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linux_dsm_epyc7002/arch/mips/include/asm/stackframe.h
Corey Minyard 9fef686863 MIPS: Make SAVE_SOME more standard 
Modify the SAVE_SOME macro to look more like a standard
function, doing the arithmetic for the frame on the SP
register instead of copying it from K1, and by saving
the stored EPC from the RA.  This lets the get_frame_info()
function process this function like any other.  It also
remove an instruction or two from the kernel entry,
making it more efficient.

unwind_stack_by_address() has special handling for
the top of the interrupt stack, but without this change
unwinding will still fail if you get an interrupt while
handling an interrupt and try to do a traceback from
the second interrupt.

This change modifies the get_saved_sp macro to
optionally store the fetched value right into sp and store the
old SP value into K0.  Then it's just a matter of subtracting
the frame from SP and storing the old SP from K0.

This required changing the DADDI workaround a bit, since K0
holds the SP, we had to use K1 for AT.  But it eliminated
some of the special handling for the DADDI workaround.

Saving the RA register was moved up to before fetching the
CP0_EPC register, so the CP0_EPC register could be stored
into RA and the saved.  This lets the traceback code know
where RA is actually stored.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16991/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-09-06 11:01:26 +02:00

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/*
* 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) 1994, 95, 96, 99, 2001 Ralf Baechle
* Copyright (C) 1994, 1995, 1996 Paul M. Antoine.
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2007 Maciej W. Rozycki
*/
#ifndef _ASM_STACKFRAME_H
#define _ASM_STACKFRAME_H
#include <linux/threads.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
#define STATMASK 0x3f
#else
#define STATMASK 0x1f
#endif
.macro SAVE_AT
.set push
.set noat
LONG_S $1, PT_R1(sp)
.set pop
.endm
.macro SAVE_TEMP
#ifdef CONFIG_CPU_HAS_SMARTMIPS
mflhxu v1
LONG_S v1, PT_LO(sp)
mflhxu v1
LONG_S v1, PT_HI(sp)
mflhxu v1
LONG_S v1, PT_ACX(sp)
#elif !defined(CONFIG_CPU_MIPSR6)
mfhi v1
#endif
#ifdef CONFIG_32BIT
LONG_S $8, PT_R8(sp)
LONG_S $9, PT_R9(sp)
#endif
LONG_S $10, PT_R10(sp)
LONG_S $11, PT_R11(sp)
LONG_S $12, PT_R12(sp)
#if !defined(CONFIG_CPU_HAS_SMARTMIPS) && !defined(CONFIG_CPU_MIPSR6)
LONG_S v1, PT_HI(sp)
mflo v1
#endif
LONG_S $13, PT_R13(sp)
LONG_S $14, PT_R14(sp)
LONG_S $15, PT_R15(sp)
LONG_S $24, PT_R24(sp)
#if !defined(CONFIG_CPU_HAS_SMARTMIPS) && !defined(CONFIG_CPU_MIPSR6)
LONG_S v1, PT_LO(sp)
#endif
#ifdef CONFIG_CPU_CAVIUM_OCTEON
/*
* The Octeon multiplier state is affected by general
* multiply instructions. It must be saved before and
* kernel code might corrupt it
*/
jal octeon_mult_save
#endif
.endm
.macro SAVE_STATIC
LONG_S $16, PT_R16(sp)
LONG_S $17, PT_R17(sp)
LONG_S $18, PT_R18(sp)
LONG_S $19, PT_R19(sp)
LONG_S $20, PT_R20(sp)
LONG_S $21, PT_R21(sp)
LONG_S $22, PT_R22(sp)
LONG_S $23, PT_R23(sp)
LONG_S $30, PT_R30(sp)
.endm
/*
* get_saved_sp returns the SP for the current CPU by looking in the
* kernelsp array for it. If tosp is set, it stores the current sp in
* k0 and loads the new value in sp. If not, it clobbers k0 and
* stores the new value in k1, leaving sp unaffected.
*/
#ifdef CONFIG_SMP
/* SMP variation */
.macro get_saved_sp docfi=0 tosp=0
ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG
