG_SMP) += setup_percpu.o
obj-$(CONFIG_X86_MPPARSE) += mpparse.o
obj-y += apic/
obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace_$(BITS).o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_X86_TSC) += trace_clock.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_RETHOOK) += rethook.o
obj-$(CONFIG_CRASH_CORE) += crash_core_$(BITS).o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec_$(BITS).o
obj-$(CONFIG_KEXEC_CORE) += relocate_kernel_$(BITS).o crash.o
obj-$(CONFIG_KEXEC_FILE) += kexec-bzimage64.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
obj-y += kprobes/
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_X86_32) += doublefault_32.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_VM86) += vm86_32.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_HPET_TIMER) += hpet.o
obj-$(CONFIG_AMD_NB) += amd_nb.o
obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o
obj-$(CONFIG_KVM_GUEST) += kvm.o kvmclock.o
obj-$(CONFIG_PARAVIRT) += paravirt.o
obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
obj-$(CONFIG_X86_PMEM_LEGACY_DEVICE) += pmem.o
obj-$(CONFIG_JAILHOUSE_GUEST) += jailhouse.o
obj-$(CONFIG_EISA) += eisa.o
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o
obj-$(CONFIG_OF) += devicetree.o
obj-$(CONFIG_UPROBES) += uprobes.o
obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
obj-$(CONFIG_TRACING) += tracepoint.o
obj-$(CONFIG_SCHED_MC_PRIO) += itmt.o
obj-$(CONFIG_X86_UMIP) += umip.o
obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o
obj-$(CONFIG_UNWINDER_FRAME_POINTER) += unwind_frame.o
obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += sev.o
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
obj-$(CONFIG_AUDIT) += audit_64.o
obj-$(CONFIG_GART_IOMMU) += amd_gart_64.o aperture_64.o
obj-$(CONFIG_MMCONF_FAM10H) += mmconf-fam10h_64.o
obj-y += vsmp_64.o
endif