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powerpc: Emulate most Book I instructions in emulate_step()

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This extends the emulate_step() function to handle a large proportion
of the Book I instructions implemented on current 64-bit server
processors.  The aim is to handle all the load and store instructions
used in the kernel, plus all of the instructions that appear between
l[wd]arx and st[wd]cx., so this handles the Altivec/VMX lvx and stvx
and the VSX lxv2dx and stxv2dx instructions (implemented in POWER7).

The new code can emulate user mode instructions, and checks the
effective address for a load or store if the saved state is for
user mode.  It doesn't handle little-endian mode at present.

For floating-point, Altivec/VMX and VSX instructions, it checks
that the saved MSR has the enable bit for the relevant facility
set, and if so, assumes that the FP/VMX/VSX registers contain
valid state, and does loads or stores directly to/from the
FP/VMX/VSX registers, using assembly helpers in ldstfp.S.

Instructions supported now include:
* Loads and stores, including some but not all VMX and VSX instructions,
  and lmw/stmw
* Atomic loads and stores (l[dw]arx, st[dw]cx.)
* Arithmetic instructions (add, subtract, multiply, divide, etc.)
* Compare instructions
* Rotate and mask instructions
* Shift instructions
* Logical instructions (and, or, xor, etc.)
* Condition register logical instructions
* mtcrf, cntlz[wd], exts[bhw]
* isync, sync, lwsync, ptesync, eieio
* Cache operations (dcbf, dcbst, dcbt, dcbtst)

The overflow-checking arithmetic instructions are not included, but
they appear not to be ever used in C code.

This uses decimal values for the minor opcodes in the switch statements
because that is what appears in the Power ISA specification, thus it is
easier to check that they are correct if they are in decimal.

If this is used to single-step an instruction where a data breakpoint
interrupt occurred, then there is the possibility that the instruction
is a lwarx or ldarx.  In that case we have to be careful not to lose the
reservation until we get to the matching st[wd]cx., or we'll never make
forward progress.  One alternative is to try to arrange that we can
return from interrupts and handle data breakpoint interrupts without
losing the reservation, which means not using any spinlocks, mutexes,
or atomic ops (including bitops).  That seems rather fragile.  The
other alternative is to emulate the larx/stcx and all the instructions
in between.  This is why this commit adds support for a wide range
of integer instructions.

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2010-06-15 14:48:58 +10:00
parent 7e27d6e778
commit 0016a4cf55
5 changed files with 1855 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/include/asm/asm-compat.h
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@ -30,6 +30,7 @@
#define PPC_STLCX stringify_in_c(stdcx.)
#define PPC_CNTLZL stringify_in_c(cntlzd)
#define PPC_LR_STKOFF 16
#define PPC_MIN_STKFRM 112
/* Move to CR, single-entry optimized version. Only available
* on POWER4 and later.
@ -55,6 +56,7 @@
#define PPC_CNTLZL stringify_in_c(cntlzw)
#define PPC_MTOCRF stringify_in_c(mtcrf)
#define PPC_LR_STKOFF 4
#define PPC_MIN_STKFRM 16
#endif

7
arch/powerpc/include/asm/ppc-opcode.h
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@ -52,13 +52,17 @@
#define PPC_INST_WAIT 0x7c00007c
#define PPC_INST_TLBIVAX 0x7c000624
#define PPC_INST_TLBSRX_DOT 0x7c0006a5
#define PPC_INST_XXLOR 0xf0000510
/* macros to insert fields into opcodes */
#define __PPC_RA(a) (((a) & 0x1f) << 16)
#define __PPC_RB(b) (((b) & 0x1f) << 11)
#define __PPC_RS(s) (((s) & 0x1f) << 21)
#define __PPC_RT(s) __PPC_RS(s)
#define __PPC_XA(a) ((((a) & 0x1f) << 16) | (((a) & 0x20) >> 3))
#define __PPC_XB(b) ((((b) & 0x1f) << 11) | (((b) & 0x20) >> 4))
#define __PPC_XS(s) ((((s) & 0x1f) << 21) | (((s) & 0x20) >> 5))
#define __PPC_XT(s) __PPC_XS(s)
#define __PPC_T_TLB(t) (((t) & 0x3) << 21)
#define __PPC_WC(w) (((w) & 0x3) << 21)
/*
@ -106,9 +110,12 @@
* the 128 bit load store instructions based on that.
*/
#define VSX_XX1(s, a, b) (__PPC_XS(s) | __PPC_RA(a) | __PPC_RB(b))
#define VSX_XX3(t, a, b) (__PPC_XT(t) | __PPC_XA(a) | __PPC_XB(b))
#define STXVD2X(s, a, b) stringify_in_c(.long PPC_INST_STXVD2X | \
VSX_XX1((s), (a), (b)))
#define LXVD2X(s, a, b) stringify_in_c(.long PPC_INST_LXVD2X | \
VSX_XX1((s), (a), (b)))
#define XXLOR(t, a, b) stringify_in_c(.long PPC_INST_XXLOR | \
VSX_XX3((t), (a), (b)))
#endif /* _ASM_POWERPC_PPC_OPCODE_H */

