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2d1b21ecea
To allow calling of DAT-off code from kernel the stack needs to be switched to nodat_stack (or other stack mapped as 1:1). Before call_nodat() macro was introduced that was necessary to provide the very same memory address for STNSM and STOSM instructions. If the kernel would stay on a random stack (e.g. a virtually mapped one) then a virtual address provided for STNSM instruction could differ from the physical address needed for the corresponding STOSM instruction. After call_nodat() macro is introduced the kernel stack does not need to be mapped 1:1 anymore, since the macro stores the physical memory address of return PSW in a register before entering DAT-off mode. This way the return LPSWE instruction is able to pick the correct memory location and restore the DAT-on mode. That however might fail in case the 16-byte return PSW happened to cross page boundary: PSW mask and PSW address could end up in two separate non-contiguous physical pages. Align the return PSW on 16-byte boundary so it always fits into a single physical page. As result any stack (including the virtually mapped one) could be used for calling DAT-off code and prior switching to nodat_stack becomes unnecessary. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
242 lines
7.4 KiB
C
242 lines
7.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_S390_STACKTRACE_H
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#define _ASM_S390_STACKTRACE_H
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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#include <asm/switch_to.h>
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enum stack_type {
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STACK_TYPE_UNKNOWN,
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STACK_TYPE_TASK,
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STACK_TYPE_IRQ,
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STACK_TYPE_NODAT,
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STACK_TYPE_RESTART,
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STACK_TYPE_MCCK,
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};
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struct stack_info {
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enum stack_type type;
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unsigned long begin, end;
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};
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const char *stack_type_name(enum stack_type type);
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int get_stack_info(unsigned long sp, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask);
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static inline bool on_stack(struct stack_info *info,
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unsigned long addr, size_t len)
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{
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if (info->type == STACK_TYPE_UNKNOWN)
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return false;
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if (addr + len < addr)
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return false;
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return addr >= info->begin && addr + len <= info->end;
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}
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/*
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* Stack layout of a C stack frame.
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* Kernel uses the packed stack layout (-mpacked-stack).
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*/
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struct stack_frame {
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union {
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unsigned long empty[9];
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struct {
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unsigned long sie_control_block;
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unsigned long sie_savearea;
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unsigned long sie_reason;
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unsigned long sie_flags;
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unsigned long sie_control_block_phys;
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};
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};
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unsigned long gprs[10];
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unsigned long back_chain;
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};
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/*
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* Unlike current_stack_pointer which simply contains the current value of %r15
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* current_frame_address() returns function stack frame address, which matches
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* %r15 upon function invocation. It may differ from %r15 later if function
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* allocates stack for local variables or new stack frame to call other
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* functions.
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*/
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#define current_frame_address() \
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((unsigned long)__builtin_frame_address(0) - \
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offsetof(struct stack_frame, back_chain))
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static __always_inline unsigned long get_stack_pointer(struct task_struct *task,
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struct pt_regs *regs)
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{
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if (regs)
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return (unsigned long)kernel_stack_pointer(regs);
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if (task == current)
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return current_frame_address();
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return (unsigned long)task->thread.ksp;
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}
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/*
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* To keep this simple mark register 2-6 as being changed (volatile)
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* by the called function, even though register 6 is saved/nonvolatile.
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*/
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#define CALL_FMT_0 "=&d" (r2)
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#define CALL_FMT_1 "+&d" (r2)
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#define CALL_FMT_2 CALL_FMT_1, "+&d" (r3)
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#define CALL_FMT_3 CALL_FMT_2, "+&d" (r4)
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#define CALL_FMT_4 CALL_FMT_3, "+&d" (r5)
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#define CALL_FMT_5 CALL_FMT_4, "+&d" (r6)
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#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
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#define CALL_CLOBBER_4 CALL_CLOBBER_5
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#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
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#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
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#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
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#define CALL_CLOBBER_0 CALL_CLOBBER_1
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#define CALL_LARGS_0(...) \
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long dummy = 0
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#define CALL_LARGS_1(t1, a1) \
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long arg1 = (long)(t1)(a1)
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#define CALL_LARGS_2(t1, a1, t2, a2) \
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CALL_LARGS_1(t1, a1); \
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long arg2 = (long)(t2)(a2)
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#define CALL_LARGS_3(t1, a1, t2, a2, t3, a3) \
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CALL_LARGS_2(t1, a1, t2, a2); \
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long arg3 = (long)(t3)(a3)
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#define CALL_LARGS_4(t1, a1, t2, a2, t3, a3, t4, a4) \
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CALL_LARGS_3(t1, a1, t2, a2, t3, a3); \
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long arg4 = (long)(t4)(a4)
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#define CALL_LARGS_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5) \
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CALL_LARGS_4(t1, a1, t2, a2, t3, a3, t4, a4); \
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long arg5 = (long)(t5)(a5)
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#define CALL_REGS_0 \
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register long r2 asm("2") = dummy
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#define CALL_REGS_1 \
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register long r2 asm("2") = arg1
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#define CALL_REGS_2 \
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CALL_REGS_1; \
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register long r3 asm("3") = arg2
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#define CALL_REGS_3 \
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CALL_REGS_2; \
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register long r4 asm("4") = arg3
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#define CALL_REGS_4 \
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CALL_REGS_3; \
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register long r5 asm("5") = arg4
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#define CALL_REGS_5 \
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CALL_REGS_4; \
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register long r6 asm("6") = arg5
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#define CALL_TYPECHECK_0(...)
