[tip: x86/entry] x86/idtentry: Provide IDTENTRY_DF

From: tip-bot2 for Thomas Gleixner
Date: Tue May 19 2020 - 15:58:25 EST


The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 9bf779984c19883354f55a54283292b927939b6a
Gitweb: https://git.kernel.org/tip/9bf779984c19883354f55a54283292b927939b6a
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 25 Feb 2020 23:33:30 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 19 May 2020 16:04:14 +02:00

x86/idtentry: Provide IDTENTRY_DF

Provide a separate macro for #DF as this needs to emit paranoid only code
and has also a special ASM stub in 32bit.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200505135315.583415264@xxxxxxxxxxxxx



---
arch/x86/include/asm/idtentry.h | 87 ++++++++++++++++++++++++++++++++-
1 file changed, 87 insertions(+)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 060f9e3..9521f32 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -132,6 +132,35 @@ static __always_inline void __##func(struct pt_regs *regs, \
#define DEFINE_IDTENTRY_RAW(func) \
__visible noinstr void func(struct pt_regs *regs)

+/**
+ * DECLARE_IDTENTRY_RAW_ERRORCODE - Declare functions for raw IDT entry points
+ * Error code pushed by hardware
+ * @vector: Vector number (ignored for C)
+ * @func: Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_ERRORCODE()
+ */
+#define DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func) \
+ DECLARE_IDTENTRY_ERRORCODE(vector, func)
+
+/**
+ * DEFINE_IDTENTRY_RAW_ERRORCODE - Emit code for raw IDT entry points
+ * @func: Function name of the entry point
+ *
+ * @func is called from ASM entry code with interrupts disabled.
+ *
+ * The macro is written so it acts as function definition. Append the
+ * body with a pair of curly brackets.
+ *
+ * Contrary to DEFINE_IDTENTRY_ERRORCODE() this does not invoke the
+ * idtentry_enter/exit() helpers before and after the body invocation. This
+ * needs to be done in the body itself if applicable. Use if extra work
+ * is required before the enter/exit() helpers are invoked.
+ */
+#define DEFINE_IDTENTRY_RAW_ERRORCODE(func) \
+__visible noinstr void func(struct pt_regs *regs, unsigned long error_code)
+
+
#ifdef CONFIG_X86_64
/**
* DECLARE_IDTENTRY_IST - Declare functions for IST handling IDT entry points
@@ -165,10 +194,58 @@ __visible noinstr void func(struct pt_regs *regs)
#define DEFINE_IDTENTRY_NOIST(func) \
DEFINE_IDTENTRY_RAW(noist_##func)

+/**
+ * DECLARE_IDTENTRY_DF - Declare functions for double fault
+ * @vector: Vector number (ignored for C)
+ * @func: Function name of the entry point
+ *
+ * Maps to DECLARE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DECLARE_IDTENTRY_DF(vector, func) \
+ DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func)
+
+/**
+ * DEFINE_IDTENTRY_DF - Emit code for double fault
+ * @func: Function name of the entry point
+ *
+ * Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
+ */
+#define DEFINE_IDTENTRY_DF(func) \
+ DEFINE_IDTENTRY_RAW_ERRORCODE(func)
+
#else /* CONFIG_X86_64 */
+
/* Maps to a regular IDTENTRY on 32bit for now */
# define DECLARE_IDTENTRY_IST DECLARE_IDTENTRY
# define DEFINE_IDTENTRY_IST DEFINE_IDTENTRY
+
+/**
+ * DECLARE_IDTENTRY_DF - Declare functions for double fault 32bit variant
+ * @vector: Vector number (ignored for C)
+ * @func: Function name of the entry point
+ *
+ * Declares two functions:
+ * - The ASM entry point: asm_##func
+ * - The C handler called from the C shim
+ */
+#define DECLARE_IDTENTRY_DF(vector, func) \
+ asmlinkage void asm_##func(void); \
+ __visible void func(struct pt_regs *regs, \
+ unsigned long error_code, \
+ unsigned long address)
+
+/**
+ * DEFINE_IDTENTRY_DF - Emit code for double fault on 32bit
+ * @func: Function name of the entry point
+ *
+ * This is called through the doublefault shim which already provides
+ * cr2 in the address argument.
+ */
+#define DEFINE_IDTENTRY_DF(func) \
+__visible noinstr void func(struct pt_regs *regs, \
+ unsigned long error_code, \
+ unsigned long address)
+
#endif /* !CONFIG_X86_64 */

/* C-Code mapping */
@@ -212,6 +289,9 @@ __visible noinstr void func(struct pt_regs *regs)
#define DECLARE_IDTENTRY_RAW(vector, func) \
DECLARE_IDTENTRY(vector, func)

+#define DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func) \
+ DECLARE_IDTENTRY_ERRORCODE(vector, func)
+
#ifdef CONFIG_X86_64
# define DECLARE_IDTENTRY_MCE(vector, func) \
idtentry_mce_db vector asm_##func func
@@ -219,12 +299,19 @@ __visible noinstr void func(struct pt_regs *regs)
# define DECLARE_IDTENTRY_DEBUG(vector, func) \
idtentry_mce_db vector asm_##func func

+# define DECLARE_IDTENTRY_DF(vector, func) \
+ idtentry_df vector asm_##func func
+
#else
# define DECLARE_IDTENTRY_MCE(vector, func) \
DECLARE_IDTENTRY(vector, func)

# define DECLARE_IDTENTRY_DEBUG(vector, func) \
DECLARE_IDTENTRY(vector, func)
+
+/* No ASM emitted for DF as this goes through a C shim */
+# define DECLARE_IDTENTRY_DF(vector, func)
+
#endif

/* No ASM code emitted for NMI */