From: Arvind Sankar Date: Thu, 3 Sep 2020 02:30:56 +0000 (-0400) Subject: x86/cmdline: Disable jump tables for cmdline.c X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=aef0148f3606117352053c015cb33734e9ee7397;p=linux.git x86/cmdline: Disable jump tables for cmdline.c When CONFIG_RETPOLINE is disabled, Clang uses a jump table for the switch statement in cmdline_find_option (jump tables are disabled when CONFIG_RETPOLINE is enabled). This function is called very early in boot from sme_enable() if CONFIG_AMD_MEM_ENCRYPT is enabled. At this time, the kernel is still executing out of the identity mapping, but the jump table will contain virtual addresses. Fix this by disabling jump tables for cmdline.c when AMD_MEM_ENCRYPT is enabled. Signed-off-by: Arvind Sankar Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200903023056.3914690-1-nivedita@alum.mit.edu --- diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index d46fff11f06fa..aa067859a70b6 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -24,7 +24,7 @@ ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_cmdline.o = -pg endif -CFLAGS_cmdline.o := -fno-stack-protector +CFLAGS_cmdline.o := -fno-stack-protector -fno-jump-tables endif inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk