diff options
| -rw-r--r-- | arch/x86/include/asm/traps.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cet.c | 23 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/ibt_selftest.S | 17 |
5 files changed, 22 insertions, 24 deletions
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 75e0dabf0c45..b1c9cea6ba88 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -18,7 +18,8 @@ void __init trap_init(void); asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs); #endif -extern bool ibt_selftest(void); +extern int ibt_selftest(void); +extern int ibt_selftest_noendbr(void); #ifdef CONFIG_X86_F00F_BUG /* For handling the FOOF bug */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 6b6bf47652ee..eca9784a46fe 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -49,6 +49,7 @@ obj-y += process_$(BITS).o signal.o signal_$(BITS).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-$(CONFIG_MODIFY_LDT_SYSCALL) += ldt.o +obj-$(CONFIG_X86_KERNEL_IBT) += ibt_selftest.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 diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index cc10d8be9d74..d2c732a34e5d 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -81,9 +81,6 @@ static void do_user_cp_fault(struct pt_regs *regs, unsigned long error_code) static __ro_after_init bool ibt_fatal = true; -/* code label defined in asm below */ -extern void ibt_selftest_ip(void); - static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code) { if ((error_code & CP_EC) != CP_ENDBR) { @@ -91,7 +88,7 @@ static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code) return; } - if (unlikely(regs->ip == (unsigned long)&ibt_selftest_ip)) { + if (unlikely(regs->ip == (unsigned long)&ibt_selftest_noendbr)) { regs->ax = 0; return; } @@ -105,24 +102,6 @@ static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code) BUG(); } -/* Must be noinline to ensure uniqueness of ibt_selftest_ip. */ -noinline bool ibt_selftest(void) -{ - unsigned long ret; - - asm (" lea ibt_selftest_ip(%%rip), %%rax\n\t" - ANNOTATE_RETPOLINE_SAFE - " jmp *%%rax\n\t" - "ibt_selftest_ip:\n\t" - UNWIND_HINT_FUNC - ANNOTATE_NOENDBR - " nop\n\t" - - : "=a" (ret) : : "memory"); - - return !ret; -} - static int __init ibt_setup(char *str) { if (!strcmp(str, "off")) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index cf5275a67f39..3c6426ce3c73 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -610,7 +610,7 @@ static __always_inline void setup_cet(struct cpuinfo_x86 *c) cr4_set_bits(X86_CR4_CET); - if (kernel_ibt && !ibt_selftest()) { + if (kernel_ibt && ibt_selftest()) { pr_err("IBT selftest: Failed!\n"); wrmsrl(MSR_IA32_S_CET, 0); setup_clear_cpu_cap(X86_FEATURE_IBT); diff --git a/arch/x86/kernel/ibt_selftest.S b/arch/x86/kernel/ibt_selftest.S new file mode 100644 index 000000000000..c43c4ed28a9c --- /dev/null +++ b/arch/x86/kernel/ibt_selftest.S @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/linkage.h> +#include <linux/objtool.h> +#include <asm/nospec-branch.h> + +SYM_CODE_START(ibt_selftest_noendbr) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + /* #CP handler sets %ax to 0 */ + RET +SYM_CODE_END(ibt_selftest_noendbr) + +SYM_FUNC_START(ibt_selftest) + lea ibt_selftest_noendbr(%rip), %rax + ANNOTATE_RETPOLINE_SAFE + jmp *%rax +SYM_FUNC_END(ibt_selftest) |