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#define CALL_TYPECHECK_1(t, a, ...) \
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typecheck(t, a)
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#define CALL_TYPECHECK_2(t, a, ...) \
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CALL_TYPECHECK_1(__VA_ARGS__); \
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typecheck(t, a)
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#define CALL_TYPECHECK_3(t, a, ...) \
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CALL_TYPECHECK_2(__VA_ARGS__); \
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typecheck(t, a)
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#define CALL_TYPECHECK_4(t, a, ...) \
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CALL_TYPECHECK_3(__VA_ARGS__); \
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typecheck(t, a)
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#define CALL_TYPECHECK_5(t, a, ...) \
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CALL_TYPECHECK_4(__VA_ARGS__); \
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typecheck(t, a)
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#define CALL_PARM_0(...) void
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#define CALL_PARM_1(t, a, ...) t
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#define CALL_PARM_2(t, a, ...) t, CALL_PARM_1(__VA_ARGS__)
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#define CALL_PARM_3(t, a, ...) t, CALL_PARM_2(__VA_ARGS__)
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#define CALL_PARM_4(t, a, ...) t, CALL_PARM_3(__VA_ARGS__)
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#define CALL_PARM_5(t, a, ...) t, CALL_PARM_4(__VA_ARGS__)
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#define CALL_PARM_6(t, a, ...) t, CALL_PARM_5(__VA_ARGS__)
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/*
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* Use call_on_stack() to call a function switching to a specified
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* stack. Proper sign and zero extension of function arguments is
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* done. Usage:
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*
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* rc = call_on_stack(nr, stack, rettype, fn, t1, a1, t2, a2, ...)
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*
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* - nr specifies the number of function arguments of fn.
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* - stack specifies the stack to be used.
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* - fn is the function to be called.
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* - rettype is the return type of fn.
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* - t1, a1, ... are pairs, where t1 must match the type of the first
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* argument of fn, t2 the second, etc. a1 is the corresponding
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* first function argument (not name), etc.
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*/
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#define call_on_stack(nr, stack, rettype, fn, ...) \
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({ \
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rettype (*__fn)(CALL_PARM_##nr(__VA_ARGS__)) = fn; \
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unsigned long frame = current_frame_address(); \
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unsigned long __stack = stack; \
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unsigned long prev; \
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CALL_LARGS_##nr(__VA_ARGS__); \
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CALL_REGS_##nr; \
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\
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CALL_TYPECHECK_##nr(__VA_ARGS__); \
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asm volatile( \
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" lgr %[_prev],15\n" \
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" lg 15,%[_stack]\n" \
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" stg %[_frame],%[_bc](15)\n" \
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" brasl 14,%[_fn]\n" \
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" lgr 15,%[_prev]\n" \
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: [_prev] "=&d" (prev), CALL_FMT_##nr \
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: [_stack] "R" (__stack), \
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[_bc] "i" (offsetof(struct stack_frame, back_chain)), \
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[_frame] "d" (frame), \
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[_fn] "X" (__fn) : CALL_CLOBBER_##nr); \
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(rettype)r2; \
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})
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/*
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* Use call_nodat() to call a function with DAT disabled.
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* Proper sign and zero extension of function arguments is done.
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* Usage:
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*
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* rc = call_nodat(nr, rettype, fn, t1, a1, t2, a2, ...)
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*
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* - nr specifies the number of function arguments of fn.
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* - fn is the function to be called, where fn is a physical address.
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* - rettype is the return type of fn.
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* - t1, a1, ... are pairs, where t1 must match the type of the first
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* argument of fn, t2 the second, etc. a1 is the corresponding
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* first function argument (not name), etc.
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*
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* fn() is called with standard C function call ABI, with the exception
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* that no useful stackframe or stackpointer is passed via register 15.
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* Therefore the called function must not use r15 to access the stack.
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*/
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#define call_nodat(nr, rettype, fn, ...) \
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({ \
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rettype (*__fn)(CALL_PARM_##nr(__VA_ARGS__)) = (fn); \
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/* aligned since psw_leave must not cross page boundary */ \
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psw_t __aligned(16) psw_leave; \
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psw_t psw_enter; \
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CALL_LARGS_##nr(__VA_ARGS__); \
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CALL_REGS_##nr; \
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\
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CALL_TYPECHECK_##nr(__VA_ARGS__); \
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psw_enter.mask = PSW_KERNEL_BITS & ~PSW_MASK_DAT; \
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psw_enter.addr = (unsigned long)__fn; \
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asm volatile( \
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" epsw 0,1\n" \
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" risbg 1,0,0,31,32\n" \
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" larl 7,1f\n" \
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" stg 1,%[psw_leave]\n" \
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" stg 7,8+%[psw_leave]\n" \
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" la 7,%[psw_leave]\n" \
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" lra 7,0(7)\n" \
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" larl 1,0f\n" \
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" lra 14,0(1)\n" \
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" lpswe %[psw_enter]\n" \
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"0: lpswe 0(7)\n" \
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"1:\n" \
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: CALL_FMT_##nr, [psw_leave] "=Q" (psw_leave) \
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: [psw_enter] "Q" (psw_enter) \
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: "7", CALL_CLOBBER_##nr); \
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(rettype)r2; \
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})
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#endif /* _ASM_S390_STACKTRACE_H */
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