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authorArvind Sankar <nivedita@alum.mit.edu>2020-10-08 15:16:23 -0400
committerBorislav Petkov <bp@suse.de>2020-10-19 13:11:00 +0200
commit103a4908ad4da9decdf9bc7216ec5a4861edf703 (patch)
tree7665d92ab4c9f42b6cbacff4814c8dfb1b1ed57e /arch/x86/kernel/Makefile
parente5ceb9a02402b984feecb95a82239be151c9f4e2 (diff)
x86/head/64: Disable stack protection for head$(BITS).o
On 64-bit, the startup_64_setup_env() function added in 866b556efa12 ("x86/head/64: Install startup GDT") has stack protection enabled because of set_bringup_idt_handler(). This happens when CONFIG_STACKPROTECTOR_STRONG is enabled. It also currently needs CONFIG_AMD_MEM_ENCRYPT enabled because then set_bringup_idt_handler() is not an empty stub but that might change in the future, when the other vendor adds their similar technology. At this point, %gs is not yet initialized, and this doesn't cause a crash only because the #PF handler from the decompressor stub is still installed and handles the page fault. Disable stack protection for the whole file, and do it on 32-bit as well to avoid surprises. [ bp: Extend commit message with the exact explanation how it happens. ] Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/20201008191623.2881677-6-nivedita@alum.mit.edu
Diffstat (limited to 'arch/x86/kernel/Makefile')
-rw-r--r--arch/x86/kernel/Makefile2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 04ceea8f4a89..68608bd892c0 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -47,6 +47,8 @@ endif
# non-deterministic coverage.
KCOV_INSTRUMENT := n
+CFLAGS_head$(BITS).o += -fno-stack-protector
+
CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
obj-y := process_$(BITS).o signal.o