#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
lui k1, %hi(kernelsp)
#else
lui k1, %highest(kernelsp)
daddiu k1, %higher(kernelsp)
dsll k1, 16
daddiu k1, %hi(kernelsp)
dsll k1, 16
#endif
LONG_SRL k0, SMP_CPUID_PTRSHIFT
LONG_ADDU k1, k0
.if \tosp
move k0, sp
.if \docfi
.cfi_register sp, k0
.endif
LONG_L sp, %lo(kernelsp)(k1)
.else
LONG_L k1, %lo(kernelsp)(k1)
.endif
.endm
.macro set_saved_sp stackp temp temp2
ASM_CPUID_MFC0 \temp, ASM_SMP_CPUID_REG
LONG_SRL \temp, SMP_CPUID_PTRSHIFT
LONG_S \stackp, kernelsp(\temp)
.endm
#else /* !CONFIG_SMP */
/* Uniprocessor variation */
.macro get_saved_sp docfi=0 tosp=0
#ifdef CONFIG_CPU_JUMP_WORKAROUNDS
/*
* Clear BTB (branch target buffer), forbid RAS (return address
* stack) to workaround the Out-of-order Issue in Loongson2F
* via its diagnostic register.
*/
move k0, ra
jal 1f
nop
1: jal 1f
nop
1: jal 1f
nop
1: jal 1f
nop
1: move ra, k0
li k0, 3
mtc0 k0, $22
#endif /* CONFIG_CPU_JUMP_WORKAROUNDS */
#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
lui k1, %hi(kernelsp)
#else
lui k1, %highest(kernelsp)
daddiu k1, %higher(kernelsp)
dsll k1, k1, 16
daddiu k1, %hi(kernelsp)
dsll k1, k1, 16
#endif
.if \tosp
move k0, sp
.if \docfi
.cfi_register sp, k0
.endif
LONG_L sp, %lo(kernelsp)(k1)
.else
LONG_L k1, %lo(kernelsp)(k1)
.endif
.endm
.macro set_saved_sp stackp temp temp2
LONG_S \stackp, kernelsp
.endm
#endif
.macro SAVE_SOME
.set push
.set noat
.set reorder
mfc0 k0, CP0_STATUS
sll k0, 3 /* extract cu0 bit */
.set noreorder
bltz k0, 8f
#ifdef CONFIG_EVA
/*
* Flush interAptiv's Return Prediction Stack (RPS) by writing
* EntryHi. Toggling Config7.RPS is slower and less portable.
*
* The RPS isn't automatically flushed when exceptions are
* taken, which can result in kernel mode speculative accesses
* to user addresses if the RPS mispredicts. That's harmless
* when user and kernel share the same address space, but with
* EVA the same user segments may be unmapped to kernel mode,
* even containing sensitive MMIO regions or invalid memory.
*
* This can happen when the kernel sets the return address to
* ret_from_* and jr's to the exception handler, which looks
* more like a tail call than a function call. If nested calls
* don't evict the last user address in the RPS, it will
* mispredict the return and fetch from a user controlled
* address into the icache.
*
* More recent EVA-capable cores with MAAR to restrict
* speculative accesses aren't affected.
*/
MFC0 k0, CP0_ENTRYHI
MTC0 k0, CP0_ENTRYHI
#endif
.set reorder
move k0, sp
/* Called from user mode, new stack. */
get_saved_sp
8:
#ifdef CONFIG_CPU_DADDI_WORKAROUNDS
.set at=k1
#endif
PTR_SUBU sp, PT_SIZE
#ifdef CONFIG_CPU_DADDI_WORKAROUNDS
.set noat
#endif
LONG_S k0, PT_R29(sp)
LONG_S $3, PT_R3(sp)
/*
* You might think that you don't need to save $0,
* but the FPU emulator and gdb remote debug stub
* need it to operate correctly
*/
LONG_S $0, PT_R0(sp)
mfc0 v1, CP0_STATUS
LONG_S $2, PT_R2(sp)
LONG_S v1, PT_STATUS(sp)
LONG_S $4, PT_R4(sp)
mfc0 v1, CP0_CAUSE
LONG_S $5, PT_R5(sp)
LONG_S v1, PT_CAUSE(sp)
LONG_S $6, PT_R6(sp)
LONG_S ra, PT_R31(sp)
MFC0 ra, CP0_EPC
LONG_S $7, PT_R7(sp)
#ifdef CONFIG_64BIT
LONG_S $8, PT_R8(sp)
LONG_S $9, PT_R9(sp)
#endif
LONG_S ra, PT_EPC(sp)
LONG_S $25, PT_R25(sp)
LONG_S $28, PT_R28(sp)
/* Set thread_info if we're coming from user mode */
mfc0 k0, CP0_STATUS
sll k0, 3 /* extract cu0 bit */
bltz k0, 9f
ori $28, sp, _THREAD_MASK
xori $28, _THREAD_MASK
#ifdef CONFIG_CPU_CAVIUM_OCTEON
.set mips64
pref 0, 0($28) /* Prefetch the current pointer */
