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Subject[PATCH v3 4/6] x86/entry/64: Update comments and sanity tests for create_gap
Commit 2700fefdb2d9 ("x86_64: Add gap to int3 to allow for call
emulation") forgot to update the comment, do so now.

Acked-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/entry/entry_64.S | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -913,15 +913,16 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
/**
* idtentry - Generate an IDT entry stub
* @sym: Name of the generated entry point
- * @do_sym: C function to be called
- * @has_error_code: True if this IDT vector has an error code on the stack
- * @paranoid: non-zero means that this vector may be invoked from
+ * @do_sym: C function to be called
+ * @has_error_code: True if this IDT vector has an error code on the stack
+ * @paranoid: non-zero means that this vector may be invoked from
* kernel mode with user GSBASE and/or user CR3.
* 2 is special -- see below.
* @shift_ist: Set to an IST index if entries from kernel mode should
- * decrement the IST stack so that nested entries get a
+ * decrement the IST stack so that nested entries get a
* fresh stack. (This is for #DB, which has a nasty habit
- * of recursing.)
+ * of recursing.)
+ * @create_gap: create a 6-word stack gap when coming from kernel mode.
*
* idtentry generates an IDT stub that sets up a usable kernel context,
* creates struct pt_regs, and calls @do_sym. The stub has the following
@@ -951,10 +952,14 @@ ENTRY(\sym)
UNWIND_HINT_IRET_REGS offset=\has_error_code*8

/* Sanity check */
- .if \shift_ist != -1 && \paranoid == 0
+ .if \shift_ist != -1 && \paranoid != 1
.error "using shift_ist requires paranoid=1"
.endif

+ .if \create_gap && \paranoid
+ .error "using create_gap requires paranoid=0"
+ .endif
+
ASM_CLAC

.if \has_error_code == 0

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