4
arch/powerpc/lib/Makefile
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@ -18,8 +18,8 @@ obj-$(CONFIG_HAS_IOMEM) += devres.o
obj-$(CONFIG_PPC64) += copypage_64.o copyuser_64.o \
memcpy_64.o usercopy_64.o mem_64.o string.o
obj-$(CONFIG_XMON) += sstep.o
obj-$(CONFIG_KPROBES) += sstep.o
obj-$(CONFIG_XMON) += sstep.o ldstfp.o
obj-$(CONFIG_KPROBES) += sstep.o ldstfp.o
ifeq ($(CONFIG_PPC64),y)
obj-$(CONFIG_SMP) += locks.o

375
arch/powerpc/lib/ldstfp.S Normal file
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@ -0,0 +1,375 @@
/*
* Floating-point, VMX/Altivec and VSX loads and stores
* for use in instruction emulation.
*
* Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/ppc-opcode.h>
#include <asm/reg.h>
#include <asm/asm-offsets.h>
#include <linux/errno.h>
#define STKFRM (PPC_MIN_STKFRM + 16)
.macro extab instr,handler
.section __ex_table,"a"
PPC_LONG \instr,\handler
.previous
.endm
.macro inst32 op
reg = 0
.rept 32
20: \op reg,0,r4
b 3f
extab 20b,99f
reg = reg + 1
.endr
.endm
/* Get the contents of frN into fr0; N is in r3. */
_GLOBAL(get_fpr)
mflr r0
rlwinm r3,r3,3,0xf8
bcl 20,31,1f
blr /* fr0 is already in fr0 */
nop
reg = 1
.rept 31
fmr fr0,reg
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Put the contents of fr0 into frN; N is in r3. */
_GLOBAL(put_fpr)
mflr r0
rlwinm r3,r3,3,0xf8
bcl 20,31,1f
blr /* fr0 is already in fr0 */
nop
reg = 1
.rept 31
fmr reg,fr0
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Load FP reg N from float at *p. N is in r3, p in r4. */
_GLOBAL(do_lfs)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
ori r7,r6,MSR_FP
cmpwi cr7,r3,0
mtmsrd r7
isync
beq cr7,1f
stfd fr0,STKFRM-16(r1)
1: li r9,-EFAULT
2: lfs fr0,0(r4)
li r9,0
3: bl put_fpr
beq cr7,4f
lfd fr0,STKFRM-16(r1)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
/* Load FP reg N from double at *p. N is in r3, p in r4. */
_GLOBAL(do_lfd)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
ori r7,r6,MSR_FP
cmpwi cr7,r3,0
mtmsrd r7
isync
beq cr7,1f
stfd fr0,STKFRM-16(r1)
1: li r9,-EFAULT
2: lfd fr0,0(r4)
li r9,0
3: beq cr7,4f
bl put_fpr
lfd fr0,STKFRM-16(r1)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
/* Store FP reg N to float at *p. N is in r3, p in r4. */
_GLOBAL(do_stfs)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
ori r7,r6,MSR_FP
cmpwi cr7,r3,0
mtmsrd r7
isync
beq cr7,1f
stfd fr0,STKFRM-16(r1)
bl get_fpr
1: li r9,-EFAULT
2: stfs fr0,0(r4)
li r9,0
3: beq cr7,4f
lfd fr0,STKFRM-16(r1)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
/* Store FP reg N to double at *p. N is in r3, p in r4. */
_GLOBAL(do_stfd)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
ori r7,r6,MSR_FP
cmpwi cr7,r3,0
mtmsrd r7
isync
beq cr7,1f
stfd fr0,STKFRM-16(r1)
bl get_fpr
1: li r9,-EFAULT