#endif
9:
.set pop
.endm
.macro SAVE_ALL
SAVE_SOME
SAVE_AT
SAVE_TEMP
SAVE_STATIC
.endm
.macro RESTORE_AT
.set push
.set noat
LONG_L $1, PT_R1(sp)
.set pop
.endm
.macro RESTORE_TEMP
#ifdef CONFIG_CPU_CAVIUM_OCTEON
/* Restore the Octeon multiplier state */
jal octeon_mult_restore
#endif
#ifdef CONFIG_CPU_HAS_SMARTMIPS
LONG_L $24, PT_ACX(sp)
mtlhx $24
LONG_L $24, PT_HI(sp)
mtlhx $24
LONG_L $24, PT_LO(sp)
mtlhx $24
#elif !defined(CONFIG_CPU_MIPSR6)
LONG_L $24, PT_LO(sp)
mtlo $24
LONG_L $24, PT_HI(sp)
mthi $24
#endif
#ifdef CONFIG_32BIT
LONG_L $8, PT_R8(sp)
LONG_L $9, PT_R9(sp)
#endif
LONG_L $10, PT_R10(sp)
LONG_L $11, PT_R11(sp)
LONG_L $12, PT_R12(sp)
LONG_L $13, PT_R13(sp)
LONG_L $14, PT_R14(sp)
LONG_L $15, PT_R15(sp)
LONG_L $24, PT_R24(sp)
.endm
.macro RESTORE_STATIC
LONG_L $16, PT_R16(sp)
LONG_L $17, PT_R17(sp)
LONG_L $18, PT_R18(sp)
LONG_L $19, PT_R19(sp)
LONG_L $20, PT_R20(sp)
LONG_L $21, PT_R21(sp)
LONG_L $22, PT_R22(sp)
LONG_L $23, PT_R23(sp)
LONG_L $30, PT_R30(sp)
.endm
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
.macro RESTORE_SOME
.set push
.set reorder
.set noat
mfc0 a0, CP0_STATUS
li v1, ST0_CU1 | ST0_IM
ori a0, STATMASK
xori a0, STATMASK
mtc0 a0, CP0_STATUS
and a0, v1
LONG_L v0, PT_STATUS(sp)
nor v1, $0, v1
and v0, v1
or v0, a0
mtc0 v0, CP0_STATUS
LONG_L $31, PT_R31(sp)
LONG_L $28, PT_R28(sp)
LONG_L $25, PT_R25(sp)
LONG_L $7, PT_R7(sp)
LONG_L $6, PT_R6(sp)
LONG_L $5, PT_R5(sp)
LONG_L $4, PT_R4(sp)
LONG_L $3, PT_R3(sp)
LONG_L $2, PT_R2(sp)
.set pop
.endm
.macro RESTORE_SP_AND_RET
.set push
.set noreorder
LONG_L k0, PT_EPC(sp)
LONG_L sp, PT_R29(sp)
jr k0
rfe
.set pop
.endm
#else
.macro RESTORE_SOME
.set push
.set reorder
.set noat
mfc0 a0, CP0_STATUS
ori a0, STATMASK
xori a0, STATMASK
mtc0 a0, CP0_STATUS
li v1, ST0_CU1 | ST0_FR | ST0_IM
and a0, v1
LONG_L v0, PT_STATUS(sp)
nor v1, $0, v1
and v0, v1
or v0, a0
mtc0 v0, CP0_STATUS
LONG_L v1, PT_EPC(sp)
MTC0 v1, CP0_EPC
LONG_L $31, PT_R31(sp)
LONG_L $28, PT_R28(sp)
LONG_L $25, PT_R25(sp)
#ifdef CONFIG_64BIT
LONG_L $8, PT_R8(sp)
LONG_L $9, PT_R9(sp)
#endif
LONG_L $7, PT_R7(sp)
LONG_L $6, PT_R6(sp)
LONG_L $5, PT_R5(sp)
LONG_L $4, PT_R4(sp)
LONG_L $3, PT_R3(sp)
LONG_L $2, PT_R2(sp)
.set pop
.endm
.macro RESTORE_SP_AND_RET
LONG_L sp, PT_R29(sp)
#ifdef CONFIG_CPU_MIPSR6
eretnc
#else
.set arch=r4000
eret
.set mips0
#endif
.endm
#endif
.macro RESTORE_SP
LONG_L sp, PT_R29(sp)
.endm
.macro RESTORE_ALL
RESTORE_TEMP
RESTORE_STATIC
RESTORE_AT
RESTORE_SOME
RESTORE_SP
.endm
/*
* Move to kernel mode and disable interrupts.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro CLI
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | STATMASK
or t0, t1
xori t0, STATMASK
mtc0 t0, CP0_STATUS
irq_disable_hazard
.endm
/*
* Move to kernel mode and enable interrupts.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro STI
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | STATMASK
or t0, t1
xori t0, STATMASK & ~1
mtc0 t0, CP0_STATUS
irq_enable_hazard
.endm
/*
* Just move to kernel mode and leave interrupts as they are. Note
* for the R3000 this means copying the previous enable from IEp.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro KMODE
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | (STATMASK & ~1)
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
andi t2, t0, ST0_IEP
srl t2, 2
or t0, t2
#endif
or t0, t1
xori t0, STATMASK & ~1
mtc0 t0, CP0_STATUS
irq_disable_hazard
.endm
#endif /* _ASM_STACKFRAME_H */
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