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| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-10-08 21:16:23 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-10-19 13:11:00 +0200 |
| commit | 103a4908ad4da9decdf9bc7216ec5a4861edf703 (patch) | |
| tree | 7665d92ab4c9f42b6cbacff4814c8dfb1b1ed57e /arch | |
| parent | x86/boot/64: Initialize 5-level paging variables earlier (diff) | |
| download | linux-103a4908ad4da9decdf9bc7216ec5a4861edf703.tar.xz linux-103a4908ad4da9decdf9bc7216ec5a4861edf703.zip | |
x86/head/64: Disable stack protection for head$(BITS).o
On 64-bit, the startup_64_setup_env() function added in
866b556efa12 ("x86/head/64: Install startup GDT")
has stack protection enabled because of set_bringup_idt_handler().
This happens when CONFIG_STACKPROTECTOR_STRONG is enabled. It
also currently needs CONFIG_AMD_MEM_ENCRYPT enabled because then
set_bringup_idt_handler() is not an empty stub but that might change in
the future, when the other vendor adds their similar technology.
At this point, %gs is not yet initialized, and this doesn't cause a
crash only because the #PF handler from the decompressor stub is still
installed and handles the page fault.
Disable stack protection for the whole file, and do it on 32-bit as
well to avoid surprises.
[ bp: Extend commit message with the exact explanation how it happens. ]
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20201008191623.2881677-6-nivedita@alum.mit.edu
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/Makefile | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 04ceea8f4a89..68608bd892c0 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -47,6 +47,8 @@ endif # non-deterministic coverage. KCOV_INSTRUMENT := n +CFLAGS_head$(BITS).o += -fno-stack-protector + CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace obj-y := process_$(BITS).o signal.o |