[PATCH] x86-64: Fix up handling of non canonical user RIPs (c33d4568) · Commits · 戴 / test

arch/x86_64/kernel/entry.S

+11 −18

Original line number	Diff line number	Diff line
		@@ -178,6 +178,12 @@ rff_trace:
		* Interrupts are off on entry.
		* Only called from user space.
		*
		* EM64T CPUs have somewhat weird error reporting for non canonical RIPs in SYSRET.
		* We can't handle any exceptions there because the exception handler would
		* end up running on the user stack which is unsafe. To avoid problems
		* any code that might end up with a user touched pt_regs should return
		* using int_ret_from_syscall.
		*
		* XXX if we had a free scratch register we could save the RSP into the stack frame
		* and report it properly in ps. Unfortunately we haven't.
		*/
		@@ -254,7 +260,9 @@ sysret_signal:
		xorl %esi,%esi # oldset -> arg2
		call ptregscall_common
		1: movl $_TIF_NEED_RESCHED,%edi
		jmp sysret_check
		/* Stack frame might have been changed. The IRET path does
		some additional checks to handle this */
		jmp int_with_check

		badsys:
		movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
		@@ -280,7 +288,8 @@ tracesys:
		call syscall_trace_leave
		RESTORE_TOP_OF_STACK %rbx
		RESTORE_REST
		jmp ret_from_sys_call
		/* Stack frame might have been changed. Use the more careful IRET path */
		jmp int_ret_from_sys_call
		CFI_ENDPROC

		/*
		@@ -408,25 +417,9 @@ ENTRY(stub_execve)
		CFI_ADJUST_CFA_OFFSET -8
		CFI_REGISTER rip, r11
		SAVE_REST
		movq %r11, %r15
		CFI_REGISTER rip, r15
		FIXUP_TOP_OF_STACK %r11
		call sys_execve
		GET_THREAD_INFO(%rcx)
		bt $TIF_IA32,threadinfo_flags(%rcx)
		CFI_REMEMBER_STATE
		jc exec_32bit
		RESTORE_TOP_OF_STACK %r11
		movq %r15, %r11
		CFI_REGISTER rip, r11
		RESTORE_REST
		pushq %r11
		CFI_ADJUST_CFA_OFFSET 8
		CFI_REL_OFFSET rip, 0
		ret

		exec_32bit:
		CFI_RESTORE_STATE
		movq %rax,RAX(%rsp)
		RESTORE_REST
		jmp int_ret_from_sys_call

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