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Revision 61f01dd941ba9e06d2bf05994450ecc3d61b6b8b authored by Andy Lutomirski on 26 April 2015, 23:47:59 UTC, committed by Linus Torvalds on 27 April 2015, 00:57:38 UTC 
x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue
 
AMD CPUs don't reinitialize the SS descriptor on SYSRET, so SYSRET with
SS == 0 results in an invalid usermode state in which SS is apparently
equal to __USER_DS but causes #SS if used.

Work around the issue by setting SS to __KERNEL_DS __switch_to, thus
ensuring that SYSRET never happens with SS set to NULL.

This was exposed by a recent vDSO cleanup.

Fixes: e7d6eefaaa44 x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 1190944
Raw File
Makefile 
#
# arch/cris/boot/Makefile
#

objcopyflags-$(CONFIG_ETRAX_ARCH_V10) += -R .note -R .comment
objcopyflags-$(CONFIG_ETRAX_ARCH_V32) += --remove-section=.bss --remove-section=.note.gnu.build-id

OBJCOPYFLAGS = -O binary $(objcopyflags-y)


subdir- := compressed rescue
targets := Image

$(obj)/Image: vmlinux FORCE
	$(call if_changed,objcopy)
	@echo '  Kernel: $@ is ready'

$(obj)/compressed/vmlinux: $(obj)/Image FORCE
	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
	$(Q)$(MAKE) $(build)=$(obj)/rescue $(obj)/rescue/rescue.bin

$(obj)/zImage:  $(obj)/compressed/vmlinux
	@cp $< $@
	@echo '  Kernel: $@ is ready'
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