x86/entry/32: Move FIXUP_FRAME after pushing %fs in SAVE_ALL (82cb8a0b) · Commits · 戴 / test

arch/x86/entry/entry_32.S

+35 −31

Original line number	Diff line number	Diff line
		@@ -213,54 +213,58 @@
		*
		* Be careful: we may have nonzero SS base due to ESPFIX.
		*/
		andl $0x0000ffff, 3*4(%esp)
		andl $0x0000ffff, 4*4(%esp)

		#ifdef CONFIG_VM86
		testl $X86_EFLAGS_VM, 4*4(%esp)
		testl $X86_EFLAGS_VM, 5*4(%esp)
		jnz .Lfrom_usermode_no_fixup_\@
		#endif
		testl $USER_SEGMENT_RPL_MASK, 3*4(%esp)
		testl $USER_SEGMENT_RPL_MASK, 4*4(%esp)
		jnz .Lfrom_usermode_no_fixup_\@

		orl $CS_FROM_KERNEL, 3*4(%esp)
		orl $CS_FROM_KERNEL, 4*4(%esp)

		/*
		* When we're here from kernel mode; the (exception) stack looks like:
		*
		* 5*4(%esp) - <previous context>
		* 4*4(%esp) - flags
		* 3*4(%esp) - cs
		* 2*4(%esp) - ip
		* 1*4(%esp) - orig_eax
		* 0*4(%esp) - gs / function
		* 6*4(%esp) - <previous context>
		* 5*4(%esp) - flags
		* 4*4(%esp) - cs
		* 3*4(%esp) - ip
		* 2*4(%esp) - orig_eax
		* 1*4(%esp) - gs / function
		* 0*4(%esp) - fs
		*
		* Lets build a 5 entry IRET frame after that, such that struct pt_regs
		* is complete and in particular regs->sp is correct. This gives us
		* the original 5 enties as gap:
		* the original 6 enties as gap:
		*
		* 12*4(%esp) - <previous context>
		* 11*4(%esp) - gap / flags
		* 10*4(%esp) - gap / cs
		* 9*4(%esp) - gap / ip
		* 8*4(%esp) - gap / orig_eax
		* 7*4(%esp) - gap / gs / function
		* 6*4(%esp) - ss
		* 5*4(%esp) - sp
		* 4*4(%esp) - flags
		* 3*4(%esp) - cs
		* 2*4(%esp) - ip
		* 1*4(%esp) - orig_eax
		* 0*4(%esp) - gs / function
		* 14*4(%esp) - <previous context>
		* 13*4(%esp) - gap / flags
		* 12*4(%esp) - gap / cs
		* 11*4(%esp) - gap / ip
		* 10*4(%esp) - gap / orig_eax
		* 9*4(%esp) - gap / gs / function
		* 8*4(%esp) - gap / fs
		* 7*4(%esp) - ss
		* 6*4(%esp) - sp
		* 5*4(%esp) - flags
		* 4*4(%esp) - cs
		* 3*4(%esp) - ip
		* 2*4(%esp) - orig_eax
		* 1*4(%esp) - gs / function
		* 0*4(%esp) - fs
		*/

		pushl %ss # ss
		pushl %esp # sp (points at ss)
		addl $6*4, (%esp) # point sp back at the previous context
		pushl 6*4(%esp) # flags
		pushl 6*4(%esp) # cs
		pushl 6*4(%esp) # ip
		pushl 6*4(%esp) # orig_eax
		pushl 6*4(%esp) # gs / function
		addl $7*4, (%esp) # point sp back at the previous context
		pushl 7*4(%esp) # flags
		pushl 7*4(%esp) # cs
		pushl 7*4(%esp) # ip
		pushl 7*4(%esp) # orig_eax
		pushl 7*4(%esp) # gs / function
		pushl 7*4(%esp) # fs
		.Lfrom_usermode_no_fixup_\@:
		.endm

		@@ -308,8 +312,8 @@
		.if \skip_gs == 0
		PUSH_GS
		.endif
		FIXUP_FRAME
		pushl %fs
		FIXUP_FRAME
		pushl %es
		pushl %ds
		pushl \pt_regs_ax

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