linux_dsm_epyc7002/arch/xtensa/include/asm/processor.h
Max Filippov 09f8a6db20 xtensa: add support for call0 ABI in userspace
Provide a Kconfig choice to select whether only the default ABI, only
call0 ABI or both are supported. The default for XEA2 is windowed, but
it may change for XEA3. Call0 only runs userspace with PS.WOE disabled.
Supporting both windowed and call0 ABIs is tricky, as there's no
indication in the ELF binaries which ABI they use. So it is done by
probing: each process is started with PS.WOE disabled, but the handler
of an illegal instruction exception taken with PS.WOE retries faulting
instruction after enabling PS.WOE. It must happen before any signal is
delivered to the process, otherwise it may be delivered incorrectly.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2019-09-01 13:11:57 -07:00

261 lines
7.6 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2008 Tensilica Inc.
* Copyright (C) 2015 Cadence Design Systems Inc.
*/
#ifndef _XTENSA_PROCESSOR_H
#define _XTENSA_PROCESSOR_H
#include <asm/core.h>
#include <linux/compiler.h>
#include <linux/stringify.h>
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/regs.h>
/* Assertions. */
#if (XCHAL_HAVE_WINDOWED != 1)
# error Linux requires the Xtensa Windowed Registers Option.
#endif
/* Xtensa ABI requires stack alignment to be at least 16 */
#define STACK_ALIGN (XCHAL_DATA_WIDTH > 16 ? XCHAL_DATA_WIDTH : 16)
#define ARCH_SLAB_MINALIGN STACK_ALIGN
/*
* User space process size: 1 GB.
* Windowed call ABI requires caller and callee to be located within the same
* 1 GB region. The C compiler places trampoline code on the stack for sources
* that take the address of a nested C function (a feature used by glibc), so
* the 1 GB requirement applies to the stack as well.
*/
#ifdef CONFIG_MMU
#define TASK_SIZE __XTENSA_UL_CONST(0x40000000)
#else
#define TASK_SIZE __XTENSA_UL_CONST(0xffffffff)
#endif
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
/*
* General exception cause assigned to fake NMI. Fake NMI needs to be handled
* differently from other interrupts, but it uses common kernel entry/exit
* code.
*/
#define EXCCAUSE_MAPPED_NMI 62
/*
* General exception cause assigned to debug exceptions. Debug exceptions go
* to their own vector, rather than the general exception vectors (user,
* kernel, double); and their specific causes are reported via DEBUGCAUSE
* rather than EXCCAUSE. However it is sometimes convenient to redirect debug
* exceptions to the general exception mechanism. To do this, an otherwise
* unused EXCCAUSE value was assigned to debug exceptions for this purpose.
*/
#define EXCCAUSE_MAPPED_DEBUG 63
/*
* We use DEPC also as a flag to distinguish between double and regular
* exceptions. For performance reasons, DEPC might contain the value of
* EXCCAUSE for regular exceptions, so we use this definition to mark a
* valid double exception address.
* (Note: We use it in bgeui, so it should be 64, 128, or 256)
*/
#define VALID_DOUBLE_EXCEPTION_ADDRESS 64
#define XTENSA_INT_LEVEL(intno) _XTENSA_INT_LEVEL(intno)
#define _XTENSA_INT_LEVEL(intno) XCHAL_INT##intno##_LEVEL
#define XTENSA_INTLEVEL_MASK(level) _XTENSA_INTLEVEL_MASK(level)
#define _XTENSA_INTLEVEL_MASK(level) (XCHAL_INTLEVEL##level##_MASK)
#define XTENSA_INTLEVEL_ANDBELOW_MASK(l) _XTENSA_INTLEVEL_ANDBELOW_MASK(l)
#define _XTENSA_INTLEVEL_ANDBELOW_MASK(l) (XCHAL_INTLEVEL##l##_ANDBELOW_MASK)
#define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT)
/* LOCKLEVEL defines the interrupt level that masks all
* general-purpose interrupts.
*/
#if defined(CONFIG_XTENSA_FAKE_NMI) && defined(XCHAL_PROFILING_INTERRUPT)
#define LOCKLEVEL (PROFILING_INTLEVEL - 1)
#else
#define LOCKLEVEL XCHAL_EXCM_LEVEL
#endif
#define TOPLEVEL XCHAL_EXCM_LEVEL
#define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL)
/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
* registers
*/
#define WSBITS (XCHAL_NUM_AREGS / 4) /* width of WINDOWSTART in bits */
#define WBBITS (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
#ifndef __ASSEMBLY__
/* Build a valid return address for the specified call winsize.