2: stfd fr0,0(r4)
li r9,0
3: beq cr7,4f
lfd fr0,STKFRM-16(r1)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
#ifdef CONFIG_ALTIVEC
/* Get the contents of vrN into vr0; N is in r3. */
_GLOBAL(get_vr)
mflr r0
rlwinm r3,r3,3,0xf8
bcl 20,31,1f
blr /* vr0 is already in vr0 */
nop
reg = 1
.rept 31
vor vr0,reg,reg /* assembler doesn't know vmr? */
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Put the contents of vr0 into vrN; N is in r3. */
_GLOBAL(put_vr)
mflr r0
rlwinm r3,r3,3,0xf8
bcl 20,31,1f
blr /* vr0 is already in vr0 */
nop
reg = 1
.rept 31
vor reg,vr0,vr0
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Load vector reg N from *p. N is in r3, p in r4. */
_GLOBAL(do_lvx)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
oris r7,r6,MSR_VEC@h
cmpwi cr7,r3,0
li r8,STKFRM-16
mtmsrd r7
isync
beq cr7,1f
stvx vr0,r1,r8
1: li r9,-EFAULT
2: lvx vr0,0,r4
li r9,0
3: beq cr7,4f
bl put_vr
lvx vr0,r1,r8
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
/* Store vector reg N to *p. N is in r3, p in r4. */
_GLOBAL(do_stvx)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
oris r7,r6,MSR_VEC@h
cmpwi cr7,r3,0
li r8,STKFRM-16
mtmsrd r7
isync
beq cr7,1f
stvx vr0,r1,r8
bl get_vr
1: li r9,-EFAULT
2: stvx vr0,0,r4
li r9,0
3: beq cr7,4f
lvx vr0,r1,r8
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
/* Get the contents of vsrN into vsr0; N is in r3. */
_GLOBAL(get_vsr)
mflr r0
rlwinm r3,r3,3,0x1f8
bcl 20,31,1f
blr /* vsr0 is already in vsr0 */
nop
reg = 1
.rept 63
XXLOR(0,reg,reg)
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Put the contents of vsr0 into vsrN; N is in r3. */
_GLOBAL(put_vsr)
mflr r0
rlwinm r3,r3,3,0x1f8
bcl 20,31,1f
blr /* vr0 is already in vr0 */
nop
reg = 1
.rept 63
XXLOR(reg,0,0)
blr
reg = reg + 1
.endr
1: mflr r5
add r5,r3,r5
mtctr r5
mtlr r0
bctr
/* Load VSX reg N from vector doubleword *p. N is in r3, p in r4. */
_GLOBAL(do_lxvd2x)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
oris r7,r6,MSR_VSX@h
cmpwi cr7,r3,0
li r8,STKFRM-16
mtmsrd r7
isync
beq cr7,1f
STXVD2X(0,r1,r8)
1: li r9,-EFAULT
2: LXVD2X(0,0,r4)
li r9,0
3: beq cr7,4f
bl put_vsr
LXVD2X(0,r1,r8)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
/* Store VSX reg N to vector doubleword *p. N is in r3, p in r4. */
_GLOBAL(do_stxvd2x)
PPC_STLU r1,-STKFRM(r1)
mflr r0
PPC_STL r0,STKFRM+PPC_LR_STKOFF(r1)
mfmsr r6
oris r7,r6,MSR_VSX@h
cmpwi cr7,r3,0
li r8,STKFRM-16
mtmsrd r7
isync
beq cr7,1f
STXVD2X(0,r1,r8)
bl get_vsr
1: li r9,-EFAULT
2: STXVD2X(0,0,r4)
li r9,0
3: beq cr7,4f
LXVD2X(0,r1,r8)
4: PPC_LL r0,STKFRM+PPC_LR_STKOFF(r1)
mtlr r0
mtmsrd r6
isync
mr r3,r9
addi r1,r1,STKFRM
blr
extab 2b,3b
#endif /* CONFIG_VSX */

1514
arch/powerpc/lib/sstep.c
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