#include <asm/processor.h>
#ifdef CONFIG_X86_64
+
+/*
+ * Macro to inline switching to an interrupt stack and invoking function
+ * calls from there. The following rules apply:
+ *
+ * - Ordering:
+ *
+ * 1. Write the stack pointer into the top most place of the irq
+ * stack. This ensures that the various unwinders can link back to the
+ * original stack.
+ *
+ * 2. Switch the stack pointer to the top of the irq stack.
+ *
+ * 3. Invoke whatever needs to be done (@asm_call argument)
+ *
+ * 4. Pop the original stack pointer from the top of the irq stack
+ * which brings it back to the original stack where it left off.
+ *
+ * - Function invocation:
+ *
+ * To allow flexible usage of the macro, the actual function code including
+ * the store of the arguments in the call ABI registers is handed in via
+ * the @asm_call argument.
+ *
+ * - Local variables:
+ *
+ * @tos:
+ * The @tos variable holds a pointer to the top of the irq stack and
+ * _must_ be allocated in a non-callee saved register as this is a
+ * restriction coming from objtool.
+ *
+ * Note, that (tos) is both in input and output constraints to ensure
+ * that the compiler does not assume that R11 is left untouched in
+ * case this macro is used in some place where the per cpu interrupt
+ * stack pointer is used again afterwards
+ *
+ * - Function arguments:
+ * The function argument(s), if any, have to be defined in register
+ * variables at the place where this is invoked. Storing the
+ * argument(s) in the proper register(s) is part of the @asm_call
+ *
+ * - Constraints:
+ *
+ * The constraints have to be done very carefully because the compiler
+ * does not know about the assembly call.
+ *
+ * output:
+ * As documented already above the @tos variable is required to be in
+ * the output constraints to make the compiler aware that R11 cannot be
+ * reused after the asm() statement.
+ *
+ * For builds with CONFIG_UNWIND_FRAME_POINTER ASM_CALL_CONSTRAINT is
+ * required as well as this prevents certain creative GCC variants from
+ * misplacing the ASM code.
+ *
+ * input:
+ * - func:
+ * Immediate, which tells the compiler that the function is referenced.
+ *
+ * - tos:
+ * Register. The actual register is defined by the variable declaration.
+ *
+ * - function arguments:
+ * The constraints are handed in via the 'argconstr' argument list. They
+ * describe the register arguments which are used in @asm_call.
+ *
+ * clobbers:
+ * Function calls can clobber anything except the callee-saved
+ * registers. Tell the compiler.
+ */
+#define call_on_irqstack(func, asm_call, argconstr...) \
+{ \
+ register void *tos asm("r11"); \
+ \
+ tos = ((void *)__this_cpu_read(hardirq_stack_ptr)); \
+ \
+ asm_inline volatile( \
+ "movq %%rsp, (%[tos]) \n" \
+ "movq %[tos], %%rsp \n" \
+ \
+ asm_call \
+ \
+ "popq %%rsp \n" \
+ \
+ : "+r" (tos), ASM_CALL_CONSTRAINT \
+ : [__func] "i" (func), [tos] "r" (tos) argconstr \
+ : "cc", "rax", "rcx", "rdx", "rsi", "rdi", "r8", "r9", "r10", \
+ "memory" \
+ ); \
+}
+
+/* Macros to assert type correctness for run_*_on_irqstack macros */
+#define assert_function_type(func, proto) \
+ static_assert(__builtin_types_compatible_p(typeof(&func), proto))
+
+#define assert_arg_type(arg, proto) \
+ static_assert(__builtin_types_compatible_p(typeof(arg), proto))
+
static __always_inline bool irqstack_active(void)
{
return __this_cpu_read(hardirq_stack_inuse);