* winsize must be 1 (call4), 2 (call8), or 3 (call12)
*/
#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
/* Convert return address to a valid pc
* Note: We assume that the stack pointer is in the same 1GB ranges as the ra
*/
#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
/* Spill slot location for the register reg in the spill area under the stack
* pointer sp. reg must be in the range [0..4).
*/
#define SPILL_SLOT(sp, reg) (*(((unsigned long *)(sp)) - 4 + (reg)))
/* Spill slot location for the register reg in the spill area under the stack
* pointer sp for the call8. reg must be in the range [4..8).
*/
#define SPILL_SLOT_CALL8(sp, reg) (*(((unsigned long *)(sp)) - 12 + (reg)))
/* Spill slot location for the register reg in the spill area under the stack
* pointer sp for the call12. reg must be in the range [4..12).
*/
#define SPILL_SLOT_CALL12(sp, reg) (*(((unsigned long *)(sp)) - 16 + (reg)))
typedef struct {
unsigned long seg;
} mm_segment_t;
struct thread_struct {
/* kernel's return address and stack pointer for context switching */
unsigned long ra; /* kernel's a0: return address and window call size */
unsigned long sp; /* kernel's a1: stack pointer */
mm_segment_t current_ds; /* see uaccess.h for example uses */
/* struct xtensa_cpuinfo info; */
unsigned long bad_vaddr; /* last user fault */
unsigned long bad_uaddr; /* last kernel fault accessing user space */
unsigned long error_code;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
struct perf_event *ptrace_bp[XCHAL_NUM_IBREAK];
struct perf_event *ptrace_wp[XCHAL_NUM_DBREAK];
#endif
/* Make structure 16 bytes aligned. */
int align[0] __attribute__ ((aligned(16)));
};
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE (TASK_SIZE / 2)
#define INIT_THREAD \
{ \
ra: 0, \
sp: sizeof(init_stack) + (long) &init_stack, \
current_ds: {0}, \
/*info: {0}, */ \
bad_vaddr: 0, \
bad_uaddr: 0, \
error_code: 0, \
}
/*
* Do necessary setup to start up a newly executed thread.
* Note: When windowed ABI is used for userspace we set-up ps
* as if we did a call4 to the new pc.
* set_thread_state in signal.c depends on it.
*/
#if IS_ENABLED(CONFIG_USER_ABI_CALL0)
#define USER_PS_VALUE ((USER_RING << PS_RING_SHIFT) | \
(1 << PS_UM_BIT) | \
(1 << PS_EXCM_BIT))
#else
#define USER_PS_VALUE (PS_WOE_MASK | \
(1 << PS_CALLINC_SHIFT) | \
(USER_RING << PS_RING_SHIFT) | \
(1 << PS_UM_BIT) | \
(1 << PS_EXCM_BIT))
#endif
/* Clearing a0 terminates the backtrace. */
#define start_thread(regs, new_pc, new_sp) \
do { \
memset((regs), 0, sizeof(*(regs))); \
(regs)->pc = (new_pc); \
(regs)->ps = USER_PS_VALUE; \
(regs)->areg[1] = (new_sp); \
(regs)->areg[0] = 0; \
(regs)->wmask = 1; \
(regs)->depc = 0; \
(regs)->windowbase = 0; \
(regs)->windowstart = 1; \
(regs)->syscall = NO_SYSCALL; \
} while (0)
/* Forward declaration */
struct task_struct;
struct mm_struct;
/* Free all resources held by a thread. */
#define release_thread(thread) do { } while(0)
extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->areg[1])
#define cpu_relax() barrier()
/* Special register access. */
#define xtensa_set_sr(x, sr) \
({ \
unsigned int v = (unsigned int)(x); \
__asm__ __volatile__ ("wsr %0, "__stringify(sr) :: "a"(v)); \
})
#define xtensa_get_sr(sr) \
({ \
unsigned int v; \
__asm__ __volatile__ ("rsr %0, "__stringify(sr) : "=a"(v)); \
v; \
})
#ifndef XCHAL_HAVE_EXTERN_REGS
#define XCHAL_HAVE_EXTERN_REGS 0
#endif
#if XCHAL_HAVE_EXTERN_REGS
static inline void set_er(unsigned long value, unsigned long addr)
{
asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
}
static inline unsigned long get_er(unsigned long addr)
{
register unsigned long value;
asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
return value;
}
#endif /* XCHAL_HAVE_EXTERN_REGS */
#endif /* __ASSEMBLY__ */
#endif /* _XTENSA_PROCESSOR_H */