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| author |   Peter Zijlstra <peterz@infradead.org> | 2020-05-12 18:17:12 +0200 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:14:40 +0200 |
| commit | 1c3e5d3f60e26415d4227aa1193cf9e2db4df834 (patch) | |
| tree | 243f10f5e8d725c4417529c8d5f514f31fb06adf /arch/x86/entry/entry_64_compat.S | |
| parent | x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline (diff) | |
| download | linux-dev-1c3e5d3f60e26415d4227aa1193cf9e2db4df834.tar.xz linux-dev-1c3e5d3f60e26415d4227aa1193cf9e2db4df834.zip | |
x86/entry: Make entry_64_compat.S objtool clean
Currently entry_64_compat is exempt from objtool, but with vmlinux
mode there is no hiding it.
Make the following changes to make it pass:
- change entry_SYSENTER_compat to STT_NOTYPE; it's not a function
and doesn't have function type stack setup.
- mark all STT_NOTYPE symbols with UNWIND_HINT_EMPTY; so we do
validate them and don't treat them as unreachable.
- don't abuse RSP as a temp register, this confuses objtool
mightily as it (rightfully) thinks we're doing unspeakable
things to the stack.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134341.272248024@linutronix.de
Diffstat (limited to 'arch/x86/entry/entry_64_compat.S')
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 7c29ed898033..0f974ae01e62 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -46,12 +46,14 @@ * ebp user stack * 0(%ebp) arg6 */ -SYM_FUNC_START(entry_SYSENTER_compat) +SYM_CODE_START(entry_SYSENTER_compat) + UNWIND_HINT_EMPTY /* Interrupts are off on entry. */ SWAPGS - /* We are about to clobber %rsp anyway, clobbering here is OK */ - SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp + pushq %rax + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax + popq %rax movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp @@ -104,6 +106,9 @@ SYM_FUNC_START(entry_SYSENTER_compat) xorl %r14d, %r14d /* nospec r14 */ pushq $0 /* pt_regs->r15 = 0 */ xorl %r15d, %r15d /* nospec r15 */ + + UNWIND_HINT_REGS + cld /* @@ -141,7 +146,7 @@ SYM_FUNC_START(entry_SYSENTER_compat) popfq jmp .Lsysenter_flags_fixed SYM_INNER_LABEL(__end_entry_SYSENTER_compat, SYM_L_GLOBAL) -SYM_FUNC_END(entry_SYSENTER_compat) +SYM_CODE_END(entry_SYSENTER_compat) /* * 32-bit SYSCALL entry. @@ -191,6 +196,7 @@ SYM_FUNC_END(entry_SYSENTER_compat) * 0(%esp) arg6 */ SYM_CODE_START(entry_SYSCALL_compat) + UNWIND_HINT_EMPTY /* Interrupts are off on entry. */ swapgs @@ -241,6 +247,8 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_after_hwframe, SYM_L_GLOBAL) pushq $0 /* pt_regs->r15 = 0 */ xorl %r15d, %r15d /* nospec r15 */ + UNWIND_HINT_REGS + movq %rsp, %rdi call do_fast_syscall_32 /* XEN PV guests always use IRET path */ @@ -328,6 +336,7 @@ SYM_CODE_END(entry_SYSCALL_compat) * ebp arg6 */ SYM_CODE_START(entry_INT80_compat) + UNWIND_HINT_EMPTY /* * Interrupts are off on entry. */ @@ -349,8 +358,11 @@ SYM_CODE_START(entry_INT80_compat) /* Need to switch before accessing the thread stack. */ SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi + /* In the Xen PV case we already run on the thread stack. */ - ALTERNATIVE "movq %rsp, %rdi", "jmp .Lint80_keep_stack", X86_FEATURE_XENPV + ALTERNATIVE "", "jmp .Lint80_keep_stack", X86_FEATURE_XENPV + + movq %rsp, %rdi movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp pushq 6*8(%rdi) /* regs->ss */ @@ -389,6 +401,9 @@ SYM_CODE_START(entry_INT80_compat) xorl %r14d, %r14d /* nospec r14 */ pushq %r15 /* pt_regs->r15 */ xorl %r15d, %r15d /* nospec r15 */ + + UNWIND_HINT_REGS + cld movq %rsp, %rdi |