Messages in this thread Patch in this message | | | Date | Thu, 24 Feb 2022 15:51:59 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v2 21/39] x86/ibt: Annotate text references |
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Annotate away some of the generic code references. This is things where we take the address of a symbol for exception handling or return addresses (eg. context switch).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/entry/entry_64.S | 9 +++++++++ arch/x86/entry/entry_64_compat.S | 1 + arch/x86/kernel/alternative.c | 4 +++- arch/x86/kernel/head_64.S | 4 ++++ arch/x86/kernel/kprobes/core.c | 1 + arch/x86/kernel/relocate_kernel_64.S | 2 ++ arch/x86/lib/error-inject.c | 2 ++ arch/x86/lib/retpoline.S | 2 ++ 8 files changed, 24 insertions(+), 1 deletion(-)
--- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -277,6 +277,7 @@ SYM_FUNC_END(__switch_to_asm) .pushsection .text, "ax" SYM_CODE_START(ret_from_fork) UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR // copy_thread movq %rax, %rdi call schedule_tail /* rdi: 'prev' task parameter */ @@ -563,12 +564,14 @@ SYM_CODE_END(\asmsym) .align 16 .globl __irqentry_text_start __irqentry_text_start: + ANNOTATE_NOENDBR // unwinders #include <asm/idtentry.h> .align 16 .globl __irqentry_text_end __irqentry_text_end: + ANNOTATE_NOENDBR SYM_CODE_START_LOCAL(common_interrupt_return) SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL) @@ -646,6 +651,7 @@ SYM_INNER_LABEL_ALIGN(native_iret, SYM_L #endif SYM_INNER_LABEL(native_irq_return_iret, SYM_L_GLOBAL) + ANNOTATE_NOENDBR // exc_double_fault /* * This may fault. Non-paranoid faults on return to userspace are * handled by fixup_bad_iret. These include #SS, #GP, and #NP. @@ -740,6 +746,7 @@ SYM_FUNC_START(asm_load_gs_index) FRAME_BEGIN swapgs .Lgs_change: + ANNOTATE_NOENDBR // error_entry movl %edi, %gs 2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE swapgs @@ -1317,6 +1324,7 @@ SYM_CODE_START(asm_exc_nmi) #endif repeat_nmi: + ANNOTATE_NOENDBR // this code /* * If there was a nested NMI, the first NMI's iret will return * here. But NMIs are still enabled and we can take another @@ -1345,6 +1353,7 @@ SYM_CODE_START(asm_exc_nmi) .endr subq $(5*8), %rsp end_repeat_nmi: + ANNOTATE_NOENDBR // this code /* * Everything below this point can be preempted by a nested NMI. --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -148,6 +148,7 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_af popfq jmp .Lsysenter_flags_fixed SYM_INNER_LABEL(__end_entry_SYSENTER_compat, SYM_L_GLOBAL) + ANNOTATE_NOENDBR // is_sysenter_singlestep SYM_CODE_END(entry_SYSENTER_compat) /* --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -713,6 +713,7 @@ asm ( " .pushsection .init.text, \"ax\", @progbits\n" " .type int3_magic, @function\n" "int3_magic:\n" + ANNOTATE_NOENDBR " movl $1, (%" _ASM_ARG1 ")\n" ASM_RET " .size int3_magic, .-int3_magic\n" @@ -757,7 +758,8 @@ static void __init int3_selftest(void) * then trigger the INT3, padded with NOPs to match a CALL instruction * length. */ - asm volatile ("1: int3; nop; nop; nop; nop\n\t" + asm volatile (ANNOTATE_NOENDBR + "1: int3; nop; nop; nop; nop\n\t" ".pushsection .init.data,\"aw\"\n\t" ".align " __ASM_SEL(4, 8) "\n\t" ".type int3_selftest_ip, @object\n\t" --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -99,6 +99,7 @@ SYM_CODE_END(startup_64) SYM_CODE_START(secondary_startup_64) UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR /* * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0, * and someone has loaded a mapped page table. @@ -127,6 +128,7 @@ SYM_CODE_START(secondary_startup_64) */ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL) UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR /* * Retrieve the modifier (SME encryption mask if SME is active) to be @@ -192,6 +194,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_ jmp *%rax 1: UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR // above /* * We must switch to a new descriptor in kernel space for the GDT @@ -299,6 +302,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_ pushq %rax # target address in negative space lretq .Lafter_lret: + ANNOTATE_NOENDBR SYM_CODE_END(secondary_startup_64) #include "verify_cpu.S" --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1023,6 +1023,7 @@ asm( ".type __kretprobe_trampoline, @function\n" "__kretprobe_trampoline:\n" #ifdef CONFIG_X86_64 + ANNOTATE_NOENDBR /* Push a fake return address to tell the unwinder it's a kretprobe. */ " pushq $__kretprobe_trampoline\n" UNWIND_HINT_FUNC --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -42,6 +42,7 @@ .code64 SYM_CODE_START_NOALIGN(relocate_kernel) UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR /* * %rdi indirection_page * %rsi page_list @@ -215,6 +216,7 @@ SYM_CODE_END(identity_mapped) SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped) UNWIND_HINT_EMPTY + ANNOTATE_NOENDBR // RET target, above movq RSP(%r8), %rsp movq CR4(%r8), %rax movq %rax, %cr4 --- a/arch/x86/lib/error-inject.c +++ b/arch/x86/lib/error-inject.c @@ -3,6 +3,7 @@ #include <linux/linkage.h> #include <linux/error-injection.h> #include <linux/kprobes.h> +#include <linux/objtool.h> asmlinkage void just_return_func(void); @@ -11,6 +12,7 @@ asm( ".type just_return_func, @function\n" ".globl just_return_func\n" "just_return_func:\n" + ANNOTATE_NOENDBR ASM_RET ".size just_return_func, .-just_return_func\n" ); --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -12,6 +12,8 @@ .section .text.__x86.indirect_thunk + ANNOTATE_NOENDBR // apply_retpolines + .macro RETPOLINE reg ANNOTATE_INTRA_FUNCTION_CALL call .Ldo_rop_\@
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