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x86/entry/64: Provide sane error entry/exit

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For gradual conversion provide a macro parameter and the required code
which allows to handle instrumentation and interrupt flags tracking in C.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134904.058904490@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-03-26 16:56:20 +01:00
parent cfa82a0053
commit 424c7d0a9a
1 changed files with 19 additions and 3 deletions
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22
arch/x86/entry/entry_64.S
View file

@ -499,8 +499,9 @@ SYM_CODE_END(spurious_entries_start)
* @vector: Vector number
* @cfunc: C function to be called
* @has_error_code: Hardware pushed error code on stack
* @sane: Sane variant which handles irq tracing, context tracking in C
*/
.macro idtentry_body vector cfunc has_error_code:req
.macro idtentry_body vector cfunc has_error_code:req sane=0
call error_entry
UNWIND_HINT_REGS
@ -514,6 +515,7 @@ SYM_CODE_END(spurious_entries_start)
GET_CR2_INTO(%r12);
.endif
.if \sane == 0
TRACE_IRQS_OFF
#ifdef CONFIG_CONTEXT_TRACKING
@ -522,6 +524,7 @@ SYM_CODE_END(spurious_entries_start)
CALL_enter_from_user_mode
.Lfrom_kernel_no_ctxt_tracking_\@:
#endif
.endif
movq %rsp, %rdi /* pt_regs pointer into 1st argument*/
@ -538,7 +541,11 @@ SYM_CODE_END(spurious_entries_start)
call \cfunc
.if \sane == 0
jmp error_exit
.else
jmp error_return
.endif
.endm
/**
@ -547,11 +554,12 @@ SYM_CODE_END(spurious_entries_start)
* @asmsym: ASM symbol for the entry point
* @cfunc: C function to be called
* @has_error_code: Hardware pushed error code on stack
* @sane: Sane variant which handles irq tracing, context tracking in C
*
* The macro emits code to set up the kernel context for straight forward
* and simple IDT entries. No IST stack, no paranoid entry checks.
*/
.macro idtentry vector asmsym cfunc has_error_code:req
.macro idtentry vector asmsym cfunc has_error_code:req sane=0
SYM_CODE_START(\asmsym)
UNWIND_HINT_IRET_REGS offset=\has_error_code*8
ASM_CLAC
@ -574,7 +582,7 @@ SYM_CODE_START(\asmsym)
.Lfrom_usermode_no_gap_\@:
.endif
idtentry_body \vector \cfunc \has_error_code
idtentry_body \vector \cfunc \has_error_code \sane
_ASM_NOKPROBE(\asmsym)
SYM_CODE_END(\asmsym)
@ -1403,6 +1411,14 @@ SYM_CODE_START_LOCAL(error_exit)
jmp .Lretint_user
SYM_CODE_END(error_exit)
SYM_CODE_START_LOCAL(error_return)
UNWIND_HINT_REGS
DEBUG_ENTRY_ASSERT_IRQS_OFF
testb $3, CS(%rsp)
jz restore_regs_and_return_to_kernel
jmp swapgs_restore_regs_and_return_to_usermode
SYM_CODE_END(error_return)
/*
* Runs on exception stack. Xen PV does not go through this path at all,
* so we can use real assembly here.